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Pharmacognostical Profile of Selected Medicinal Plants

Authored by: Maurice M. Iwu

Handbook of African Medicinal Plants

Print publication date:  February  2014
Online publication date:  February  2014

Print ISBN: 9781466571976
eBook ISBN: 9781466571983
Adobe ISBN:

10.1201/b16292-4

 

Abstract

Botanical Name — Abelmoschus esculentus (L.) Moench

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Pharmacognostical Profile of Selected Medicinal Plants

Abelmoschus Esculentus — Okra

 

Botanical Name — Abelmoschus esculentus (L.) Moench

Synonyms — Hibiscus esculentus L.; Abelmoschus bammia Webb; Abelmoschus officinalis; Abelmoschus longifolius (Willd.) Kostel.; Abelmoschuspraecox Sickenb; Abelmoschus tuberculatus

Related Species — Abelmoschus manihot (L.) Medik

Synonyms — A. caillei (A.Chev.) Stevels; A. pseudomanihot DC. Endl; A. platidactylus (Bakh.) Nakai and Hibiscus manihot; Hibiscus papyriferus Salisb

Family — Malvaceae

Common Names — Common okra, Okro, Okra, lady’s finger, ladies’ finger, gumbo

African Names — Akan (Twi): nkruman, nkruma (okra); Bantu: ki ngombo, ngumbo, gombo; Congo, Angola: quillobo, ki ngombo; Swahili: gumbo; Igbo: okwuru.

Description — Okra is a stout annual herb typically reaching 2 m in height, but some African varieties may grow up to 5 m tall, with a base stem 10 cm in diameter. The heart-shaped, lobed leaves are attached to the thick, woody stem. They may reach 30 cm in length and are generally hairy. Flowers are borne singly in the leaf axils and are usually yellow with a dark red or purple base. Some of the African varieties bloom only in late fall in temperate zones and are photoperiod sensitive. It is largely self-pollinated, although some outcrossing is reported, and it is often visited by bees.

The pod (capsule or fruit) is 10–25 cm long (shorter in the dwarf varieties). Generally, it is ribbed or round and varies in color from yellow to red to green. It is pointed at the apex, hairy at the base, and tapered toward the tip. It contains numerous oval seeds that are about the size of peppercorns, white when immature and dark green to gray-black when mature. 972

Habitat and Distribution — The genus Abelmoschusis is believed to have originated in SouthEast Asia. The common okra, Abelmoschus esculentus, however, is a cultigen of uncertain origin. The vast occurrence of primitive types and wild relatives in Africa (especially Ethiopia, Nigeria, Cameroon, and Ghana) indicates that okra is certainly African. It is, however, widespread in tropical, subtropical, and warm temperate regions but is particularly popular in West Africa, India, the Philippines, Thailand, and Brazil. The common okra, Abelmoschus esculentus, grows in the whole of tropical Africa, whereas West African okra, Abelmoschus manihot (L.) Medik [synonyms: A. caillei (A.Chev.) Stevels; A. pseudomanihot DC. Endl; A. platidactylus (Bakh.) Nakai; and Hibiscus manihot] is a cultigen occurring mainly in West and Central Africa. It has been reported from Guinea to Nigeria in West Africa; in Cameroon, Gabon, and the Democratic Republic (DR) of the Congo in Central Africa; and in Uganda in East Africa. Its distribution is restricted to humid and perhumid climates in Africa, between 12° N and 12° S, most commonly between 5° N and 10° N, whereas the common okra, Abelmoschus esculentus (L.) Moench, can be found worldwide throughout the tropics, subtropics, and warm temperate regions.

Ethnomedicinal Uses — The immature fruits and the leaves are eaten in various ways. Fruits, fresh or sliced and dried, are used for soups (West African draw-soup), also fried in oil. Leaves are used as a potherb. Young shoots are also eaten. The mucilage is used medicinally and technically as an industrial raw material. A decoction of the immature okra fruits is demulcent, diuretic, and emollient. It is also used in the treatment of catarrhal infections, ardor urinae, dysuria, and gonorrhea. It has been used as a plasma replacement or blood volume expander. The seeds usually obtained from mature and hard capsules are antispasmodic, cordial, and stimulant. An infusion of the roasted seeds has sudorific properties. Leaves are sometimes used as a basis for poultices; as an emollient, sudorific or antiscorbutic; and to treat dysuria.

Constituents — All the aerial parts of the plant are useful, although the ends of the fruits are usually trimmed, leaving about 80% of the product as the edible portion. The composition of okra fruits per 100 g edible portion is water 88.6 g (85.7–90.2), energy 144 kJ (36 kcal), protein 2.1 g (1.1–3.0), fat 0.2 g, carbohydrate 8.2 g, fiber 1.7 g, Ca 84 mg (55–142), P 90 mg, Fe 1.2 mg (1.1–1.5), ß-carotene 185 μg (180–190), thiamin 0.04 mg, riboflavin 0.08 mg, niacin 0.6 mg, ascorbic acid 47 mg (20–126). The composition of okra leaves per 100 g edible portion is water 81.5 g (75.3–92.4), energy 235 kJ (56 kcal), protein 4.4 g (2.8–5.6), fat 0.6 g, carbohydrate 11.3 g, fiber 2.1 g, Ca 532 mg (258–635), P 70 mg, Fe 0.7 mg, ß-carotene 385 μg, thiamin 0.25 mg, riboflavin 2.8 mg, niacin 0.2 mg, ascorbic acid 59 mg (9–75). Compared to other fleshy fruit-vegetables (tomato, eggplant), okra is particularly rich in Ca and ascorbic acid. Okra seed meal contains more than 20% of good-quality protein on a fat-free, dry-weight basis, whereas most of the suitable amino acids in okra seed protein are present in amounts that are equal to or exceed the amounts in eggs and casein, and the U.N. Food and Agriculture Organization (FAO) references okra as a protein source. The seed protein is similar in amino acid composition to soya bean protein. It contains 20% oil (similar in fatty acid composition to cottonseed oil). The seeds are rich in phenolic compounds, mainly composed of oligomeric catechins (2.5 mg/g of seeds) and flavonol derivatives (3.4 mg/g of seeds). The skin’s polyphenolic profile is composed principally of hydroxycinnamic and quercetin derivatives (0.2 and 0.3 mg/g of skins). 1

Pharmacological Studies — Because of its high nutrient value, okra is considered a good source for food fortification strategies. Okra has also been used in the management of duodenal ulcers and diabetes. The glycosylated molecules found in the okra mucilage have been related to the inhibition of adhesion of Helicobacter pylori to human gastric mucosa. 2 Such molecules could also contribute to glucose entrapment and alpha-glucosidase inhibition, which might be advantageous in the management of diabetes. 3 The fruit and the leaves have antioxidant properties. It has been observed that the distribution of phenolics in methanolic extracts of okra correlates with distribution of antioxidant activity. Studies have also shown that roasting of okra seed flour at 160°C for up to 40 min caused an increase in antioxidant activity, as determined by free-radical scavenging using the DDPH (2,2-Diphenyl-1-picrylhydrazyl) assay. 4 A methanolic extract of okra seeds was shown to have antioxidant activity, as evidenced by several criteria, and to exert antihypoxic activity in two mouse models. 5

Toxicity — Okra is a common and popular vegetable with no known toxicity report. Both okra tofu and the protein-rich residue left after oil extraction showed no acute toxicity and offer promise as food additives and animal feed ingredients. The seeds in the mature fruits yield oil that is similar to cottonseed oil, and some varieties are said to contain gossypol or a gossypol-like compound. In some okra seed varieties, the oil contains small quantities of cyclopropenoid fatty acids with their strong physiological properties.

Formulation and Dosage Forms — Okra is usually available in food stores and health food outlets as fresh fruits or as frozen materials. Sun-dried and horizontally or vertically sliced fruits are often sold in West African markets. Freeze-dried, microwave-dried, and controlled temperature backed fruits prepared with the aim of preserving the secondary metabolites have been packaged for the dietary supplement industry.

Commerce — Okra is grown throughout the world as an article of commerce. Countries in Asia and Africa are the major producers. World production of okra as a fresh fruit-vegetable is estimated at 6 million tons/year. Common okra makes up 95% of this amount, and the West African species accounts for about 10% of world production. In West and Central Africa, the common okra and its local variety share the market equally.

Agriculture — Farmers usually use seeds harvested from their own local cultivar or rather heterogeneous landrace. The easiest way to keep the seed is to leave it in the pods. Seed weight varies from 30 to 80 g/1000 seeds. To soften the hard seed coat, the seed is often soaked in water or chemicals prior to sowing. The seed is usually dribbled directly in the field (1–3 seeds per hole). Optimum plant densities are in the range of 50,000–150,000 plants/ha. Emergence is within 1 week. When the plants are about 10 cm tall, they are thinned to one plant per hole.

Germination and initial growth are improved greatly by cultural practices that lower soil temperature (e.g., mulching, watering before the hottest part of the day, and sowing on ridge sides least exposed to direct sunlight). The robust West African okra should be grown at 20,000–50,000 plants/ha. Emergence is also within 1 week, and the plants are then thinned to one plant per hole for optimum growth.

Commercial okra growers usually practice sole cropping and prefer the early, homogeneous, introduced cultivars of common okra (Abelmoschus esculentus). In traditional agriculture, farmers grow their okra landraces in home gardens or in fields with other food crops. The landraces often consist of a mixture of Abelmoschus caillei and Abelmoschus esculentus, the former being predominant in humid climates and the latter in drier climates. The uptake of minerals is rather high. Indicative figures for total nutrient uptake per hectare of a crop with fruit yield of about 10 t/ha are 100 kg N, 10 kg P, 60 kg K, 80 kg Ca, and 40 kg Mg. Under humid tropical conditions, a full-grown crop consumes about 8 mm of water per day. Some farmers practice ratoon cropping. A ratoon crop flowers soon after cutting but usually results in poor-quality fruit with a high percentage of bent fruits. 1 Organic cultivation of okra in north central Nigeria yielded good fruits comparable in both composition and biomass with plants grown with chemical fertilizer.

Abrus Precatorius

Botanical Name — Abrus precatorius Linn.

Synonyms — Abrus abrus (L.) Wright, Abrus cyaneus R. Vig., Abrus maculatus Noronha, Abrus minor Desv., Abrus pauciflorus Desv., Abrus squamulosus E. Mey., Abrus tunguensis Lima, Glycine abrus L.

Family — Leguminosae

Common Names — Crab’s eye, love bean, lucky bean, prayer beads, wild licorice

African Names — Ewe: dedekuade, adekude; Hausa: da marzaya, idon Zakara; Chagga: mdela; Giriam: Igbo: anya nnunu; Lozi: mutiti; Luvale: mukakenjenge; Ndebele: amabope; Nyamwezi: Kachenche; Shambala: lufyambo; Sukuma: lufiambo; Swahili: mongaluchi, mtipitipi; Tiwi: dammabo, obereku-aniwa; Yoruba: iwere-jeje; Mozambique: cessane, mini-mini, mpanamene, namecolo, tsangariorio; Swaziland: umphitsi; Zanzibar, Tanzania: matscho ya tipitipi; Afrikaans (Namibia): mini-minies, minie-minies, paternostertjies; Afrikaans (South Africa): minnie-minnies.

Description — A woody twining plant with characteristic red and black seeds. The seeds are pinnate and glabrous, with many leaflets (12 or more) arranged in pairs. The leaflets are oblong, measuring 2.5 cm long and 1.5 cm wide. The plant bears orange-pink flowers, which occur as clusters in short racemes, sometimes yellowish or reddish purple in color, and small and typically pea-like. Abrus produces short and stout, brownish pods, which curl back on opening to reveal pendulous red and black seeds (4–6 in each pod).

Habitat and Distribution — It is found occurring wild in thickets, farms, and secondary clearings and sometimes in hedges. The plant is widely distributed throughout the continent.

Ethnomedicinal Uses — The leaf decoction is used for treatment of coughs, constipation, colic, and general pains. The leaves are chewed to relieve hoarseness and bronchial constrictions; the vapor from crushed leaves boiled with water is used to treat eye inflammation. 6 The aqueous extract of the seed is used for the treatment of cancer of the epithelioma and as a vermifuge and an abortifacient. A single dose of the powdered seeds acts as a long-acting contraceptive, with the effect lasting up to 13 menstrual cycles. 7 The seed infusion has been employed to hasten labor and for treatment of conjunctivitis granulosa and trachoma. 8 The entire plant is drunk for treatment of venereal disease, headaches, and snakebites. A poultice prepared from the seeds of Abrus, salt, and the unripe fruits of Musa paradisica is applied topically to boils and abscesses. 9

Constituents — The seeds contains abrin (a highly toxic glycoprotein), hyapaphnorine, precatorine, and some other uncharacterized indole alkaloids. 10 Abrin, being a toxalbumin, is inactivated by heat. Trigonelline and other related pyridonium derivatives have been isolated from the plant. The plant contains phytosterols β-sitosterol and stigmasterol and flavonoids abrecatorin (6,4′-dimethoxy-7,3′-dihydroxyflavone) and desmethoxycentaureidin-7-O-rutinoside. 11 Two anthocyanins have also been identified (xyloglucosyldelphinidin and p-coumarylgalloyl ester of glucosyldelphinidin) in the seed coat of pigment of the plant. The free sugars present in the leaves, stems, roots, and seeds of the plants have been characterized as galactose, arabinose, and xylose. 12 Sweet-tasting glycosides, the abrusosides, based on the novel cycloartane-type aglycone (abrusogenin), have been isolated from the leaves of the plant. 13

Pharmacological Studies — The activity of the seed powder against cancer of the epithelioma of the hand, skin, and mucosa has been reported. 14 The aqueous extract of the seed elicits a biphasic response on the field-stimulated guinea pig ileum, being inhibitory at low concentrations but excitatory at high concentrations. The excitatory exponent contracts most smooth muscles, including the uterus. Its actions are atropine sensitive. The inhibitory fraction also contracts the uterus but relaxes the other smooth muscles; it is resistant to common pharmacological blocking agents but is inhibited by indomethacin, a prostaglandin synthetase inhibitor. 15 The antifertility activity of the root has been reported. 15

Nwodo had shown that trigonellyl glycoside possesses both nicotinic and muscarinic activity at the ganglion (i.e., it produces a depressor cum pressor activity on close arterial injection). He maintained that while the activity of the isolates of Abrus is blocked by indomethacin, these activities were not essentially due to prostaglandin release. 8 The sweet-tasting glycosides found in the leaves, the abrusosides, have been shown to be 30–100 times sweeter than sucrose. The glycosides were neither acutely toxic when tested on mice nor mutagenic to Salmonella typhimurium strain TM677. 13

A steroidal fraction of extract of the seeds has been shown to cause dose-dependent degenerative changes in the testicular weights, sperm count, later stages of spermatogenesis, and Leydig cells in testes of rats. 16 The steroidal fraction also caused a dose-dependent decrease in the enzyme activity of 3α,3β,17β-hydroxysteroid dehydrogenase, glucose-6-phosphate dehydrogenase, sorbitol dehydrogenase, and leucine aminopeptidase. A probable mechanism of the alterations in the testes could be at the pituitary level by a feedback mechanism that may result in decrease in production and release of testosterone. 16 Oral administration of a 50% ethanol extract of Abrus seeds (250 mg/kg) in albino rats for 30 and 60 days induced absolute, but reversible, infertility in males, with marked suppression of sperm motility in the cauda epididymis. 17 The treatment did not appear to affect the histological and histocytometric characters of the testes and parareproductive tissues, but protein, sialic acid, acid phosphatase, and succinic dehydrogenase levels were significantly depleted. 17 An isolate of the seeds, BN, was shown to inhibit contractions of guinea pig ileum to field stimulation, acetylcholine, and histamine and to reduce rhythmic activity of rabbit isolated intestine. 18 The seed oil was also found to cause dose-dependent contractions of both gravid and primed virgin uteri. 19 The contractions were blocked by indomethacin but resistant to the effects of atropine. Furthermore, the sensitivity of the tissue to oil could be restored by subeffective doses of prostaglandin E2 following blocking with indomethacin. 19 These effects appear to support the use of the seed extract as an antidiarrheal agent in traditional medicine.

The extracts of the Abrus have also been shown to possess trypanosocidal action, 20 aldose reductase inhibition, 21 antidiabetic properties, 22 milk-induced leukocytosis and eosinophilia in the management of asthma, 23 antitumor and immunomodulatory activities, 24 and anthelmintic activities. 25 A polyherbal preparation containing extract of Abrus leaves has demonstrated hair-growth properties in clinical studies. 26

Toxicity — Fatal incidents have been reported for ingestion of well-chewed seeds of Abrus; because of its hard seed coat, it can pass through the gastrointestinal tract undigested and remain harmless. The unripe seed has a soft and easily broken seed coat and is thus more dangerous. It has been reported that poisoning has been experienced through a finger pricked while stringing the seed. Symptoms may develop a few hours to several days after ingestion; they include severe gastroenteritis with pronounced nausea and vomiting. Mydriasis will occur as well as muscular weakness, tachycardia, cold sweating, and trembling. There is no known physiological antidote. The treatment is essentially symptomatic. Since there is a long latent period associated with abrin poisoning, little value can be placed on induction of emesis or gastric lavage; these measures are useful only if digestion has just occurred. Bismuth trisilicate may be given during poisoning with Abrus to reduce the degree of gastrointestinal damage. If the emesis or diarrhea become excessive, replacement fluids and electrolytes are advocated. If hemorrhage occurs, blood transfusion may be necessary.

Toxicity of Abrus to goats has been evaluated. Doses of 2, 1, or 0.5 g/kg/day via stomach tube caused death between days 2 and 5 for those given 2 or 1 g/kg; one goat that received 0.5 g died on day 32, and another was killed on day 33. The main signs of poisoning include inappetence, bloody diarrhea, dyspnea, dehydration, loss of condition, and recumbency. 19 Abrin, the main toxic compound in Abrus, is antigenic, and animals can thus be immunized with small doses before being allowed to graze on pastures infested with Abrus. Because of the potential use of abrin and the related castor bean toxin ricin in terrorism as a chemical or biological warfare agent, human immunization against both toxins is under development. 27

Acacia Senegal

Botanical Name — Acacia senegal (L.) Wild

Synonyms — Mimosa senegal L., Acacia verek Guill. et Perr., Acacia circummarginata Chiov., Acacia cufodontii Chiov., Acacia oxyosprion Chiov., Acacia rupestris Boiss., Acacia spinosa Marloth & Engl., Acacia volkii Suess., Acacia senegal (L.) Britton

Family — Leguminosae

Common Names — Gum Arabic tree (E), Gommier, Gommier blane (F)

African Names — Arabic: shagar; Samgh Arabic: konait; Bambara: patukill; Hausa: akovia, dakwara; Fulani: dibehi; Kanuri: kolkol; Ndebele: umhlahalinye; Nyamwezi: katatula, mgwata, kakakantunda; Peuhl: patuki, bulbi; Swahili: kikwata mgunga; Zinza: mkoto

Description — Acacia senegal is a small tree or shrub, up to 7 m high, with a short bole, gray-fissured stem, usually coming off as papery patches to reveal a powdery underlayer. It branches low, and its dense foliage gives it the appearance of a somewhat large thorn at the base of the branchlets, with 3 to 6 pairs of pinnae and 6 to 15 pairs of narrow leaflets, about 6–8 mm long. The cream-color, fragrant flowers are borne in axillary clusters, as densely crowded spikes, usually longer than the leaves. The fruits occur as membranous flat cloves, about 11 cm long and 2–4 cm wide, hairy and pale brown in color; containing 7 or 8 flat and circular beige seeds. 9,28

Habitat and Distribution — It is found in subdesert regions, the Sahelian, and dry tropical zones. It occurs in Mauritania, Sudan, Niger, Mali, Senegal, Gambia, Nigeria, Burkina Faso, Kenya, Uganda, Tanzania, and parts of southern Africa.

Ethnomedicinal Uses — In West Africa, especially in the Senegal-Gambia region, the gum is used in the preparation of a remedy for dysentery and diarrhea and applied externally for modular leprosy. In East, Central, and North Africa, the leaves have been used in remedies for ophthalmia, colds, and hemorrhage, 17 and gum was used for the treatment of local inflammations. The root is used in the mainland of Tanzania as a gonorrhea remedy.

Constituents — The most important constituent of this plant is gum arabic, a colorless, odorless, nontoxic solid substance soluble in water (1:2) that forms a sticky solution used in a variety of consumer products. 29 The gum exudes from branches and by stripping off a patch of the bark. Gum arabic consists of a glycosidal acid of high molecular weight that has been termed arabic acid, and it is combined with potassium, magnesium, and calcium. It also contains diastases and oxidase enzyme (African Pharmacopoeia 436 ). Acacia gums consist of galactose, arabinose, rhamnose, and glucuronic acids as the only sugars found in all types of the gums. The difference between A. senegal and A. seyal (and the other Acacia exudates) is the level of each sugar. The polysaccharide fraction is composed of a linear chain of β-1,3-linked galactose. This chain is ramified in position with chains of galactose and arabinose. Rhamnose, glucuronic acid, or methyl-glucuronic acid units are found as chain terminations. 30

Pharmacological Studies — Acacia gum is used in the food industry and pharmacy as a suspending and emulsifying agent, emollient, and adhesive in the manufacture of tablets and other oral dosage forms. Acacia gum is highly appreciated in technical applications due to its unique properties; it is used not only as a film former in the printing industry and as an adhesive agent in glues, but also as a binding agent when used as a natural substitute for chemicals. The gum’s technological properties (texturing and film forming in confectionery, emulsifying, and encapsulating in flavors and colors) and, for about 20 years, nutritional properties (fiber and prebiotic) in enriched foods and nutritional complements have made it a preferred edible industry gum. 31 Various modifications have been made to the natural gum for use in specific pharmaceutical formulations. 31

The unique properties of Acacia gum have also been adapted to provide a protective coating to natural foods. For example, shiitake mushrooms coated with gum arabic plus natamycin (GANA) maintained tissue firmness and showed a reduction in microbial counts from yeasts and molds compared with the control. In addition, GANA coating delayed changes in the soluble solids concentration, total sugar, and ascorbic acid. Sensory evaluation proved the efficacy of GANA coating by maintaining the overall quality of shiitake mushrooms during the storage period. The efficiency was better than that of gum arabic or natamycin treatment alone. Our study suggested that GANA has the potential to improve the quality of shiitake mushrooms and extend their shelf life up to 16 days. 32

Achyranthes Aspera

Botanical Name — Achyranthes aspera L.

Synonyms — A. canescens R. Br., A. argentea Decne., A. grandifolia Moq., A. obovata Peter, A. repens L.

Family — Amaranthaceae

Common Names — Chichiri (Indian); chirchita or onga (English)

African Names — Hausa: hakoorin-maciijii, kaimin-kadangaree; Igbo: odu-ngwere; Kibende: buhulula; Kiluguru: nara; Kisafwa: ndadaulo; Kiswahili: purura, purule; Kihehe: nugulukauna; Kirangi: kyululankanga; Kinyaturu: munyori, mnyoli; Kinyamwezi: lukululankanga; Yoruba: abora

Description — It is an erect or suberect, annual or perennial herb 0.5–1.5 m high. The leaves (1.5–1.6 cm long and 0.7 cm wide) are simple, opposite, with stipules absent, the blade ovate to ovate-lanceolate or ovate-oblong with rounded apex. The base is cuneate, and the margins are entire, pubescent above and below, with a petiole 0.5–3 cm long. It produces solitary hermaphrodite flowers in the axil of the bract, 3.5–5.5 mm long, pinkish or greenish sepals, ovate-lanceloate. The flowers enlarge with age, hardening and becoming pungent. The fruits are small, 2–5.3 mm long, and detach from the plant with the perianth and bracteoles. Both the flowers and fruits are borne concurrently throughout the year. It has a characteristic woody rootstock. 9,28,33

Habitat and Distribution — The plant occurs widely throughout the continent in different vegetation zones. It grows well in semiarid areas receiving about 250 mm rainfall and also high-rainfall savannas with over 2000 mm annual rainfall and can be located in secondary clearings. The species grows in open areas; it does not tolerate shade and therefore cannot be found as undercrops in dense tropical canopies. It grows well in Nigeria, Ghana, Zaire, and Cameroon and has been located in Mali, Kenya, Ethiopia, and Tanzania.

Ethnomedicinal Uses — The root is used as a hemostatic agent to stop wound bleeding. A decoction of the roots or stem bark is administered to children for constipation. The leaves, when fire cured like tobacco, are used as an embrocation for sprains and headache. When boiled, the steam is inhaled for the treatment of severe catarrh and colds. The decoction of the root bark is taken as a remedy for venereal diseases. A poultice made from the ash of the burned leaves is applied on boils and as an ointment for scabies; the ash mixed with honey is administered for coughs. The root infusion is used as an emetic and mixed with lime as a remedy for bronchitis, malaria, and helminthic infestation. The root has also been dispensed as a gargle for toothache, as a snakebite topical remedy, for the treatment of heartburn, to prevent miscarriage in pregnancy, and as a poison antidote to control vomiting. 33 In India, the plant extract is used for the treatment of infectious diseases and in the management of leprosy. 34

Constituents — The plant yields saponins and steroids, and the fruit has been shown to contain a large percentage of alkaline potash. Betaine and ecdysterone may be present in the plant. 33 A betaine, achyranthine, based on N-methylpyrrolidine 3-carboxylic acid, has been isolated from the plant. 35 Two fully characterized saponins, Achyranthes saponins A and B, have been shown to be constituents of the seeds. 36

Pharmacological Studies — The saponins are cardiotonic. The benzene extract has been found to be abortifacient. The plant also possesses fungicidal activity. Oral administration of the crude extract at a dose of 5 mg/kg exerts diuretic, purgative, and hypoglycemic action in rats. 3739 It has been suggested that the diuretic action may be due to its high potassium content. 39 The saponin fraction of the extract significantly increased the tone and contractility of the isolated hearts of frog, guinea pig, and rabbits, with the observed activity quicker in onset but of a shorter duration than that induced by digitoxin. 4042 The biological activity of achyranthine has been investigated. 38 The compound has hypotensive, cardiac depressant, and vasodilatory activities, as well as analeptic action on the respiratory system and spasmogenic effect on smooth muscles. Achyranthine is also diuretic, purgative, and mildly antipyretic. The cardiac contractility caused by the saponin has been attributed to its phosphorylase activity. 38

Studies have shown that Achyranthes possesses antiviral, 43 immunostimulant, 44 anti-inflammatory, 45 wound-healing 46 and antidiabetic properties. 47 The activity of the polysaccharides found to be associated with the antiviral and antidiabetic activities of Achyranthes species appears to be significantly enhanced in the sulfated derivatives.

Acokanthera Schimperi

Botanical Name — Acocanthera schimperi Benth. & Hok

Synonyms — A. oubaio, A. abyssinica K. Schum., A. deflersii Schweinf. ex Lewin., A. friesiorum Markgr., A. scabra Schweinf. ex Markgr., Arduina schimperi (A. DC.) Baill., Carissa deflersii (Schweinf. Ex Lewin) Pichon., Carissa friesiorum (Markgr.) Cufod., Carissa inepta Perrot & Vogt., Carissa schimperi A.DC.

Family — Apocynaceae

Common Name — Acokanthera

Description — This is an evergreen tree or shrub, growing up to 6 m in height. The leaves are elliptic, with sharply cuspidate apex and acute base; they are ceraceous, shiny, and smooth above. The leaves, 11 by 4.5 cm, display 7–13 lateral nerves on each side, with prominent venation showing on both surfaces. The flowers are pink colored, up to 1.5 cm long in short, dense, axillary cymes.

Habitat and Distribution — The plant occurs in both savanna and rainforest vegetation. It grows in Ghana, Nigeria, Zaire, and parts of East Africa.

Ethnomedicinal Uses — Acokanthera is the primary source of the dreaded African arrow poisons, which are considered so dangerous that even minute quantities transmitted through small injuries by the arrow prick could lead to fatal cardiac arrest within a few minutes of reaching the bloodstream. Strophanthus species are employed as adjuncts or alternative ingredients in the preparation of the arrow poisons. Acokanthera species are generally unavailable, and they are not considered an economical source of the pharmacologically important cardiotonic ouabain. In traditional African medicinal practice, the most important species are A. schimperi, A. venanta G. Don, and A. longiflora. Githens 48 listed the species for the treatment of snakebite and tapeworm infestation.

Constituents — The wood of African Acokanthera species yields very potent cardiotonics, of which the principal compound is ouabain. Other constituents of Acokanthera species include G strophanthin, acokantherin, and acovenoside A, B, and C. The seeds of the closely related species Carissa acokanthera yield similar glycosides. Pichon has suggested that the plant should be treated as a section of the genus Carissa. 49

Adansonia Digitata

 

Botanical Name — Adansonia digitata Linn.

Synonyms — Adansonia bahobab Gaertn., Adansonia integrifolia Raf., Adansonia scutula Steud., Adansonia situla (Lour.) Spreng., Adansonia somalensis Chiov., Adansonia sphaerocarpa A.Chev., Adansonia sulcata A.Chev., Baobabus digitata (L.) Kuntze, Ophelus sitularius Lour

Related Species — Adansonia fony Baill., Adansonia grandidieri Baill., Adansonia gregorii F. Muell., Adansonia madagascariensis Baill., Adansonia perrieri Capuron, Adansonia suarezensis H. Perrier, Adansonia za Baill.

Family — Malvaceae

Common Names — Baobab, monkey-bread tree, dead-rat tree, cream-of-tartar tree, magic tree, chemist tree, symbol of the earth, upside-down

African Names — Ashanti: odade; Hausa: kuka, bumbu, murna; Bambara: sira; Bisa: hor-go, poh-go; Gourounsi-Lele: koukoulou, ekoulou; Peul: boki, olohi; Igbo: Oyili-akpu; Wolof: gui, bui, gif; Yoruba: ose, oske; Baoule: frondo; Malinke: sira; Senoufo: ngigue; Swahili: mbuyu, mkuu hapingwa, mkuu hafungwa, muuyu

Description — This is a huge and dominant species in the savanna and Sahel regions of Africa. Its massive structure with its bottle shape makes it easy to identify. The tree is rather remarkable for its enormous trunk in comparison with the small crown of foliage. The trunk is comparatively short, 13–17 m high but 10–14 m or more in girth, with short, thick branches. A specimen with a girth of 37 m has been recorded. The bark is unarmed. The leaves are palmate with 5 sessile leaflets. The flowers are large, 12.5–15 cm in diameter, white, with numerous monadelphous purple stamens. The flowers are oblong, 15–20 cm long, pendulous on long stalks, woody, indehiscent, with large seeds embedded in dry acid pulp.

Habitat and Distribution — Baobab occurs naturally throughout the drier parts of the continent, and it is available all year round. Outside Africa, it has been widely introduced in tropical and subtropical regions as a commercial crop. Although it was introduced late in many Central African countries, it is now a valued crop in many countries in that region. It is still not common in Rwanda, Burundi, Djibouti, and Uganda. It has been introduced in Madagascar and many other Indian Ocean islands. In West Africa, it often occurs in northern parts of the subregion from Nigeria to Senegal in savanna forests and in baobab orchards around villages.

Ethnomedicinal Uses — This majestic tree is revered in Africa for its medicinal and nutritional value. Many parts of the plant are used to treat various ailments, such as diarrhea, malaria, and microbial infections. Other activities include use for urinary tract disorders; as a diaphoretic for fevers; as an anti-inflammatory; for mild asthma, fatigue, dysentery, kidney and bladder diseases; and as an expectorant, astringent, and tonic. It is reported that it is an excellent antioxidant due to the vitamin C content. It has a widely held reputation as an antiviral and anti-inflammatory medicine. The leaves are most valuable for medicinal uses, but the fruits and stem bark are also used in the preparation of remedies.

Constituents — Baobab fruit pulp has 10 times the vitamin C content of orange (w/w). It also contains the following, per 100 g: water 8.7 g, energy 1290 kJ (308 kcal), protein 2.7 g, fat 0.2 g, carbohydrate 73.7 g, fiber 8.9 g, Ca 335 mg, Mg 167 mg, P 76.2 mg, Fe 2.7 mg, Zn 1.0 mg, thiamin 0.62 mg, riboflavin 0.14 mg, niacin 2.7 mg, ascorbic acid 209 mg. The seed, which is about 55% seed coat and 45% kernel, contains the following, per 100 g of kernel: water 8.1 g, energy 1805 kJ (431 kcal), protein 33.7 g, fat 30.6 g, carbohydrate 4.8 g, fiber 16.9 g, Ca 273 mg, Mg 640 mg, P 5.1 mg, Fe 6.6 mg, Zn 6.7 mg, thiamin 0.25 mg, riboflavin 0.14 mg, niacin 1.0 mg. The fatty acid composition is linoleic acid 34.9%, oleic acid 32.3%, palmitic acid 26.5%, and stearic acid 4.4%. Phytochemical investigation has also revealed the presence of flavonoids, amino acids, fatty acids, vitamins, and minerals. Phytosterols such as campesterol, stigmasterol, isoflucasterol, and avenasterol are present in the seeds. An alkaloid, adansonin, has been identified from the bark of the baobab tree, and it is believed to be the active agent that is responsible for the antimalarial properties of baobab tree bark. The seed protein contains a large amount of lysine, but its use as a protein source is limited by the presence of antinutritional factors such as trypsin, tannins, oxalic acid, protease inhibitors, phytate, and amylase inhibitors (African Herbal Pharmacopoeia 1141 ).

Pharmacology — The plethora of biological activities attributed to baobab are traceable to the constituents found in the plant. The analgesic effect of the hot aqueous fruit of A. digitata in vivo (mice) has been established. It was noted that the extract exhibited analgesic activity 2 h after administration. At 800 mg/kg, the reaction time was 15.4 min in comparison to the negative control (10.2 min). The petroleum ether extract containing seed oil of baobab also showed analgesic activity. The extract exhibited analgesic activity with the tail flick response in 6.1 s, which was not statistically different from aspirin used as a positive control. The antipyretic activity of baobab extract has been established by laboratory studies in rats.

The hot water extract of the fruits showed in vivo anti-inflammatory activity in the rat paw formalin-induced edema test. The extract tested at a dose of 400 and 800 mg/kg inhibited formalin-induced edema. After 24-h administration of the aqueous extract, the mean swelling of the foot was 1.81 and 1.75 mm for 400 mg/kg and 800 mg/kg, respectively, in comparison to the negative control (6.35 mm). 1131 The DMSO (dimethylsulfoxide) of fruit pulp extract and aqueous leaf extract showed significant inhibition against cytokine interleukin 8 (IL-8). 1132

The capacity of baobab extracts to reduce the mobility of Trypanosoma brucei, which causes sleeping sickness, was evaluated using four different extracts (petroleum ether, chloroform, water, and methanol) obtained from the leaves and the bark. The time at which mobility stopped ranged between 10 and 45 min for the root bark, while with the leaves, the mobility ceased between 25 and 45 min when various extracts were tested at 2 mg/ml. 1133 The extracts also possess only modest activity against the malaria-causing parasite Plasmodium falciparum.

Because of the widespread use of baobab extract in the treatment of viral infections in West African traditional medicine, several in vitro and in vivo studies have been carried out to determine the antiviral activity of various baobab plant parts. In comparative studies by Ananil et al., 1134 baobab extract was found more active than several herbal extracts tested against the herpes simplex virus (HSV) and sindbis and polio viruses. A later investigation was made by Vimalanathan and Hudson 1132 on the antiviral activity of the leaves, fruit pulp, and seed extracted with water, DMSO, and methanol. The study was conducted using the minimum inhibitory concentration (MIC) method against influenza virus, HSV, and the respiratory syncytial virus. It was shown that the influenza virus was very susceptible, while the respiratory syncytial virus was resistant. The leaf extract exhibited the most promising activity against the influenza virus, with the MIC value ranging from 0.12 μg/ml (DMSO) to 2.8 μg/ml (water). The activity of the leaf extract was promising against the HSV (MIC value 1.0 to 11.7 μg/ml), while the pulp and the seed exhibited much lower activity (MIC value 72.5 μg/ml). The study clearly demonstrated variation in biological activity when different plant parts are investigated. Furthermore, the anti-HSV activity was considerably enhanced by light, especially long-wavelength ultraviolet (UV) light, although they all showed “dark” antiviral activity as well. Thus, all the extracts contained antiviral photosensitizers. 1132,1135

Baobab extracts have also been proved effective in laboratory studies to possess insecticidal and insect repellant activity; antioxidant, drug permeation enhancement; and hepatoprotective, hypoglycemic, and hypolidemic activities. 1136

Formulation and Dosage Forms — All parts of the plant are used for either food or medicine. Several proprietary products are available with baobab as a major ingredient. In most parts of Africa, the leaves of baobab are used either fresh as a cooked vegetable or dried and powdered as an ingredient of soups and sauces. The shoots and roots of seedlings are eaten as well. The roots are boiled and eaten in West Africa in times of famine. The flowers are eaten raw. The fruit contains soft, white, edible, and nutritious flesh (“monkey bread”). It northern Nigeria, it is used to curdle milk; it is eaten as a sweet and is used in making gruel and refreshing drinks and ice cream. In Sudan, it is made into a milk-like drink called “gubdi.” The powdered fruit flesh is added to cold liquid, thus preserving vitamins. An emulsion of the fruit pulp may be used to adulterate milk. The dried pulp is used as a substitute for cream of tartar in baking. 1140

The seeds are eaten raw or roasted and are used to thicken and flavor soup. Fermentation of the seed kernels improves the nutritional value. In coastal Kenya and Tanzania, the pulp-coated seeds are colored and sugar coated and sold as sweets. The seeds are used to adulterate groundnuts and sometimes as a coffee substitute. The oil extracted from the seed kernels by boiling and distillation is semifluid, golden yellow, gently scented, and nondrying and has a long shelf life. It is used for cooking and in the cosmetics industry. The most prominent commercial product is the sun-dried fruit pulp. Roasting and fermentation of both the fruit pulp and the seeds improve their chemical composition, and it is believed that the fermented product with decreased tannin content provides a better ingredient in traditional medicine.

Commerce — Baobab is a major nontimber forest product (NTFP) that plays a significant role in the lives of communities in the savanna, and its many products (seeds, oil, leaves, and fruits) constitute a source of income for many rural people in Africa. Baobab products are used in pharmaceutical and cosmetic industries. According to a United Nations Conference on Trade and Development (UNCTAD) report (p. 7), 1145 baobab is highly sought after in several market segments, such as for food and beverages (Germany, France, and the Netherlands); botanical remedies (Germany, France, and the Netherlands); and nutraceuticals as well as natural cosmetics (European Union, United States, and Japan). Baobab fruit is an ideal candidate in the functional food market as it is very high in vitamin C and other vitamins and minerals; the powder may be used as a thickener due to its high pectin and fiber contents. The import value of the product class of rare edible dried fruit, which includes baobab fruit pulp, grew by 13% in 2003.

The U.S. Food and Drug Administration (FDA) approved on 25 July 2009 the designation of baobab dried fruit pulp (BDFP) as GRAS, indicating it is a substance that is generally recognized as safe, which was based on a submission by PhytoTrade in 2008 to that agency. According to the Federal Food, Drug, and Cosmetic Act, Sections 201 2 and 409, any substance that is intentionally added to food as an additive is subject to premarket review and approval by the FDA. This makes baobab a major article of international commerce. The designation of BDFP as GRAS, through scientific procedures, allows for its use as an ingredient in blended fruit drinks and fruit cereal bars at levels of up to 10% and 15%, respectively. Similar classification of baobab as a safe food ingredient exists in the European Union.

Adenia Cissampeloides

Botanical Name — Adenia cissampeloides

Synonyms — Adenia gracilis Harms (1897), Adenia gummifera (Harv.) Harms (1897), Adenia guineensis W.J. de Wilde (1971)

Related Species — Adenia lobata

Family — Passifloraceae

Common Names — Monkey rope, snake climber, wild granadilla

African Names — Swahili: mandali, mkengeti; Ashante-Twi (Ghana): homakyem; Ga: akpeka, peteha (A. lobata); Luguru (Tanazania): gale; Digo (Kenya): mgore, mugore, munua nyoka; Shambaa: ghoye; Zigua: zokambago

Description — A. cissampeloides is a dioecious liana, growing up to 30 m long, with a stem up to 10 cm in diameter, striped bluish-green and older stems often with whitish powder; stems have simple or 3-fid tendrils 10–20 cm long. Leaves are alternate, simple; stipules 0.5(–1) mm long, broadly rounded to triangular, irregularly cleft; petiole (1–)1.5–11 cm long; blade entire or more or less deeply 3(–5) lobed, orbicular to ovate or rhomboid in outline, (1–)3–14 cm long, base cordate to truncate or cuneate, apex obtuse or retuse, rarely acute, with a single gland at the base, up to 4 glands on the lower leaf surface and 3–7 glands on the margins. Inflorescence an axillary cyme, often with up to 2 (–4) cm long tendrils between the branches, up to 35 flowered in male, 2–6 flowered in female inflorescence; peduncle (0.5–)1–12(–16) cm long; bracts and bracteoles narrowly triangular, 0.5–1 mm long, acute, minutely toothed. Flowers unisexual, regular, 5-merous, pale greenish; pedicel 2–10(–15) mm long in male flowers, slightly shorter in female ones; sepals and petals free; male flowers with sepals up to 8 mm long and petals 8–11 mm long, filaments of stamens fused at base, ovary rudimentary; female flowers with sepals up to 6.5 mm long and petals up to 4.5 mm long, ovary superior, ovoid, 3–6 mm long, 3(–6) ribbed, stigmas almost sessile, kidney shaped, stamens rudimentary. Fruit an ovoid capsule 2.5–4.5 × 1.5–3 cm, leathery to woody, pale green, 30–50 seeded. Seeds ovoid, 3.5–5.5 × 3–4 × 2 mm, pitted. 1140

Habitat and Distribution — The genus Adenia consists of about 95 species, about 60 of them occurring on the African continent, 20 in Madagascar, and 15 in Asia. The genus is subdivided into six sections. Adenia cissampeloides belongs to section Ophiocaulon, while Adenia lobata belongs to section Blepharanthes. A. cissampeloides occurs from Senegal east to Somalia and south throughout Central and East Africa to southern Africa, including South Africa. It is also found in the Seychelles. A. lobata occurs from Senegal east to Ethiopia and has been found south to Angola and Mozambique.

Ethnomedicinal Uses — Adenia species are used as fish poisons. The dried leaves have been employed as diuretics, febrifuges, and abortifacients. Various parts of the plant have been used as a diaphoretic and for the treatment of gallbladder problems, colic, dysentery, cholera, gonorrhea, infertility, threatened abortion, and dysmenorrheal and chest problems. The stem and roots are used in a limited extent for the same purpose. The exudate or sap from the plant is highly toxic and should not be used.

Constituents — The plant contains cacogenic glycosides barterin (tetraphyllin B) and volkenin (epitetraphyllin B) in the leaves, fruits, stem, and roots. The leaves also yield gummiferol, a cytotoxic polyacetylenic diepoxide with in vitro anticancer activity. Leaves and root bark are rich in iron; the average iron content of the leaves per 100 g dry matter is 32.5 mg, of stem bark 9.9 mg, and of root bark 32.1 mg.

Pharmacology — Adenia cissampeloides extract has been shown to contain hepatotoxic compounds with in vivo liver-damaging activity, and the excessive use of the plant has been associated with liver complaints among the Zulu people in South Africa. Stem pulp showed a significant parricidal effect on the beet armyworm Spodoptera exigua. In a laboratory test, aqueous extracts of the plant had a dose-dependant depressing effect on the blood pressure of cats. The effect was neutralized by small doses of atropine. Possible sympathomimetic and vasoconstrictive activity were also shown. An extract of the plant showed poor in vitro activity when tested against Plasmodium falciparum. A diethyl-ether extract from the bark, formulated as an emulsifiable concentrate, was found to be an effective anesthetic for the African honeybee (Apis mellifera adansonii). 1 An extract of A. gummifera exhibited antioxidant and acetylcholinesterase inhibition (AChEI) activity. 50

Aframomum Melegueta

Botanical Name — Aframomum melegueta K. Schum

Synonyms — Aframomum grana-paradisi (L.) K. Schum; Aframomum meleguetella K. Schum; Alexis grandiflora (Sm.) Salisb.; Alpinia grana-paradisi (L.) Moon; Amomum grandiflorum Sm.; Amomum grana-paradisi L.; Amomum melegueta Roscoe; Cardamomum grana-paradisi (L.) Kuntze; Cardamomum grandiflorum (Sm.) Kuntze; Torymenes officinalis Salisb.

Family — Zingiberaceae

Related Species — A. daniellii, A. strobilaceum, A. exscapum, A. korarim

Common Names — Grains of paradise, guinea grain, alligator pepper, melegueta pepper

Description — A. melegueta is an aromatic plant cultivated for its edible spicy fruit. It is a perennial herb growing up to 4 m high. The stem is short, marked with the encircling scars of fallen aerial leaves, and it is highly branched. The lower surface bears the roots, which are adventitious and slender. It yields an aromatic rhizome, which is horizontal and tuberous and bears scaly leaves with occasional buds in axils. The leaves are large, about 30 cm long and 12 cm wide, with close nerves below. They occur in two rows with an open or closed sheath sessile or stalked on the sheath; the blades are usually large, with numerous closely parallel pinnate nerves diverging obliquely from the midrib. The bracts are few and about half overlapping. The plant yields beautiful aromatic flowers with orange-colored lip and a rich pinkish-orange part. They are solitary, borne separately from the leafy stem. The fruits are fleshy and indehiscent and contain numerous small seeds embedded in pleasant-tasting aril. The seeds are golden or red-brown when fresh but darken on drying; they are angular and granular, strongly aromatic, and pungent. 9

Geographical Distribution — Aframomum occurs throughout tropical Africa, but it is cultivated mainly in West and Central Africa.

Ethnomedicinal Uses — The genus is employed extensively in traditional medicine in West and Central Africa. In Ewe (Ghana), the common name for the plant, megbe-dogboe, means “never lacking for the sick.” In Southern Nigeria, it is typically chewed with kola nut as a masticatory agent. The fresh fruit is used as an aphrodisiac. The leaf is dispensed for measles and applied externally for the treatment of leprosy. The root decoction is taken by nursing mothers to check excessive lactation and to control postpartum hemorrhage. The rhizome is used as an ingredient for the preparation of a remedy for infertility to promote conception, and the fruit is used as a tonic for sexual stimulation. The plant is also used as a purgative, galactogogue, anthelmintic, and homeostatic (hemostatic) agent. The seeds are used with the leaves of Urera oblongifolia as an external treatment for tumors. In Senegal, the seeds are mixed with salt and rubbed on the interior of the mouth as a treatment for sleeping sickness.

Constituents — The members of the genus yield essential oil in most parts of the plants. The seeds of A. melegueta have been shown to contain the benzenoids gingerol, shagaol, and paradol. 51 The seeds of A. danielli obtained from Cameroon have been shown to contain labdane diterpenoids. 52 Other constituents of the genus include flavonoids, 53 monoterpenes, 54,55 and quinoids. 56 The chloroform extract of the seeds contains antiestrogenic diarylheptanoids, named gingerenone D, dihydrogingerenone A, dihydrogingerenone B, and dihydrogingerenone C. 57

Pharmacological Studies — The essential oil obtained from the seeds and the benzenoid components paradol, gingerol, and shagaol have been shown to possess antimicrobial and antifungal activity. 58 The alcoholic extract was lethal to snail hosts of schistosomes. 59 Extracts of the plant showed positive activity in a cytotoxicity assay. 60 Studies of sexual behavior in rats have shown that A. melegueta modified the sexual behavior of male rats by increasing sexual arousal. The aqueous extract of the seeds of this plant was shown to significantly increase the penile erection index, as well as the frequencies of intromission and ejaculation. The plant extract was also found to enhance the orientation of males toward females by increasing mounting and anogenital investigatory behavior. 61 A review of Aframomum indicated its potential as a dietary supplement or spice for foods and as a potential source of new medicines for a variety of diseases, including inflammation, infections, and central nervous system (CNS) disorders. 62 It has been suggested that the selective inhibition of cyclooxygenase 2 (COX-2) enzyme by Aframomum constituents may be indicative of more tolerable anti-inflammatory and analgesic compounds than most conventional nonsteroidal anti-inflammatory drugs (NSAIDs). 63 The phenolic component has been shown to possess a significant antiglycation and antioxidant effect, 63 which may be useful in its application as a dietary supplement. 64

The potential benefit of grains of paradise in weight management has been demonstrated by the effect of an extract of Aframomum and 6-paradol on the activation of thermogenesis in brown adipose tissue. 65 Intragastric injection of an extract of 6-paradol enhanced the efferent discharges of the sympathetic nerves in a dose-dependent manner. The enhanced nerve discharges were sustained for as long as 3 h. The rats did not become desensitized to the stimulatory effects of these compounds on sympathetic nerve activity. The temperature of brown adipose tissue showed a significant increase in rats injected with 6-paradol. These results demonstrated that Aframomum may be useful for the regulation of weight loss and weight maintenance. 66

Toxicity — Aframomum is considered a safe herbal supplement, and no human toxicity or allergic reaction has been reported. A 28-day subchronic toxicity study in male and female Sprague-Dawley (SD) rats to evaluate the safety of a grains-of-paradise extract showed a dose-related increase in absolute and relative liver weights in males and females dosed with 450 and 1500 mg/kg, respectively. There was a corresponding increase in alkaline phosphatase (ALP) with no signs of steatosis or cirrhosis. At the same doses, there was a significant decrease in blood glucose in male rats. 66

Agathosma Betulina

Botanical Name — Agathosma betulina (P.J. Bergius) Pillans

Synonyms — Barosma betulina (P.J. Bergius) Bartl. & H.L. Wendl.; Barosma orbicularis Sweet; Bucco betulina Schult; Hartogia betulina P.J.Bergius

Related Species — Agathosma crenulata (L.) Pillans

Family — Rutaceae

Common Names — Buchu, diosma

African Names — Khoi: buchu; Afrikans: boegoe, rondeblaarboegoe; South Africa: Bucco, Bookoo; Xhosa: ibuchu

Description — Agathosma betulina is a resprouting, broad-leaved aromatic shrub with erect woody stems reaching 2 m tall, but low-growing and prostrate varieties also occur. The leaves are of pale green color, leathery and glossy, with a blunt, strongly curved tip and a fine-tooth margin; round pellucid oil glands are conspicuously scattered throughout the leaf, along the margins and lower surfaces. They are strongly aromatic, usually opposite, ericoid, often crowded, simple, entire, from 0.5 to 3.5 cm long. The star-shaped flowers are produced in terminal clusters, 0.7–2 cm diameter, with five white, pink, red, or purple petals. The brownish fruits are five chambered. The two related buchu plants can be differentiated by the shape of the leaves: A. betulina is described as “round-leaf buchu,” whereas A. crenulata is known as “oval-leaf buchu.” The latter species has been described as a pungently aromatic, woody, single-stem shrub that reaches a height of 2.5 m. The glossy, dark green leaves are more than twice as long as they are broad, with many oil glands throughout. The delicate stems bear one to three, relatively large, white or mauve flowers in the leaf axils. 67

Habitat and Distribution — Buchu is a southern African plant that appears to be naturally restricted to the Cederberg Mountain range of the Western Cape Province of South Africa. Agathosma betulina is particularly adapted to dry conditions and can be found on sunny hillsides where other crops will not succeed. It can be found on the rocky sandstone slopes of the northwestern Cape region. A. crenulata grows on the damp lower and middle slopes and valleys, from Ceres to Swellendam (South Africa).

Ethnomedicinal Uses — Buchu is a highly valued traditional medicine for the treatment of inflammatory conditions and kidney and urinary tract infections. It has also been used as an appetite stimulant, digestive, antispasmodic, and carminative and for the treatment of coughs, cystisis, prostatitis, influenza, colds, hangover, rheumatism, and gout. Buchu is a general restorative tonic in African ethnomedicine. It is also an effective insect repellant. In the pharmacopoeias, buchu is categorized as a diuretic and urinary tract antiseptic. Herbal medicine shops include the plant in formulations to treat arthritis, cellulite, cystitis, diarrhea, flatulence, kidney infections, nausea, rheumatism, and wounds.

Constituents — Both commercially important species of Agathosma yield essential oils (1–2% w/w). A. betulina is characterized by the dominant presence of diosphenol in the oil (ca. 40% of total oil) with limonene, menthone, l-pulegone (<5%), and (ψ)-diosphenol (anisomer of diosphenol), whereas A. crenulata elaborates a high pulegone content of about 50% with near total absence of the diosphenol found in A. betulina. Buchu also contains flavonoids, diosmin, diosmetin, quercetin-3, 7-diglucosides, and rutin. It has been reported that the characteristic black currant smell and flavor of buchu oil is due to the presence of sulfur-containing minor compounds (8-mercapto-p-menthan-3-one). 1141 The two species can be standardized and qualitatively differentiated easily by liquid and gas chromatographic (GC) techniques with or without coupling to mass spectroscopy (MS) based on the analysis of the composition of the oils. The use of vibrational spectroscopy has also been reported for the quality assessment of the two commercially important species. 68

Pharmacological Studies — The essential oil obtained from A. betulina has been shown to inhibit 5-lipoxygenase (5-LOX) enzyme, which is involved in the inflammatory process (IC50 = 35.2 μg/ml). 69 The data clearly indicate that the Agathosma essential oil blocks the synthesis of 5-LOX products in vitro. Since leukotrienes, for which 5-LOX is the key enzyme, are considered to be involved in the initiation and maintenance of a variety of inflammatory diseases, it may be reasonable to state that the inhibition of leukotriene synthesis may, at least in part, be responsible for the anti-inflammatory action of these species. The spasmolytic activity on guinea pig ileum by the same species has been demonstrated, which is indicative of apparent blockage of calcium channels. 1141 Although buchu contains flavonoids, studies have shown that the plant has only weak antioxidant activity in the DPPH (2,2-diphenyl-β-picrylhydrazyl) assay, both species having IC50 values greater than 100 μg/ml. Neither was found to exhibit radical scavenging activity equivalent to that of the standard, ascorbic acid (IC50 value of 2.47 ± 0.178 μg/ml).

The antimicrobial activity of various extracts of buchu has been investigated by several scholars who showed that buchu possesses moderate antimicrobial properties. In vitro antimicrobial studies of A. betulina extracts (water, dichloromethane: methanol, and methanol) of seven pathogenic microorganisms (Listeria monocytogenes, Pseudomonas aeruginosa, Candida albicans, Escherichia coli, Proteus vulgaris, Staphylococcus aureus, and Enterococcus faecalis) using the MIC microplate assay showed that the dichloromethane:methanol extracts had the greatest activity, with MIC values ranging between 3 and 6 mg/ml. 70 The study also evaluated the effect of buchu extracts on the growth and development of biofilms using the crystal violet (CV) assay. The dichloromethane:methanol extracts prevented attachment of bacteria to the polyvinyl chloride surface; however, exposure of Candida albicans to the extracts enhanced attachment and subsequent biofilm formation. The growth and development of a preformed biofilm was also inhibited, but to a lesser extent. 70

An evaluation of the efficacy of buchu oil applied topically to treat pain resulting from muscle damage has been conducted by the Research Unit of Exercise and Sports Medicine, University of Cape Town (South Africa). In the study, 30 male participants did a bout of exercise using their nondominant arm with the intention of causing exercise-induced muscle damage. The results from the double-blind, placebo-controlled trail indicated that the group treated three times daily with buchu gel showed a reduction in swelling that may be ascribed to the anti-inflammatory properties of buchu. 71

Toxicity — The extracts of A. betulina and A. crenulata were shown to be nontoxic at the concentrations tested (IC50 values > 100 μg/ml) using the MTT (3-[4, 5-dimethyl-2-thiazol-yl]-2, 5-diphenyl-2H-tetrazoliumbromide) cellular viability assay. In the same assay, the essential oils exhibited higher toxicity at the concentration tested, both having IC50 values less than 0.0001 μg/ml when compared to the control. 71 The compound cis-isopulegone present in both species may contribute to the observed toxicity. R-(+)-Pulegone is known to be a hepatotoxic compound; large oral doses have been shown to deplete glutathione (GSH), which is needed in one of several biological detoxification steps. This depletion along with excess pulegone leads to centrilobar hepatocellular necrosis. 71

Formulation and Dosage Forms — The leaves are usually air dried and may be steam distilled to obtain the oil. Apart from its use in the dietary supplement industry, it is a major ingredient in the flavor and fragrance industry, where buchu is used to enhance fruit flavors. It is particularly used to boost black currant-like flavors. Its fragrance has a minty camphoraceous, sweet berry, catty, tropical guava, apricot and peach, green herbal taste. The oil is also used in perfumes and colognes. Several proprietary products exist in which buchu is used either alone or in combination with ginger, Garcinia kola, Curcuma longa for arthritis and with G. kola and Cola nitida (InterCEDD Health Products) as a “hangover” tonic.

Commerce — The two species of Agathosma are articles of international trade. The crude drug as well as the volatile oils are traded extensively. Herbalists and trade associations in South Africa export buchu to Europe, especially Germany and France. Although producer prices have fluctuated wildly in recent years, the demand for this crop has been stable since 2002. According to the Market News Service (MNS) Bulletin on Medicinal Plants and Extracts—2011, 1146 the wholesale price for dried leaves of buchu was US$38.36/kg on cost insurance freight (CIF) terms.

Agriculture — Buchu is restricted to South Africa and is a typical component of fynbos vegetation of the Cape region. Although some cultivation has been embarked on since the 1970s to raise improved varieties with more desirable properties, most of the commercial products are still wild crafted. Recent efforts in crop development have resulted in buchu now being a viable option for small-scale farming. Recently, growers experienced severe losses, ascribed to a soil-borne disease. The bioequivalence of some of the hybrids and cultivars is yet to be determined.

Agave Sisalana

Botanical Name — Agave sisalana Perrine

Synonym — Agave rigida Mill

Family — Asparagaceae

Common Name — Sisal

African Names — Arabic: sisal, bambara, tangeka; Hausa: axomyis; Swahili: katani, mkonge

Description — This is a perennial plant with a short stem, numerous leaves (in a rosette) that are thick, fleshy, and thorny and can reach 2 m in height and 15 cm in width. The inflorescence occurs in panicles at the apex of a hardy and long central stem of 3 to 8 m; greenish-yellow flowers that are rare develop into capsular fruits and into seed but produce a lot of plantlets that ensure fast propagation.

Habitat and Distribution — The plant is widely distributed throughout East and Central Africa. It is, however, cultivated in most tropical parts of the continent, requiring much sunlight and preferring areas such as highlands with two rainy seasons. Sisal is a major crop in Tanzania, Uganda, Angola, Mozambique, and Kenya.

Ethnomedicinal Uses — Sisal is used primarily as a source of commercial fiber. In traditional medicine in East Africa, the sludge obtained from the sap is used in the preparation of a lotion for the treatment of local inflammatory conditions.

Constituents — The fibers contain about 78% polysaccharide, of which about 84% consists of cellulose and the remainder pentosan. The juice of the leaves contains hecogenin as the major component and other steroidal sapogenins, such as sisalagenin, tigogenin, and neotigenin. Other constituents include mucilage, pectins, mannitol, and reducing sugars. Agave contains phenolic compounds, including flavonoids. The use of high-temperature and high-pressure reactors (PARR model 4560) for phenolic extraction of Agave proved to be more efficient compared to the conventional solid-liquid extraction at room temperature. It has been observed that an increase in both temperature and extraction time led to a corresponding increase in the amount of phenolic compounds extracted and suggested that, after process optimization, Agave could be used as an interesting source of polyphenols.

Pharmacological Studies — Extracts of the plant have been found to be devoid of antibacterial activity. 72 The inflorescence and leaf, as well as the juice, showed a positive hemolysis test, 73 probably due to the saponin content of the plant. The d-mannitol present in the A. sisalana biomass waste may add economic value to the natural sisal fiber production chain since the compound is widely used in the pharmaceutical industry and is also used as a raw material for producing several types of polymers. 74 Hecogenin found in Agave has been shown to possess anti-inflammatory, antioxidant, and gastroprotective activities. 75 Agave sisalana constituents showed antiparasitic action against gastrointestinal nematodes (GINs) in livestock, and the extracts could therefore be employed in parasite management methods in the livestock sector. 76

Ageratum Conyzoides

 

Botanical Name — Ageratum conyzoides

Synonyms — Eupatorium paleaceum Sesse & Moc., Chrysocoma maculata Vell., Carelia conyzoides (L.) Kuntze., Caelestina microcarpa Benth. ex Oerst., Caelestina latifolia (Cav.) Benth. ex Oerst., Cacalia menstrasto Vell., Alomia pinetorum L.O. Williams., Alomia microcarpa (Benth. ex Benth.) B.L.Rob.

Family — Compositae

African Names — Chagga: ifuna; Efik: ikongifoiyen; Igbo: akwukwo-nwosinaka; Masai: ol crowil el ajok; Ndoga: tongolla; Yoruba: imi-eshu

Description — Ageratum is an erect herb with many branches. It is up to 1 m tall, with characteristic hairy stalks. The leaves are simple, oval shaped, 7.5 cm long and 5 cm broad, and oppositely arranged on the stem; they are roughly heart shaped, pointed at the apex and rounded at the base. They have toothed margins, with two main veins arising from the midrib. The plant bears fruits having angular achenes with five narrow and pointed bristles. 77

Habitat and Distribution — It is a deciduous forest plant that occurs in western and eastern regions of the continent.

Ethnomedicinal Uses — Ageratum is used in folk medicine for the treatment of various diseases, 77 especially for the treatment of wounds and burns. 78 It has been dispensed as an emetic, for treatment of fevers, and externally in lotions for scabies and in eyedrops for inflammations. 77 For wound healing, the juice of the bruised leaves is squeezed into the wound and covered by a bruised but intact leaf. 78 The root decoction or weak infusion of the whole herb is used by the Chagga as a general remedy for abdominal discomfort and pain. The plant is used in East Africa for the treatment of syphilitic sores; for this purpose, it has been reported that the root is placed in a small shell, and an adolescent boy, who must be wearing a copper armlet, urinates into it; then, the fluid is rubbed over a stone, and the slimy mess is applied to the sore with a cock’s feather. 79

Constituents — The plant yields essential oil (about 0.16%), of which ageratochromone is the principal constituent. 80 The oil from the leaves also contains 6-dimethoxyagertochromone, phenols, phenolic esters, coumarin, and traces of eugenol. 80,81 Other constituents of the plant include the flavonoid conyzorigun, dotriaconthene, 7-methoxy-22-dimethylchromene, and 5,6,7,8,3′,4′5′-heptamethoxyflavone. 80,82 An isoflavone glycoside, 5,7,2′,4′-tetrahydroxy-6, 3′-di-(3,3-dimethylallyl)–isoflavone 5-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranoside 1, has been isolated from the stems of Ageratum conyzoides. 83

Pharmacological Studies — The plant has broad-spectrum antimicrobial activity. 84 Ageratum extract has been found effective against Helicobacter pylori, a Gram-negative microaerophilic bacterium that is a major etiological agent in duodenal, peptic, and gastric ulcers. 85 It has proved useful in treating wounds, but the activity does not appear to be due to direct antibacterial activity as the extract has been shown not to be active against microbes isolated from wounds. 86 The incorporation of Ageratum extract in the preparation of traditional West African black soap did not show any significant effect on the antimicrobial activities exhibited by the various soaps against the bacterial and fungal organisms tested. 87 The extract also showed in vitro anthelmintic activity. 80 The extract has been evaluated against human lung cancer cell lines (SK-LU 1 and SK-MES1) and the human skin fibroblast cell line (FS5 cells), with encouraging results. 88

Ageratum has been used in the management of Alzheimer’s disease (AD), a neurodegenerative disease of the CNS that leads to dementia and behavioral and cognitive impairments. To evaluate the herb as a possible treatment for the preliminary symptoms of AD, the effect of Ageratum conyzoides on learning and memory has been investigated in mice. Ageratum conyzoides (250, 500, and 750 mg/kg p.o.) produced a dose-dependent improvement in the memory of young and aged mice. Furthermore, it also reversed the amnesia induced by scopolamine (0.4 mg/kg i.p.) and natural aging. It also produced a profound reduction in the whole-brain acetylcholinestrease activity. 89 The dichloromethane extract from the aerial parts of Ageratum conyzoides was found to exhibit broad-spectrum antiprotozoan activity, with pronounced activity (IC50 = 0.78 μg/mL) against bloodstream forms of Trypanosoma brucei rhodesiense, the etiologic agent of East African human trypanosomiasis (East African sleeping sickness). The extract also exhibited noticable activities against Leishmania donovani (kala azar, IC50 = 3.4 μg/mL) as well as Plasmodium falciparum (malaria tropica, IC50 = 8.0 μg/mL). Five highly methoxylated flavonoids along with the chromene derivative encecalol methyl ether were isolated. All the isolated compounds did not give the antiprotozoan activity found in the dichloromethane extract, which is indicative of the fact that none of the known isolates from Ageratum is responsible for its activity. 90 Of immense therapeutic importance is the finding that an aqueous extract of A. conyzoides has the ability to potentiate the antimalarial activity of chloroquine and artesunate against induced plasmodiasis in mice. 91 If clinical evaluation in humans replicates the animal studies, then A. conyzoides could be used with antimalarial compounds in the treatment of malaria.

The essential oil of Ageratum conyzoides inhibited the mycelial growth and aflatoxin B1 (AFB1) production by Aspergillus flavus. 92 AFB1 is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. The essential oil inhibited fungal growth to different extents depending on the concentration and completely inhibited aflatoxin production at concentrations above 0.10 μg/ml. The analysis of the oil by GC/MS showed that its main components are precocene II (46.35%), precocene I (42.78%), coumarin (5.01%) and trans-caryophyllene (3.02%). Comparison by transmission electron microscopy of the fungal cells, a control, and those incubated with different concentrations of essential oil showed ultrastructural changes that were concentration dependent of the essential oil of A. conyzoides. Such ultrastructural changes were more evident in the endomembrane system, affecting mainly the mitochondria. Degradation was also observed in both surrounding fibrils. 93 The ability to inhibit aflatoxin production by A. conyzoides may prove useful in the preservation of agricultural products.

Ageratum has also been shown to posess anti-inflammatory, 93 anticoccidial, 94 antioxidant, and gastroprotective activities. 95

Alchornea Cordifolia

 

Botanical Name — Alchornea cordifolia (Schum et Thon.) Muell. Arg.

Synonyms — Alchornea cordata Benth., Cacoucia caudifolia (Schumach. & Thonn.) Walp., Schousboea cordifolia Schumach. & Thonn.

Family — Euphorbiaceae

Common Names — Christmas bush

African Names — Hausa: bambami; Igbo: ububo; Efik: mbom; Yoruba: ewe-epa; Bwari: tahi; Ijaw: epai; Bini: uwonowen; Igara: oje, ose

Description — Alchornea cordifolia is a multistemmed shrub or small tree, sometimes climbing but most times an erect spreading plant, up to 5 m high and 30 cm girth. The leaves are simple, broadly ovate, and cordate, with a drawn-out apex and heart-shaped base, 15–28 cm long and 8–16 cm broad. The margins are entire, wavy, or slightly dentate. They are sparsely hairy on the lower surface with glands in axils of basal nerves. The stalks are from 5 to 14 cm long. The plant produces small, greenish-white flowers, often dioecious, borne on common stalks in the axils of the leaves, with the individual flowers sometimes having no stalk. The fruits are greenish-gray in color, two celled, and usually split to expose red seeds when they are ripe. 9

Habitat and Distribution — It is found in secondary forests and is widespread in tropical Africa. It has been located in Ghana, Nigeria, Senegal, Angola, Zimbabwe, Cameroon, and Tanzania.

Ethnomedicinal Uses — The leaves and stem bark are used in the preparation of remedies for urinary, respiratory, and gastrointestinal disorders. A slurry of the fruits is administered for cough. A complex laxative is prepared with the fresh leaves, the fruits of Xylopia aethiopica, and leaves of Psidium quajava. A decoction of the leaves alone is used as an eye lotion. The leaves and bark, when powdered, are drunk in water or eaten in food for piles. The juice of the leaves and fruits is rubbed on ringworm and other skin infections. An extract of the roots of A. floribunda (Nianndo) prepared by macerating the plant material for several days in palm wine is used in Zaire as a stimulating intoxicant and aphrodisiac. 96

Constituents — An indole alkaloid resembling yohimbine and related indole alkaloids has been detected in several Alchornea species. 96 In a later investigation, the presence of yohimbine in the stem bark of Alchornea could not be confirmed; however, four unidentified alkaloidal compounds were detected with terpenes, sterols, and their glycosides. 97 The root bark has been found to contain about 0.03–0.26% total alkaloids. 98 The plant also contains the hexahydroimidazopyrimidine alkaloids alchorine and alchornidine. 99 Other constituents of the species include gentistic and anthranilic acids, as well as tannins.

Pharmacological Studies — Extracts of the leaves have been shown to inhibit the growth of both Gram-positive and Gram-negative bacteria. 100 It has also been found active against methicillin-resistant Staphylococcus aureus (MRSA). 101 Its antistress activity has been positively assessed by the ability of the extract to alter the duration of immobility; in the forced swim endurance test, a picrotoxin-treated animal was employed as the model to assess its activity against convulsive seizures. 102 The root extract has sympatholytic and hypotensive activity. Positive results were obtained in clinical experiments with root and stem extracts in the treatment of icterus. 103

The leaf and root bark extracts showed significant topical anti-inflammatory activity in the mouse ear edema model using croton oil at a dose of 90 μg/cm. Six compounds isolated from the active extracts also exhibited significant topical anti-inflammatory activity. Of these, daucosterol, acetyl aleuritolic acid, N1,N2-diisopentenyl guanidine, and N1,N2,N3-triisopentenyl guanidine were found to be more active than indomethacin, while β-sitosterol and di(2-ethylhexyl) phthalate were less effective. 104 In egg-albumen-induced rat hind paw edema model, the leaf extract showed impressive anti-inflammatory activity. 105 Alchornea extracts have been shown also to possess immunomodulatory, 106 analgesic, and antiprotozoal activities. 107

Allium Sativum

Botanical Name — Allium sativum L.

Synonyms — Porrum sativum (L.) Rchb., Porrum ophioscorodon (Link) Rchb., Allium pekinense Prokh., Porrum ophioscorodon Link., Allium longicuspis Regel, Allium controversum Schrad. Ex Willd.

Family — Amaryllidaceae

Common Names — Garlic, ail commun (French)

African Names — Hausa: tafanuwa; Igbo: ayo-ishi; Swahili: kitunguu-sumu; Yoruba: ayu

Description — Garlic is a herbaceous plant. It occurs as a bulb of fleshy scale leaves on the lower part of the stem; each bulb consists of a number of bulbets or “cloves” that rest on a common bulb base and are covered with membranous bracts. It has a very strong and disagreeable odor that is noticeable in the breath and a strongly pungent and persistent taste; both the odor and taste linger for several days following the ingestion of the plant. Garlic includes two basic varieties: hardneck and softneck. Hardneck garlics, which include A. sativum var. ophioscorodon and A. sativum var. pekinense, are characterized by hard, woody central stalks that extend down to the basal plate at the bottom of the bulb.

Habitat and Distribution — It is indigenous to Asia but has been introduced to Africa, where it is cultivated in many parts of the continent.

Ethnomedicinal Uses — It is used for the treatment of respiratory infections and as an anthelmintic. It is applied externally in northern Nigeria for the treatment of skin diseases. In parts of Chad, the fresh bulbs are used in the preparation of tonics for diabetes and hypertension.

Constituents — Garlic yields 0.1% to 0.3% of a volatile oil consisting of sulfur-containing compounds, including S-allyl-2-propenthiosulfinate (allicin), methylallyltrisulfide (MATS), diallydisulfide, diallytrisulfide, diallytetrasulfide, allylpropyldisulfide, ajoene (4,5,9-trithiododeca-1,6,11-triene 9-oxide), 2-vinyl-4H-1, 3-dithiin, and allin, which yields allicin on enzymatic hydrolysis. 108,109 The oil also contains the terpenes citral, geraniol, linalool, and α- and β-phellandrene and various enzymes, including allinase, vitamins of the B group, flavonoids, and several minerals. 82 Studies have shown that aged garlic has a chemical profile that is distinct from the fresh materials, and whenever possible, aged garlic should be used.

Pharmacological Studies — It has been established that extracts of garlic possess demonstrable antiatheromatous properties. In feeding experiments with rabbits, the animals given garlic had a much less marked increase in blood cholesterol than those given the same diet but without garlic. 110 The oil extracted from garlic prevents fat-induced hypercholesterolemia 111 and sucrose-induced hyperlipidemia 112 and enhances fibrinolytic activity. 113 In vitro studies showed that garlic inhibits platelet aggregation. 114 It has also been observed that conversion of labeled arachidonate (AA) in garlic oil-treated platelets was impaired compared to a control in the elaboration of platelet COX and LOX products. 115 Aqueous extract of garlic inhibited aggregation induced by adenosine diphosphate (ADP), collagen, AA, epinephrine, and calcium ionophore A23187 in a dose-dependent manner. 116 It has demonstrable antioxidant properties. 117 These effects have an indirect relationship to the use of garlic in the treatment of hypertension. The drug has been shown in five consecutive cases of hypertension to reduce the blood pressure to satisfactory levels. 118

Other pharmacological activities include pronounced hypoglycemic activity in animals and humans; 119 the drug also contains substances with hyperglycemic activity. 120 In rabbits, the maximum fall in blood sugar level given a glucose loading dose with garlic juice was 12% compared with 20% for those treated with tolbutamide and 2% for those given a water control. 121 It has also been observed that in a group of mice injected with cancer cells incubated with garlic extract, no deaths occurred for up to 6 months while mice injected with untreated cancer cells died within 16 days. 122 Garlic extracts and more specifically allicin have been shown to be active in vitro against Candida albicans, Trichomonas spp., Staphylococcus aureus, Salmonella typhi, and paratyphi, Shigella dysenterica, Vibrio cholerae, and Escherichia coli. 123,124 It was active against some mutidrug-resistant bacteria in vitro. 125 One of the active metabolites of garlic, allicin, possessed significant antifungal activity in vitro against Candida, Cryptococcus, Trichophyton, Epidermophyton, and Microsporum species. 124

Garlic shows a general tonic effect even at very low doses due to the stimulation of hypophyseal function, and this property has been exploited in relation to Seyle’s stress syndrome. 128 The beneficial effects of garlic extract injections on lindane-induced damages in testes, brain, and thyroid function have been evaluated experimentally, and it was found that 300 mg fresh garlic/kg/day counteracted the damage to these organs caused by lindane. 126

Clinical Applications — The lower incidence of heart disease in Italy and Spain when compared to that in the United States has been attributed, at least in part, to the greater consumption of garlic by the general population of these Mediterranean countries. The effect is believed to be related to the herb’s hypolipidemic and antiplatelet aggregating effects. 127

In clinical practice, garlic is used for long-term treatment of hypertension, 128 degenerative heart disease, and atherosclerosis. 129 The medication should be given for an extended period, at least 3 months, to achieve the desired results. A social problem with garlic medication is the persistent smell. Attempts to present garlic in dosage forms that mask the odor have not been successful since the disagreeable odor comes about when constituents containing sulfur are eliminated via the skin and respiratory passages. It has also been observed that reduction of the smell by encapsulation and adsorption to charcoal invariably leads to reduced activity. 127 The dosage is determined relative to the severity of the condition being treated and lies between 10 and 25 g of the whole drug or 2 and 8 ml of the syrup. Garlic is available in health food shops in the following forms: garlic bulbs, tincture, capsules, and garlic juice.

Garlic is also used as an expectorant, diaphoretic, disinfectant, and diuretic. Extracts of the plant, as well as the constituents diallyldi- and trisulfides, are active against the Culex mosquito. The isolates were larvicidal at 5 ppm. 130 According to some Chinese doctors, application of thin slices of garlic bulb aided healing during repair of perforations of the eardrum in 17 of 18 patients. 131

Although garlic and onion are frequently recommended for degenerative heart disease, an analysis of the relationship of garlic and onion consumption to mortality from ischemic heart disease in 27 countries raised doubts about the protective effect of garlic. 132 Several clinical trials, however, have demonstrated the beneficial effects of garlic as a dietary supplement.

Toxicity — Garlic is not known to cause any serious toxicity when consumed in moderate quantities. Allicin yields a degradation product that often causes severe halitosis following the ingestion of large quantities of garlic. 133 Contact dermatitis to garlic has been reported. 134 There is a case report of prolonged inhalation of garlic dust by a food industry worker that resulted in the development of a severe asthmatic reaction with subsequent cross-allergenicity to other plants of the families Liliaceae or Amaryllidaceae. 135 Garlic medication is contraindicated in ambulatory patients taking anticoagulant drugs due to possible prolongation of bleeding time. According to Martindale’s Extra Pharmacopoeia, 205 the administration of preparations of garlic to children is dangerous, and fatalities have been recorded.

Aloe Barbadensis

 

Botanical Name — Aloe barbadensis Miller

Synonyms — A. vera., A. vulgaris Lamk., A. indica Royle

Family — Liliaceae

Common Names — Aloe vera, curacao aloe, aloe vera gel (AVG)

Description — Aloe barbadensis is a perennial herb with rosettes of long pointed leaves from a shortly branched creeping rhizome. The leaves are brittle and exude a clear yellowish viscous sap when broken. They have soft marginal prickles. The flowers are yellow and borne in an elongated compact raceme from the center of the rosette. Propagation is by means of the rhizome branches since it does not produce fruit. 32

Habitat and Distribution — It grows in subtropical regions of the continent. The plant is probably a native of South and East Africa and the Mediterranean regions, although it is widespread throughout the continent. It is not very discriminatory to soil types and climatic conditions, but as a member of the Liliaceae family, it will prefer a well-drained clayey loam, with rainfall of at least 80 in. per annum.

Ethnomedicinal Uses — The fresh leaf is used for wound dressing and for the treatment of vertigo. In Nigeria, the exudate from freshly cut leaf is used in the treatment of guinea worm infestation. In Trinidad and Tobago, the exudate is mixed with egg white and taken for colds and asthma and to heal bruises; it is taken with seawater for stomach ulcers. 136 The dried exudate is used in the treatment of severe constipation. Aloe vera possesses healing, moisturizing, and emollient properties useful in a wide range of cosmetic formulations. It is employed as a humectant in skin preparations such as moisturizers, suntan lotions, and aftershave creams. It has been found useful for application to severely chapped skin.

Constituents — Aloes contain C-glycosides and resins. The crystalline glycoside known as aloin is used in pharmacy as a cathartic. It is, however, the gel, said to contain several organic acids and the so-called biostimulators, that the plant secretes as a repair agent on physical injury that has the topical healing properties. The plant also contains polysaccharides, glycoproteins, sterols, organic acids, and saponins. 123,137

Preparation of Aloe vera AVG is prepared in various ways depending on the manufacturing house. A common practice is to drain the free-flowing aloes first and then allow the leaves to be soaked in 15% ethanol solution in the dark for up to 14 days; then, the finely chopped material is subjected to a mill press. There is no scientific report on the differences (if any) between the pharmaceutical aloes and those processed for cosmetic use. The methods of preparation are highly customized and are the subjects of several patents, with each manufacturing house claiming the superiority of its own method and product.

Pharmacological Studies — Aloe vera is one of the most effective wound- and burn-healing agents in current use. Several publications are available in the literature substantiating the healing properties of AVG, and only recent reports are reviewed here. Animal studies have shown that it possesses both oral and topical wound-healing activity. 138 In the oral experiment, animals were administered 25% aloe vera in their drinking water for 2 months. The animals in the topical experiment were given 25% of the drug in a cream. The results showed that a 62.5% reduction in wound diameter was noted in mice that received a 100 mg/kg/day oral dose of the substance; for the topically treated animals, a 50.8% reduction was recorded. In both groups, the wounds were induced on both sides of the vertebral column of ICR mice with a biopsy punch. 138

In another study, full-face dermabrasion was used to evaluate the wound-healing activity of AVG in comparison with the standard polyethylene oxide gel dressing. 139 It was found that by 24–48 h, there was dramatic vasoconstriction and accompanying reduction in edema on the side treated with aloe vera; by the third to fourth day, there was less exudate and crusting at the site treated with the drug; the fifth to sixth day witnessed the complete reepithelialization of the aloe site. It was estimated that there was a 72-h acceleration of wound healing in the aloe-vera-treated sites against the side of the face dressed with standard polyethylene oxide gel. It was observed that the acceleration of wound healing is significant in the reduction of bacterial contamination, possible keloid formation, and pigmentary changes. 139 A suggestion has been made that the cicatrizant activity of aloe vera is due, at least in part, to the gibberellin content of the plant. 140 Both aloe and gibberellins were shown to inhibit polymorphonuclear (PMN) leukocyte infiltration to a site of gelatin-induced inflammation in diabetic animals. 141,144

In the management of burn wounds, it was found that Hartley guinea pigs that received full-thickness burns covering 3% of their body surface area by direct contact with a hot plate were completely healed in 30 days versus 50 days for the control group dressed with gauze occlusive dressing. 142 One comparative study of the burn wound-healing activity of aloe vera and that of 1% silver sulfadiazine cream concluded that AVG hindered the healing process in second-degree burns in the guinea pig. 143 The aloe juice has been found effective in the treatment of third-degree X-ray burns; more recently, it has been advocated in treating atomic radiation burns. 144,145

At a dose of 60 mg/kg, aloe vera powder was found to increase both the fertility rate and the litter size of female rabbits. 146 The plant was also useful in menstrual irregularities and functional sterility. 147,148 Aloe vera is incorporated in several dietary supplements for its beneficial effects as an antioxidant and in the prevention of premature tissue aging. Interestingly, AVG does not include the sap of Aloe vera, which contains anthraquinones. AVG is widely used in cosmetics and toiletries for its moisturizing and revitalizing action. The organic whole leaf of Aloe vera is reported to aid in cellular repair and in digestion and assimilation of foods, vitamins, minerals, and other vital nutrients. 149 The rheological characteristics of native Aloe gel and juice under dynamic and steady shear have been evaluated for its use in topical formulations. The damping of the elastic moduli and viscous moduli at various temperatures for the Aloe gel under oscillatory shear tests have been reported and were observed due to the presence of the weak, fibrous, and random structure of polysaccharides in it. The moduli for gel increased with increasing temperature and that for juice decreased with temperature. Prior to attaining the plateau region after a certain shear rate, AVG and juice exhibited shear thinning behavior, with a flow behavior index for Aloe gel samples of 0.1 in the shear thinning region. 150

Aloe vera has been found useful for the treatment of various diseases, including diabetes, and studies have established that it possesses antifungal, 151 antihyperlipidemia, antiatherosclerosis, and anti-inflammatory 152 properties and is used in management of gastrointestinal disorders. 153

Toxicity — Aloe vera is generally regarded as safe and no serious adverse effects or toxicity have been reported. However, a caution was raised by the U.S. National Toxicology Program, which has found that rats grew tumors after drinking water spiked with an extract of the plant. The rodents were given relatively high doses of a whole-leaf extract of Aloe vera over 2 years. 154 In rats that had drunk water containing 1.5% by weight of the extract, 39% of females and 74% of males had malignant or benign tumors in their large intestines. The report indicated that none of these growths was seen in rats given pure drinking water. It is believed that the tumors were probably caused by aloin A. In 2002, products containing aloin A or aloe extracts were removed from laxatives sold over the counter in U.S. pharmacies because manufacturers did not provide sufficient safety information to the U.S. FDA. 155

Aloe Ferox

Over 80 species of Aloe (family Liliaceae) occur in various parts of the world. The main species found growing in Africa is Aloe ferox, which yields the so-called Cape aloe. Another common species is Aloe barbadensis (discussed in the preceding section), which is the source of Curacao aloe. Socotrine and Zanzibar varieties originate from Aloe perryi.

Botanical Name — Aloe ferox Miller

Synonyms — Pachidendron ferox (Mill.) Haw., Pachidendron supralaeva (Haw.) Haw., Pachidendron pseudo ferox (Salm-Dyck) Haw., Aloe galpini Baker., Aloe horrida Haw., Aloe muricata Haw.

Family — Asparagaceae

Common Names — Aloe, Cape aloe

African Names — Arabic; Swahili: shubiri

Description — The genus Aloe includes herbs, shrubs, and trees, bearing spikes of white, yellow, or red flowers. The leaves are fleshy, strongly cuticularized, and prickly at the margins. A. ferox is a shrub, 3–4 m in height and about 12 cm in diameter, with a large rosette of leaves. The leaves are oval-lanceolate, 40–60 cm long and 10–12 cm wide, with a thorny ridge and edges. Flowers have a perianth 2.5 cm in diameter, tinged with yellow and purplish-blue, striped with red and green. 28

Habitat and Distribution — It is a subtropical plant but widely cultivated in dry forest areas of the continent.

Constituents — Aloe contains anthraquinone glycosides, the principal one being a yellow, crystalline substance called barboloin. It also contains resin and aloe-emodin. The pharmaceutical “aloe” is the solid residue obtained by evaporating the liquid that drains from the parenchyma tissue in the center of the leaves of various species of Aloe. The aloe mostly used in cosmetics formulations is the Curacao aloe from A. barbadensis Miller (see Aloe vera Linne). The major aglycone found in A. ferox is aloe-emodin and is associated with decomposition product aloe-emodin-9-anthrone.

Production of Aloes — Aloes for pharmaceutical uses are prepared from the wild species of A. ferox or are cultivated species of A. barbadensis by making transverse cuts near the base of the leaves and collecting the ensuing juice for about 6 h. It is concentrated by boiling for about 4 h in an open flame. Aloe ferox gel can be differentiated from AVG by the analysis of their monosaccharide content; A. ferox yields a mixture of glucose and galactose, whereas A. vera contains mainly mannose. 156

Pharmacological Studies — The main pharmaceutical use of the aloes is as a laxative, the activity being due to anthraquinone glycosides. An anaerobic bacterium, Eubacterium sp., has been isolated from human feces, which is capable of transforming barboloin to aloin-emodin anthrone, and the bacterium is believed to be one of the bacteria responsible for metabolizing barboloin in the intestine. 157 The mechanism of cathartic action of aloe-emodin-9-anthrone causes a significant increase in water content of the rat large intestine, which has been attributed to its inhibition of rat colonic Na+, K+-adenosine triphosphatase (ATPase) in vitro and an increase in the pericellular permeability across the rat colonic mucosa in vivo. 158 Aloes have also been found effective as antihyperglycemics and hypoglycemics in experimental animals. 159 Aloe has been identified as one of the most commonly used herbal proprietary products. 160

In a comparative analysis of the gels from various Aloe species for wound healing and antifungal properties, A. ferox was found to have the highest antifungal activity, measured as absence of or low percentage of infected wounds. 161 The antifungal activity was positively correlated with gel aloin content. The use of Cape aloe in traditional medicine in Africa as a general tonic and restorative medicine seems to be validated by the scientific evidence of its anti-inflammatory, anticholinesterase, and antioxidant activities, 162 as well as its antimicrobial and wound-healing properties. 163

Alstonia Boonei

Botanical Name — Alstonia boonei de Wild.

Family — Apocynaceae

Common Names — Boone’s, Alstonia, stool wood, pattern wood

African Names — Igbo: egbu; Bini: ukhu; Efik: ukpo; Yoruba: awun

Description — The plant is a large tree commonly found in the drier areas of the lowland and rain forest. It often grows to significant heights (33 m high and 3 m in girth) with a straight and fluted stem and without buttress roots. The bark occurs in commerce as brownish-gray, deeply fissured pieces, with irregular fragments, up to about 1 cm thick. The dark brown bark is fairly rough and flakes off in small patches. A cut through the bark exudes copious white latex, a characteristic of most members of the family Apocynaceae. The latex can be used as a rubber adulterant. The plant is often confused with A. congensis, even in the scientific literature; both plants differ substantially in their appearance and habitat. 164

The leaves of A. boonei are simple, about 20–20 cm long and 5–8 cm broad, appearing in whorls of 5–8 leaves at each node. The individual leaf is glossy, dark green on the upper surface with some bluish tint on the lower surface; it is leathery and smooth to the touch. Leaves are very shortly pointed at the apex and gradually wedge-shaped common stalks at the base. The individual flower is shortly stalked. Flowering occurs between October and March. The fruits (December–March) are borne in follicles of up to 50 cm long, hanging down in pairs from the branches. They are finely hairy and contain numerous elongated seeds about 5 cm long, which bear a tuft of long, silky hairs at each end. When ripe, they split lengthwise. 9,28,33

Habitat and Distribution — It is found in forest fringes, deciduous forest, swampy land. It occurs in Ghana, Nigeria, Angola, Kenya, and southern Sudan.

Ethnomedicinal Uses — The plant is highly prized in African ethnomedicine for the treatment of malaria, especially when the allopathic antimalarial drugs are found ineffective either because of the presence of the drug-resistant malaria infection strains or because of acquired tolerance from repeated dosing with synthetic antimalarials. For this purpose, Alstonia stem bark or leaves are administered as a strong decoction or “teas” and sometimes as an ingredient in malaria “stem therapy.” Alsonia was listed in the British pharmacopoeia of 1914 as an antimalarial drug. The infusion of the bark alone is dispensed as a remedy for snakebite and sometimes for the treatment of arrow poison.

The latex of the plant is smeared on swellings caused by filarial worms and then bandaged with the crushed bark of the ordeal tree (Erythrophleum guineense) for cure. 81 The plant has also been reported to be an astringent, an alterative tonic, and a febrifuge for relapsing fevers; it has been claimed to be useful in muscle tone after debilitating fevers. 165 The leaves and latex are used topically to reduce swellings and for the treatment of rheumatic pains. The latex has also been used to stimulate lactation. A decoction of the bark is taken after childbirth to facilitate the expulsion of the placenta. 123 Extracts of Alstonia boonei have been employed in folk medicine for the treatment of muscular pains, spasms, and hypertension. The plant has also been dispensed as an emmenagogue, astringent, galactagogue, and anthelmintic. 166

Constituents — The plants contain several indole alkaloids, including echitamine, echitamidine, akuammidine, picraline, quebrachidine and its esters, vincamajine, alstonine, and akuammiline. 167 The triterpenes β-amyrine and lupeol have been reported as occurring in the bark and ursolic acid in the leaves. 168

Pharmacological Studies — The extracts of Alstonia have been shown to have antipyretic, analgesic, and anti-inflammatory activity. Echitamine, one of the major constituents of A. boonei, has been reported as being able to lower carotid pressure and increase renal output. 169 This finding was corroborated by later using hypertensive cats; it was observed that the compound caused a significant fall in blood pressure. 170 In a later investigation, however, it was observed that the hypotensive effect of the compound occurred only occasionally after a first intravenous injection of 6 mg/kg, and it was suggested that the diuretic action on saline-loaded dogs and cats may explain the hypotensive action. 171 The same investigators reported the effect of the triterpene ursolic acid, hitherto considered an inert compound, on the electrolytic balance. They established that a dose of 3 mg produced sodium retention in suprarenalectomized rats equivalent to that of 3 g DOCA (deoxycortisone acetate) and considerably higher potassium retention. They also reported that echitamine in particular potentiated the barbiturate sleeping time of mice and rats and enhanced the lethality of strychnine; on an isolated toad rectus abdominis preparation, increased concentrations of acetylcholine enhanced its action, whereas in isolated rat hemidiaphragm, its action was reversed by physostigmine. Echitamine also regressed methylcholanthrene-induced fibrosarcoma by 80% and 53% in Wistar rats at doses of 7.5 and 5 mg/kg, respectively, when given subcutaneously. The compound also showed activity against p-388 lymphocytic leukemia at a dose of 16 mg/kg. 172

The antipyretic and antihypertensive activity of the drug has been experimentally shown to be due (at least partly) to echitamine. 173,174 Although Alstonia has enjoyed a folk reputation in three continents as a remedy for malaria, there is apparently no laboratory evidence to confirm its efficacy. An alkaloid-rich extract obtained from the New Guinea species was found to significantly inhibit (in vitro) the growth of W-2 and D-6 clones of Plasmodium falciparum. 175 An in vivo antimalarial evaluation of extracts of A. scholariss showed no significant activity. 176 An evaluation of A. congensis in Nigeria showed that the methanol of the species suppressed early infection chloroquine- sensitive Plasmodium berghei in mice but had no effect when infection was already established. 177 A combination therapy with Khaya ivorensis has been found to be effective in malaria prophylaxis. 178 The herbal mixture, when given to mice subjected to the 14-day repeated-dose toxicity test (subacute toxicity test), did not cause any serious toxicity, such as weight loss, liver or kidney morphological modifications, significant alterations in locomotor activity, or any other sign of illness.

A major component of Alstonia, the indole alkaloid alstonine, has been evaluated for its possible use in the treatment or management of negative symptoms in schizophrenia. Negative symptoms of schizophrenia are particularly problematic due to their deleterious impact on a patient’s social life. The indole alkaloid exhibited an antipsychotic-like profile in mice, as well as anxiolytic properties. Subchronic (but not acute) treatment with alstonine at 0.5 mg/kg (but not 1.0 mg/kg) significantly increased social interaction in mice. Moreover, MK801-induced social withdrawal was completely prevented by sulpiride (10 mg/kg) and alstonine 1.0 mg/kg and was partially prevented by alstonine 0.5 mg/kg. The study indicated that alstonine not only increased social interaction in normal mice but also averted social deficits attributable to negative symptoms of schizophrenia. 179

Anacardium Occidentale (Cashew)

 

Botanical Name — Anacardium occidentale L.

Synonyms — Acajuba occidentalis Gaertn., Cassuvium pomiferum Lam., Anacardium microcarpum Ducke

Family — Anacardiaceae

Common Name — Cashew

African Names — Krio: kushu; Mende: kusui; Temme: e-lil-e-potho; Yoruba: kaju; Hausa: kadinnia; Kanuri (Hausa): kanju; Igbo: kashu

Description — Cashew is a small tree, with leaves that are alternate, simple, entire, obtuse, and borne on short leafstalks. The flowers are abundant, small, and fragrant and are produced in terminal, loose panicles. The enlarged juicy peduncle that bears the nut is known as the “cashew apple.” When ripe, it is of a golden-yellow color and obovate in shape; it has a pleasant, acid flavor and is somewhat astringent. The cashew nut hangs from the end of the cashew apple and is kidney shaped and about 2.5 cm long. It consists of an edible kernel surrounded by two shells. The outer shell is smooth and of a bright brown color. Between the two shells, there is a very caustic oily substance. The cashew kernel is considered to be of high nutritive quality and is covered with a thin reddish-brown skin or testa. 180

Habitat and Distribution — The cashew tree was originally native to Brazil and was later introduced by the Portuguese to Mozambique and then India in the sixteenth century as a means of controlling coastal erosion. It was not until the nineteenth century that plantations were developed, and the tree then spread to a number of other countries in Africa, Asia, and Latin America. The cashew is now distributed throughout the tropics and in parts of the warm subtropics. Cashew processing, using manual techniques, began in India in the first half of the twentieth century, when cashews were exported to the wealthy Western markets, particularly the United States.

Ethnomedicinal Uses — All parts of the tree are used in traditional medicine. Cashew leaves are used extensively in traditional medicine for the treatment of fevers, skin disease, diabetes, and hypertension. The fresh juice from the fruit is effective for the treatment of syphilis, cholera, and kidney disease and is antiscorbutic, astringent, and diuretic. Root infusion is an excellent purgative. The stem bark is astringent, counterirritating, rubefacient, and vesicant and is used for ulcers. Cashew nut shell oil is antihypertensive and purgative; it is used for blood sugar problems, kidney diseases, cholera, cracks on the soles of feet, hookworms, corns, and warts. The kernel is a demulcent and an emollient and is used for diarrhea. The resinous juice of seeds is used for mental derangement, heart palpitation, and rheumatism. A gum exudes from the trunk and repels insects. An extract of the pericarp and nut is used to treat wood to give complete protection against beetles. Cashew syrup is a good remedy for coughs and colds. Cashew apple juice is said to be effective for the treatment of syphilis.

Constituents — Cashew elaborates a complex mixture of compounds in different parts of the plant. The kernel testa (skin) is reported to contain huge amounts of tannin, and the tannin extracted from cashew kernel testa is used in the leather industry. The juice of the cashew apple is rich in riboflavin (vitamin B2), ascorbic acid (vitamin C), and calcium. The nutrient composition of the cashew fruit apple is as follows:

  Composition of Cashew Apples

Moisture

86.1 (g/100 g)

Proteins

0.8 (g/100 g)

Fat

0.2 (g/100 g)

Carbohydrate

12.6 (g/100 g)

Fiber

0.6 (g/100 g)

Ash

0.3 (g/100 g)

Ca

0.2 (mg/100 g)

P

19.0 (mg/100 g)

Fe

0.4 (mg/100 g)

Vitamin B1

0.2 (thiamine mg/100 g)

Vitamin B2

0.2 (riboflavin mg/100 g)

Niacin

0.5 (mg/100 g)

Vitamin C

200 (mg/100 g)

The seed contains 21% protein and 35–45% oil. The oil contains 60–74% oleic acid and 20–8% linoleic acid. Cashew nut shell liquid (CNSL) contains 90% anacardic acid (C22H32O3) and 10% cardol (C32H27O4). It also yields glycerides; linoleic, palmitic, stearic, and lignoceric acids; and sitosterol. Other constituents include anarcardol, cardanol, quercetin, and kaempferol glycosides. The presence of the phenolic lipids related to anacardic acid in cashew is of immense industrial and therapeutic importance. The testa contains α-catechin, β-sitosterol, and 1-epicatechin, as well as proanthocyanidin leucocyanidin and leucopelargonidin. The dark color of the nut is due to an iron-polyphenol complex. The oil content of the shell ranges from 16.6% to 32.9%, of the kernel from 34.5% to 46.8%. Reducing sugars range from 0.9% to 3.2%, nonreducing sugars from 1.3% to 5.8%, total sugars from 2.4% to 8.7%, and starch from 4.7% to 11.2%. Gum exudates contain arabinose, galactose, rhamnose, and xylose.

Pharmacological Studies — The pharmacological properties of cashew are usually classified according to the plant part of interest. Leaves derive their activity due to the presence of flavonoid glycosides. The leaves have been shown to be effective antimicrobial agents. 181 The so-called cashew apple contains nutrients that play health restorative roles. The most active components of cashew are in the oils obtained from the shell. Anarcadic acid has been shown to possess broad-spectrum activity against various bacteria, fungi, and algae 182 and has proved useful in treating tooth abscesses. Perhaps of greater importance is its potentiating effect on antibiotics used for the treatment of drug-resistant Gram-positive and Gram-negative bacteria. 183 It has also been shown to possess insecticidal and molluscicidal activities, as well as enzyme inhibition with potential application in certain cancers. 184

Toxicity — Some persons are allergic to raw cashew nuts and cardol and anacardic acid in CNSL. Other proteins have been identified as contributing to the allergic reaction to cashew. Cooking often does not remove or change these proteins. These allergic reactions can be life threatening or even fatal; prompt medical attention is necessary. Care must be taken before cashew products are taken by sensitive individuals. Dermatitis among cashew nut workers has been reported in many countries. During processing, care should be taken to ensure that CNSL does not contaminate the kernels.

Commerce — Cashew is cultivated for the nuts. Botanically, the nut is the fruit; the cashew apple is the swollen, fleshy fruit stalk. The seed kernels are extracted by shelling the roasted nuts. In production areas, cashew serves as food. Elsewhere, it forms a delicacy. The nut contains a high-quality oil; the cake remaining after extraction serves as animal feed.

Value-Added Products from Cashew

Cashew kernels are used worldwide as a snack, but most of the exports from Africa are raw cashew kernels sent to India and Europe for processing. Various diversified products can be obtained from the raw cashew kernels with minimum product development. Value addition through minimum processing can substantially enhance the economy of cashew production as follows:

  1. Cashew Kernel Flour: The low-grade kernels, which can neither be exported nor sold in the domestic market, are made into cashew flour, which is highly proteinaceous and is easily digested. It is an excellent supplement to usual wheat flour.
  2. Cashew Kernel Oil (“Caribbean Oil”): The kernel contains 35–40% oil, 1137 which can be used as a substitute for imported olive oil. As in the case of cashew kernel flour, lower-grade kernels are also used to extract kernel oil, which is comparable with olive oil in its healthy and nutritious properties.
  3. Cashew Kernel Butter: The residue of the kernel after oil extraction is used to produce cashew kernel butter, which can be used as a substitute for peanut butter. The oil-expelled kernel can also be processed into cashew nut cake, which can be used as animal feed.
  4. Cashew Kernel Milk: Sweetened and flavored cashew milk can be prepared from cashew baby bits.
  5. Cashew Spread: Baby bits and other nonwhole seeds can be used to prepare cashew spread, which can be sweetened with various flavors. (Adapted from Prabhakaran. 1137 )

Agriculture — Nigeria was the world’s largest producer of cashew nuts with shell in 2010. Most of the cashew nuts produced in Africa are still exported as raw nuts. Propagation is generally by seeds but may be vegetative from grafting, air layering, or inarching. Cashew germinates slowly and poorly; several nuts are usually planted in the hole and thinned later. Plantings are better done in situ as cashew seedlings do not transplant easily. Recommended spacing is 10 × 10 m, thinned to 20 × 20 m after about 10 years, with maximum planting of 250 trees/ha. Once established, a field needs little care. Intercropping is common and may be done the first few years, with cotton, peanut, or yams. Fruits are produced after 3 years, during which lower branches and suckers are removed. Full production is attained by the 10th year, and a tree continues to bear until it is about 30 years old. In dry areas, such as Tanzania, flowering occurs in the dry season, and fruits mature in 2–3 months. Flowers and fruits in various degrees of development are often present in the same panicle. From the flowering stage to ripe fruit requires about 3 months. Mature fruit falls to the ground, where the “apple” dries away. In wet weather, they are gathered each day and dried for 1–3 days. Mechanical means for shelling have been unsuccessful, so hand labor is required. Cashews are usually roasted in the shell (to make it brittle and the oil less blistering), cracked, and the nuts removed and vacuum packed. 185

Andrographis Paniculata

 

Botanical Name — Andrographis paniculata (Burm.f.) Nees

Synonym — Andrographis paniculata var. glandulosa Trimen

Family — Acanthaceae

Common Names — Andrographis, green chirayta, creat, king of bitters, India echinacea, Kalmegh or Kalamegha

Description — Andrographis paniculatais is an erect herb that grows to a height of 30–110 cm. The slender stem is dark green, squared in cross section with longitudinal furrows and wings along the angles. The lance-shaped leaves have hairless blades measuring up to 8 cm long by 2.5 wide. The small flowers are borne in spreading racemes. The fruit is a capsule around 2 cm long and a few millimeters wide. It contains many yellow-brown seeds (Wikipedia). 1138

Habitat and Distribution — A. paniculata is often found in moist, shady places in a variety of habitats, such as plains, hillsides, coastlines, and disturbed and cultivated areas such as roadsides, farms, and wastelands. Native populations of A. paniculata are spread throughout Asia, especially China, India, and Sri Lanka. The herb has only been identified in Africa as occurring in Kaduna and other northern parts of Nigeria. It may be an introduced species as it is not widely known in the country.

Ethnomedicinal Uses — Andrographis paniculatais is used in traditional medicine for the treatment of many ailments. It has been used as an antibacterial, antifungal, antidiabetic, antihypercholesterolemic, and antiviral agent. The leaves are used in Nigeria for the management of hypertension. 186 In the Indian subcontinent, it is used as an immunostimulant, for hypertension, and for cold and colic pains in children; it is a diuretic, an emmenagogue, an astringent, an emollient, a gastric and liver tonic, an antipyretic, and a “blood purifier.” It is recommended in the Indian traditional system of medicine for gonorrhea, leprosy, boils and skin eruptions, scabies, and chronic and seasonal fevers because of its supposedly blood-purifying properties. 187

In China, the herb known as Chuanxinlian, Yijianxi, or Lanhelian is described as bitter and cold and is used as an antipyretic, detoxicant, and anti-inflammatory and is thought to remove “pathogenic heat” from the blood. A. paniculata is used for the treatment of pharyngolaryngitis, diarrhea, dysentery, cough with thick sputum, carbuncle, sores, and snakebites. Various preparations and compound formulas of the herb have been used to treat infectious and noninfectious diseases, with significant effective rates reported for conditions such as epidemic encephalitis B, suppurative otitis media, neonatal subcutaneous annular ulcer, vaginitis, cervical erosion, pelvic inflammation, herpes zoster, chicken pox, mumps, neurodermatitis, eczema, and burns. 188

Constituents — A. paniculata contains diterpenes, diterpene-glycosides, lactones, and flavonoids. The main active chemical constituent is the diterpene lactone andrographolide, a colorless, crystalline substance with a very bitter taste. Andrographolide is considered a marker compound for the identification of this herb. Another bitter principle isolated from the leaves is a compound called kalmeghin. Flavonoids occur in the roots and leaves. The aerial parts contain alkanes, ketones, and aldehydes. Chinese investigators isolated five lactones—chuanxinlian, deoxyandrographolide, andrographolide, neoandrographolide, and 14-deoxy-11,12-didehydroandrographolide—from the aerial parts of the plant. A diterpene glucoside (deoxyandrographolide-19-beta-D-glucoside) has been detected in the leaves, and six diterpenoids of the ent-labdane type, two diterpene glucosides and four diterpene dimers (bis-andrographolides A, B, C, and D), have also been isolated from aerial parts. Two flavonoids identified as 5,7,2′,3′-tetramethoxyflavanone and 5-hydroxy-7,2′,3′-trimethoxy flavone were isolated from the whole plant. Previous reports indicated that 12 flavonoids and 14 diterpenoids have been isolated from the aerial parts of the plant in China. 189,190

Pharmacological Studies — Andrographis paniculata extracts and isolates are known to possess a variety of pharmacological activities and have been tested against a variety of biological systems to correlate the observed traditional uses with evidence from laboratory and clinical studies. They exhibit antipyretic, antiinflammatory, antimalarial, antihepatotoxic, antityphoid, antihypertensive, and antifungal activities. Their use as a general immunostimulant agent has also been the subject of many investigations. A study conducted at Bastyr University (USA) showed a significant rise in the mean CD4 lymphocyte level of HIV subjects after administration of 10 mg/kg andrographolide, the main constituent extracted from the leaves of the plant. 191 In another study conducted on the cellular processes and targets modulated by andrographolide treatment in human cancer and immune cells, andrographolide treatment inhibited the in vitro proliferation of different tumor cell lines, representing various types of cancers. The compound exerts direct anticancer activity on cancer cells by cell cycle arrest at the G0/G1 phase through induction of cell cycle inhibitory protein and decreased expression of cyclin-dependent kinase 4 (CDK4). Immunostimulatory activity of andrographolide is evidenced by increased proliferation of lymphocytes and production of interleukin 2. Andrographolide also enhanced the tumor necrosis factor alpha (TNF-α) production and CD marker expression, resulting in increased cytotoxic activity of lymphocytes against cancer cells, which may contribute to its indirect anticancer activity.

Antioxidant and anti-inflammatory activities of A. paniculata and its constituents have been validated in several experimental models. For example, in nicotine-induced inhibition of mitochondrial electron chain complexes, the resultant increase in nitric oxide (NO) in different parts of rats’ brains was prevented by simultaneous treatment with the water and ethanol extracts of A. paniculata or andrographolide; the water extract exhibited greater antioxidant activity than the ethanol extract. 192 The antioxidant activity of the aqueous extract on liver defense systems in lymphoma-bearing AKR mice has also been investigated. The aqueous extract significantly increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase enzymes and reduced lactate dehydrogenase activity. 193 A methanol extract inhibited formation of reactive oxygen species (ROS) in vitro and completely inhibited carrageenan-induced inflammation. Andrographolide pretreatment significantly attenuates accumulation of phorbol-12 myristate-13-acetate (PMA)-induced formation of ROS and N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced adhesion of rat neutrophils. 194 A double-blind, placebo-controlled study has shown that the king of bitters also had a reproducible effect on rheumathoid arthritis. 195

The antihyperglycemic and hypoglycemic properties of A. paniculata have been invesigated in several animal models and controlled clinical studies. It appears that the water extract does not exert any hypoglycemic effect on nondiabetic animals, whereas the methanolic extract and andrographolide showed reduction in serum glucose of both diabetic and normal laboratory animals. Chronic administration of the extract for 6 weeks showed no effect on the fasting blood glucose level but significantly prevented orally administered glucose-induced hyperglycemia in nondiabetic rabbits without affecting epinephrine-induced hyperglycemia. However, in chemically induced diabetic laboratory animals, it significantly reduced the serum blood sugar levels. 187 It has been suggested that the hypoglycemic effect of A. paniculata may be due to insulin release from pancreatic β-cells through ATP (adenosine triphosphate)-sensitive potassium channels, similar to other insulinotropic antidiabetic agents. In vitro experiments indicated that inhibition of alpha-glucosidase and alpha-amylase enzyme could be the mechanism by which the ethanol extract of A. paniculata and andrographolide produce a hypoglycemic effect. It is highly possible that the hypoglycemic and antihyperglycemic activities of the extract and andrographolide may involve different mechanisms in normal and diabetic conditions. Water extract seems to be a more suitable candidate for use as a dietary supplement as it does not affect fasting blood glucose levels of nondiabetic animals.

For its use in the treatment of hypertension, A. paniculata aqueous extract produced a dose-dependent fall in systolic blood pressure of both spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats, with a corresponding significant decrease in plasma angiotensin-converting enzyme (ACE) activity and lipid peroxidation in kidneys in extract-treated SHRs. It was also observed that the decreases in ACE activity and lipid peroxidation were not significantly altered in normotensive Wistar-Kyoto rats, which suggests that the hypotensive effect in hypertensive and normotensive rats is not mediated through identical mechanisms. 187,196 Other studies have supported this observation and validated the use of the aqueous extracts of Andrographis in the treatment of cardiac insufficiency and myocardial ischemic-reperfusion injury.

On reproductive systems, the current evidence suggests that A. paniculata affects the productive system in both male and female animals, but the results are too inconsistent, with some findings directly contradicting others, to reach any definitive conclusion about the reproductive effects of A. paniculata and its possible role in human fertility.

Toxicity — Andrographis is well tolerated in mild doses, and no acute toxicity has been reported in clinical studies. The LD50 of the alcohol extract and andrographolide is 1.8 g/kg and 11.46 g/kg in mice, respectively. In a study of HIV-positive patients, a dose of 1500–2000 mg of andrographolides was given daily for 6 weeks. Side effects led to the early discontinuation of the study despite some improvements in CD4+ counts. Because of the inconsistency in the effect on the reproductive system, it would be advisable for both men and women to avoid this herb during desired conception and for women during pregnancy. Concurrent use of A. paniculata with a prescription should be carefully monitored because of reports of possible drug-herb interaction. It was found that some of the components of A. paniculata interact with theophylline and retard its elimination when theophylline was administered at a high dose. The study suggested that patients who want to use CYP1A2-metabolized drugs such as caffeine and theophylline should be advised of the potential herb-drug interaction to reduce therapeutic failure or increased toxicity of conventional drug therapy. 197

Commerce — Andrographis paniculata is a global article of commerce. The whole drug and isolated compounds are used in the production of many proprietary phytomedicines.

Agriculture — The plant is not cultivated commercially in Africa. A successful trial cultivation of A. paniculata was done in the Bioresources Institute of Nigeria in collaboration with the Natural Remedies Company of India. It was found that the Nigerian cultivar had a good yield of andrographolide, which suggests that the crop can be grown commercially in Africa.

Anthocleista Nobilis

 

Botanical Name — Anthocleista nobilis G. Don

Synonyms — A. parviflora Baker., A. macrophylla G. Don

Family — Gentianaceae

Common Names — Carbage tree, cabbage palm

African Names — Fante: hororoho; Twi (Ashanti): awudifoakete, bontodi

Description — Anthocleista nobilis is a tall tree, growing up to 20 m high, 50–90 cm wide. The bark is light gray and smooth, with the bole free of branches for up to 15 m nestled with a small crown with ascending hollow branches. It has a cream-yellow and granular slash. The leaf axils accommodate twigs with two divergent spines. The leaves appear to be crowded at the apices of the branchlets, opposite, subequal, sessile, or shortly petiolate. An FAO monograph of this species showed that the petioles are up to one-sixth as long as the blade; the blade is oblong elliptic, obovate-elliptic, or obloncheolate, up to 6.5–12 cm long, 4–12 cm wide, larger on young trees, discolorous, dark green above, glaucous below. 33 It produces erect hermaphrodite flowers, with branched, terminal cymes, 12–16 cm long, borne on conspicuously long peduncles with the stamens attached to the corolla tube and protruding. Fruits occur as dark brown ellipsoid berries 2–2.5 cm in diameter with persistent calyx and contain many seeds. The plant appears to produce flowers most times of the year. 9,28,33

Habitat and Distribution — Anthocleista inhabits transitional and secondary forests. It can be found dotted in semidecidous forests and semisavanna regions. It is reported as preferring well-drained soils, a rainfall of between 1100 and 2000 mm a year, and a temperature not exceeding 35°C. It generally prefers low-lying ground not exceeding 300 m above sea level but can occur up to 1200 m. 37 It occurs in the West Coast in Senegal, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Cameroon, and Nigeria.

Ethnomedicinal Uses — It is a common ingredient in several traditional remedies in Gabon and neighboring regions of West Africa. 198 The bark is dispensed in Nigeria and Ghana as an antimicrobial agent for the treatment of venereal diseases. The bark is used as a mixture with those of Bosqueia angolensis and Spathodea campanulata as a weak decoction once a week as an antifertility agent. The preparation can also be administered as an enema. In the Ivory Coast, it is prescribed as a purgative. 199 The genus is reputed to have antidiabetic activity. In Ghana, the bark is boiled with water and the liquid extract taken once a day for the cure of piles, intestinal and abdominal troubles, and worms. 33 The same prescription, sometimes mixed with the bark of Morinda lucida, is drunk as a purgative for jaundice in Akwapim. The root bark mixed with red pepper, ginger, and guinea grain (Piper) is used by the Fanti as an enema for the management of hernia. In the Central African Republic, the roots steeped and mixed with guinea grain and pepper are used for the treatment of hemorrhoids, and an infusion of the stem bark after exposure to the sun in an open bottle is used for gonorrhea. In the same region, the bark decoction is used as a enema and a sitz bath for colic and stomach troubles, and the pulped bark is applied per rectum to children as an anthelmintic. The bark decoction is drunk or used in a bath and vapor bath as an antidote to poisoning and also for leprosy, gonorrhea, or menstrual troubles or as a purgative. 33 In Sierra Leone, the plant features extensively in the treatment of gynecological problems; the leaf decoction is taken with lemon for abdominal pains of uterine origin. 6 It is an ingredient for the preparation of a long-term contraceptive. The decoction of the leaves with lemon is also used in Ghana for the treatment of epilepsy. A related species, A. djalonensis, is used in folk medicine for the same indications as listed in Irvine. 9

Constituents — The bark contains indole alkaloids similar to brucine. 200 The genus yields a bitter monoterpene heteroside swertiamaroside or swertiamarin.

Pharmacological Studies — The alcoholic extract of the root has been shown to possess antidiabetic effects. 33 It has been suggested that the hypotensive and hypoglycemic activity of the plant may be valuable in the clinical management of obese adults with secondary hypertension. 200

Toxicity — Cases of accidental poisonings have been reported, and the symptoms include colic, obstinate constipation, pronounced pallor, and heart weakness. 199

Areca Cathechu

 

Botanical Name — Areca cathechu L.

Synonyms — Areca faufel Gaertn., Areca himalayana Griff. ex H. Wendl., Areca hortensis Lour., Areca nigra Giseke ex H. Wendl.

Family — Arecaceae

Common Names — Betel nuts, Arecae semen, Arekasame, noix d’arec

Description — Areca fruit is ovoid, bright orange in color when fully ripe, and about 3 to 5 cm in diameter and 6 to 8 cm long. The nut consists of a hard kernel, grayish brown in color with a network of paler depressed lines and a deep testa showing fawn marbling. It is slightly acidic in taste and astringent, and the odor is faint. The plant itself grows as an erect, rather graceful palm with a slender, tall stem crowned by a tuft of the large ornately ordered leaves.

Habitat and Distribution — The plant is pantropic and prefers dry deciduous forestland. It is indigenous to East and North Africa, Malaysia, the Philippines, Indonesia, Sri Lanka, and India. It is cultivated in many tropical countries for its valuable nuts. It grows in the savanna belt and in deciduous forests and secondary clearings. It is a major crop in North Africa and parts of South Africa.

Ethnomedicinal Uses — It is used as a masticatory agent and tonic in most parts of Africa. Areca chewing custom appears to be almost universal among traditional societies, such as in Papua New Guinea, Melanesia, and many Asian countries. It is an effective anthelmintic, laxative, and astringent. Although there is a decline in the use of the nut in human medicine, there has been a renewed interest in the drug due to the beneficial effects of arecoline in the treatment of AD. 201 In India, the nut is dispensed for infections, urinary diseases, vaginal disorders, and heartburn in pregnancy. 166

Constituents — The principal compound in Areca nuts is the alkaloid arecoline, accounting for 0.5% of the plant material. Other constituents include guvacoline, arecaine, arecaidine, guvacine, and several other amino acids, as well as phlobaphene tannins, fixed oils, and procyanidins (PACs).

Pharmacological Studies — Areca is a taeniacide, and it is employed often in veterinary medicine, where it is used for the eradication of roundworms and the tapeworms. Chewing the nuts as a masticatory is said to act as a tonic; it refreshes the breath and removes unpleasant tastes, strengthens the gum, and checks perspiration. 166 Areca chewing promotes the flow of saliva, and this habit has been associated with the increased incidence of some types of oral leukoplakia and cancer. The quids are often composed of areca, lime, and occasionally tobacco leaf or “snuff.” The carcinogenic principle in Areca is probably the alkaloid arecaidine. 202 Two of the components of Areca, guvacine and arecaidine, have been found to possess competitive inhibition of γ-aminobutyric acid in vitro. 203 Areca nuts possess CNS activity, and the use of these nuts can be addictive; the development of severe pyramidal symptoms has been reported in two chronic schizophrenics after chewing betel nuts. 204

Arecoline, methyl-1,2,5,6-tetrahydro-1-methylnicotinate, is the major anthelmintic alkaloid isolated from betel nuts. It has parasympathomimetic activity and has been employed sometimes as a substitute for pilocarpine. It is a strong taeniafuge, but lacks pronounced taeniacidal activity, and has been commonly used in veterinary medicine as a purgative and taeniafuge. It has been used extensively in many countries to control infestation of Echinococcosis granulosum in dogs.

Artemisia Afra

Botanical Name — Artemisia afra Jacq. ex Wild.

Synonyms — Absinthium ponticum (L.) Garsault., Absinthium tenuifolium Gaterau., Artemisia altaica Desf., Artimisia balsamita Willd., Artemisia grandiflora Fisch. ex Herder., Artemisia pallida Salisb., Artemisia pontica Burm.f., Artemisia pseudopontica Schur., Artemisia tenuifolia Moench.

Family — Compositae

Common Names — Als, wild-als, wild wormwood, African wormwood

African Names — Kisambaa: fivi; Kinyakyusa: lusanje; Kisafwa: luyanga; Swati: umhlonyane; Tsawana: lengana, iliongana; Xhosa: umhlonyane; Zulu: umhlonyane

Description — The plant is a medium-size perennial herb, rarely exceeding 2 m high. It has a ribbed stem, and the aerial parts have the strong characteristic odor of wormwood; it is much branched and woody, shortly rhizomatous. The leaves are 6 cm long, gray-green, alternately arranged, and oval in shape. It produces pale yellow tubular florets, with few outer female and inner bisexual inflorescence occurring in an elongated racemose panicle. The capitula is small, the receptacle is flat and naked. (achenes cylindrical, pappus absent). The African wormwood flowers between March and July, and the seeds are produced from August to November. 28,33

Habitat and Distribution — According to the FAO report, 33 Artemisia afra is a clump-forming perennial herb of the highland areas of eastern and southern Africa at an altitude between 1500 and 2500 (3000) m. The soils range from volcanic ash, loamy sands, to sandy or calcareous clay loams of volcanic or granitic origin. 33 The plant grows in the southern and eastern regions of the continent. It has been located in Ethiopia, Kenya, Zimbabwe, Malawi, Angola, and the Republic of South Africa.

Ethnomedicinal Uses — A decoction of the leaves is used for the treatment of bronchial diseases. 37 It is a common ingredient for the preparation of remedies for cough, colds, dyspepsia, stomachache, gout, and constipation. In South Africa, a decoction of the leaves and lemongrass is used as an antipyretic and for the treatment of malaria. A fermentation prepared with the heated herb is given to children with a sore throat (Kokwaro). Other uses of the African wormwood include the treatment of indigestion, as an anthelmintic, and as an anti-inflammatory agent. Externally, the plant is used in the treatment of skin infections, as a hot bath in measles, and as a local application for hemorrhoids. In Tanzania, a weak infusion of the leaves is administered for the treatment of colic. 205

Constituents — The plant yields a pleasant-smelling volatile oil, which contains cineole, thujone, umbelliferone, and some polyacetylenes. Earlier reports indicated the probable presence of ceryl cerotate, triacontane, scopoletin, and quebrachitol. 33

Pharmacological Studies — The volatile oil has been shown to be abortifacient when administered per os to rabbits. The extract is known to produce hemophagic nephritis, nonfatty degeneration of the liver, and pulmonary edema. 206 The Asian species, A. annua, has been shown to possess significant activity against multidrug-resistant malaria. 207

Aspalathus Linearis — Rooibos

Botanical Name — Aspalathus linearis (Burm. f.) R. Dahlgren

Synonyms — Aspalathus tenuifolia DC., Prodr.; Aspalathus contaminatum Druce; Aspalathus corymbosa C.A. Mey.; Lebeckia linearis (Burm. f.) DC.; Psoralea linearis Burm. f.

Family — Leguminosae

Common Names — Rooibos, rotbush, aspalathus, Herba Aspalathi, bush tea, bushman, mountain tea, red bush, red bush tea, rooibos tea

African Names — Afrikaans: rooibos; South Africa: koopmanstee, naaldtee rooibostee

Description — Aspalathus linearis has been described as an erect to spreading, highly variable shrub or shrublet up to 2 m high. Its young branches are often reddish. The leaves are green and needle-like, 15–60 mm long and up to about 1 mm thick. They are without stalks and stipules and may be densely clustered. The yellow flowers, which appear in spring to early summer, are solitary or arranged in dense groups at the tips of branches. The fruit is a small, lance-shaped pod, usually containing one or two hard seeds. 1140

Habitat and Distribution — Rooibos is native to South Africa, where it appears to be restricted only in the Cedarberg area and around the villages of Clanwilliam and Citrusdal, which are situated to the north of Cape Town in South Africa. Apparently, rooibos needs a very specific climate and soil to grow and elaborate its characteristic compounds as efforts to cultivate rooibos in other areas or countries with similar climates have not been very successful.

Ethnomedicinal Uses — Aspalathus linearis is a major South African medicinal plant and has been used in the Cape region of that country for centuries. Its main uses in South African traditional medicine include alleviating infantile colic, allergies, asthma, and dermatological problems. It has also been used for its anti-inflammatory and antiallergic properties.

Constituents — Rooibos is the only known source of the chalcone aspalathin. Other phytochemicals found include nothofagin, caffeic acid, chrysoeriol, isoquercitrin, orientin, isoorientin, luteolin, vitexin, isovitexin, luteolin, rutin, flavonoids, quercetin, and polyphenols.

Pharmacological Studies — Although reports of double-blind clinical studies with rooibos are scarce in the scientific literature, animal studies suggested it has potent antioxidant, immune-modulating, and chemopreventive effects. Clinical outcome observations have shown that consumption of rooibos tea may relieve fever, asthma, insomnia, colic in infants, and skin disorders. Rooibos extracts are used in ointments against eczema. In South Africa, it is common to give rooibos tea to babies who suffer from stomach cramps (colic).

The presence of quercetin and lutein has been linked to prevention of cardiovascular diseases, some cancers, and stroke and has been supported by in vitro and animal studies. A trial to test the effects of rooibos on various biological markers considered to be indicative of risk for cardiovascular disease and other degenerative diseases has shown that a high intake of rooibos tea resulted in significant reductions in lipid peroxidation, low-density lipoprotein (LDL) cholesterol, and triglycerides and an increase in high-density lipoprotein (HDL) cholesterol levels compared with the control group. The investigators concluded that rooibos lowered risk factors associated with degenerative heart diseases. 208 Rutin has been associated with the maintenance of blood vessel walls. The low level of tannins in rooibos is believed to prevent problems with iron absorption associated with some tannin-rich herbal teas. Some trade journal publications have suggested that rooibos extracts from fermented rooibos leaves could reduce cancerous transformation of mouse cells irradiated with X-rays, but extracts from unfermented green rooibos tea did not show this protective effect.

According to entries in the Internet free encyclopedia, Wikipedia, rooibos is purported to assist with nervous tension, allergies, and digestive problems. Rooibos tea has been shown to inhibit in vitro activity of xanthine oxidase (XO), yet an in vivo study has not been conducted. XO plays a role in conversion of purine to uric acid in humans, and reducing the activity of XO could limit uric acid production, which would aid in treatment of gout.

Toxicity — Rooibos is generally considered as nontoxic, but a recent report identified a possible case of hepatotoxicity due to rooibos consumption. 209 However, it has been suggested that it was possible that the tea may have been contaminated by another hepatotoxic compound or that the person may have had a genetic predisposition to react negatively to any one of the other bioactive properties found in the tea.

Commerce — Rooibos is a major herbal tea from South Africa. A trade controversy surrounding the name Rooibos became a case study on the possible abuse of intellectual property rights to gain an illegal monopoly. In 1994, Burke International obtained a patent from the U.S. Patent and Trademark Office for the use of the name Rooibos, which gave the company a monopoly on the use of the name in America at a time when it was virtually unknown in America. When the plant later entered more widespread use, Burke demanded that companies either pay fees for use of the name or cease its use. In 2005, the American Herbal Products Association and a number of import companies succeeded in challenging the trademark through petitions and lawsuits, and after losing one of the cases, Burke surrendered the name to the public domain. 210 However, it is interesting that South Africa has a legal framework for the protection and restriction of commercial use of the name Rooibos in that country. It has drawn parallel inferences to similar legislation that already exists in Europe (for the protection of the names Champagne and Port, for example). This is despite Rooibos South Africa’s decision to contest the Burke trademark on the grounds that rooibos is a generic term, rather than claiming it as a geographic indication. 211

Agriculture — Attempts to grow Aspalathus linearis outside its natural home in South Africa have not been successful. PROTA4U 1140 outlined the following methodology: The seeds must first be scarified and then planted in acid, sandy soils. The local rooibos tea management board supplies seeds that have been treated and germinate easily. They are planted in seedbeds in March to a depth of 5–10 cm and are ready for planting out by July. Plants are generally rainfall dependent but prefer not to be too wet. No fertilizing is required, and the plants grow quite well in nutrient-poor conditions. Seedlings are transferred to plantations. It takes 12–18 months before the shrubs are ready to be harvested. They are harvested once each year, from December through April for a period up to 5 years. They are then pulled out, and new plants are planted. The basic method of rooibos harvesting has remained largely the same as the process used centuries ago. An environmentally friendly way of harvesting tea is used that involves cutting only the young branches. Once they are cut, they are neatly bound and transported to the process yards. The older branches are left on the tree, and the bushes become slightly taller every year. The tea cuttings are chopped very fine and then bruised to ensure that the important chemical reaction that develops the characteristic color and flavor of the tea can take place. After watering and airing, the tea is left to “sweat” in heaps, and it is at this point that the tea acquires its typical reddish-brown color and develops its sweet flavor. After the sweating process has been completed, it is spread out in a large drying yard to dry in the sun. The rest of the process involves sorting and grading the tea according to length, color, and flavor. The finished rooibos is finally weighed, bagged, and sold to companies that pack the product in either teabags or in loose-leaf form under their own brand names. 1140

Asparagus Africanus

Botanical Name — Asparagus africanus Lam.

Synonyms — Protasparagus africanus (Lam.) Oberm.

Family — Asparagaceae

African Names — Bambara: sogoba kenessi; Falor: simboul; Fulani: pelol fouru, nombo; Ga: adende, enene; Hausa: sark’a, sansarin kura; Malinke: inaniaga; Mende: ningei; Tukulor: narari; Wolof: narara; Yoruba:aluki, kadankobe

Description — The plant is a member of the plant subfamily Asparagae (Liliaceae). It is a tall, climbing undershrub, with wiry stem and small white fragrant flowers. 212

Habitat and Distribution — Members of the genus grow in the savanna and deciduous forest zones of West Africa and parts of East Africa. It is distributed from Guinea to Kenya.

Ethnomedicinal Uses — Several species of Asparagus yield edible fruits or leaves. The cladodes (leaves) are used as an external application when crushed to stimulate hair growth in women. In Sudan, the plant is administered for diuresis and as a remedy for syphilis. It has also been used as a poultice for the treatment of swellings and guinea worm sores and internally as a remedy for hematuria.

Constituents — Saponins, named A4–A8, have been isolated from the roots of A. racemosus. One of the saponins, A4, yields glucose and rhamnose on hydrolysis with acid sarsapogenin. 213

Pharmacological Uses — The root extracts of the related Racemosus have been shown to possess cardiotonic and antioxytocic effects. 214,215 The plant exhibited an inhibitory effect against Entamoeba histolytica 218 and showed galactogogue effects, which were accompanied by an increase in weight of the mammary glands in rats 219 as well as in buffaloes. 114 Dhar et al. reported the in vitro activity of extracts of the plant against human epidermal carcinoma of the nasopharynx. 216

An aqueous extract of the root has been shown by Thatte and Dhanukar to exert immunotherapeutic effects in diverse experimental infections. 217 It was found that the extract protected rats against mortality induced by intra-abdominal sepsis following cecal ligation. In the animals treated with the extract, only 27.2% mortality occurred compared to 66–100% recorded for the untreated group on the 5th day. The extract and the serum from rats treated with A. racemosus were devoid of any in vitro antimicrobial activity, which indicated that the mechanism of protection against mortality induced by cecal ligation was not mediated through a direct antibacterial activity. 213 The extract also significantly reduced mortality due to E. coli-induced peritonitis in mice. 213

A. racemosus extract abolished neutropenia produced by a single dose (200 mg/kg s.c.) of cyclophosphamide (a known myelosuppressive agent) and compared favorably with the effects of lithium carbonate and glucan in checking the myelosuppressive effects of both single and multiple doses of cyclophosphamide. 218 The test substances produced leukocytosis with a predominant neutrophilia and prevented the cyclophosphamide-induced leukopenia. It has also been reported that the extract of the plant improved macrophage function and reduced stress-induced gastric vascular damage. 219 In mice with hemisplenectomy, A. racemosus significantly reduced the mortality, 219 (28% vs. 100% in controls) due to E. coli-induced sepsis.

Clinical Properties — Asparagus racemosus is used in Indian medicine for the treatment of dysentery, inflammation, biliousness, epilepsy, and ophthalmic diseases. Animal studies, summarized previously, showed that the drug exerts its activity at least in part due to its immunostimulant property.

Astragalus Gummifer

Botanical Name — Astragalus gummifer Lab.

Synonyms — A. strobiliferus Royle, A. erianthus Willd., A. adpressus Ehrenb. ex Walp, A. noemiae Eig. var. brantii Eig.

Family — Leguminosae

Common Name — Tragacanth tree

African Names — Arabic: shagal et ketira; Tuareg: adrilel.

Description — Astragalus species occur as thorny shrubs. A. gummifer is an umbellate shrub with leaves composed of thorny rachis with 4–7 pairs mucronated and smooth leaflets. The flowers are borne in clusters of two or three at the axils of the leaves. 9

Habitat and Distribution — Plants are found in steppe pastoral land and dry highlands up to an altitude of 1800 m in the Sahel region. The species occurs in Sudan, Niger, Chad, and the Kano Emirate of Nigeria.

Ethnomedicinal Studies — The plant is employed in folk medicine as a laxative. The leaves are used in the preparation of a wound-healing lotion. Tragacanth is the source of the pharmaceutical suspending agent tragacanth gum.

Constituents — The gum consists of a water-soluble polysaccharide portion known as bassorin. Tragacanthin is made up of an arabinogalactan, tragacanthic acid, and alcohol and has a high molecular weight (<800,000). The high-quality gums contain less tragacanthin. 220 Tragacanthin yields on hydrolysis D-galacturonic, D-galactopyranose, L-fucose, D-xylopyranose, and L-arabofuranose. The gum also contains trace amounts of amino acids and their derivatives.

Pharmacological Studies — The polysaccharides from A. gummifer have been shown to have stimulatory activity on phagocytosis and to increase the plasma cell counts of T-lymphocytes. 123 Tragacanth has also been found active against a variety of experimental tumors. 221 Mice pretreated with extracts of the plant showed a reduction in the number of positive “takes” of translated Erlich ascites cells. 221

A fraction of the aqueous extract of A. membranaceous roots, with molecular weight of 20,000– 25,000, has been shown to exert complete immune restoration of local xenogeneic graft-versus-host reaction (XGVHR) in cancer patients. 222 The in vitro immunomodulatory activity of the fractions of A. membranaceus was first determined from their effects on mononuclear cells (MNCs) derived from healthy normal donors using the local XGVHR test system. 223 The extracts of MNCs derived from 13 cancer patients induced a significant increase in local XGVHR when compared to untreated MNCs derived from normal donor controls with the relative index (ratios) of 1.60 ± 0.48 and 1.23 ± 0.17, respectively (p < 0.005). 226 Chu and his colleagues also found that when the active fraction was injected intravenously into phosphamide-primed rats at various concentrations prior to grafting of MNCs from healthy donors, maximum abrogation of the local XGVHR mounted by the MNCs was observed. 225

It was shown that the reversal of the cyclophosphamide-induced immunosuppression by the administration of the active fraction of the plant drug was complete since the volume of the abrogated local XGVHR (39.78 ± 8.3 mm 3 ) was comparable to the value of 34.79 ± 5.69 mm 3 (p > 0.1) in the negative saline control group without cyclophosphate priming. 124

Astragalus membraneceus was also tested on a chemiluminescent oxidative burst system as an indicator of phagocytic function in a murine macrophage cell line J774. 224 The J774 cells were incubated with the aqueous herbal extract for 18 h at 37°C and 5% CO2, and chemiluminescent oxidation was triggered by adding a zymosan. A suspension containing luminol was assayed in an automated luminometer. It was observed that a significant dose-related augmentation of chemiluminescence occurred with the addition of the extract. 228 The drug also potentiates the LAK cell cytotoxicity generated by low-dose recombinant interleukin-2. 225 Extracts of Astragalus are therefore indicated in the treatment of patients suffering from iatrogenic or inherent immune deficiency.

Azadirachta Indica

Botanical Name — Azadirachta indica A. Juss

Synonyms — Melia azadirachta L., M. indica (A. juss) Bandis

Family — Meliaceae

Common Names — Neem, nim, margosa tree, bead tree, holy tree, Indian lilac tree

African Names — Arabic: zanzalacht; Hausa: dogon yaro; Igbo: ogwu akom; Yoruba: aforo-oyinbo

Description — A. indica is a shady tree with an evergreen crown; it grows up to 25 m high in some places but occurs in West Africa mostly as a medium-size tree. It has rough, dark brown bark with wide, shallow longitudinal fissures separated by flat ridges. The bole is short and stout. It is easily confused with Melia azedarach, an Asian tree, which has also been introduced to other tropical parts of the world; references to A. indica in very old literature should be viewed with caution. The leaves are compound, imparipinnate, each comprising 5–15 leaflets; they are very diagnostic and measure about 6 m long and 2 cm broad. The tree bears many flowered panicles, mostly in the leaf axils; sepals are ovate-, sub- or bicullar, about 1 cm long, with sweet-scented white oblanceolate petals. It produces yellow drupes, which are ellipsoid, glabrous, and 12–20 cm long. 9,33

Habitat and Distribution — This is an introduced plant that is now naturalized in Africa. It is widely cultivated throughout West and Central Africa as an ornamental plant. It is a drought-resistant plant and therefore grows well in the arid parts of the continent.

Ethnomedicinal Uses — The plant is used widely in Africa, especially on the West Coast, for the treatment of malaria. It is such a favorite malaria remedy that it is uncommon near homes to see an intact tree without the stem bark scraped for medicinal use. The extracts from neem have been acclaimed as effective in malarial attacks for which the allopathic antimalarial drugs were found ineffective either because of the presence of resistant Plasmodium strains or because of acquired tolerance from repeated dosing with 4- or 8-hydroxyquinoline derivatives and their analogues. The dried flowers are used as a tonic and stomachic and externally for the treatment of chronic eczema and as a fly repellant. A weak infusion of the bark is drunk as an antipyretic and a bitter. There is a limited use of the aqueous decoction of the root as an anthelmintic agent. The seed, which yields an oil of undistinguishable quality with the Indian “margosa oil” (technically the oil from Melia azedarach), is used extensively as an ingredient in the preparation of remedies for hemorrhoids, jaundice, and peptic ulcers. In Bendel State, Nigeria, the fruit juice is said to be useful in the treatment of boils, syphilitic sores, skin diseases, glandular swellings, jaundice, and peptic ulcers. The fruit is also favored as a laxative and for the treatment of urinary diseases, leprosy, and intestinal worm infestation. The stem and root yield bitter but effective chewing sticks.

Azadirachta is a native to India, and it is employed widely in the Indochina region for a variety of medicinal uses and nonmedicinal purposes. Perry 226 indicated that a tincture of the bark is helpful for people with chronic malaria or with jaundice and generalized fatigue and for the treatment of fevers following injuries. It was also stated that the tincture of the leaves gives an aperitif but constipating tonic and a stimulating rub to treat bruises, sprains, or muscular pains (see Der Marderosian and Liberti 127 for other uses of this plant in Asia). A proprietary product, Silvose, containing extract of the bark of Azadirachta is claimed to reduce dental caries and inflammation of the mouth when used as an ingredient in dental preparations. Powdered plant parts and extracts of neem have been incorporated into toothpastes and tooth powders. 227 Infusion or tincture of Azadirachta is listed as a bitter; 205 for this purpose, the usual dose is 15 to 30 ml of 1-in-20 c. infusion, or 4 to 8 ml of a 1-in-15 c. dilutions tincture.

Methods of Preparations, Administration, and Doses — In traditional medical practice, the leaves, stem bark, and root are used for the treatment of malaria in the form of an aqueous decoction. The selected part is usually reduced to small sizes, placed in a suitable container with water, and set aside to macerate for a period ranging from 1 day to several weeks. Portions of the extract are often dispensed as soon as an acceptable brew is achieved, and the marc replenished with freshwater. The average concentration is about 100 ml, taken 2 or 3 times a day for about 2 to 3 days. The drug can also be prepared by macerating the coarsely powdered plant part for a few hours in cold water and using the hand to press out fluid from the marc. In urban areas, the drug is prepared either as a decoction with hot water or as an alcoholic extract.

Complementary to the oral therapy is steam treatment, in which the patient is covered with a thick blanket or cloth and subjected to the vapors from a boiling pot of herbs. Azadirachta is a common ingredient in such hot pot herbs. Other ingredients in the steam therapy include the leaves of Cymbopogon citratus (lemon grass), Psidium guajava (guava), Mangifera indica (mango), and Hyptis suavelens. The drug is used prophylactically once a month in the form of a weak infusion called “neem tea.”

Constituents — All plant parts have been shown to contain some bitter principles, composed of nimbin, nimbidin, nimbinin desacetylnimbin, and structurally related compounds. The seed oil contains about 45% of these bitter substances, the stem bark yields 0.04%, while the fruit pulp and leaves contain about 25%. 228,229 Salannolide, a meliacin with a unique feature by the presence of a hydroxybutenolide side chain in place of the usual furan ring attached at C-17, has been found to be one of the bitter principles of neem seed oil. 230 A number of other nortriterpenoids, meliacins, have also been isolated from the plant. Kraus and his colleagues have reported the presence of azadirone and nimbin/salannin-type compounds from the seeds of neem. 231 They also isolated pentanortriterpenoids (nimbadiol and 6-O-acetylnimbandiol) for the first time in nature, from the seed oil, leaves, and stem bark. 232 Perhaps the most studied constituent of the seed is azadirachtin, which was isolated together with meladanin by Connolly in 1968 and was later found to inhibit the feeding response of the desert locust. 233 The structure of this tetranortriterpenoid was determined by Butterworth and others using modern chemical methods, including spectroscopy. 234 The seeds have also been shown to contain tiglic acid (5-methyl-2-butanoic acid), which is believed to be responsible for the distinctive odor of the oil. 235 The fatty acid (diethernoid) present in the seed is said to aid the ripening of seeds. The gum lavones, which is a good emulsifying agent, is a unique gum by having D-glucosamine, an amino sugar, as one of its constituents. Other constituents of the gum include other simple sugars (such as fructose, rhamnose, xylose, and mannose), uronic acid and proteinaceous materials (e.g., amino acids and dipeptides). The plant contains relatively large amounts of carotene and vitamin C. 236

Flavonoids have also been found in Azadirachta. Simple flavonoids, such as kaempferol and quercetin, have been isolated from the flowers. The chloroform-soluble fraction of the ethanolic extract of the leaves has been found to contain an isoprenylated flavone, nimbaflavone, which was characterized from its spectroscopic data to be 8,3′-diisoprenyl-5,7-dihydroxy-4′-methoxyflavone. 237 Rutin and quercetin-3-rhamnoside are the main constituents of the polar fraction of the alcoholic extract of the leaves.

Pharmacological Studies — The extracts of A. indica have been shown to possess antipyretic, analgesic, and anti-inflammatory activities. 238 The leaf decoction decreased the parasite count in chloroquine-sensitive strains of Plasmodium berghei injected in mice and inhibited the growth of P. falciparum. 239,240 The antimalarial activity has been estimated to be equivalent to half the therapeutic dose of chloroquine sulfate on a dry weight basis. It had earlier been reported that the leaf extract of A. indica showed no antiparasitic activity when tested (in vitro) against Plasmodium berghei drawn from infected albino rats. 239 Etkin, however, found that preincubation of plasmodium-carrying blood with aqueous leaf extract of the herb led to lack of infection in mice. 241 Furthermore, a field evaluation of patients using extracts of neem in self-medication for the treatment of malaria showed that the drug does indeed have antimalarial activity. 242

The antimalarial activity of neem may be considered as established; what is unclear is the mechanism of its action. It does appear that the activity of this herb may not be due to a direct antiparasitic activity per se, but to a possible drug-catalyzed parasite-host interaction. Etkin and others have studied the significance of the oxidation-reduction or “redox” status of red blood cells on parasites and host cell biochemistry during malarial infection. They observed that increased levels of red cell oxidation attendant on plasmodial infection was a consistent feature of malaria. The suggestion has been put forward that while plasmodial parasites might be responsible for generating oxidants, excessive oxidation may in the long run be detrimental to continued and successful malarial infection. 243245 An approximate redox balance must therefore be maintained to ensure red cell integrity and proper metabolic functioning, which is also essential for the development of the Plasmodium parasite. In effect, under a drug-induced physiological condition where excess oxidation occurs and cannot be compensated, a variety of damaging effects will ensue, resulting in the destruction of both red blood cells (hemolysis) and the malaria parasites.

It has been shown that an aqueous extract of A. indica leaf significantly increased the generation of methemoglobin (by the oxidation of hemoglobin) and the conversion of compound GSH to its oxidized counterpart (GSSG) in in vitro studies using normal red cell hemolysates in dilute hemoglobin suspensions. 245 Similar oxidant effects on hemoglobin and GSH have been observed in vivo. The antimalarial activity of Azadirachta is therefore believed probably due to redox perturbation in the form of the imposition of substantial oxidant stress during malaria treatment. The aqueous leaf extract inhibits NADPH-cytochrome c (P-450) reductase activity in rats with a significant increase in microsomal protein. The aniline hydroxylase activity and the phenobarbitone metabolism are also enhanced by the administration of 400 mg/kg of the extract per os. 246 The ubiquitous flavonoids quercetin-3-rhamnoside and quercetin-3-rutinoside (rutin) have been suggested as the active constituents.

Azadirachta extract possesses modest in vitro antimalarial activity against drug-resistant strains of Plasmodium falciparum. 247 It has been shown that two of the constituents of neem, quercetin and the limonoid gedunin, exhibited activity against P. falciparum in vitro, with IC50 values of 6.4 and 0.8 μg/ml, respectively. 248 It has also been suggested that the beneficial therapeutic effects of the neem tree claimed by patients might be due to the anti-inflammatory and immunomodulatory activities of the plant. 249 There is extensive literature on other pharmacological properties of Azadirachta, and what is summarized in the following paragraph is only a random selection from the major publications.

An aqueous extract of the leaves was found to act on isolated guinea pig ileum with a histamine-like effect. It had a biphasic action on the blood pressure of a dog; following an intravenous injection, an initial increase in blood pressure was observed, followed by a prolonged decrease followed by accelerated breathing. 250 It also exhibited hypoglycemic and antihyperglycemic effects in dogs; when administered intravenously, it prevented both adrenalin- and glucose-induced hyperglycemia, with the activity lasting up to 4 h after the dosing. 251 One of the constituents, nimbidin, showed significant anti-inflammatory and antiarthritic properties. 252 The insecticidal and antifeedant properties of neem on various insects have been well documented, and the activity has been claimed to be comparable with conventional insecticides such as DDT, hexachlorocyclohexane (B-isomer) (HBC), and carbamyl. The antibacterial activity of the oil has been evaluated (for further reading on the insecticidal, antifeedant, and antimicrobial activities, see References 253–258). Azadirachta extracts and constituents have shown significant broad-spectrum antibacterial activity, 259 as well as anti-inflammatory, antitumor, and antiproliferative activities. 260

Toxicity — Neem has been associated with liver toxicity. It is likely that it is the nonpolar extractives that cause the hepatotoxicity, and the therapeutically useful aqueous dosage form may be devoid of any serious side effects. Liver biopsy of experimentally induced margosa-oil-poisoned mice demonstrated pronounced fatty infiltration of the liver and proximal renal tubules as well as cerebral edema and mitochondrial damage. Toxicity of neem has been associated with the etiology of Reyes syndrome—usually characterized by vomiting, drowsiness, metabolic acidosis, PMN leukocytosis, and encephalopathy—observed in 13 infants within a few hours of ingestion of the oil. 261 Such serious toxicity symptoms have not been reported from the leaves, stem, or root extract. Some of the constituents of Azadirachta have been shown to be cytotoxic. 253,262

Neem-based consumer products used in health care and for cosmetic purposes appear to be well tolerated, and the toxicity has been detected only in very high doses and after chronic use. Histopathological exams showed that toxicity was observed in the testicles, liver, and kidneys at a very high dose of 1600 mg/kg/day. 263 Detailed investigation of the biochemical mechanism of action and toxicity of this very important medicinal plant is strongly advocated.

Balanites Aegyptiaca

 

Botanical Name — Balanites aegyptiaca (L) Del.

Synonyms — Ximenia aegyptiaca L., Agialida senegalenses v. Tiegh, A. barteri v. Tiegh., Balanites zizyphoides Mldbr. & Schltr.

The genus Balanites has hitherto been placed in the plant family Zygophyllaceae or Simaroubaceae.

Related Species — Balanites wilsoniana Dawe and Sprague

Family — Zygophyllaceae

Common Names — Desert date, soap berry, thron tree

African Names — Arabic: bhanitez; Hausa: aduwa; Fulani: tanni; Kanauri: kingo; Swahili: mnyara, njienja; Yoruba: adowa. For B. wilsoniana: Igbo: ngwu-awusa; Bini: ubogho; Yoruba: budare.

Description — This is a savanna tree that grows up to 10 m, easily recognized by the long, straight, green spines arranged spirally along the branches; each spine has a two-leaflet compound leaf below it. It has a remarkably fluted trunk and a spherical crown; the bark is grayish-brown and has ragged fissures and yellowish-green patches that are exposed by scaling of the bark. 264 It has distinctive leaves, with two leaflets up to 5 cm long on leafstalks about 2 cm long that are broad, slightly obovate, blunt, or rounded at the apex and cunneate; young leaves have short hairs. The yellowish-green flowers are borne above the leaf axils in short clusters; the (five) greenish petals are about 5 cm long; individual flower stalks (five) are up to 1 cm long with yellow 6 stamens and an ovary of five fused shiny, dark-green carpels (March–June). Fruits are produced between March and October. The fruit has a single hard, pointed seed, about 2.5 cm long and 1.2 cm in diameter; it is broadly oblong, ellipsoid, green, and shortly velvety when young, turning yellowish and glabrous when ripe and resembling a small date; it has a thin hard skin and a pale brown sticky edible fleshy pulp. 28,33

The related species B. wilsoniana is a lowland large forest tree found in the southern parts of West Africa and in parts of East Africa. It is distinguishable from B. aegyptiaca, which grows in the north, by its large leaves and by the lack of spines on the flowering branches. The leaflets have distinct stalks, and the petals are hairy inside. The uses, constituents, and other notes on B. aegpyptiaca should apply also to B. wilsoniana.

Habitat and Distribution — It is found in Sahel-savanna regions and drier parts of middle-belt zones of Nigeria, Ghana, and Ivory Coast and is cultivated as a fruit tree in semisavanna parts of the continent.

Ethnomedicinal Uses — The plant features prominently in Hausa ethnomedicine and has been found most useful for other household purposes. A Bornu proverb extols Balanites thus: “A bito tree and a milk cow are just the same.” The fruit pulp is a mild purgative but when ripe can be used in making pleasant drinks or fermented into alcoholic beverages. The fruit and bark are lethal to small freshwater snails (mollusks), which act as intermediary hosts to bilharzia, and has been recommended for the control of schistosomiasis. The bark decoction is used as an abortifacient. The oil of the fruit kernel is employed for the dressing of wounds and as an embrocation in rheumatism. 6,265 The roots and fruits are used as anthelmintics and as an arrow poison antidote; the fruit alone is employed for the treatment of liver and spleen disorders; the root has been indicated for the treatment of malaria, herpes zoster, and venereal diseases. For a comprehensive account of the various medicinal uses, please consult the references cited and see the work of Ainslie, 266 Ayensu, 7 and Irvine. 9

Other Uses — The gelatinous substance on top of the fruits is used in making sweetmeats. Saponin occurs in the roots, bark, wood chips, and fruits; hence, they are used in washing clothes. The gum from the trunk, when fresh, is pleasant to suck. The leaves are occasionally used as a vegetable and are eaten by goats, camels, and cattle. The root is processed with charcoal and oil to produce local ink, and the hard seeds are used for rosary beads and necklaces and in the game of darra. 9 The fine-grained wood is used for implements and furniture, and various plant parts are used for religious rituals.

Constituents — The dried seeds yield about 48% of a fixed oil, zachunoil, and the seedcake contains 50% protein. 267 The seeds, leaves, fruit pulp, bark, and root contain saponin, including the tetraglycoside of diosgenin. 268 The diosgenin content of the whole dried plant has been evaluated as 5.6%; the predominant genin (two-thirds) in the plant is, however, yamogenin, the C-25 epimer of diosgenin. 269 The plant holds promise as a source of steroidal sapogenins for the hemisynthesis of corticosteroids and hormones. 270 Two furanocoumarins, bergapten and (+)-marmesin, have been isolated from Balanites. 271

Pharmacological Studies — The molluscicidal activity of the plant has been investigated, and because of its lethality to both the freshwater snails (which act as an intermediate host for bilharzia) and the minute free stages of the schistosomes, the plant has been recommended for planting along the banks of infested rivers. 272 Malcom and Sofowora reported on the antimicrobial properties of the plant. 273 The anticancer principles of the plant have also been investigated. 274

Bersama Abyssinica

 

Botanical Name — Bersema abyssinica Fresen. subsp. Paullinioides

Synonyms — B. paullinioides (Planch.) Bak., B. cloroleuca Brehmer., B. coriacea Baker f., B. erythrocarpa Brehmer., B. gallensis Brehmer., B. giuliarellii Chiov., B. goetzei Gurke

Family — Melianthaceae

Common Names — Bersema bark, bitter bark

African Names — Basa: je-ra-kpar; Baule: daunt; Chagga: maranguwe, mrandangube; Fanti: samangya; Lunda: kapachi; Mbulu: wamis; Mende: kpondeblokai; Shona: chereke, munyahlawa, munyohava

Description — At least two varieties of the subspecies are known: var. paullinioides and var. engleriana (Gurke) Verkcourt. The two varieties are similar and occur as small- or medium-size tree 6–9 m tall, rarely exceeding 25 m in height. It branches low, with smooth gray bark and cream-colored slash, which darkens on exposure. The leaves are imparipinnate, occurring in clusters, rather clouded at the end of branchlets, about 35 cm long, with 5–10 pairs of leaflets, and displaying wings between the distal pairs of leaflets. The leaflets are variable in size and shape; the middle pairs are usually the largest, 5–15 cm long and 2–5 cm broad, lanceolate, elliptic or oblong elliptic, gradually acuminate, or tapering to a sharp ovate and unequally rounded at the base. The margin is entire, crenate-serrate, or sharply serrate. It produces white or pinkish flowers in stout upright racemes (up to 25 cm long). The fruits are globose and tardily dehiscent with a woody capsule with four valves spreading horizontally and persisting. The pericarp is densely hairy and reddish when ripe; seeds are scarlet with yellow arils. 77

Habitat and Distribution — The plant is widespread throughout tropical Africa, preferring higher rainfall or evergreen forests. It is distributed from Senegal to Zaire and parts of southern Africa.

Ethnomedicinal Uses — Aqueous extract of the stem bark is administered as a purgative, and it is claimed to be anthelmintic, with the worms expelled during purgation. It is also used as an aphrodisiac. The root bark is added to tobacco as snuff and dispensed for the treatment of severe headache. The twigs of the plant are used as a ritual plant in Liberia during treatment of fractures, in which the plant is used as a dressing to a fowl’s leg that is deliberately broken as a vicarious treatment for a man’s broken limb; 6 it is believed that the fractured limb will heal in the same manner as that of the bird. The plant is used as an ingredient in remedies for the treatment of hemorrhoids, dysentery, epilepsy, and colds.

Constituents — Bersema has been shown to contain a mixture of cardenolides, including abyssinol A, B, C; bersaldegenin; hellerigenin; and bufadienolide-O-acetate, 275278 as well as saponins, 279 manferin, 280 and gallic acid derivatives. 281

Pharmacological Studies — The plant extracts exhibit strong insect antifeedant activity, 285 the activity being due to the cardenolides, with abyssinin as one of the most active isolates. 278 The extracts also showed activity as insect sex attractants. The bufadienolides isolated from the plant exhibited antitumor activity against a variety of experimental tumor systems. 283285 The plant has also been found to possess antimicrobial activity. 286

Borreria Verticillata

Botanical Name — Borreria verticillata (L.) G.F.W. Mey.

Synonyms — Spermacoce verticillata L., Spermacoce globosa Schum. et Thonn.

Family — Rubiaceae

African Names — Bambara: som som; Hausa: damfark’ami, feshe; Peuhl: samtarde, gudurdel; Yoruba: irawo-ile

Description — This is a perennial busy subshrub, 1 m high, that branches out in slightly regular stalks with oblanceolate smooth leaves 10 to 15 mm in diameter and small white flowers. The fruit is a drupe, dry and dehiscent. Seeds are mostly with endosperm and are ruminate. The embryo is either straight or curved.

Habitat and Distribution — The species grows in tropical Africa and Madagascar. In the West Coast, the plant grows only in the wet season.

Ethnomedicinal Uses — The juice obtained from the aerial parts is applied topically for the treatment of skin diseases. The plant is reputed to be very effective as an antieczematic. It is also used as a diuretic and abortifacient. A related species, B. compacta, is also used externally in southern Africa. Another species, B. natalensis, is employed by the Zulu in the form of an enema for infantile hyperprexia and in the treatment of leprosy, furuncles, and paralysis. 247

Constituents — The plant contains indole alkaloids, of which borrerine and borreverine are the major compounds. 287 The root bark has been shown to contain iridoids, 288 including asperuloside, feretoside, and daphyloside. The reported presence of emetine in the earlier literature 289 has not been confirmed by recent studies. The leaves yield a volatile oil that consists of hydrocarbon sesquiterpene, lactones, phenolic compounds, and aromatic polycarboxylic acids.

Pharmacological Studies — The essential oil inhibited the growth of the bacterial Escherichia coli and Staphylococcus aureus. 290 It had no action on the blood pressure and respiration of the cat and had an effect on guinea pig intestine and striated frog muscle.

Boscia Senegalensis

 

Botanical Name — Boscia senegalensis Lam.-Holl.

Synonyms — Boscia firma Radlk., Boscia hypoglauca Gilg., Boschia octandra Hoscst. ex Radlk.

Family — Capparaceae

African Names — Bambara: bere; Bargami: kungassa; Fulani: anzagi; Hausa: anza, hanza, dilo; Songhai: horregna; Temajegh (Tuareg): tandeni, tandomei; Wolof: diendoun, ndiandam

Description — It occurs as a stout shrub or short tree, with a black stem, up to 5 m high. The leaves are broad, elliptical to ovate, with 5–6 pairs of prominently looped lateral nerves. The flowers are greenish and sweet scented and are borne in short, dense racemes. The fruits are spherical, sometimes warted, up to 2 cm in diameter.

Habitat and Distribution — The plants occur in the drier parts of the continent. Dalziel 6 listed it as being present “in barren and fire-scorched soil.” It is distributed from Mauritania to northern Nigeria.

Ethnomedicinal Uses — The leaves and berries are commercially available in many parts of northern Nigeria and Sudan as food condiments for soups in times of scarcity. The leaves are used in the preparation of a malaria remedy and for the treatment of jaundice, fungal infections, and venereal diseases. It is applied externally for a wound dressing. The fruits and roots are used as an aphrodisiac, and the root decoction is used for stomachache and to facilitate labor.

Constituents — The plant contains alkyl glucosinolates 291 and the alkaloids stachydrine and hydroxystachydrine. 292 The genus has been shown to elaborate several flavonoids, 293 sesquiterpenes and their glycosides, 294 sulfur compounds, 295 and lipids. 296

Pharmacological Studies — The plant possesses antimicrobial and antifungal activities. 297299 It has also been shown to be an effective uterine stimulant. 300 A related species, B. salicifolia, has been evaluated for its sweetening properties.

Boswellia Sacra

Botanical Names — Boswellia sacra Flueck.

Synonyms — Boswellia carterii Birdw. var. undulato-crenata Engl.; Boswellia bhar-dajiana Birdw.; Boswellia bhar-dajiana var. serrulata Engl.; Boswellia undulatocrenata (Engl.) Engl.

Family — Burseraceae

Common Names — Arabian frankincense, bible frankincense, frankincense, incense, olibanum, olibanum tree

African Names — Somali: mohor (tree), beyo (resin); Swahili: ubani

Description — The tree may be 1.5 –8 m tall, branching from the base or with a distinct trunk; bark is pale brown with some outer flaking, papery layers, and a thick reddish-brown inner resiniferous layer; young shoots are tomentos or rarely glabrous, and resin is copious and milky and dries yellowish-brown. 1148 The leaves are clustered at tips of branches and are imparipinnate; leaflets are opposite, in 6–8 pairs, oblong, with a crenate margin, and tomentose. Flowers are often in axillary racemes, crowded at the end of branches; racemes are up to 10 cm. The calyx is 5-lobed. There are 5 petals, which are yellow-white and spreading. There are 10 stamens. The ovary is surrounded by a fleshy disk. Fruits are capsules, obovoid, broadly pyriform, reddish-brown, glaborous, 8–12 mm, 3–5 angled, and opening by 3–5 valves. 1140

Habitat and Distribution — The trees grow in stony soil. They adhere to boulders of rock faces by means of a cushion- or disk-like swelling at the base of the trunk. This swollen base seems to be important in stabilizing the tree and is best developed in trees growing on very steep or exposed rocks but less so, or not at all, in the occasional trees that grow in gravel or in planted specimens. 1140 They are found in Somalia and most parts of the Horn of Africa and up to Arabia.

Ethnomedicinal Uses — Frankincense is used in traditional medicine for treatment of skin diseases, wound healing, and general inflammation. Boswellia has been used for acne, amenorrhea, cancer, analgesia, diuresis, antisepsis, cystitis, cervical spondylosis, and genital infections and as a carminative, expectorant, and sedative. It is also used in religious ceremonies for spirit invocation during serious negotiations and in burial rites. Frankincense resin is eaten as a general restorative tonic and for skin care in the Horn of Africa and parts of the Sahel region. Edible frankincense must be pure for internal consumption, meaning it should be translucent, with no black or brown impurities. It is often light yellow with a (very) slight greenish tint. It is often chewed like gum, but it is stickier because of its resinous composition.

Constituents — The oleo-gum resin frankincense or olibanum is the most important component of Boswellia species, and the chemical composition is of immense value in differentiating members of the genus. Olibanum has been reported to be a rich source of monoterpenes, sequiterpenes, and iridoids, as well as nonvolatile triterpenoic constituents such as ursane, oleanane, and lupine, which are in many cases responsible for some of the observed biological activities. The presence of isoincensole acetate in both B. sacra and B. carteri has been used as the main diterpenic chemotaxonomic biomarker. Although the diterpene also occurs in Boswellia serrata olibanum, the presence of methylchavicol, methyleugenol, and an unidentified oxygenated sesquiterpene distinguishes B. serrata olibanum from the two other species. The characteristic chemical compounds of Boswellia papyrifera are the diterpenic biomarkers incensole and its oxide and acetate derivatives n-octanol and n-octyl acetate. Boswellia frereana olibanum is devoid of diterpenes of the incensole family but contains a high amount of many dimers of β-phellandrene. The chemical composition of olibanum, which is demonstrated to be different for each Boswellia species, allowed the determination of the taxonomic origin of frankincense samples purchased on various markets in East Africa, in the Near East, and in Yemen. Moreover, terpenic fingerprints allowed the botanical origin of olibanum used in traditional incense mixtures to be identified. 301 The volatile oil derived from the olibanum consists of 75% monoterpenes, sesquiterpenes, monoterpenols, sesquiterpenols, and ketones. It has a good balsamic and sweet fragrance, while the Indian frankincense oil has a very fresh smell. The steam- or hydrodistilled frankincense oil does not contain any boswellic acid (BA) as these components (triterpenoids) are nonvolatile and too large to come over in the steam distillation process, and such claims in proprietary products should be disregarded.

The botanical designation of B. carterii as a synonym of B. sacra has been challenged based on the detailed chemical profile of both varieties. 49 A transnational team of investigators led by Cole Woolley has evaluated the Somalian (B. carterii) and Omani/Yemeni (B. sacra) species by chemical analyses to determine if there were any minor or major differences between the two species of frankincense. Components identified with their average percentage for B. sacra were α-thujene (0.6%), α-pinene (68.2%), camphene (2.1%), sabinene (2.9%), β-pinene (2.0%), myrcene (0.7%), and limonene plus β-phellandrene (6.2%). Components identified with their average percentage for B. carterii were α-thujene (7.9%), α-pinene (37.3%), camphene (0.8%), sabinene (4.9%), β-pinene (1.8%), myrcene (7.3%), and limonene plus β-phellandrene (14.4%). Initially, GC/MS analysis did not reveal major statistical differences. However, optical rotation values for B. sacra (+30.1°) and B. carterii (−13.3°) demonstrated a greater significant difference. Enantiomeric ratio (+)/(−) values of α-pinene for B. sacra and B. carterii of 8.24 and 0.68, respectively, were also calculated, aiding the investigators to conclude that B. sacra and B. carterii are not synonymous but rather two distinct and individual frankincense species. 302

Pharmacological Studies — The volatile oils from several species of Boswellia have been evaluated for their antimicrobial activity. The antimicrobial activity (MIC assay) of the oils ranged from 4–16 mg/ml (Staphylococcus aureus), to 1.5–8.3 mg/ml (Bacillus cereus), to 4.0–12.0 mg/ml (Escherichia coli), to 2.0–12.8 mg/ml (Proteus vulgaris), to 5.3–12.0 mg/ml (Candida albicans). 303 The gum exudate of some Boswellia species contains four major triterpenic acids known as BAs, that is, β-boswellic acid (BA), 3-O-α-acetyl-β-boswellic acid (ABA), 11-keto-β-boswellic acid (KBA), and 3-O-α-acetyl-11-keto-β-boswellic acid (AKBA). The BA acylates, including their epimers, were synthesized and screened against a panel of human cancer cell lines. They exhibited a range of cytotoxicity against various human cancer cell lines, thereby leading to the development of a possible structure–activity relationship (SAR). One of the identified lead compounds was found to be an inhibitor of the NF-jB and STAT proteins, and it is currently being investigated for development as an anticancer agent. 304

The anti-inflammatory activity of BAs has been shown to be probably due to direct inhibition of lipopolysaccharide (LPS) functionality and LPS-induced cellular responses. In pull-down experiments, LPS could be precipitated using an immobilized BA, implying direct molecular interactions. Binding of BAs to LPS leads to an inhibition of LPS activity, which was observed in vitro using a modified limulus amoebocyte lysate assay. Analysis of different BAs revealed clear structure-activity relationships, with the classical β-BA the most potent derivative (IC50 = 1.8 μM). 305

Boswellia has been used clinically for the management of ulcerative colitis; however, the second European evidence-based consensus on the diagnosis and management of ulcerative colitis found the clinical evidence insufficient to approve the use of Boswellia sacra extract (BSE) and BAs in the treatment of this serious disease. 306 It has also been used for the treatment of asthma, depression, and osteoarthritis (OA).

Commerce — Frankincense occurs in various forms in commerce. The crude olibalum is sold in markets in Somalia, Djibuti, Yemen, and neigboring countries in the Horn of Africa and Middle East. The essential oils are exported for the perfumery industry and for use in aromatherapy. The product from Sudan is mostly Boswellia papyrifera, and the Indian frankincense is Boswellia serrata. The edible frankincense, which is translucent, often light yellow with a slight greenish tint, and with no black or brown impurities, is consumed in most parts of the Horn of Africa. It is often chewed like gum, but it is stickier because it is a resin. It is the frankincense produced along the northern coast of Somalia from which the Roman Catholic Church draws its supplies.

Agriculture — The propagation of Boswellia sacra trees is difficult, although the plant can adapt to extremely harsh environments. Their ability to grow in environments so unforgiving is considered unusual; they sometimes grow directly out of solid rock. The trees start producing resin when they are about 8 to 10 years old. Tapping is done two to three times a year, with the final taps producing the best tears due to their higher aromatic terpene, sesquiterpene, and diterpene content. In commerce, the more opaque resins are considered to be the best quality. According to recent surveys, frankincense tree populations are declining, partly due to overexploitation. Heavily tapped trees have been found to produce seeds that germinated at only 16%, while seeds of trees that had not been tapped germinated at more than 80%. It has been further observed that bush burning, grazing, and attacks by the longhorn beetle have reduced the tree population. 1138

Bridelia

Botanical Name — Bridelia spp. Willd.

Family — Euphorbiaceae

The genus is characterized by the presence of easily recognized stalkless and markedly persistent flower clusters in the leaf ails along the branchlets. Four species—B. atroviridis, B. speciosa, B. micrantha, and B. ferruguinea—are employed in the preparation of traditional remedies. The last-named species, however, is the most common of these savanna plants. They bear flowers with greenish-yellow sepals and very small and narrow petals; the males have 5 stamens in a central column surrounded by a conspicuously yellowish disk, and the females usually have two branched styles. Both male and female flowers are found in each flower cluster. The distinctive leaves are marked with lateral nerves that continue to the margin to form a marginal nerve. 168 They bear persistent fruits that are egg shaped and smooth; the ripe ones are usually black with a hard seed.

According to Keay et al., 164 the species can be differentiated by the following characteristics:

  1. B. atroviridis: lateral nerves looped close to the margin, but not forming a marginal nerve like other Bridelias 2. B. speciosa: midrib projecting a short spine beyond the acuminate leaf tip; leaves almost glabrous on both surfaces
  2. B. micrantha: midrib not projecting; branchlets and undersurfaces of leaves shortly hairy; hairs lying flat, particularly along the nerves and veins beneath
  3. B. ferruguinea: hairs spreading; leaves with 6–10 pairs of lateral nerves and very characteristic down-curved acuminate tip forming a short, rigid hook

All members of the genus Bridelia have been used in the preparation of folk remedies. Decoction of the plants has been recommended for the treatment of a variety of illnesses, such as fevers, diabetes, rheumatism, gonorrhea, and diarrhea.

Bridelia Ferruguinea

 

Botanical Name — Bridelia ferruguinea Benth

Synonyms — Gentillia chevalieri Beille

Family — Phyllanthaceae

African Names — Hausa: kirni; Igbo: orha (ola); Yoruba: ira

Description — It is a shrub, sometimes growing up to 18 m high and about 1.5 m in width. The stem is often crooked, with branches occurring at lower regions; the bark is gray, rough, and often scaly. It has thin and red slash. The thin branches often grow spines. The twigs are usually densely covered with short, rust-colored hairs. The plant has characteristic broadly elliptic leaves, 4–10 cm long and about 3–5 cm in breadth. The margins are slightly wavy, with the apex drawn out, rigid, and curved downward. It has a thick, short, and very hairy leafstalk. B. ferruguinea produces creamy-yellow, sweet-scented flowers that appear between February and August. The fruits occur in July–September and are small and nearly round. 13

Ethnomedicinal Uses — The stem bark was used in the western states of Nigeria as an antidote for arrow poison. The roots, bark, and leaves are ingredients in some varieties of the Yoruba “agbo pot” used for pediatric illness. Dalziel 6 listed the whole plant for the treatment of intestinal and bladder disorders and externally for skin infections and eruptions and the leaves and stem bark are indicated for arthritis. A popular mouthwash called epo-ira in Yoruba is prepared from the stem bark of this plant. 269 The leaves are cooked as a vegetable and eaten in times of famine.

Perhaps the most important use of B. ferruguinea is in the treatment of diabetes in certain parts of West Africa. Ampofo made the first report on the clinical use of this herb for the treatment of diabetes. 307 He documented the positive results of a pilot clinical trial of the antidiabetic properties of Bridelia on 12 patients. An evaluation of 10 patients who received treatment at another herbal home in Nigeria confirmed the value of B. ferruguinea in the treatment of diabetes. In Yoruba (Nigeria) ethnomedicine, the plant is used in the preparation of a traditional gargle called “Ogun Efu,” which is employed in the treatment of “Efu,” a pathological disorder characterized by a furred tongue caused by overgrowth of papillae that produces a creamy curd-like coating on the tongue. 308 It is also used as a diuretic, antihypertensive, antifungal, and antidepressant. Other uses of the plant include the preparation of an embrocation for the treatment of bruises, boils, dislocation, and burns and as an oral decoction for the treatment of ulcers and persistent coughs.

Constituents — The first chemical screening of the genus Bridelia was carried out by Treub in 1907, who reported the presence of hydrocyanic acid in B. ovate and B. tomentosa. 309 The pulverized stem bark contains tannins and reducing sugar but no alkaloid. 310 A chemical examination of the leaf of Bridelia ferruginea resulted in the isolation and characterization of two coumestan-flavonoids, bridelilactone and bridelilactoside, as the main constituents of ethyl acetate extract. The diethyl ether-soluble extractive yielded two coumarins, aesculetin and scopoletin, and six flavonoids, including quercetin, galangin, and naringenin. Lupeol, β-amyrin, and β-sitosterol were isolated from the petroleum spirit extract. 311 It has been shown that the petrol extract yielded mainly flavonoid glycosides, of which quercetin-3-neohersperisdoside (rutin) was the major constituent. 312

Pharmacological Studies — The hypoglycemic properties and the antihyperglycemic activity of Bridellia in experimentally induced diabetes have been investigated. The fasting blood levels of maturity onset diabetic patients are lowered to normal values by daily doses of aqueous extracts of B. ferruguinea leaves. Glycosuria was eliminated after 2 weeks of therapy even when ketosis had been established. In experimental animals, alcoholic and aqueous extracts of this plant significantly lowered fasting blood sugar but failed to protect the animals against alloxan-induced diabetes. 313,314 Rutin, isolated from the plant, has been proposed as the active constituent of Bridelia. 315 The milk-coagulating activity of the ethanol extract of the bark of Bridelia ferruguinea and lime juice has been evaluated as an index to determine the usefulness of the gargle prepared from these plants in the treatment of papillary hypertropyhy. 308 Both plants appear to act synergistically as astringents in milk coagulation which by extrapolation may explain their use in the preparation of Ogun efu. 308 Aqueous extract of the leaves of B. atroviridis administered in a concentration-dependent manner induced contractions on rat uterus that were antagonized by various calcium entry blockers. 316 The cellular basis for the uterotonic activity of the plant extract appeared to be complex and probably involves mechanisms including calcium mobilization from both intra- and extracellular compartments and activation of phospholipase C through a G-protein. 316

The β-amyrin-rich extracts of B. ferruginea leaves possess antioxidant and cytotoxic activities. 317 Intraperitoneal administration of aqueous extract of B. ferruginea at the dose of 10 mg/kg produced a significant increase in urinary excretion of creatinine (p < 0.01 compared to a control) and creatinine clearance in rats. The urinary urea and plasma urea were not affected by the extract, whereas urinary urea and urea clearance were affected by furosemide used as an active control. 318 Its wound-healing property has been established by laboratory studies, as evidenced by its antibacterial, 319321 antioxidant, and fibroblast growth stimulation activity of the crude extracts. 322

B. ferriginea has been evaluated for its anti-inflammatory activity, 323 and its anti-inflammatory activity has been linked to possible involvement of the suppression of TNF-α upregulation based on results from tests in models that are mediated by TNF-α. The effect of the extract on LPS-induced septic shock was determined by measuring the number of deaths and the levels of serum alanine and aspartate aminotransferases following intraperitoneal injection of LPS (1 μg/kg) into d-galactosamine-primed mice. LPS-induced vascular permeability on the back skin of mice was measured by the local accumulation of Evan’s blue after subcutaneous injection of LPS. Pretreatment with Bridelia ferruginea extract (10–80 mg/kg) produced a dose-dependent inhibition of the septic shock syndrome in mice, with 80 mg/kg of the extract exhibiting comparable activity as pentoxifylline (100 mg/kg). LPS-induced dye leakage in the skin of mice was also suppressed by the extract (10–80 mg/kg). 318

Bryophylum Pinnatum

 

Botanical Name — Bryophylum pinnatum (Lam.) Oken

Synonyms — B. calycinum Salisb., Cotyledon pinnata Lam., Kalanchoe pinnata (Lam.) Pers., Vereia pinnata (Lam.)., Sedum madacasriense Clus., Kalanchoe floripendula Steud., Kalanchoe calycinum Salisb., Crassuvia floripenula Comm., Cotyledon rhizophylla Roxb.

Family — Crassulaceae

Common Names — Never die, wonder of the world, leaf of life

African Names — Yoruba: abamodo; Igbo: nkwonkwu; Efik: afia-ayo

Description — This is a glabrous, laxly erect, fleshy herb 60–120 cm tall that branches from the base. The leaves are opposite and usually in pairs; the lower leaves are simple; the upper ones are pinnate, almost rounded but larger toward the apex, and about 10 cm long and 5–6 cm broad. The margins have curved crenations (notches) with regular, blunt, or rounded teeth, which sometimes bear small plantlets or bulbils. The flowers nodding in terminal panicles are greenish-yellow but purplish at the base. The calyx is tubular and inflated, 4-lobed (the lobes triangular and shortly pointed), and about 3 cm long. The corolla is united, tubular, concentrated above the base, a little longer than the calyx, and also 4-lobed. The upper part of the lobes is ovally pointed and reddish-purple in color. The stamens are attached to the constriction of the corolla tube. 9,77

Habitat and Distribution — The plant is widely distributed throughout the continent but is more abundant in warm and dry areas; it thrives in rocky terrain with little water.

Ethnomedicinal Uses — The crushed leaves or the juice expressed from them are warmed as a poultice with shea butter or palm oil and rubbed on abscesses or other inflammatory conditions 266 (see also Agoha 77 ). The topical application is also used for the treatment of external ulcers and burns and on the bodies of young children to prevent fits during high fevers. It is used with “sterilized” palm oil as a dressing after circumcision of male children. It has also been reported that a decoction of the leaves is taken in the West Indies for the treatment of arthritis and to clean the bladder. 140 The plant is listed by the Wong for the treatment of earache and in ophthalmia, and the poultice is used for sprains, dysmenorrhea, and colds in the head. 324

Constituents — Preliminary chemical work on this plant revealed the presence of xanthones, flavonoids, anthraquinones, and traces of alkaloids. Potent cytotoxic bufadienolides bryophyllin A and B have been isolated from the species. 325,326 Cardiac glycosides, known as bryotoxins, are also present in the plant. 327 An extract of the leaves with activity against chemically induced wounds has been shown to contain bryophyllol, bryophollone and bryophollenone, bryophynol, and two phenanthrene derivatives, as well as 18α-oleanane, ψ-taraxasterol, and α- and β-amyrin and their acetates. 328

Pharmacological Studies — The pressed juice as well as the organic and aqueous extracts of the leaves has been shown to possess moderate antibacterial microbial activity. 329 The plant has been shown to have antihypertensive activity. Both the aqueous and methanolic leaf extracts of B. pinnatum produced dose-related, significant (p < 0.05–0.001) decreases in arterial blood pressures and heart rates of anesthetized normotensive and hypertensive rats. The hypotensive effects of the leaf extracts were more pronounced in hypertensive than in normotensive rats. 330

Bryophyllum has been used in clinical medicine in Europe (mainly Germany) since the 1970s as a sedative and for the treatment of premature labor. 331 The preparation was usually administered parenterally at a dose of 580 mg/h until contractions ceased, after which it was administered as a 50% slurry at a dose of 200 mg/h, supplemented by fenoterol at 120 mg/h if insufficiently effective alone. Clinical outcome and inhibition of labor were similar to those for fenoterol. 332 However, in contrast to the well-documented side effects of conventional labor inhibitors, especially of the cardiovascular system, which can be serious for both for mother and baby, no adverse signs or symptoms are known to date. B. pinnatum 5% is also used as a 10 ml i.v. bolus during delivery if contractions are too strong, frequent, or painful; the effect, which is rapidly visible on the cardiogram, is much less a matter of direct inhibition than of inducing more rhythmic contractions. 319 The tocolytic activity of B. pinnatum observed in alternative medicine centers in Europe has been validated by laboratory studies. 333335

B. pinnatum has also been shown to possess the following pharmacological properties: analgesic, anti-inflammatory, 155 and antinociceptive and hypoglycemic activities. 336 It has shown promise as a possible treatment for overactive bladder 337 and ulcers 338 and as a neurosedative and muscle relaxant. 339

Toxicity — The bufadienolides found in Bryophyllum species are toxic to cattle and other farm stocks. 331 Bryophyllum poisoning causes anorexia, depression, ruminal atony, diarrhea, heart rate and rhythm abnormalities, dyspnea, and death. Myocardial degeneration and necrosis with hemorrhages of the heart and alimentary tract have been observed. 340 The median lethal doses for the Australian species, B. tubiflorum, flowers, roots, and leaf plus stem were found to be 0.7, 2.3, and 5.0 g dry matter/kg liver weight, respectively (7, 7, and 40 g wet weight/kg, respectively). 215 A treatment regime consisting of the administration of activated carbon, electrolyte replacement solution, and antiarrhythmic drugs has been used to abort the lethality of bryotoxin intoxication in farm animals. 216

Bulbine Frutescens

Botanical Name — Bulbine frutescens (L.) Willd.

Synonyms — Anthericum frutescens L., Anthericum incurvum Thunb., Anthericum multiceps Poelln., Anthericum rostratum Jacq., Bulbine caulescens L., Bulbine incurva (Thunb.) Spreng., Phalangium frutescens (L.) Kuntze, Phalangium rostratum (Jacq.) Kuntze

Related Species — Bulbine asphodeloides, B. abyssinica, B. natalensis

Family — Xanthorrhoeaceae (formerly Asphodelaceae)

Common Names — Bulbine, bulbinella, burn jelly plant, cat’s tail, snake flower

African Names — Afrikaans: geelkatstert, wildekopieva; Zulu: ibhucu; Xhosa: intelezi; Sotho: moetsa-mollo

Description — According to the African Herbal Pharmacopeia, 1141 Bulbine frutescens is a perennial herb up to 0.5 m high but occasionally growing up to 1.2 m. It has woody stems that bear succulent leaves. The leaves are linear, cerete or somewhat flattened, 30–250 mm long, 4–10 mm in diameter, bright green or yellowish green, and glaucous glabrous. Flowers are small, mostly yellow, sometimes partly orange, in multiflowered racemes on sender peduncles; the pedicel is thin, usually curved, petals are six, yellow, sometimes orange, erect to recurved, and somewhat persistent. Stamens are six; filaments are densely hairy. Fruit occurs as a small capsule. The plant can be distinguished from related members of the genus by its woody stem and details of the floral bracts. 1141

Habitat and Distribution — Bulbine frutescens is widespread throughout Southern Africa.

Ethnomedicinal Uses — In most parts of South Africa and Lesotho, fresh leaf sap of Bulbine frutescens is used externally for the treatment of skin infections, especially ringworm and eczema. The sap is applied to wounds as a disinfectant and to promote healing. In Lesotho, crushed leaves are used as a dressing for burns, and leaf sap is applied to cracked lips. It has also been reported as used for the treatment of scrofula, a form of tuberculosis that affects the lymph nodes. The root decoction is used for the treatment of diabetes, venereal diseases, rheumatism, convulsion, and diarrhea. The related species B. abyssinica is used as a tea for the treatment of gynecological disorders.

Constituents — The gel of B. frutescens yields a complex mixture of polysaccharides. The plant is also known to have knipholone-type compounds. The roots contain phenylanthraquinones, gaboroquinones A and B, and 4′-O-demethylknipholone-4′-O-beta-D-glucopyranoside. 341 Also isolated from the roots are sulfated phenylanthraquinones co-occurring with their known sulfate-free analogs. Their structures were elucidated by spectroscopic and chiroptical methods, by acid hydrolysis, or by partial synthesis. 342

Pharmacological Studies — The in vivo wound-healing property of Bulbine species has been confirmed by many investigators, thereby validating the traditional use of the leaf gel extracts of B. frutescens and related species in the treatment of wounds. In animal studies, the wound contraction following treatment with Bulbine natalensis on days 2, 4, and 10 (p = 0.004, 0.007, and 0.03, respectively) and Bulbine frutescens on day 4 (p = 0.004) increased significantly when compared to the corresponding untreated wounds. The tensile strength of the wounds treated with the leaf gels was significantly stronger than that of the untreated wounds. There was also a significant increase in the collagen, protein, and DNA content of the Bulbine natalensis– and Bulbine frutescens–treated wounds compared with that of the untreated wounds (respectively, collagen content: p = 0.014 and 0.018; protein content: p = 0.03 and 0.04; DNA content: p = 0.04 and 0.04) over the 16-day experimental period. Treatment with both leaf gels followed the same pattern in hexosamine content, with a maximum hexosamine content on day 4 followed by a steady decrease to day 16. The authors found no significant difference between the hexosamine content of the wounds of animals treated with either Bulbine frutescens or Bulbine natalensis. 343 In related studies, the leaf extracts increased tensile strength by increasing fibroplasia, differentiation of fibroblasts into myofibroblasts, and increased collagen deposition and maturation in pigs. Knipholone, a major constituent of Bulbine species, showed strong antispasmodic activity but was devoid of antibacterial activity. 1148

Clinical outcome studies conducted in about 300 patients clearly showed that Bulbine gel improved postoperative scar management and scar maturation. 344 These results suggest that Bulbine species can be formulated as a low-cost effective topical treatment for wounds. In an antiviral assay using CEM.NKR-CCR5 cells, ethanolic extract of Bulbine alooides showed HIV-1 inhibition with an IC50 of 94 μg/ml. 345 Several isofuranonaphthoquinones isolated from the roots of the related B. capitata showed antioxidant activity in a human lipoprotein oxidation assay, some of them with activity comparable to that of quercetin, a flavonoid with established antioxidant activity. These compounds also demonstrated weak antiplasmodial activities in vitro. 1141

Toxicity — No serious toxicity has been reported from the use of Bulbine. A temporary sensitivity to the topical application of Bulbine gel was observed in 2 of the total of about 300 patients during a clinical study. 1141

Commerce — The Bulbine species are articles of trade in the local South African Muti market and in some medicinal plant markets in parts of eastern and southern Africa. No significant international trade has been recorded.

Agriculture — The plant is mostly collected from the wild. Bulbine is easy to cultivate and there are small plantations in South Africa for the production of the gel.

Formulation and Dosage Form — The only known formulations are gels for external use. The herb is used alone or in a mixture with other wound-healing agents.

Cajanus Cajan

 

Botanical Name — Cajanus cajan Millsp.

Synonyms — Cyticus cajan L., Cajanus indicus Spreng.

Family — Leguminosae

Common Names — Pigeon pea, field pea, pois d’Angol, ambrebdade (Comores), pois de pigeon (F).

African Names — Arabic: bisellat el-Haman; Hausa: waken-masar, waken-turawa; Igbo: fio-fio; Swahili: mbaazi; Yoruba: otili, otinli

Description — This is an annual or biennual shrub 2 m high with ribbed, silky pubescent stems. The stalks and leaves are covered with white down. It has 3 leaflets that are oblong lanceolate in short stalks. The flowers are brownish-yellow, borne on corymbiform racemes. The fruits occur as oblong linear pods (over 5 cm long), obliquely constricted between the seeds, which vary from 3 to 4. 28

Habitat and Distribution — It is pantropic and is cultivated in most parts of the continent. The plant prefers savanna vegetation and dry forestlands.

Ethnomedicinal Uses — The leaves are used as a weak decoction for the treatment of measles, catarrh, and hepatitis. An aqueous infusion of the seeds sometimes mixed with the leaves is dispensed for the management of sickle-cell anemia.

Constituents — Cajanus contains amino acids, proteins, fats, carbohydrates, saponins, stilbenes, flavonoids, and isoflavones. 346 It also yields minerals, such as calcium, phosphorus, and iron. The leaves contain the phytoalexins pinostrobin and cajaninstilbene acid and the coumarin cajanuslactone (7-hydroxy-5-O-methyl-8-(3-methyl-2-butylene)-4-phenyl-9,10-dihydro-benzopyran-2-one). 347 Urease has been isolated from pigeon pea. The enzyme is used in diagnostics to determine the urea present in the blood serum.

Pharmacological Studies — The seed extract has been shown to possess hypoglycemic and antimicrobial activities. 348 Later studies of the hypoglycemic activity showed that the extract produced transient hypoglycemia at a dose of 300 mg/kg. Extracts of the seeds were effective in restoring normal morphology of erythrocytes from blood samples of patients affected by sickle-cell anemia. 349,350 The aqueous alcohol extract, as well as cajaminose, an amino sugar isolated from it, prevented the sodium metabisulfite-induced sickling of red blood cells. 351 Phenylalanine has been isolated as the main constituent of the antisickling fraction of the seed extract and has been suggested as probably responsible for the hematological effect. 352

Viclin, a holoprotein that occurs in seeds, exhibits an unusual stability to the denaturation by 8 M and 6 M guanidine-HCl. 353 The presence of urease in the plant may play some role in its use as an antisickling agent.

A Cajanus flavanone, pinostrobin, inhibits voltage-gated sodium channels of mammalian brain (IC50 = 23 μM) based on the ability of this substance to suppress the depolarizing effects of the sodium channel selective activator veratridine in a synaptoneurosomal preparation from mouse brain. The resting membrane potential of synaptoneurosomes was unaffected by pinostrobin. The pharmacological profile of pinostrobin therefore resembles that of depressant drugs that block sodium channels. 354 Cajanus has demonstrated antifungal, antioxidant, and hypercholesterolemia effects in laboratory experiments. Genistein and apigenin from the roots showed remarkable antioxidant properties using the DPPH scavenging activity model. 355 The antidyslipidemic activity of pigeon pea was evaluated by a high-fat diet (HFD) hamster model, in which the levels of high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), total cholesterol (TC), and total triglycerides (TG) were examined. Pigeon pea administration was found to promote cholesterol converting to bile acid in HFD-induced hamsters, thereby exerting hypolipidemic activity. It significantly increased hepatic carnitine palmitoyltransferase 1 (CPT-1), LDL receptor, and cholesterol 7α-hydroxylase (also known as cytochrome P450 7A1, CYP7A1) expression to attenuate dyslipidemia in HFD-fed hamsters and markedly elevated antioxidant enzymes in the liver of HFD-induced hamsters, further alleviating lipid peroxidation. This activity was attributed to a possible role of the large quantity of unsaturated fatty acids (UFAs; C18:2) and phytosterol (β-sitosterol, campesterol, and stigmasterol) present in pigeon pea. 356

Caloncoba Echinata

Botanical Name — Caloncoba echinata (Oliv.) Gilg.

Synonym — Oncoba echinata Oliv.

Family — Achariaceae

Common Names — Gorli

African Names — Igbo: udara-nwewe; Bini: otiemme; Yoruba: Kakandika

Description — Caloncoba echinata is a shrub or small tree about 7 m high, 1 m or less in girth, with a hard, grayish bark, which appears somewhat corrugated. The leaves are yellowish-green in color, oblong elliptic, and about 10–30 cm long and 5–10 cm broad. It is narrowly acuminate, entire, with a long and tapering apex, and rounded base. Leaves have a thin and slightly leathery texture. The lateral veins (5–6 pairs) are prominent and run wide angles to the midrib, looping well away from the margins. The stalks are about 2.5 mm long. The plant produces small whitish flowers, borne in the axils of the leaves and in clusters on common stalks, which are a few millimeters long. The sepals are about 2.5 mm long, and the petals are 3–4 mm. It flowers from May to November, and the fruiting begins in August and lasts to May. The fruits are round and yellow or orange-red in color, bear numerous prickles (echinate), are about 4 cm in diameter, and contain many black or brown seeds, which are embedded in a white, pithy pulp.

Habitat and Distribution — This is a forest tree found mainly in undergrowth and secondary clearings; it occurs in western, central, and parts of southeastern regions of the continent.

Ethnomedicinal Uses — The fruit pulp is used by the Mendes of Sierra Leone to prepare a sweet refreshing drink. The seeds, when chewed, are sweet and oily and leave a peculiar aromatic aftertaste. The seed oil has been used for making soaps and candles. The plant has a reputation as a drug for the treatment of leprosy and was cultivated in the past for this purpose. The seeds of Hydnocarpus wightiana are, however, preferred for the treatment of leprosy. A lotion made from the plant has been used in parts of West Africa for pustular eruptions of the skin.

Constituents — The seeds contain oil whose fatty acids have the cyclopentane nucleus of chaulmoogric acid. The acid is used in a mixture with hydnocarpic acid for treating leprosy. The stem bark contains friedelane triterpenes kokoonol, kokoonal, and 3β,21β-dihydroxy-30-nor-(D:A)-friedo-olean-27-oic acid, 357 as well as cycloartane-type triterpenoids glaucartanoic acids A and B isolated from the fruits.

Pharmacological Studies — Caloncoba echinata has not been investigated much pharmacologically. The cycloartanes isolated from the fruits of the related C. glauca have been found to possess cytotoxic activity. 358

Capsicum Annuum

Botanical Name — Capsicum annuum L.

Synonyms — Capsicum cerasiforme Lank.m, Capsicum chamaecerasus Nees., Capsicum longum DC. Over 30 synonyms and varieties are known to exist.

Related Species — Capsicum annuum var. glabriusculum (Dunal) Heiser & Pickersgill

Family — Solanaceae

Common Names — Red pepper (English), piment doux, piment des jardins, gros piment, poivron (French)

African Names — Arabic: filfil romi; Bambara: forotu, kilikili; Hausa: barkono, barkhannu; Igbo: totoshi; Swahili: pilipili-hoho; Yoruba: ata wewe

Description — Capsicum annuum L. is an annual or biennial suffrutescent plant that can reach over 1 m in height. The leaves are ovale lanceolate, 6 × 3.5 cm. The flowers are greenish-white and borne on axillary bunches. It produces polymorphic berries 18 cm long; usually globular, ovoid, or oblong in shape; green colored and yellow to red when ripe. 28

Habitat and Distribution — The species is cultivated throughout tropical Africa; several hybrids and strains are known.

Ethnomedicinal Uses — The fruits are used as a carminative, tonic, spasmolytic, antiseptic, rubefacient, and stimulant. In traditional medicine, they are employed mainly as a flavoring agent in compound formulations. A poultice prepared with the ground fruits, kaolin, and bark of Newbouldia laevis is used in postpartum medication as a general tonic. An ointment prepared with the fruit extract is used topically for skin infections.

Constituents — The fruit contains capsaicin, dihydrocapsaicin, nordihydrocapsaicin, and related alkaloids. The capsaicin content increases with maturation of the fruit. The color of the fruits is due to the presence of carotene, capsanthin, and capsorubin, as well as steroidal saponins. Vitamins A and C also occur in the plant. The common carotenoids with provitamin A activity, β-carotene and β-cryptoxanthin, occur in the plant. 359

Pharmacological Studies — The alkaloid capsaicin has been studied extensively and has been shown to possess antimicrobial, spasmolytic, vasodilatory, rubefacient, counterirritant, and stimulatory activity on the digestive system. 123 It has a somewhat ambiguous effect in the stomach mucosa. It has shown the ability to excite and later defunctionalize a subset of primary afferent neurons and has been extensively used as a probe to elucidate the function of these sensory neurons in a number of physiological processes. In the rat stomach, experimental data provided clear evidence that capsaicin-sensitive (CS) sensory nerves are involved in a local defense mechanism against gastric ulcer. Stimulation of CS sensory nerves with low intragastric concentrations of capsaicin protected the rat gastric mucosa against injury produced by different ulcerogenic agents. High local desensitizing concentrations of capsaicin or systemic neurotoxic doses of the agent markedly enhanced the susceptibility of the rat gastric mucosa to later noxious challenge. 360

One of the steroidal saponins found in the fruits exhibited antibacterial activity. 361 The fruit extract has been employed in various formulations: a gargle for laryngitis, improvement of peripheral circulation, alleviation of flatulence and colic, and externally as an ointment for lumbago, unbroken chilblains, muscle pains, and stiffness. 124 Hot pepper has an antioxidant activity that is due to its phenolic content. Both ripe and unripe hot peppers prevented Fe2+-induced lipid peroxidation in the rat brain. The unripe pepper had a significantly (p < 0.05) higher total phenol, Fe2+ chelating ability and inhibitory effect on the basal and Fe2+-induced lipid peroxidation in the brain tissues than the ripe pepper. 362

Most pharmaceutical applications of Capsicum is done with Capsicum oleoresin, a thick, dark reddish-brown liquid concentrate produced by the extraction of fruits with volatile solvents or by supercritical fluid extraction. The capsaicin content of Capsicum oleoresin is highly variable, and the oleoresin exhibits differences in its ability to mediate substance P release, the neuropeptide which causes vasodilation due to the release of NO from the endothelium. The quality of the oleoresin has to be tightly controlled for uniform pharmacological outcome since the liquid contains over 100 chemicals, alcohols, carbonyls, carboxylic acids, esters, pyrazine compounds, and terpenes in the volatile component of the resin.

Capsicum Frutescens

Botanical Name — Capsicum frutescens L. (= Variety: Capsicum annuum APG)

Synonyms — C. frutescens var. minimum, C. baccatum L., C. fastigiatum BI.

Family — Solanaceae

Common Names — Fructus capsici, African Capsicum, Japanese chilies, piment de cayenne, piment enrage (F), pilipili (francophone Africa), cayenne pepper

Description — This is a perennial branchy shrub, about 1 m in height. It produces yellowish-white flowers. The fruits are smaller than those of C. annuum and are oblong, conical, obtuse, and binocular, rarely exceeding 4 cm. They are more pungent than those of C. annum, with color ranging from red, yellowish red, to brownish red; they have a characteristic odor that can be modified by selective breeding.

Constituents — The plant contains up to 14% capsaicin, the pungent principles in the genus. It yields in varied concentrations the compounds reported for C. annum. The pungent properties of Capsicum can be distinguished from those of gingerol and paradol (found in Zingiberaceae) by the ability of the pungent substance in Capsicum to be resistant to destruction by solutions of caustic alkalis (1 in 50) but destroyed by potassium permanganate.

Pharmacological Studies — The biological activities are similar to those reported for C. annum. The dietary hot short pepper showed antioxidant activity and prevented cyclophosphamide-induced oxidative stress in the brain. Although the flesh is a better protectant, the possible contributory role of the seeds cannot be ruled out. 363

Carapa Procera

 

Botanical Name — Carapa procera DC.

Synonyms — Carapa guineensis Sweet et A. Juss., C. touloucouna Guill. et Perr., C. gummiflua DC, C. velutina DC, C. microcarpa Chev., Trichilia procera Forsyth., Granatum surinamensis (Miq.) Kuntze

Family — Meliaceae

Common Names — Monkey cola, crabwood

Description — It is a tall tree, often attaining a height of up to 17 m, with wide spreading branches and large leaves that are clustered at the end of the twigs. The bark is pale brown, thin, and smooth with pinkish or red slash. The leaves are large, up to 2 m long, with 8–20 pairs of opposite or alternate leaflets. Leaflets vary enormously is size and shape, usually from 12 to 24 cm long and 1.8 to 9 cm broad. They are elliptic to elongate-oblong in shape, rounded or wedge shaped. The leaf surface displays about 10 pairs of lateral veins, widely spaced. The flowers appear from August to October and January to February. They are creamy white with reddish or pinkish centers, are sweet scented and about 6 mm long, and are borne on long common stalks. The fruits are almost globular in shape with long or short beaks. They open by means of valves (five), which may have ridges running through the entire length. The seeds are 15–20 per fruit, somehow resembling cola nuts. Each seed is about 2.5 cm in diameter, obliquely ovoid with flattened surfaces, reddish-brown, and have a thick, woody, oily kernel.

Habitat and Distribution — This is a lowland rainforest plant; it occurs in Ghana, Ivory Coast, Nigeria, Cameroon, Zaire, and Tanzania.

Ethnomedicinal Uses — The seeds yield fat that is used for skin and hair and for treating sores, burns, rheumatic pains, insect bites, jiggers, eruptions, ringworm, and yaws. It is also used as a vermifuge for both tapeworms and roundworms.

Constituents — The plant contains fatty acids, triterpenes, and a bitter principle, tulukinin. 82

Pharmacological Studies — The extract was shown to be apparently devoid of any activity against malaria. The LD50 of the root bark extract in mice was determined as 1.2 g/kg.

Carica Papaya L.

 

Botanical Name — Carica papaya L.

Synonyms — C. hermaphrodita Bianco, C. mamaya Vellon., Vasconcellea peltata (Hook. & Arn.) A. DC.

Family — Caricaceae

Common Names — Pawpaw, papaya

African Names — Arabic: anbah hindi, babaya, babog fruta bomba; Hausa: gwandu; Igbo: okworo-beke; Efik: etighi-mbakara; Swahili: papaya; Yoruba: ibepe, sayinbo

Description — This is a small tree with a weak soft-wooded stem and palm-like appearance. The stem is usually unbranched and hollow; the bark is gray and visibly marked by the numerous large orbicular leaf scars. The leaves are dark green, very large, and crowded on the upper part of the tree, each borne in a long, hollow, and cylindrical petiole. They are suborbicular, 20–60 cm wide, usually palmately lobed, with each lobe pinnatilobulate, obtuse or acute. It is usually dioecious, with male and female inflorescences borne on different plants, although rarely some plants bear bisexual flowers. The male inflorescences are carried in the axils of the upper leaves, a long pendulous raceme carrying the numerous sessile male flowers on the branches. The male flowers are usually very fragrant. The female flowers are remarkably much larger than the male and more or less without stalks (sessile) and are borne on the main axils.

The plant produces fruits that vary enormously in shape and size; most are oblong, globular, or round, often five angled and narrowed to the stigma tip, although flask-shaped fruits narrow at the base are not uncommon. The ripe fruit is yellow or bright orange in color. The pulp is thick and yellow-orange in color. The seeds are small, dark green or brown, enclosed in a mucilaginous mass. The whole plant yields copious white latex when cut. 9,28,33

Habitat and Distribution — This is cultivated and grows wide in most parts of the continent. It is native of tropical Africa.

Ethnomedicinal Uses — Pawpaw is used in traditional medicine for a variety of purposes. The green fruit is applied on ringworm and is claimed to effect a cure if rubbed hard until the skin bleeds. The ripe fruit is edible and rich in vitamin A and has some vitamin C. A weak decoction of the leaves is taken for malaria, and the mixture with lemongrass and guava leaves is used in the treatment of hypertension. The three plants are also used with leaves of neem, Azadirachta indica, in steam therapy for malaria, 318 in which the patients are covered with a thick blanket and made to bathe in and inhale the vapor from the cook pot.

The leaves and seeds are used for the treatment of amebiasis and as an anthelmintic. The fresh fruits are carminative and administered for digestive conditions and used as a diuretic, stomachic, and antiseptic. The sap of the plant contains a ferment, which has the property of coagulating milk and of softening or digesting the fibrous tissues of flesh; hence, it is used to make meat tender, either by adding a piece of unripe fruit to the water when cooking, by wrapping the meat in the leaves to roast or bake, or as a preliminary treatment for some hours before cooking. 81 The seeds are used as an oxytocic and externally as an antifungal agent.

Constituents — The principal constituents of papaya are the proteolytic enzymes found in the latex, which abounds in all parts of the plant but is obtained mainly from the fruit, seeds, and leaf. The two major enzymes in the mixture are papain and chymopapain, with less papain occurring but with twice the proteolytic activity of chymopapain. Commercially available “purified papain” usually consists of a mixture of the two enzymes and small amounts of other enzymes. An alkaloid carpaine occurs in the seeds and leaf, with traces in the unripe fruit. The air-dried seeds yield 660 to 760 mg/100 g of the aglycone of glucotropaeolin, benzyl isothiocyanate (BITC). The fruit is rich in vitamins B and C and traces of vitamin A and has a high content of potassium and other minerals. The leaves and the root yield the alkaloids carpaine, isocarpaine, and dihydrocarpaine I and II. 364 In the young leaves, the alkaloid content is about 0.28%. 365 The seeds also contain fixed oils, carbohydrates, glycosides, carpasemine, and benzene senevol. 366 The bark contains a pentalcohol, xylitol, and saponins.

Pharmacological Studies — The proteolytic activity of the enzymes has been exploited as an aid in digestive disorders and malabsorption syndrome. The crude enzyme preparation is used in wounds and surgical incisions to promote healing and prevent sloughing in infected wounds. 367 A related enzyme, leucopaine, has been shown to aid the regenerative processes of the injured tissue of rabbits and in treatment of purulent wounds in 303 patients under clinical conditions. 368 The papaya enzymes are used as a topical debriding agent, sometimes in conjunction with urea, in wound healing to facilitate wound cleaning from necrotic tissues, and to arrest local inflammation and purulent exudation. They are also applied in eye and spinal disorders.

The fruit is edible and rich in vitamin A and has some vitamin C; it is used in a variety of ways as a food and as a meat tenderizer. Chymopapain has been employed, with remarkable success, as an intervertebral disk injection in the lumbar spine (chemonucleolysis). For this purpose, it is recommended that the drug should be administered under local anesthesia rather than under general anesthesia. 369 The leaves have been shown to possess antiplasmodial activity against both chloroquine-sensitive and chloroquine-resistant P. falciparum. 370

Aqueous extract of Carica papaya (CP) leaves exhibited antitumor activity and immunomodulatory effects. 371 In human peripheral blood mononuclear cells (PBMCs), the production of IL-2 and IL-4 was reduced following the addition of CP extract, whereas that of IL-12p40, IL-12p70, interferon gamma (IFN-γ), and TNF-α was enhanced without growth inhibition. In addition, cytotoxicity of activated PBMCs against K562 was enhanced by the addition of CP extract. Moreover, microarray analyses showed that the expression of 23 immunomodulatory genes, classified by gene ontology analysis, was enhanced by the addition of CP extract. In this regard, CCL2, CCL7, CCL8, and SERPIN B2 were representative of these upregulated genes and thus may serve as index markers of the immunomodulatory effects of CP extract. It is interesting to note that the identified active components of CP extract, which inhibited tumor cell growth and stimulated antitumor effects, have a molecular weight of less than 1000. It has been suggested that the CP leaf extract may potentially provide the means for the treatment and prevention of selected human diseases, such as cancer and various allergic disorders, and may also serve as a immunoadjuvant for vaccine therapy. 372

The methanolic extract of the seeds showed male contraceptive activity in laboratory animals. 372 Treatment at various dose regimens daily for 52 weeks did not show significant changes in body weight, organ weight, food and water intake, or preterminal deaths compared to those of control animals. Sperm count and viability in animals treated with 50 mg/kg body weight and the weight of epididymis, seminal vesicle, and prostate of all the treated animals showed significant reduction compared to a control. Cauda epididymal spermatozoa of animals treated with 50 mg/kg body weight were immotile. Azoospermia was observed at various doses in the treated animals. Serum clinical parameters, serum testosterone, and histopathology of vital organs were comparable to those of control animals. It was also reported that the histology of testes revealed adverse effects on the process of spermatogenesis, while the histology of the epididymis, seminal vesicles, and ventral prostate showed no changes compared to the control. 373

Clinical Applications — The proteolytic enzymes are listed in most pharmacopoeia and are incorporated into proprietary products for digestive disorders. Papain has been given as enteric-coated tablets in a dose of 1.98 g with every meal to reverse a malabsorption syndrome that was incompletely controlled by gluten-free diet and considered to be due to transient gluten intolerance. 374 The enzyme is dispensed as an antitoxic agent for diphtheria and tetanus and is used externally for the healing of wound sores. A 4% w/v solution of the homogenized fruit pulp and 1% boric acid has been found effective in the healing of tropical sores. 313,314 Chymopapain is employed in the treatment of herniated disks by chymonucleolysis. Reviews of the use of chymopapain in the repair of disk disorders are available. 375,376

The alkaloids have broad-spectrum antimicrobial activity. Carpaine inhibits the tuberculosis bacteria, Mycobacterium tuberculosis, but in high doses possesses a digitalis-like action that may cause cardiac paralysis and depression. In small doses (0.01–0.02 mg/day p.o. or 0.006–0.01 mg/day s.c.), carpaine hydrochloride was found useful in hypertension. 377 Tropaoline is bactericidal and has been indicated for intestinal and injury infections. 368 Xylitol possesses antihemolytic activity and has been reported to lower bilirubin levels in rats intoxicated with parenteral administration of saponins. 378 A paste made from the leaves of pawpaw, mixed with opium and sodium chloride, applied for 3 days was helpful in the relief of symptoms and easy extraction of guinea worm from the body. 379 The leaf extract is also effective against dengue fever. 373

Toxicity — Allergic reactions to papaya appear to be common. 380 Rhinitis, asthma, and other allergic reactions are sometimes experienced by health professionals handling papain-containing powders. 367 A major adverse reaction associated with chymopapain is anaphylaxis, which can occur in up to 1% of patients. 381 Papaya, in addition to glucosinolates, contains low levels of cyanogenic glycosides (CNGs), an unusual occurrence because it was assumed that the two classes of metabolites were mutually exclusive. It is suggested that CNGs may be responsible for the antibiotic effects of the seeds and the laxative effect of the immature fruit. The accumulation of CNGs in the latex and leaves of papaya, although currently detected in edible parts at very low levels, may have potential human health implications. 382

Cassia Species (Cesalpiniaceae, Apg = Leguminosae)

Many members of the genus Cassia are indigenous to Africa, and several more have been introduced as ornamental plants. The major African species include Cassia abbreviata, C. fistula, and C. sieberiana. A recent revision of the genera Cassia and Senna has placed C. alata, C. acutifolia, C. angustifolia, and C. occidentalis as belonging to the genus Senna. They are mostly small shrubs with attractive flowers. They are used interchangeably with some Senna species.

Cassia Acutifolia

Botanical Name — Cassia acutifolia Del.

Synonyms — Cassia senna L., C. lanceolata, C. lentiva Brisch.

Family — Leguminosae

African Names — Arabic: sana, senamiki, sena; Hausa: illesko, rinji, filaskon maka; Peul: falajin, sanjerehi; Swahili: msahala

Description — It is a shrub or small tree up to 10 m tall and deciduous; young twigs are glabrous or hairy. Leaves are arranged spirally, paripinnately compound with 5–12 pairs of leaflets; stipules are linear, about 1.5 mm long and caducous; leaflets are ovate-elliptical to oblong-elliptical, 3–6 × 1–3 cm, with the base rounded to obtuse and apex obtuse to subacute. Inflorescence is a terminal, lax raceme, 0.5–9 cm long, and many flowered; bracts are persistent during flowering. Flowers are bisexual, slightly zygomorphic, 5-merous, and fragrant; sepals are obtuse; petals are oblanceolate to obovate, 15–35 × 7–18 mm, and yellow; stamens are 10, 3 with filaments about 3 cm long, 4 with shorter ones, and 3 with rudimentary ones; the ovary is superior, stipitate, with the style very short and stigma small. Fruit is a pendulous cylindrical pod 30–90 × 1.5–2.5 cm, transversely partitioned, dehiscent by 2 valves, woody, black, and many seeded with seeds embedded in pulp. Seeds are ellipsoid, 9–12 mm long, and brown to black. 1140

Habitat and Distribution — Cassia abbreviata is indigenous from Gabon east to Somalia and throughout southern Africa to South Africa. It has been introduced into Mauritius. The plant occurs in secondary forests and savannas.

Ethnomedicinal Uses — The plant is employed as a general tonic and laxative and mixed with other herbs for the treatment of various diseases. The leaves are smoked as a treatment for hematuria, whereas the smoke of smoldering twigs is inhaled to cure headache. A root infusion is kept in the mouth or roots are chewed and swallowed to relieve toothache. A root decoction or the dried powdered roots in water are drunk to treat gastrointestinal disorders, stomachache, bilharzia, venereal diseases, pneumonia, uterus complaints, heavy menstruation, and snakebites and used as a purgative, stomachic, aphrodisiac, abortifacient, and vermifuge. Malaria (including blackwater fever) is also treated with extracts from the roots. A water extract of the roots is used as an eyewash to cure eye inflammation. The powdered stem bark is applied to abscesses and added to food to cure diarrhea. A decoction of the stem bark is used as a purgative and to cure malaria and diarrhea. The seed is used as a tonic. 1140,1147

Constituents — The major constituents of Cassia species are anthrones and anthraquinones, amino acids, and proteins. The pods yield 2–5% anthraquinone glycosides, known as sennosides. They also contain kaempferol, chrysophanol, isorhamnetin, rhein, sennacrol, and cathartic acid. The leaves contain free anthraquinones, and the seeds do not contain anthraquinones. Triterpenes and organic acids have also been isolated from the leaves.

Pharmacological Studies — The fruits, leaves, and extracts of these parts of the plant, as well as the purified sennosides, are used in clinical medicine as a laxative, in various dosage forms. In laboratory studies, the extracts of the roots and leaves showed remarkable in vitro antiplasmodial activity, and the crude stem bark extracts caused a drop in blood pressure in rats, which was dose dependent. The stem extracts also exhibited no abortifacient activity in pregnant mice and no apparent toxicity to the animals. Methanol, acetone, and water extracts of the stem bark showed significant inhibition against a number of Gram-positive and Gram-negative bacteria. Tests of a root extract showed only modest levels of cytotoxicity. 1140

Catha Edulis

 

Botanical Name — Catha edulis Forsk

Synonyms — C. forskalii A. Richard, Celasterus edulis Vahl., Methyscophyllum glaucum E. & Z., Dillonia abyssinica Sacleux

Family — Celastraceae

Common Names — Khat, kat, Abyssinia kat, African tea, Arabian tea, Boesmans tea, bushman’s tea, cafta, ciat, chrinda redwood

African Names — Kikuyu: Kambo: mira, miraa; Rungwe: Msuruti, msuvuti; Shambala: mandama, mfeike, m’mke; Shona: muysawhare, muzaramashawa; Somali: mulungi; Swahili: mlonge

Description — Catha edulis is a small tree in its cultivated form, but in the wild state the plant can grow to a height of 25 m. The plant is polymorphic, with the branches having either opposite or alternate leaves. Khat leaves are brownish green and leathery, with a glossy upper surface. They have a faintly aromatic odor and an astringent and slightly sweet taste. The mature leaves are usually 1–4 cm wide and 5–10 cm long with a serrated edge and are elliptical or lanceolate in shape. Anatomical differentiation of the species is often unreliable, and the use of chromatographic identification has been advocated. 383

Habitat and Distribution — It is a native to Somalia, Ethiopia, and Djibuti. It is a savanna crop and prefers dry elevated regions.

Ethnomedicinal Uses — Khat chewing has been common in some countries of East Africa and the Arabian Peninsula for many centuries. Khat chewing has a stimulating effect on the CNS and was an effective inhibitor of the sensations of hunger and fatigue. The use of khat for the treatment of depressive states was known as early as AD 1237 by the Arabian physician Naguib Ad Din, who reported its use for that purpose. 384 The plant is usually chewed when fresh, and the younger leaves are preferred because they are more potent and are also more tender to chew. It takes 3 to 5 years for a newly planted khat tree to produce mature harvestable leaves. The shoots at the tips of the branches are cut in the early hour of the morning, bundled, and then usually wrapped in banana leaves to preserve their freshness; the material is speedily transported to the market to be sold by late morning. 385 Since khat leaf rapidly losses its effect on wilting, the khat habit remained endemic mainly at the areas where the plant is grown. The major countries where khat is grown include Ethiopia, Kenya, Saudi Arabia, Sudan, Malagasy, Somalia, and Yemen Arab Republic, where many houses have a room called muffraj that is set aside and specially arranged for regular sessions of khat chewing. With improved transportation and communication, the habit has spread to other parts of Africa and Arabia. It has been reported that shipment of khat has been observed by customs departments in Europe and the United States. 385

Khat chewing has taken deep roots in the social and cultural tradition of the natives of the region where the plant is grown. The leaves are frequently chewed by craftspeople, laborers, and farmers to reduce physical fatigue, and the masticated plant material can be observed as a bulge in the cheek of consumers. The juice from the bolus stored in the cheek is swallowed; the residue is ejected and replenished with fresh plant materials as desired. In the traditional social setting, khat is employed during weddings and burials and as a beverage during important family events.

In the United Kingdom, there has been a growing khat trade in immigrants from the Horn of Africa, and it is fast becoming a major social problem. Although the World Health Organization in 1980 classified khat as a drug of abuse that can produce mild-to-moderate psychological dependence, it is not illegal in the United Kingdom to import, sell, buy, transport, or consume khat. It is legal, in the unprepared plant form, in the United Kingdom and the Netherlands but is a controlled substance and illegal in the United States, Canada, Australia, New Zealand, Denmark, Finland, Germany, Norway, and France. 386

Constituents — There is no agreement on the actual constituents of khat and those that are artifacts produced during extraction of the plant material. The khatamines (−)-cathinone, (+)-norpseudoephedrine and the related phenylalkylamines are the major components found in fresh leaves of Catha edulis. Another group of alkaloids found in khat leaves is the cathedulins, with molecular weight ranging from 600 to 1200. 387,388 The cathedulins are polyesters or lactones of sesquiterpene polyols. A representative structure for the members of this group is that reported for cathadine D. 389

The plant also contains volatile oils, 390 flavonoids, 391 sterols, and triterpenes, 392 as well as proteins, vitamins, and minerals. The phenylalkylamines are, however, responsible for the observed CNS stimulant activity, and (−)- cathinone accounts for more than two-thirds of the total phenylalkylamines present. The market value of the drug is usually determined by the (−)-cathinone content of the plant.

Pharmacological Studies — The structure of the active constituents of khat, (–)-cathinone and norpseudoephedrine, closely resembles that of amphetamine, and this similarity is further evident by the amphetamine-like properties of the khatamines. (–)-Cathinone exhibited a positive inotropic and chronotropic effect on isolated guinea pig atria. The compound at a bath concentration of 10 μg/ml had twice the activity of either (+)-norpseudoepedrine or (+)- amphetamine. The three compounds were equipotent in increasing the heart rate when injected intravenously (1 mg/kg) in anesthetized rats. In anesthetized cats, intravenous injection of (–)-cathinone caused a transient rise in the blood pressure by 30 to 35 mm Hg. The pressor effects of (–)-cathinone were, however, inferior to those of (+)-norpseudoepedrine and (+)-amphetamine, and with the khatamines, the pressor effects were characterized by the rapid development of tachyphylaxis. 393

Other amphetamine-like activities of the khatamines include the enhancement of electrically induced constriction of rat and guinea pig vas deferens, potentiation of noradrenergic transmission, increased lipolysis, and sympathomimetic effects usually associated with amphetamine. The phenylpentenylamine alkaloids also found occurring in khat leaves showed only weak effects on dopamine release and therefore are considered unlikely to contribute to the stimulating properties of khat leaves. 394 The flavonoid fraction of khat, when administered at a dose of 200 mg/kg orally, produced significant anti-inflammatory activity against the carrageenan-induced paw edema and cotton pellet granuloma. 395 An aqueous solution of the methanol extract of khat has been shown to possess a likely mutagenicity on male germ cells following chronic oral administration to albino mice. 396 The chloroform extract has been shown to exert cytotoxicity against a variety of cultured mammalian cell lines, including KB, 1BR.3, and XP2bi, and the effect may be due to inhibition of de novo RNA synthesis. 397 (–)-Cathinone has also shown a mitodepressive effect on the dividing cells of Allium cepa root tips. 398

Another form of khat use is via a semisynthetic methyl derivative of cathinone called methcathinone, an illicit drug also known as ephedrone. Its intoxication is difficult to diagnose and cure properly for two reasons: (1) Target consumers are usually “well-educated people” aware of the risks and precautionary measures, and (2) intoxication by cathinone derivatives of synthetic or natural (derived from the khat) origin induce misleading symptoms. 399

Clinical Properties — The effects of chewing khat are contained in recent reviews on the subject. 385,400402 The effects of the drug, which closely resemble those of amphetamine, include sympathetic activation, anorexia, euphoria, increased intellectual efficiency, and alertness. 402 The subjective effects reported by users of khat also include relief from fatigue, enhanced creativity, hyperactivity, and mild analgesic activity. Khat chewing by pregnant women appears to be deleterious to the fetus. It has been reported that healthy full-term singletons, born after uneventful pregnancies and deliveries, had a significantly lower birth weight when the mothers were khat chewers. 403 Norpseudophedrine was found to be excreted in breast milk in several lactating women who chewed khat leaves, and the compound was also detected in the urine of the breast-fed infants. 404

The effects of the “flower of paradise,” as khat was once called, are short lasting, and like coca, the leaves have to be replenished several times in the day to maintain the state of euphoria. It has been observed that after 2 h of consumption of khat, the initial gaiety and the loquacity brought about by the reduction of social inhibition soon give way to tension, depressive tendencies and sluggishness, and logorrhea, which brings the khat-chewing session to an end, usually with the discussions becoming animated with loud talk often unrelated to the subject under discussion.

Toxicity — Khat chewing causes gastrointestinal disturbances. The high concentration of polyphenolic tannins in khat causes constipation, periodontal diseases, mucosal lesions, and increased risk of esophageal cancer. The drug induces cardiac arrhythmias, and the cardiovascular response to physical effort is exaggerated. Habitual use of the drug may change to a transient hypotensive state on abstinence. 395

The mutagenicity of khat has been evaluated in animal studies, and it has been established that the intravenous administration of khat induced nucleic acid synthesis in brain and liver and produced abnormalities in bone marrow. 405 The drug therefore has possible carcinogenic and teratogenic properties. Habitual khat use causes spermatorrhea, which is sometimes accompanied by testicular pain, and impairment of male sexual function, which may lead to impotence. Khat consumption causes several adverse sympathomimetic effects, including mydriasis, dryness of the mouth, and increases in respiratory and pulse rate. Chronic consumption has led to liver failure. 406

The habitual consumption of khat has been implicated in many socioeconomic problems of the endemic regions. In Djibouti, where khat is used by 90% of the men and about 10% of the women, the drug consumed up to a third of the earned wages. Within the family, the drug affects family interaction, with the father becoming more irritable and quarrelsome while high on the drug or silent and withdrawn when the effect has worn off. The drug has been identified as the causative factor in one of two divorces in Djibouti, attributed to its effect on the male reproductive system and the subsequent estrangement between husband and wife. 407 The importation of the drug also causes a severe strain on the country’s balance of payment, while a special khat sales tax accounts for 10% of the government’s revenue. In the communities where khat is consumed, there is a general agreement among observers that there is high incidence of absenteeism and decreased productivity, which leads to unemployment and poverty.

It has been reported that there is a Somali saying that, “Children play, women work, and the men chew khat.”

Catharanthus Roseus

 

Botanical Name — Catharanthus roseus (L). G.Don

Synonyms — Lochnera rosea Reichenb. F., Vinca rosea L., Pervinca rosea (L.) Moench., Lachnea rosea (L.) Rchb., Hittonia littoralis Lour., Ammocallis rosea (L.) Small

Family — Apocynaceae

Common Names — Madagascar periwinkle, periwinkle (English), pervenche de Madagascar (French)

Description — Catharanthus roseus is a small, erect perennial subshrub reaching 80 cm in height; it is profusely branched and produces milk latex. The leaves are oblong elliptic, 2 to 7 cm long and 1.5 to 3 cm wide, opposite, smooth and rounded at the apex, with a short petiole. They are slightly bitter, the epidermis is glabrous with some fibers, and they turn slightly green with iodine. The flowers are solitary or twin, axillary, white or pink, and are borne all year in upper leaf axils. The color of the flowers is used to characterize the varieties: variety album is white with a grayish-yellow eye; variety roseus, or forma violacea, is lavender-pink with a purple-red eye; and white with a purple-red eye is characteristic of variety ocellatus, or forma oculata. The fruits are follicular with two subulated mericaps and numerous black small seeds. 9,28,353

Habitat and Distribution — The plants grow in most parts of tropical and subtropical Africa. They are used as ornamental herbs throughout the continent.

Ethnomedicinal Uses — Aqueous extract of the leaves has been used as a laxative. The plant is reputed to be used in southern Africa as an antidiabetic. In eastern Transvaal, the plant is taken as a remedy for ingestion dyspepsia. Catharanthus has been used also in other continents as a medicinal plant. In Britain, a patent medicine, called Vinculin, was sold for many years as a cure for diabetes. In South and Central America, the infusion of the plant is employed, among other things, for the treatment of laryngitis and sore throat and as an eye bath.

Constituents — The plant contains at least 63 indole alkaloids, of which 2 of them, vincaleukoblastine (vinblastine) and vincristine (leurocristine), are dimeric compounds used in clinical medicine for the treatment of certain forms of cancer. Other alkaloids found in the plant include reserpine, ajmalicine, alstonine, and their congeners. The leaf volatile oil contains loganin and sulfurous compounds. 408 Organic acids have been shown to be major constituents, including protocathechuic, caffeic-p-hydroxybenzoic acid, and ursolic.

Pharmacological Studies — The dimeric alkaloid vincaleukoblastine is used in the treatment of Hodgkin’s disease and choriocarcinoma. Vincristine is administered in the treatment of childhood leukemia and breast cancer. The two drugs are combined in chemotherapy and sometimes with steroids for different types of carcinoma with good results. A concentrated aqueous extract, when given parenterally, lowered the blood sugar level in cats and abated the symptoms in human diabetes. 367

The alcoholic extracts demonstrated in vitro antibacterial activity, and the ethanolic extract gave a maximum zone of inhibition (21.15 ± 1.64 mm) against Salmonella typhi (S. typhi) and a minimum zone of inhibition (06.24 ± 0.69 mm) with ethanolic extract against Staphylococcus aureus. The methanolic extract gave a maximum (15.61 ± 1.35 mm) against S. typhi and a minimum (05.20 ± 0.86 mm) zone of inhibition against Escherichia coli. 409 The phenolic and organic acids found in the roots have been evaluated as potential antioxidants. 410

Centella Coriacea

 

Botanical Name — Centella coriacea Nannf.

Related Species — C. asiatica (L.) Urban.

Family — Apiaceae

Common Names — Pennywort, pepperwort

African Names — Arabic: herba, centella; Sotho: bodila-ba-dinku

Description — Centella is a small tropical plant with kidney-shaped leaves up to 2 cm wide and 1 cm long. The margin is crenate, and the apex is rounded. It is native to Asia, and most of the available supplies are obtained mainly from Asia. 28

Habitat and Distribution — It is distributed in savanna and secondary forest clearings. The plant grows in North Africa, Senegal, Ivory Coast, northern Nigeria, Kenya, and southern Africa.

Ethnomedicinal Uses — The drug is used in both Africa and Asia as a remedy for leprosy and lupus. In East Africa, it has been dispensed for fevers, abdominal distress, and venereal diseases. The Xhosa and the Mfengu of southern Africa use the leaves as a food vegetable. 79 The plant is used in West Africa as a fever remedy and as an ingredient in steam treatment of malaria.

Constituents — Hydrocotyle yields a volatile oil, the principal components of which are β-caryophyllene, β-farnesene, germacrene D, β-elemene, and bicycloelemene. 411 The plant contains several saponins, including centelloside, madecassoside, asiaticoside, oxyasiaticoside, brahmoside, thankuniside, and brahminoside and the related terpenoid aglycones, such as centellinic, brahmic, madecassic, betulic, and Asiatic acids. 412,413

Pharmacological Studies — The plant has been employed in folk medicine for a long time in the treatment of various skin diseases. Several proprietary products available in Europe containing Centella are indicated for the treatment of indolent ulcers, wounds, and keloid and hypertrophic scars. The drug has been found useful in the management of postoperative wounds and in the prevention and treatment of scarring from burns. 414 The wound-healing properties of a tincture of Hydrocotyle have been confirmed by a controlled clinical trial. 369 The drug inhibits the growth of human fibroblasts in vitro 415 and was found effective in patients with venous disorders of the lower limbs. 416

Chasmanthera Dependens

Botanical Name — Chasmanthera dependens Hochst

Family — Menispermaceae

African Names — Igbo: ogbo; Yoruba: ato oloriraun

Description — The plant is a woody climber with a rough stem. The young stem is hairy. The leaves are oval or rounded, 3–10 cm long and about the same size in width. The leaf surface is papery and sparsely hairy on both sides. It has a heart-shaped base, and the apex is very shortly drawn out; the stalks are leafy and up to 30 cm long. The plant produces many flowers in the axils of the leaves; they are tiny and hairy and borne on long, slender common stalks covered with soft hairs.

Habitat and Distribution — It grows in wild forest margins and savanna, especially in rocky terrains. It is cultivated as a medicinal plant in West and Central Africa. The plant is distributed from Sudan in the north to Ghana in the West Coast and spreads down to Ethiopia and South Africa. 9,77

Ethnomedicinal Uses — The root is used as a decoction for the treatment of venereal diseases. Fresh leaves are rubbed on sprained joints and bruises, used as a dressing for fractured limbs, or mixed with shea butter and used as an embrocation for pains and stiffness. A general tonic for physical and nervous debilities and for inflammatory and exhausting diseases is produced by boiling the stem bark.

Constituents — Chasmanthera and the other members of the plant family Menispermaceae contain nonnitrogenous bitter principles such as chasmanthin, columbin, and palmatine. Berberine-type alkaloids, palmatine, colombamine, and jateorhizine also occur in the plant.

Pharmacological Studies — Berberine sulfate inhibits Leishmania tropica in very low concentrations. The compound also possesses uterine stimulant activity. 417 A methanol extract of the dried leaves of Chasmanthera dependens exhibited anti-inflammatory and analgesic activities. The extract (100–400 mg/kg p.o.) produced dose-related inhibition of carrageenan-induced paw edema and cotton pellet-induced granuloma in rats. The extract also inhibited the leakage of Evan’s blue induced by acetic acid in mice. The analgesic property was determined by its effect on writhing response induced by acetic acid as well as on the early and late phase of formalin-induced paw licking in mice. 418

Chlorophora Excelsa

Botanical Name — Chlorophora excelsa (Welw.) Benth. & Hook.

Synonyms — Maclura excelsa (Welw.) Bur., Chlorophora tenuifolia Engl., Chlorophora alba Chev.

Family — Moraceae

Common Names — Iroko, African oak

African Names — Bini: iroko; Hausa: ioko; Igbo: orjih; Kisi: kemo; Lunda: sanga; Runqwa: mwala; Yoruba: rook; Zinza: msule.

Description — The iroko tree is a large, tall tree, growing to more than 60 m high and exceeding 2.5 m in diameter; the bole is straight and cylindrical with about 25 m clear of branches. The trunk is gray to dark brown or blackish, smooth at first, later rough and flaking, seldom fissured, with slash cream with brown spots exuding a copious white latex. It is sometimes deciduous, dioecious (rarely monoecious) with short buttresses, blunt, and sometimes with rootspurs and large exposed reddish-brown lateral roots with horizontal lenticels. The branches are ascending, forming a flat crown that graces the forest canopy it occupies. The foliage is dark green and dense. The leaves are simple, with alternate petiole 2.5–6 cm long, stipules 0.5–5 cm long; the blade is broadly elliptic, 10–25 cm long, 5–15 cm wide, with an apex rounded with a very short acuminate tip, a base unequally cordate or sometimes rounded, margins entire, and thick glabrous above and below except for minute hairs between the network of veins; lateral veins are 10–22 pairs, up-curving near the margin, prominent, and looped below. The leaves of the seedlings and saplings are slightly different in shape, appearing oblong-elliptic, with serrate margins and densely hirsute below. 33 It produces greenish flowers with protruding styles. The fruits are borne on subcylindrical, wrinkled syncarp, 4–7.5 cm in diameter and fleshy. 9

Habitat and Distribution — The plant is a prized inhabitant of the rainforest belt, and sometimes in deciduous, semi-deciduous, or evergreen forests, often in gallery forests, and sometimes in isolated relic forests. The plant grows better in well-drained soils and is intolerant of impeded drainage. Its very tall size is partly due to its high light demand, and it must grow above the dense forest setting to survive. The plant is widespread in tropical Africa, occurring in Senegal, Sierra Leone, Ghana, Ivory Coast, Benin, Kenya, Tanzania, Zaire, Mozambique, Malawi, and Zimbabwe.

Ethnomedicinal Uses — The leaf extract and the embrocation prepared with it are used in West Africa as fungicides and as a tropical antibacterial agent. In Ghana, parts of the plant are used for the preparation of cough remedies, especially for bronchitis. The stem bark is an ingredient in a mixture used in a hip bath for venereal sores and as a wash for chancre. 6 The ashes from the bark with palm oil are rubbed on swelling in Liberia. In southern Zaire, the latex is used to reduce tumors and obstructions of the throat and for stomach diseases, 273 and the bark infusion is used as a purgative. The latex, infusion of the bark, and soups prepared with the leaves have been administered to aid lactation. 198 The leaf decoction has been used in Sierra Leone as a wash for fevers. 6 It is also applied as an enema for the cure of piles, diarrhea, and dysentery. The pounded bark mixed with the kernel of Okoubaka aubrevillei fruit is dispensed as an alcoholic extract for the treatment of hemorrhoids.

The species has been listed as an ingredient for the preparation of a remedy for leprosy, cardiac diseases, lumbago, and general fatigue and is taken orally or in a sitz bath for the treatment of elephantiasis of the scrotum. 33 The roots are employed in northern Nigeria as a remedy for rheumatism. 419 Among the Igbo of southern Nigeria, the plant is considered sacred and is featured in rituals and ceremonies.

Constituents — The plant is believed to contain a high quantity of calcium salts in the wood, of which calcium carbonate is the dominant compound. 420 A phenolic substance called chlorophorin has been shown to be present in the plant. 199

Pharmacological Studies — The plant extract has been found active against the wood termite Reticuli termis. 421 The phenolic compounds found in the plant are fungicidal. The latex has been used as an oral application to aid in the extraction of carious teeth. 422 Chlorophorin and Iroko exhibited remarkable broad-spectrum antimicrobial activity and have shown the potential to be exploited as natural multifunctional safe control agents in the treatment of bacterial, fungal, and protozoal infections. 423

Chromolaena Odorata — Eupatorium

 

Botanical Name — Chromolaena odorata (L.) R.M. King & H. Rob.

Synonyms — Osmia odorata (L.) Schultz.; Eupatorium odoratum Willd.

Family — Compositae

Common Names — Baby bush

African Names — Igbo: obialofulu, obiarachu, akwukwo-Eliza, etc.; Yoruba: akintola-ta-ku

Description — It is an erect or scrambling, much-branched shrub, growing up to about 3 m high. The leaves are alternate or opposite in pairs; usually, they are simple ovate-lanceolate, abruptly narrowed at the base, and acute or acuminate at the tip; they are 5–15 cm long, toothed and three nerved; rarely, they are whorled and without stipule; they are odorous, with a gland dotted beneath. It produces numerous small individual flowers called florets, usually white to light mauve in color; achenes are 5 angled, 4 mm long with many spreading bristles. The florets are of one or two kinds in each capitulum: hermaphrodite, unisexual or neutral, rarely dioecious. The fruits are one seeded, indehiscent, nearly always dry; the seed has no endosperm, but the embryo is straight with planoconvex cotyledons.

Habitat and Distribution — It is a native of the North and South American subtropics and tropics but is almost pantropic having been introduced to tropical regions of Asia, Africa, and the Pacific. It is a common weed found in waste places, along roadsides, and in neglected farmlands.

Ethnomedicinal Uses — A decoction of the leaf is valued in traditional medicine as a cough remedy and as an ingredient with lemongrass and guava leaves for the treatment of malaria. The juice pressed out of the crushed leaves is applied to cuts to stop bleeding. The fresh leaves in limited quantities have been used to enrich the fodder for domestic animals. Other medicinal uses include as an antidiarrheal, astringent, antispasmodic, antihypertensive, anti-inflammatory, and diuretic. 424

Constituents — Odoratin (2′-hydroxy-4,4′,5′,6′–tetramethoxychalcone), the rarely occurring flavone salvingenin, the triterpene alcohol lupeol, and β-amyrin have been isolated from this shrub. 439 Also found occurring in the leaves are the flavonoids isosakuranetin (5,7-dihydroxy-4′-methoxyflavone) sakuranetin, and quercetin. 425 Differential solvent extraction of the leaves showed lupeol, β-amyrin, and isosakuranetin in the light petrol extract; the chloroform extract yielded kaempferide and betuletol, while the polar alcohol extract gave sakuranetin, 3,5,7,3′-tetra-G-methvlquercetazetin, and quercetin. The aqueous extracts were chromatographed on polyamide plates to yield sakuranetin-7-O-arabinoside and isosakuranetin-rhamnoglucoside. 426 The roots have been shown to contain a diterpenoid, 15-angeloyloxy-16,17-epoxy-19-kauronic acid, along with five known metabolites (16-kauren-19-oic acid, 6′-hydroxy-2′,3′,4,4′-tetramethoxychalcone, isosakuranetin, acacetin, and kaempferide). 427

Pharmacological Studies — The chloroform and acetone extracts of the plant exhibited significant in vitro antimicrobial activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Aspergillus niger, while the alcoholic and aqueous extracts were inactive. 430 The chloroform extract, which contained mainly isosakuranetin and kaempferide, displayed the maximum inhibitory activity on all the microorganisms tested. The aqueous extract of the leaves showed hepatotropic activity in vitro. 364 The aqueous alcoholic extract of the plant has been found to possess in vitro antispasmodic activity in the guinea pig ileum and blocked the histamine-induced spasms. 428 The chloroform-soluble extractive has been shown to be cytotoxic to cell line CA-9KB, with an IC50 of 20 μg/ml. 429 The isolated flavonoids, however, did not show any significant activity. Kaurenoic acid found in the roots has significant α-glucosidase inhibitory and antibacterial activities against Escherichia coli and Bacillus subtilis.

Chrysophyllum Albidum

 

Botanical Name — Chrysophyllum albidum A. DC.

Synonyms — Gambeya albida (G.Don) Aubrev. & Pellegr., Planchonella albida (G.Don) Baehni.

Family — Sapotaceae

Common Name — White star apple

African Names — Ashanti: adesawa, adesaa; Bini: otien; Ewe: adansawa; Igbo: udara, udala; Twi: adios, asamfona-fufu; Yoruba: osan

Description — Chrysophyllum albidum is a tree up to 30 m high and about 2.5 m in girth, with small buttresses at the base. The bole is long and often straight, occasionally branched low down. The bark is grayish brown, with crisscross depressions and a pale brown slash, and exudes copious, gummy white latex. The leaves are oblanceolate, acuminate at the apex and wedge shaped at the base, about 30 cm long and 8 cm wide. The lower surface is densely covered with silvery white or faintly yellowish silky hairs. It has a channeled midrib, with 10–15 pairs of lateral nerves; venation on the lower surface is not very distinct. The flowers are borne in clusters in the leaf axils and are shortly stalked, small and yellow; sepals are about 2.5 mm long and covered with minute yellowish hairs. The fruits occur in January–February; they are edible, glabrous when mature, ovoid to subglobose, pointed at the apex, up to 6 cm long, and pale orange when ripe. A cross section of the fruit, like that of C. africanum, reveals seeds arranged as a star. The seeds are 2.5 × 1 cm, with one sharp edge and the other blunt. 9

Habitat and Distribution — Often cultivated, the wild species occur in closed forests and in the lowland rainforest regions. It is distributed from Gambia, Sudan, and Uganda to parts of South Africa.

Ethnomedicinal Uses — The bark is used in southern Nigeria as a remedy for malaria, sleeping sickness, and yellow fever. The Igbo regard the plant as a symbolic tree for the creative spirits, and it is featured in healing rituals for female infertility. The leaves are used as emollients and for the treatment of skin eruptions. The leaf decoction is administered for diarrhea and for stomachache. The fruit pulp is taken by pregnant women to prevent nausea.

Constituents — The leaves and stems have been shown to contain β-amyrin acetate, 430 gentisic acid, 28 and alkaloids. 431,432 The isoprene content of the latex has been characterized and was found to consist of polyisoprene, 1–4. 433 The fruits are rich in ascorbic acid.

Pharmacological Studies — The methanol extract of the seeds and roots exhibited antihistaminic activity and potentiated the effects of antihistamine agents. The extracts also produced hypotension with simultaneous depression in respiration when administered to cats. 434 At a concentration of 100 ppm, the methanol extract of the seeds was found to possess strong molluscicidal activity against schistosomiasis-transmitting snails. 435

Cinchona Succirubra

Botanical Name — Cinchona succirubra Pav. ex Klotzsch

Synonym — C. pubescens Vahl.

Family — Rubiaceae

Related Species — C. ledgeriana, C. calisaya (calisaya bark or yellow cinchona), Cinchona officinalis Linne (pale cinchona or Quinquina). Each species consists of several hybrids; the pharmacognostic specification is that the crude drug must yield not less than 5% of Cinchona alkaloids, of which at least 50% consists of quinine and cinchonine.

Common Names — Peruvian bark, Jesuit bark, fever tree

African Names — Arabic: kina; Swahili: mkwin

Historic Notes — Cinchona has enjoyed a rich history and very colorful legend for many centuries. Legend has it that the plant derived its name from the wife of the viceroy of Peru, Countess Anna del Chinchon, who was allegedly treated with the drug in 1638, and that her miraculous cure resulted in the introduction of Cinchona into Spain in 1639 for the treatment of ague. Although the drug has been known for many years as “los polvos de la Condesa,” there is no evidence that the countess ever used the drug. The name of the plant may have been derived from the Incan word Kinia, which means “bark.” The drug’s other names, “Jesuit bark” and “cardinal’s bark,” are due to the fact that the Jesuit fathers controlled the trade in Cinchona bark for a long time, and its introduction into Rome and other parts of Europe is credited to the eminent philosopher Cardinal de Lugo.

Description — Cinchona stem bark occurs in quills or flat pieces up to 30 cm long, 1–4 cm wide, and 3–8 mm thick, with the outer surface gray or grayish brown to reddish brown, usually fissured with an exfoliating cork, and bearing whitish, green, or gray lichens or mosses, more or less rough, with or without reddish warts. It has a pale yellowish-brown to brown inner surface with fine-to-coarse longitudinal striations. The fracture is fibrous, the taste is bitter and astringent, and the odor is very characteristic but faint. The microscopic characteristics of Cinchona are described in African Pharmacopoeia. 436

The genus Cinchona consists of about 40 species, occurring as shrubs or medium-size trees, growing up to 30 m in height. The leaves of C. succirubra (ca. 20–25 cm long) are hairy below, elliptic to obovate-lanceolate, simple, entire, and evergreen with prominent midrib and lateral veins. The flowers are borne in terminal panicles, are pinkish or whitish and fragrant; they are tubular with a 5-flaring capsule, which splits open at the base when ripe to reveal 40 to 50 flat, slender, winged seeds.

Habitat and Distribution — Cinchona is native to the mountainous regions of tropical America from where it has been introduced to Africa. The plant is cultivated in Cameroon, Congo, Rwanda, and Tanzania.

Ethnomedicinal Uses — Cinchona yields up to 16% of quinolone alkaloids, consisting mainly of quinine, quinidine, cinchonine, and cinchonidine and their epimers and hydroxyderivatives. The plant also contains other alkaloids, such as cinchonamine, quinamie, and the tannin conjugates of these alkaloids known as cinchotannic acids. Tannins, resins, and waxes co-occur with these alkaloids.

Pharmacological Studies — The Peruvian bark Cinchona has been recognized as a potent antimalarial agent since the seventeenth century. The drug is antiplasmodial, febrifuge, orexigenic, spasmolytic, astringent, and tonic. Quinine and quinidine are the most clinically important of the Cinchona alkaloids; quinine is the most potent of the alkaloids as an antimalarial, whereas quinidine has stronger cardiac depressant activity. Quinine is used clinically for the treatment of malaria, especially in infections by parasites that are resistant to the newer synthetic drugs.

Quinine — Quinine, C20H24N2O2, (8S, 9R)-6′-methoxycinchonana-9 ol; (αR)-α-(6-methoxy-4-quinoyl)-α-[(2S, 4S, 5R)-(5-vinylquinuclidin-20yl)] methanol, is the most important alkaloid occurring in Cinchona. The compound was first isolated in 1820 by Pelletier and Caventou. It is available as the bisulfate, dihydrochloride, and sulfate. Quinine sulfate is a colorless or white, odorless, fine acicular crystal or a white or almost white crystalline powder that darkens on exposure to light; the hydrochloric occurs as colorless, fine, silky, acicular crystals, and the dihydrochloride is a white or almost white odorless or almost odorless powder. Quinine salts have differential solubility; the hydrochloric is soluble in a ratio of 1:23 in water, freely soluble in alcohol and chloroform, and very slightly soluble in ether. The dihydrochloride is soluble in a ratio of 1:0.5 in water and 1:14 in alcohol; the sulfate is soluble in a ratio of 1:500 in water and 1:20 in alcohol.

Pharmacological and Clinical Properties — Quinine is a rapidly acting blood schizonticide used orally for the treatment of malaria. It has activity against the blood schizonts of Plasmodium falciparum, P. malariae, P. vivax, and P. ovale and the gametocytes of P. malariae and P. vivax, but is not active against P. falciparum gametocytes. The compound has no activity against the exoerythrocytic forms of the infection and therefore does not produce a radical cure in malaria due to P. vivax or P. ovale.

Quinine, its congeners, and salts are readily absorbed when given orally or intramuscularly. In the treatment of uncomplicated attacks of falciparum malaria due to chloroquine- or multidrug-resistant strains, quinine is given by mouth at dose of 1.8 to 2 g in three divided doses for at least 7 days. Following oral administration, over 80% of the drug is absorbed mainly from the upper small intestine, and peak plasma concentrations are achieved within 1 to 3 h. The dosage is adjusted according to the salt used, and corresponding lower doses are indicated for children. In complicated or severe cases of malaria for which it may not be suitable to give the drug orally, quinine is administered by the parenteral route, usually as a slow intravenous infusion. About 90% of plasma quinine is bound to proteins; the concentration of the alkaloid in the cerebrospinal fluid is only about 2% to 5% of that in the plasma, and the drug readily crosses the placenta. 437

Quinine has been used with clindamycin in the treatment of babesiosis and cryptosporidiosis infections. The drug has also been useful in the treatment of nocturnal leg cramps, and the incidence of cramps among patients during hemodialysis was found to be less among those given quinine. The drug possesses mild analgesic and antipyretic activity. Quinine is used in low doses as a bitter tonic and flavoring agent; a concentration of 0.03% is employed in carbonated tonics and “bitter lemon” drinks.

Toxicity — In therapeutic doses, when quinine is repeatedly administered, a cluster of characteristic symptoms called cinchonism may develop. These include ringing in the ears, headache, nausea, and visual disturbance. Increased doses intensify these symptoms as well as cause gastrointestinal, cardiovascular, and dermal effects. Visual dysfunction and functional impairment of the eighth nerve, which result in tinnitus, decreased auditory acuity, and vertigo, are common manifestations of quinine toxicity. It has also been observed that therapeutic doses of quinine and its congeners may lower blood glucose concentrations by stimulating insulin secretion. 438,439 Recurrent hyperinsulinemic hypoglycemia should be considered very seriously when these alkaloids are used during pregnancy or when there are severe infections with the attendant malaise and anemia. The lethal dose of quinine in adults is about 8 g, although death has resulted in doses as low as 2 g in hypersensitive individuals.

Clutia Abyssinica

Botanical Name — Clutia abyssinica Jaub. & Spach.

Synonyms — Nil

Family — Peraceae

African Names — Chagga: indundu; Hehe: nyakirunbi; Masai: engemarna; Shambala: mhende, muhende; Xhosa: umbezo

Description — Clutia abyssinica is a shrub, up to 2 m high, sparsely branched with glabrous twigs. The leaves are lanceolate or elliptic-lanceolate, tapering to an obtuse apex and narrowed at the base.

Habitat and Distribution — It is found at high elevations and in dry grassland. The plant is distributed in Tanzania, Kenya, Zimbabwe, Ethiopia, and South Africa.

Ethnomedicinal Uses — Clutia species are used for the preparation of a malaria remedy. The leaves are used as an oral decoction for the treatment of hepatitis and externally as a local anti-inflammatory and as a medication for sores. The root extract is employed in the treatment of threatened abortion, convulsions, influenza, and enlarged spleen and for the management of habitual miscarriage. A weak infusion of the roots is administered for stomachache and chest pains.

Constituents — Methylcoumarins, including coumarin, 4-methoxy-3,5-dimethylcoumarin, 5-methyl-4-thiomethyl, pereflorin, and 8-hydroxyperiflorin, have been isolated from the roots. 440 The roots also yield flavonoids and diterpenes, 441,442 as well as the sesquiterpenes bergamotene, cadiene, α- and β-cuberene caryophyllene, santalol, and selinene, which occur in the volatile oil. 443 The leaf also yields volatile oil, which consists of farnesyl acetate, α-farnesene, kaurane, 16-β-17-dihydroxy, β-ionone, methyl palmitate, and alkanes and several other trace compounds. 443

Pharmacological Studies — The methanol extract has been shown to exert a weak relaxant activity on guinea pig smooth muscle, a uterine stimulant effect, and no effect on skeletal muscle. 444 The alcohol extract of C. richardiana exhibited inhibitory activity against both Gram-positive and Gram-negative bacteria. 445 Extracts of Clutia species have been found to be devoid of in vitro antimalarial 446 or cytotoxic activity. 296

Cocculus Pendulus

 

Botanical Name — Cocculus pendulus (J.R & G. Forst.) Diels

Synonym — C. leaba (Del.) DC.

Family — Menispermaceae

African Names — Falor: tiati; Songhai: lilgui; Wolof: tiahat, mboum sehel; Tukulor: safatou

Description — This is a slender climbing shrub, but it is prostrate in open forests. It has thin, glabrous branches. The leaves are glabrous, variable, entire (sometimes obscurely lobed), and ovate-lanceolate. Male and female flowers are borne, with the male in axillary fascicles and the female single or paired. It produces red subglobose fruits.

Habitat and Distribution — It is a semitropical plant, occurring mainly in savanna vegetation. It is distributed from northern Nigeria to Angola and the Arabian peninsula and from Senegal to Cameroon.

Ethnomedicinal Uses — Many of the species Cocculus have been used in folk medicine in India and Africa for the treatment of hypertension and symptoms related to the disease. The fruits are used by the Arabs to make an intoxicating drink. The roots are used as an antipyretic, diuretic, and cholagogue. The leaves are used as an ingredient in the preparation of fertility medicine for women and to regulate the menstrual cycle.

Constituents — The plant contains the bitter principle colombin and the alkaloids palmatine, sangaline, and pelosine. 297 Chromatographic analysis of the plant yielded the bisbenzylisoquinoline alkaloids penduline, pendulin, cocsulinin, and N-methylpendin.

Pharmacological Studies — Hypotensive activity on laboratory animals has been observed in the 50% alcoholic extract of the leaves and stems. 81 One of the isolated alkaloids, pendulin, has been shown to possess hypotensive activity. 81

A related species, Cocculus laurifolius, has also been shown to be hypotensive. 298 Several alkaloids belonging to the Erythrina group have been isolated from the plant, together with dibenz[df] azonine, proaporphine, quaternary aporphine, morphinandienone, and 1-benzyl-tetrahydroisoqui-none alkaloids. 229 Isococculidine, which is the major alkaloid found in the leaves, has been shown to have neuroblocking and hypotensive activities. 108 Cocculudine and cocculine were also found to be hypotensive. It has been suggested that the activities of these bases could be due to a ganglionic blocking action. 71 The quaternary aporphine alkaloids isolated from the plant, magnoflorine laurifoline chlorides, O-methyl isocorydine, and boldine methochlorides, exhibited d-tubercuranine-like curarizing action on sciatic skeletal muscles, as well as a hypotensive effect in dogs, cats, and rabbits. 81 Isocorydine methochloride has been shown to exert its neuromuscular activity by the induction of a nondepolarizing effect, as observed in the rat phrenic nerve diaphragm and cat anterior tibialis peroneal nerve preparations. 300 The antihypertensive activity of the drug has been related to its effect on histamine release. It was found that, at the dose at which complete blockage of neuromuscular transmission was observed and blood pressure was lowered, ganglionic transmission was not affected. 301

Cocos Nucifera

 

Botanical Name — Cocos nucifera L.

Synonyms — Coccus mammilaris Blanco., Calappa nucifera (L.) Kuntze., Cocos indica Royle., Cocos nana Griff., Palma cocos Mill

Family — Arecaceae

Common Names — Coconut

African Names — Arab: gos el-hind; Bambara: coco; Hausa: kwarkwar-attagara; Igbo: aki-beke; Swahili: nazi (mbata = copra); Yoruba: igi agbon

Description — The coconut is a monoecious palm tree 200 m in height. Its trunk is striated or curved but unbranched, with marked foliar scars, and topped by a crown of pinnet leaves, ranging from 3 to 5 m in length and about 30 in number. There is a central bud, which if cut off leads to the death of the whole tree. The inflorescence is surrounded by spathes; the male and female flowers are produced separately in the leaf axils, usually succeeding each other on a long stalk. It produces many fruits, but only a few reach maturity, about 70% being shed during the year-long development. The fruit encloses a seed, the coconut, which is spherical in shape with a hard shell that encloses an oil-rich albumen and the coconut milk. A ripe fruit can be recognized by shaking the milk inside the nut.

Habitat and Distribution — Coconut palms grow best in pure sand, usually in coastal regions. They tolerate the high-salt concentration of ocean beaches, but need a humid climate and plenty of sunlight. The plant is a major crop in Ghana, Ivory Coast, Kenya, Nigeria, Mozambique, Togo, Somalia, Seychelles, Malagasy Republic, and Tanzania.

Ethnomedicinal Uses — All parts of the plants are useful in Africa. The oil obtained from the dried endocarp is used in cosmetics and for food, coir fiber is obtained by soaking the outside husk in salt for 6–12 months, the midribs of the leaves are made into brooms, and the leaves and trunks are used in erecting and roofing temporary buildings. The palm fronds are used for making mats, baskets, and artworks. The coconut (water) milk is a refreshing drink, and it is mainly used as a poison antidote. It is not usually recommended for those with cardiac problems. The oil from the nuts is valued as an emollient and used as an ingredient in remedies for skin infections. Perhaps of greatest therapeutic application is the oil from the fresh endocarp, called virgin coconut oil (VCO)

Constituents — The African Pharmacopoeia 436 indicates that dry copra (coconut meat) contains 6.3% protein, 57.3% fat (oil), 38% carbohydrate, and 2% minerals. It also contains 14.33% sucrose, 2.42% raffinose, 2.42% galactose, 2.40% pentose, 1.20% fructose, 1.19% glucose, 0.58% dextrin, and 0.87% starch. The fatty acid profile of coconut oil is as follows (percentages in parentheses): capric acid (0.2–0.5), acrylic acid (4–9.5), capric acid (4.5–9.7), lauric acid (44.1–51), myristic acid (13.1–18.5), palmitic acid (7.5–10.5), stearic acid (1.0–3.2), arachidic acid (0.2–1.5), oleic acid (5.0–8.2), and linoleic acid (1.0–2.6).

Pharmacological Studies — Phenols obtained from the nutshell possess significant antifungal activity at 100 μg/ml against three Microspermum and four Trichophyton species, as well as antitubercular activity. 302,303 The fresh coconut milk has been found to interfere with the absorption of some orally administered drugs and to exhibit a moderate antihistaminic effect. 304 The most abundant fatty acid in coconut, lauric acid, possesses several biological activities. Lauric acid is known to have antiviral, antibacterial, and antiprotozoal qualities. It is converted to the monoglyceride monolaurin in the human or animal body. Monolaurin itself is antiviral, antibacterial, and antiprotozoal.

Available publications indicated that monolaurin is capable of destroying lipid-coated viruses such as HIV, herpes, cytomegalovirus, and influenza; various pathological bacteria, including Listeria monocytogenes and Helicobactor pylori; and protozoa such as Giardia lamblia and Plasmodium falciparum. It is believed that the compound is synthesized in babies from the lauric acid of mother’s milk. 447 Capric acid, another fatty acid found in coconut, also has antimicrobial activities. Reports also suggest that coconut oil is useful as an antioxidant, antihypertensive, and antidiabetic functional food. The fatty acids can be used for the production of biodiesel through an enzymatic conversion process. 448

There is no unanimity regarding the health benefits of coconut oil. 449 It has been suggested that the initial negative recommendation on the nutritional value of coconut oil was based on faulty scientific evidence and propaganda to promote the use of nontropical oils from industrialized countries, such as corn oil and cottonseed oil. The nutritional experts in the United States and Canada still caution against the use of coconut oil because of the abundance of saturated fatty acids in the oil and the potential risk of high cholesterol and its health risks. 450

Virgin Coconut Oil

Virgin coconut oil (VCO) is unprocessed oil obtained from fresh coconut endocarp. It contains medium-chain fatty acids, which are assimilated more easily by the body than the long-chain fatty acids found in many other cooking oils. It has become a major dietary supplement with many beneficial properties. VCO has the following constituents:

  • Lauric acid, medium-chain triglycerides, and other saturated fatty acids, including capric, caprylic, myristic, and palmitic acids
  • Monounsaturated fatty acids: oleic acid
  • Polyunsaturated fatty acids: linoleic acid
  • Polyphenols, gallic acid, and phenolic acids
  • Derivatives of fatty acid: betaines, ethanolamide, ethoxylates, fatty esters, fatty polysorbates, monoglycerides, and polyol esters
  • Fatty chlorides, fatty alcohol sulfate, and fatty alcohol ether sulfate, all of which are derivatives of fatty alcohols
  • Vitamin and minerals: vitamins E and K, iron

Advocates of VCO as a dietary supplement claim health benefits on the following: immunemodulation, diabetes, high blood pressure, cancer, hair care, skin care, stress relief, cholesterol levels, weight loss, bone strength, proper digestion and metabolism, heart diseases, dental care, HIV, and relief from kidney problems. It is believed that these health benefits of VCO can be attributed to the presence of the medium-chain fatty acids and phenolic compounds, with their known antimicrobial, antioxidant, antifungal, antibacterial, and anti-inflammatory properties, for example.

Tender Coconut Water

Tender coconut water (TCW), the liquid endosperm, is an excellent natural refreshing drink, with a caloric value of 17.4/100 g. Coconut water contains vitamin B, namely, nicotinic acid B3 (0.64 μg/ ml), pantothenic acid B5 (0.52 μg/ml), biotin (0.02 μg/ml), riboflavin B2 (<0.01 μg/ml), folic acid (0.003 μg/ml), and trace amounts of thiamine B1 and pyridoxine B6. Coconut water also contains sugars; sugar alcohols; vitamin C; folic acid; free amino acids; phytohormones (auxin, 1,3-diphenylurea, cytokinin); enzymes (acid phosphatase, CAT, dehydrogenase, diastase, peroxidase, RNA polymerases); and growth-promoting factors. 451

Cola Acuminata

Botanical Name — Cola acuminata (P. Beauv.) Schott & Endl.

Synonyms — Cola pseudo-acuminata Engl., Sterculia acuminata P. Beauv., Cola grandiflora Schott & Endl., Cola ledermannii Engl. & K. Krause., Cola macrocarpa Schott & Endl., Bichea acuminata (P.Beauv.) Farw., Bichea solitaria Stokes., Bichea sulcata Pierreex A.Chev., Braxipis grandiflora Raf., Braxipis nitida Raf., Clompanus longifolia Kuntze., Colaria acuminata Raf., Edwardia acuminata (P.Beauv.) Kuntze., Edwardia lurida Raf., Sterculia laxiflora Rusby

Family — Malvaceae

Common Names and African Names are similar in most cases: Bini: evbe; Efik: ibong; Igbo: oji-awusa; Yoruba: obi abata

Description — Resembles C. nitida, but the leaves are usually smaller. The fruits are composed of up to 5 carpels borne at right angles to the stalk or slightly drooping; they are narrowed to the straight apex, 20 cm long and 7 cm wide, and produce up to 14 seeds covered with white skin, usually bearing 3–5 cotyledons (rarely 2 or 6).

Uses, Constituents, and Pharmacology are as in C. nitida.

Cola Nitida

 

Botanical Name — Cola nitida (Vent.) Schott & Endl.

Synonyms — Cola vera K. Schum., Cola acuminata (P. Beauv.) Schott & Endl. var. latifolia K. Schum., Sterculia nitida Vent., Bichea nitida (Vent.) Farw.

Family — Malvaceae

Common Names — Kola nut, bitter kola nut

African Names — Aowin (Sefwi): awase; Arabic: guro, woro; Fanti: bose; Hausa: goro; Igbo: oji; Nupe: chigban’bi; Nzima: esele; Twi (Ashanti, Wasaw): bese, bese-pa; Yoruba: obi gbanja

Description — Cola nitida is an evergreen tree, usually 9–12 m high, but sometimes growing up to 20 m, and 1.5 m in diameter. It has narrow buttresses, extending for 1 m in old trees, or absent; the bole is not always straight and cylindrical. The bark is gray or grayish brown, rough with longitudinal fissures, and there is pinkish-red slash, which darkens to brown on exposure. The leaves are simple, alternate, petiolate; the petiole is 1.2–10 cm long; the blade is broadly oblong to broadly elliptic or elliptic-oblanceolate, 10–33 cm long, 5–13 cm wide, apex abruptly and shortly acuminate, base obtuse or rounded, margins wavy, glabrous, or nearly so; there are leathery, dark-green lateral nerves (6–10), the lowest arising close to the base and running parallel to the margin, obscure above, prominent below. Inflorescence is axillary, on irregularly branched panicles 5–10 cm long, shorter than the leaves; flowers are unisexual, appearing May to July and fruiting October to December; they are 5-merous, apetalous. Male flowers have the calyx cup shaped, about 2 cm in diameter, deeply lobed, and stamens are numerous, in two whorls. Female flowers have a calyx about 5 cm in diameter, with 5 carpels and numerous rudimentary anthers at the base. The various kola species can easily be differentiated by their fruits. C. nitida fruits are oblong-ellipsoid follicles 13 cm long, 7 cm in diameter, and green with a shiny surface, smooth to the touch but knobby with large tubercles. They contain 4–6 (sometimes up to 10) seeds per carpel. The seeds are ovoid or subglobose, 3–3.5 cm long, 2–2.5 cm in diameter, covered with a white skin, and having only 2 cotyledons, very rarely 3. 9,28,33

Habitat and Distribution — The plant is native to the lowland forests of Sierra Leone, Liberia, Ivory Coast, and Ghana. It has been introduced and is cultivated in Nigeria, Mali, and Guinea. Although it tolerates shade, it thrives better in the open and prefers well-drained soils and an annual rainfall between 1300 and 1800 mm with temperature of 26°C and 35°C.

Ethnomedicinal Uses — The main use of kola nuts is as a stimulant to the nervous system when chewed and as a restorative. It is an effective appetite suppressant. The kola nuts are used mainly as a masticulatory agent and as a ritual plant. An infusion of the bark mixed with ginger is administered as a treatment for stomach ulcer. In Ghana, the nuts are boiled with leaves of Morinda lucida and dispensed as an oral treatment for hemorrhoids. The nuts ground to a fine paste together with the leaves of Scoparia dulcis are dissolved in a little water, and a few drops are administered orally to babies for headache. The FAO monograph 33 indicates that the nuts, preferably the white variety, ground to a fine paste together with white clay, a little pepper, ginger, or Piper guineense fruits, are applied as an enema for the cure of diarrhea and dysentery.

Constituents — The plant contains purines, caffeine (about 2.5%), and small quantities of theobromine (usually about 0.025%). The plant also contains two phenolic substances, kolatin and kolatein, as well as catechols (-)-epicatechol and kolanin. An anthocyanin pigment called kola red, a phlobaphen, occurs as an oxidation product of the catechols. 452,453 The plant also contains proteins (1.5%), fat (0.5%), calcium (3.1%), iron (1.4%), vitamin A (31%), thiamin (11%), riboflavin (47%), nicotinic acid (0.7%), and ascorbic acid (9.8%); 37 the kernel contains about 1.6% tannin. 454 It has been shown that there is a significant variation in the yield of caffeine among the different varieties and genotypes of the plant. 455

Pharmacological Studies — Kola extracts exhibit the activities observed with caffeine, but unlike coffee, the activity is milder but persistent due to the presence of catechols and other constituents. It is a smooth muscle relaxant but produces overexcitement of the CNS, followed by depression at very high doses. 78 It has a tonic action on the heart by an indirect effect through the nervous system and by direct effect on the heart muscles and the walls of the blood vessels. The sense of fatigue is prevented, and a longer and more sustained muscular effort is encouraged. The extract is used in the preparation of several nonalcoholic beverages and has also been incorporated into tonic wines and health foods. Kola nuts chewed at night tend to prevent sleep.

Kola extracts and the dried whole nut are ingredients in several weight loss products and dietary supplements used as instant energy boosts and antioxidants. The proanthocyanidin isolated from the related C. acuminata showed activity against the sleeping sickness vector, Trypanosoma brucei, and low cytotoxicity against mammalian cells. 456

Combretum Micranthum — Kinkeliba

 

Botanical Name — Combretum micranthum G. Don

Synonyms — C. altum Lerr., C. floribundum Engl. & Diels, C. raimbaultii Heck

Family — Combretaceae

Common Name — Kinkeliba bark

African Names — Hausa: geza; Igbo: obi-agwu; Swahili: mlama muepe; Yoruba: okan

Description — It is a bushy shrub or creeper and grows up to 20 m in length. The leaves are opposite and oval acuminate with the lamina covered with reddish scales on the inner side with downy tufts at the axis of lateral ribs. The flowers are borne as short axillary clusters on scaly stalks, with a whitish corolla and ferruginous scales covering the calyx. The fruits are small, 1.5 m in diameter, scaly and ferruginous, and four winged.

Habitat and Distribution — The genus is found all over the continent, but the subject species appears to be dominant in the savanna belt. It is found from Sudan to Nigeria and from Gambia to Congo. Several related species are used medicinally in southern African.

Ethnomedicinal Uses — Decoction of the root of Combretum micranthum (also C. mucronatum, Fam. Combretaceae) is used in West Africa for the treatment of guinea worm infestation. 457 An oral dose (0.03 g/kg) of the decoction caused a complete extrusion of the worms in 43 of the 44 patients treated. There was a marked reduction in the inflammation around the lesions. Ampofo also found that application of sterilized palm oil aided in the healing of the wounds. 457 Combretum has been used as an antidiuretic, anticholagogue, and antibacterial. 138 The leaves of this plant yield a drug called “kinkeliba,” which has been listed in the French, Spanish, and British Extra Pharmacopoeia under supplementary drugs and indicated for blackwater and other fevers. 205 A decoction of the leaf and root is applied as a vapor bath, as a wash for febrile conditions, and as a remedy for lumbago. 138 An ointment prepared with the pulverized dry fruits has been used as an application to suppurating wounds and abscesses. Various members of the genus are also employed as an anthelmintic in many parts of Africa and Asia. Kinkeliba “tea” is used in West Africa as a general tonic or morning hot beverage as a substitute for tea. It enjoys a reputation in Guinea, Mali, and Senegal as a supplement for the management of diabetes, obesity, and high cholesterol.

Constituents — Combretum species yield catechins, glycosides, choline, organic acids, tannins, and resin. The isomeric flavonoids vitexin and saponaretin have been shown to be present in the leaves. 458 The leaves also contain the alkaloids combretacins. 459 The stem bark has been shown to yield similar alkaloids. 460

Pharmacological Studies — Extracts of the leaves are inhibitory against strains of Staphylococcus, Streptococcus, and Escherichia. 461 The stem bark extract has also been shown to possess broad-spectrum antimicrobial activity. 273 The catechins are strongly diuretic with a mild hypotensive action. 462 The young leaves of a related species, C. racemosum, are effective as an anthelmintic. 463 The aqueous extract of the leaves showed dose-dependent antidiabetic activity on alloxan-induced hyperglycemic rats. 464

Combretum species have demonstrated significant anti-inflammatory, antiviral, antifungal, and antioxidant activities. 465 The relatively low toxicity of the decoction used as teas makes kinkeliba a potential dietary supplement for the treatment of the chronic diseases for which it is used in traditional medicine.

Commiphora Molmol

Botanical Name — Commiphora molmol Engl.

Synonyms — C. hildebrandtii., C. serrulata., C. rivae., C. cuspidate., C. coriacea., Balsamea myrrha (T. Nees) Oken., Balsamea myrrha Baill., Balsamodendrum myrrha T. Nees

Family — Burseraceae

Common Names — Myrrh, oleo-resine (Fr.), molmol

African Names — Arabic: morrh; Hausa: dashi, biskiti; Yoruba: turari; Swahili: mbebe, mbele

Description — Myrrh is the oleo-gum-resin obtained from several species of the genus Commophora, especially C. molmol Engl., C. abyssinica (Berg.) Engl., and C. mukul Hook ex Stocks. The drug, also known as Somalian or Arabian myrrh, is collected from wild trees of C. molmol in Somali and parts of northeastern Africa and Arabia. Two varieties of myrrh are known in commerce, the “guban” myrrh, which is rather oily, and the more powdery “Ogo.” The oleo-resin is collected as exudates from fissures or incisions in the bark, which dries in the collecting vessels as irregular masses or tears. It has a somewhat reddish-yellow color, turning slightly brownish with time. It is dotted with whitish marks and has thin translucent splinters. It has a bitter but pleasant taste and aromatic odor. Guggul resin or gum is obtained from C. mukul and referred to sometimes as Guggulu. 9,28

Habitat and Distribution — Various species of the genus grow in the arid and tropical regions of the continent. Somalia is the natural habitat of the plant, but it is also cultivated in Kenya, Tanzania, Ethiopia, and some North African countries.

Ethnomedicinal Uses — It is employed as a mouthwash and gargle for the treatment and prevention of oral infections. It is also used as a stimulant and emmenagogue. A decoction of the stem bark is used by the Masai as a purgative and by the Nyamwezi as a snakebite remedy. In East Africa, various species of the genus Commiphora are used for wound dressing and for indigestion. The stem bark of C. Africa is used in Niger Republic as an oral treatment for various diseases. 466 In West Africa, vapor from the gum resin in boiling water is used for the treatment of eye inflammation, and the bark is applied as a remedy for scorpion bite.

Constituents — Myrrh consists of about 60% buns, which are usually composed of arabinose, galactose, 4-O-methylglucuronic acid, and xylose. 467 Other constituents, eugenol, cadinene, furanodiene, furanosesquiterpenes, heerabolene, cuminaldehyde, and elemol, are found in the volatile components. 468 The resinous fraction is about 30% of the total weight and contains commiferin; α-, β-, and γ-commiphoric acid; α- and β-heerambomyrrhols; commiphorinic acid; and heeraboresene. It also contains sterols and proteins. 469

Pharmacological Studies — The petroleum ether extract of myrrh, at a dose of 500 mg/kg body weight, has been shown to produce significant inhibition of carrageenan-induced inflammation and cotton pellet granuloma. 470 It also showed significant antipyretic activity in mice. Myrrh has been found to inhibit the growth of microorganisms in in vitro assay. 471

The oleoresin from C. mukul, Guggul gum, inhibits platelet aggregation and increases catecholamine biosynthesis and activity in cholesterol-fed rabbits. 472,473 It is also hypolipidemic and hypocholesteremic in both humans and animals. 474,477 Guggul resin has been found to activate the thyroid glands in chickens and rats. 475 It has also been reported to have significant anti-inflammatory and antiarthritic activity. 476 The anti-inflammatory activity of C. mukul oleoresin has been associated with the presence of steroids such as E- and Z-guggulsterone, the Z-guggusterols. 476,477 The volatile oil contains cembrene A in addition to the other constituents found in the volatile oil of C. molmol. Delaveau has reported that the extracts of C. abyssinica stimulate phagocytosis in mice inoculated with E. coli. 1139

Clinical Applications — Myrrh is an ingredient in mouthwashes because of its antiseptic and stimulant properties. It is used in folk medicine as an expectorant, anti-inflammatory, and antispasmodic and for the treatment of orodental infections. The crude drug is sold throughout northern and eastern Africa and in Saudi Arabia as a remedy for inflammatory conditions and rheumatism.

Costus Afer

 

Botanical Name — Costus afer Ker

Synonyms — Costus anomocalyx K. Schum., Costus littoralis K. Schum., Costus oblitterans K. Schum., Costus prodigiosus A. Chev., Costus pterometra K. Schum.

Family — Costaceae

Common Names — Ginger lily, bush cane

Local Names — Hausa: kakizuwa; Igbo: okpete; Yoruba: tete-egun; Efik: mbritem

Description — Costus afer is a herbaceous plant that grows up to 3 m high in rich soil, with succulent unbranched stem. The leaves are smooth, velvety green, and large; they are lanceolate, up to 20 cm long and 6.5 cm broad; they are long pointed at the apex and narrowly rounded at the base. The veins are parallel with the midrib. The leaves are borne on the stem bracts. The flowers are tubular, yellowish or pink, and attached to a swollen terminal bulb. It has a tubular calyx with 3 blunt lobes. The corolla is tubular, unsymmetrical, and with three yellowish or pinkish lobes. 9

Habitat and Distribution — It is found growing wild in secondary forest and more so in the wetter areas. The species is limited to the rain forest and deciduous forests. It is widely distributed in the West Coast, in the Nile Valley, and in parts of Zimbabwe.

Ethnomedicinal Uses — The succulent stem is chewed as a remedy for cough, and a tea made from the dry aerial parts is used for treating hypertension. The root decoction is administered for the treatment of sleeping sickness. The plant is also used for the treatment of diabetes mellitus. An infusion of the whole plant is taken as a stimulant and aphrodisiac. The root extract is used for the treatment of stomachache. The rhizome is applied as a paste for skin eruptions and inflammation. The stem, stripped of the leaves and bark, is used to suppress nausea. 266

A related species, C. schlechteri, has been cited for the treatment of diabetes. 461 The leaves of another species, C. spectabilis, are chewed and swallowed for the treatment of pyrexia. 478 In Tanzania, the juice from the stem of Costus is used as an anthelmintic alone or in combination with the juice of Dissotus rotundifolia or the stalk of Aframomum species. Costus lucanusianus is used in the Ivory Coast for the treatment of threatened abortion. 479

Constituents — The genus Costus is rich in steroidal saponins and sapogenins. 480 The rhizome of the subject species has been shown to contain various sapogenins, namely, diosgenin, stigmasterol, and costugenin. 481 The rhizome of the Asian species C. speciosus, in addition to the presence of saponins and sterols, contains aliphatic hydroxyl ketones, benzoquinones, and α-tocopherolquinone. 334

Pharmacological Studies — Extracts of the aerial parts and rhizome have been shown to possess anti-inflammatory activity. 335 An extract of C. lucanusianus exhibits uterine-relaxant activity. 331 The root oil from Costus causes contact dermatitis, and sensitivity to the oil is employed as a diagnostic agent for examining delayed cell-mediated immune system reactions. 336 In lung cancer patients, it was found that the incidence of positive reactions to Costus root oil decreased with the progress of the cancer. The percentage of lung cancer patients who survived was significantly greater for positive than negative patients. 336 It has also been established that patients with localized cancer showed no impairment of sensitivity to Costus root oil. 337 The oil has also been shown to inhibit the growth of transplanted tumors in sensitized BALB/c mice. 339 The Costus oil sensitivity is believed to be due to several sesquiterpenes found in the plant. An analysis of cross-reactions in Costus-sensitive patients has revealed that the most active sesquiterpene lactones are the ones with fewer oxygenated substituents close to the α-methylene-γ-butyrolactone ring. 341

The antifungal activity of C. speciosus has been shown to be due to the presence of a methyl ester of p-courmaric acid. 341 The methanolic extract exhibited a biphasic activity and antihyperglycemic activity. 482 At 200 mg/kg body weight p.o., it decreased the blood glucose level by 50% in streptozotocin (STZ)-induced hyperglycemia in male rats in 60 min post dosing. However, doses above 200 mg/kg body weight p.o. caused an increase in blood glucose level, potentiating the action of STZ. At 10 g/ml, the extract induced about 98% glucose uptake in differentiated 3T3-L1 adipocytes when compared with insulin (340 nm). The extract also induced expulsion of whole fetuses still enveloped within the placental membrane at the third trimester of pregnancy in rats. 486

Crescentia Cujete

 

Botanical Name — Crescentia cujete L.

Synonyms — C. cuneifolia Gardner, C. fasciculata Miers, C. acuminata Kunth., C. arborea Raf., C. plectantha Miers, C. pumila Raf., C. spathulata Miers

Family — Bignoniaceae

Common Names — Calabash tree, gourd tree

African Names — Igbo: oba; Yoruba: igisogba

Description — The plant is a small, low-branching tree 10 m high and up to 0.5 m in girth. The leaves are simple, about 18 cm long and wide, shaped almost like a spatula with the top occasionally pointed. They are arranged in clusters around the stem. The flowers are tubular, variegated, with green, red, purple, and yellow colors, delicately fringed with red stripes. It produces large green fruits, or calabashes, attached to the trunk and branches. They are almost spherical, about 40 cm in diameter, and contain numerous seeds covered by cream-colored pulp. 1147

Habitat and Distribution — The plant is a native of South America but grows widely in tropical Africa. It is grown as an ornamental plant in Ghana, Nigeria, Cameroon, and southeastern regions of the continent.

Ethnomedicinal Uses — The plant has rather limited medicinal use as an oral drug but is widely employed in the treatment of skin infections. The fruit, emptied of its content, is used by traditional healers as a vessel for mixing and storing oral medications. In the Caribbean, the fruit pulp is used as an analgesic, anti-inflammatory, antitumor, and purgative substance and for hematoma. 228 The leaves are reported to be used in the same region as an antidiarrheal and for trauma and ganglion inflammation. In Haiti and the Dominican Republic, an instillation of the leaf juice is used for earache. 228

Constituents — The fruit pulp has been shown to contain hydrocyanic acids, cinnamic acid, dihydrocinnamic acid, and related organic acids; the fruit also yields quaternary alkaloids and polyphenols; the seeds contain oleic acid, and naphthoquinone derivatives have been isolated from the stem wood. 342344

Pharmacological Studies — The pulp extract and cinnamic acid derivative isolated from the plant have been found to possess broad-spectrum antifungal activity. 344 The leaf extract exhibits antibacterial activity against Bacilus subtilis and Staphylococcus aureus. 345 The plant has been shown to be remarkably anti-inflammatory; the leaf extract at an oral dose of 1200 mg/kg showed an anti-inflammatory activity that was found to be effective even 24 h after administration of the extract. 228 The anti-inflammatory activity of the extract was comparable to that of sodium dichlofenac.

Toxicity — The fruit pulp contains hydrocyanic acid and should be considered dangerous. The pulp has also been shown to be carcinogenic in the rat by the induction of neoplasms. 229,346

Cryptolepis Sanguinolenta

 

Botanical Name — Cryptolepis sanguinolenta Lindl. Schltr.

Synonyms — Cryptolepis triangularis N.E. Br., Pergularia sanguinolenta Lindl., Strophanthus radcliffei S. Moore

Family — Apocynaceae

Common Names — Yellow dye root, Ghana quinine, nimbima

African Names — Bambara: ouidoukoi; Dioule: nombon; Fulani: delboi; Hausa: gangamau; Mende: kpokpo-yangolei, shona mukangaza (C. oblongifolia)

Description — The plant is a twining, scrambling shrub, with characteristic thin stems and tuberous rootstock. The leaves are opposite, thinly herbaceous, elliptic oblong to ovate or lanceolate in shape. The margin is entire; the apex is curved and acuminate, and the base is symmetrical and obtuse or rounded. The midrib projects prominently on the lower side and is pinnately nerved. The dried leaves have a slightly bitter taste. The roots are rather tortuous and branched with little or no rootlets, with longitudinal ridges apparent in the dried samples. The root is distinctly yellow in color and breaks with a short fracture exposing a smooth transverse surface, which is yellow in color. 347

Habitat and Distribution — The plant grows in the rainforest and deciduous forest belt. It is distributed throughout the West Coast of Africa. Related species occur in eastern and southern regions of the continent.

Ethnomedicinal Uses — The main use of the root of Cryptolepis is in the treatment of fevers. Extracts of the plant have also been employed for the treatment of urogenital infections, especially Candida infections of nonvenereal origin. 348 In southern Nigeria, a weak decoction of the root is administered as a tonic and for the treatment of anti-inflammatory conditions. The plant appears to be used as an ingredient in several folk remedies for a multiplicity of diseases, but the major uses are in the preparation of remedies for the treatment of malaria, hypertension, microbial infections, and anti-inflammatory conditions.

Constituents — The principal constituent is the quindoline alkaloid cryptolepine, which occurs at a yield of 0.52% w/w in the roots, 0.48% in the stem, and 1.03% in the leaves. 347 The compound co-occurs with the related bases and their derivatives.

Pharmacological Studies — The aqueous extract and the isolate cryptolepine have been shown to possess significant inhibitory activity against some bacteria and yeasts. 349,350 The alkaloid has also been found to inhibit carrageenan-induced edema of the rat hind paw in a dose-dependent manner. The activity was shown to be less potent than that of aspirin or indomethacin. The in vitro studies showed 1–20 μg/ml of cryptolepine did not inhibit prostaglandin synthesis in the isolated lizard lung, but it antagonized the effects of E2 prostaglandin and did not affect that of 5-hydrotryptamine on a perfused isolated stomach strip of the rat. The compound also antagonized the action of histamine and of acetylcholine on the isolated guinea pig ileum. 351,352 The biological activity of the compound may be due to its demonstrated adrenoreceptor blockage activities. 352,353 Cryptolepine also possesses hypotensive 354 and vasodilatory activities. 354,355

Clinical studies have shown that extracts of the roots produced antimalarial cures in patients with the concomitant elimination of parasitemia in the blood. 356 The extract also showed antipyretic activity in the patients evaluated. Several modifications have been made on the structure of the naturally occurring antiplasmodial compound cryptolepine, which have resulted in remarkable improvement in the antimalarial activity. Cryptolepine derivatives containing alkyldiamine side chains also possess potent inhibitory activity against Trypanosoma brucei brucei. These derivatives are also potent inhibitors of the trypanosome papain-like cysteine protease cruzain, which could, at least in part, explain their antitrypanosomal activity. Such compounds with good antitrypanosomal activity and selectivity provide an encouraging starting point for the rational design of new and effective antitrypanosomal agents. 483

Cryptolepis alkaloids and their semisynthetic derivatives are subjects of ongoing studies to evaluate their antiprotozoal, antidiabetic, analgesic, anti-inflammatory, and antituberculosis activities.

Curcuma Longa

 

Botanical Name — Curcuma longa L.

Synonyms — C. domestica Val., Stissera curcuma Raeusch., Amomum curcuma Jacq.

Family — Zingiberaceae

Common Name — Tumeric

African Names — Shambala: kitambwe: Swahili; mandano, manjano, kilunga kuku

Description — Tumeric consists of the rhizomes of Curcuma longa. They occur as primary and secondary rhizomes. The primary rhizomes are ovate or pear shaped, while the secondary rhizomes or “fingers” are more cylindrical and lateral. Tumeric has an inner yellowish-brown color, with a characteristic odor and slightly bitter taste. 279

Ethnomedicinal Uses — The plant is employed in West Africa as an anthelmintic and as an ointment for skin diseases. It is used as an anti-inflammatory agent and applied as an eyewash for conjunctivitis. In West Africa, the powdered rhizome is mixed with flour into a paste applied to the head for the relief of headache. 37 It is also applied as anointment on the body of smallpox patients, and the patients are made to stay out in the sun. The rhizome and the juice are used in Mauritius as an emmenagogue.

Constituents — The plant contains about 5% diaryl heptanoids called curcuminoids. The principal ones are curcumin (diferuloylmethane), monodes-methoxycurcumin, and dihydrocurcumin. 357 The volatile oil contains sesquiterpene ketones borneol, α-phellandrene, and zingiberine. 358

Pharmacological Studies — Curcumin has anti-inflammatory activity that was found comparable in potency to that of phenylbutazone. 359 It inhibits carrageenan-induced inflammation in rats and blocks arachidonic acid (AA) metabolism via both the COX and the 5-lipooxygenase pathways. 360362 The crude drug has antimicrobial, antiprotozoal, and anti-infertility properties. 50

Srivasta has used 14 C-labeled AA to establish that curcuma extract inhibited thromboxane B2 (TxB2) production. He showed that less TxB2 was produced in blood samples treated with curcuma extract when they were allowed to clot. It was also observed that the extract inhibited the incorporation of [ 14 C] AA into platelet phospholipids and deacylation of AA-labeled phospholipids on stimulation with calcium ionosphere A23187. 363 Dixit et al. showed that the extract caused a significant reduction in the ratio of total cholesterol/phospholipid and elevated the HDL-cholesterol/total cholesterol ratio 364 in triton-induced hyperlipidemic rats.

The effects of turmeric in liposomal and lipid peroxidation and peroxide-induced DNA damage have been investigated. 365 Curcumin and the aqueous extract of curcuma were found to be an effective antioxidant. Curcumin showed activity comparable to that of butylated hydroxyanisole (BHA). It has been shown that the inhibition obtained using aqueous extract, incorporated into the liposome itself, was 70% at 300 ng/μg and protected DNA (80%) against peroxidation injury at 100 ng/μg. Curcumin and the crude extract have also been shown to be cytotoxic to lymphocytes and Dalton’s lymphoma (DL) cells at concentrations of 4 and 0.4 mg/ml, respectively, and also inhibited the cell growth in Chinese hamster ovary cells at the same concentrations. 366 Curcumin possesses a selective phototoxic effect on bacteria. 367 Lee and Lin have shown that curcuma extract had mild antimutagenic activities against benzo[α]pyrene-induced mutation in a salmonella/microsomal system. 368 It also inhibited mutagenicity induced by several environmental mutagens, including bidi and cigarette condensates, tobacco, and dimethyl benzo-[α]anthracene, in a dose-dependent manner.

Curcumin has cortisone-like inhibitory activity on healing of wounds. In an experiment on the healing of superficial and penetrating corneal wounds in albino rabbits, 369 aqueous extract (2.8%) of curcuma definitely delayed healing superficial corneal wounds when compared with the effect of placebo and preservative eyedrops and also markedly reduced the tensile strength of corneal wounds. The 1:1 w/v aqueous extract has been shown to antagonize the toxic action of cobra, Najanaja siamensis, neurotoxin possibly via direct inactivation of the toxin. The plant extract also possesses proteolytic activity, which was shown not to be a likely mechanism for its antagonism to the cobra neurotoxin. 370

The antitumor properties of curcuma may be due to the presence of β-elemene, which has been found to be one of the cytotoxic constituents of the plant, showed 100% anti-infertility action in albino rats at a dose of 100 mg/kg. The petroleum ether extract showed 80% anti-infertility activity in the same assay and also caused resorption of the implants. 50,372

Clinical Properties — Tumeric is a spice used as food condiment in many countries. It has anti-inflammatory activity that is comparable in potency to that of phenylbutazone. A proprietary preparation known as Temoe-lawak-Singer (RVG 08637) used on various inflammatory conditions has been shown to reduce both the serum and the liver cholesterol in rats. RVG 08637 consists of a mixture of extracts of Curcuma species and Rhammi purshianae and is known to have choleretic and cholagogic activity in humans. 372

An ethanol extract of curcuma and the ointment of curcumin were found to produce remarkable symptomatic relief in patients with cancerous lesions. Reductions in smell were noted in 90% of the cases, and in almost all the cases there were reductions in itching. 374 It was also observed that dry lesions occurred in 70% of the cases, and 10% of the patients had a reduction of lesion size and pain. The observed effects continued in many of the patients for several months. The rhizomes of curcuma have been investigated for antioxidant, anti-inflammatory, insect antifeedant, antiviral, cytotoxic, and trypanocidal activities and in the treatment of AD, cancer, arthritis, and other clinical disorders. 484 Curcuminoids, labdane, halimane, and clerodane-type diterpenoids, considered the major biological constituents of the Curcuma genus, have been incorporated into many nutraceuticals or dietary supplements 485 and as potential antitumor drug. 486

Toxicity and Adverse Reactions — Tumeric is used in various parts of the world as a food item, and no incidence of toxicity has been recorded. In the controlled clinical studies by Kuttan et al., only one patient reported adverse effects. 487 A feeding experiment with raw turmeric and the alcoholic extract at very high doses of up to 2–5 g/kg and 300 mg/kg, respectively, resulted in no apparent toxicity to rabbits, guinea pigs, and monkeys. 488

Cyclopia Species — Honeybush Tea

Botanical Name — Cyclopia intermedia E. Mey, Cyclopia subternata Vog., Cyclopia genistoides (L.) Vent., Cyclopia sessiliflora Eckl. and Zeyh, Cyclopia maculata, and related species

Family — Leguminosae

Common Names — The various Cyclopia species are collectively called “honeybush tea,” but the individual species are known by a variety of names, which include the following:

  • Cyclopia intermedia, known as “mountain tea,” found between Port Elizabeth and the edge of the Langkloof
  • Cyclopia subternata, known as “marshland tea” or “valley tea”
  • Cyclopia genistoides, known as “coastal tea,” found mostly in the western Cape near Yserfontein and Darling and also thriving in the South Cape if cultivated
  • Cyclopia sessiliflora, known as “Heidelberg-tee,” named after the town Heidelberg in South Africa, where it grows in the local mountain range

African Names — Bergtea (C. intermedia), vleitee (C. subternata), Kustee (C. genistoides)

Description — The genus Cyclopia includes over 20 species of shrubs, endemic to the southwest and southeast of South Africa and mainly associated with the fynbos plant formation. They are collectively called honeybush tea, and their leaves are commonly used to make tisanes or “herbal teas.” It has many similarities with rooibos. Honeybush is so named because the flowers smell of honey. The taste of honeybush tea is similar to that of rooibos but a little sweeter. Both are devoid of caffeine and much more fragrant than any true tea prepared from Camellia species or even other tisanes. In some rural districts, it used to be common practice to keep a kettle of honeybush tea infusing on the stove ready for drinking while scenting the whole house—unlike tea prepared from Camellia sinensis, the product does not rapidly spoil as it simmers.

Most Cyclopia species have resisted attempts at domestication or cultivation and must be harvested in the wild, but a few can be cultivated. The major problem has been poor knowledge of the ecology of fynbos. It is not always easy to discover what the seeds need to enable them to germinate; some kinds bear elaiosomes and might be dependent on the services of particular ants or birds. C. intermedia is one of the teas that is harvested in the Kouga mountains, where it grows naturally. Mountain tea regenerates within 3 years after harvesting or devastation by fire; consequently, less than one-third of the mountain yield is available for harvesting each year by rotation. Mountain tea and valley tea flower in September/October, whereas coastal tea flowers in May/June.

Constituents — Honeybush does not contain caffeine and is low in tannin (0.45%) but rich in minerals. Some of the active compounds found in honeybush include isoflavones, flavones, flavonols, cinnamic acids, coumestans, xanthonoids, mangiferin, and isomangiferin.

Pharmacological Studies — The antioxidant activity and antimutagenic activity of the aqueous extracts of both the fermented and unfermented honeybush tea have been established by several studies. 489 In comparative studies on the antioxidant activities of Cyclopia intermedia, Aspalathus linearis (rooibos), and Hibiscus sabdarifa (zobo), it was found that the anti-free-radical potential (removal of hydroxyl radicals and superoxide anions) of honeybush extract was lower than in water infusions of rooibos, which was probably due to the lower concentration of polyphenols in the honeybush tea, but higher than the antioxidant activity of H. sabdariffa. 490 It has been shown that the degree of antimutagenic activity of honeybush varies according to the type of mutagen tested. For example, extracts demonstrated stronger protective activity against mutagens that require metabolic activation, such as 2-AAF and AFB1. Significant differences were also observed in antimutagenic activity among various honeybush species and between extracts from nonfermented and oxidized material. Research showed that nonfermented material has a higher antioxidant and antimutagenic potential, both in vitro and in vivo. Depending on the type of mutagen, research model, and honeybush species and the type of material used, extracts from Cyclopia plants demonstrated antimutagenic activities comparable with extracts from green, black, and rooibos teas. 65

The phytoestrogenic activity of extracts of honeybush has only been demonstrated in vitro. Their antimicrobial activity has also not been well established. 491 The chemical constituents found in honeybush tea have been linked to the activities of the extracts. Although not backed by conclusive experiments, the inferences listed next have been drawn by promoters of honeybush as a dietary supplement.

Isoflavones and Coumestans

  • Regulation of menstruation cycles
  • Prevention of breast, prostate, and uterus cancer
  • Reduction of the risk of osteoporosis
  • Antifungal properties
  • Antiviral properties
  • Anticholesterolemic: lowers cholesterol levels
  • Hypolipidemic: lowers fat levels
  • Antimicrobial
  • Antioxidant

Xanthones

  • Anti-inflammatory
  • Antihepatotoxic
  • Antiviral
  • Antidiarrheal
  • Antifungal
  • Antioxidant
  • Antidepressant

Flavones

  • Vitamin-type activity (mixture of eriodictyol and hesperidien)
  • Antioxidants
  • Antimicrobial
  • Antiviral
  • Anti-inflammatory
  • Spasmolytic
  • Diuretic (increases urination)
  • Nonfeeding sweeteners

Commerce — Cyclopia species have now become established commercial teas but are not as popular as rooibos tea. The biggest hindrance to commercial growth is the fact that honeybush is not one distinct species, and trade in the tea varies according to region. Differentiation of the four major commercial species is often difficult. Microscopic pharmacognostical profiling, using the leaf and stem microstructure of the species, has proved useful in determination of ultraspecific identity of the commercially important Cyclopia species (Cyclopia intermedia, Cyclopia subternata, Cyclopia maculata, Cyclopia genistoides). Leaflet characters of diagnostic value include the shape; margin (flat or revolute); bundle sheath extensions; crystals (aggregates, solitary crystals, and crystal sand); relative size of the upper and lower epidermal cells; and thickness of the cuticle. Studies also revealed an abundance of phenolic compounds, not only in the leaf epidermal cells and leaf bundle sheaths, but also in the secondary phloem, xylem rays, xylem parenchyma, and pith, showing that the inclusion of older stems may be acceptable and does not necessarily lower the quality of the product. 492

Agriculture — Like most members of the fynbos ecosystem, the honeybush tea plants are not easy to cultivate. Some of the species are nonsprouting, which means that replanting requires a lot of care, but once the plant is established, it is a hardy shrub. The life span of the nonsprouters is 7 to 8 years, while that of sprouters is estimated to be at least 10 years, based on the productive age of the oldest C. genistoides plantation. 493

Cymbopogon Citratus

 

Botanical Name — Cymbopogon citratus (DC) Stapf.

Synonyms — Andropogon citratus, A. ceriferus Heckel, A. nardus L. var. Ceriferus (L.) Rendle.

Family — Poaceae

Common Names — Lemongrass, citronnelle (Fr.), fever grass

African Names — Bambara: ce kala; Igbo: nche awuta, ahihia tii; Turag (Arab): hhashellaymum; Yoruba: koriko oyibo, koko oba

Description — Cymbopogon citratus is a densely tufted tall grass, usually growing up to 120 cm. Leaves are grass-like, with blades tapered at both ends up to 90 cm long and 1.25 cm wide. It seldom flowers; when the plants do, the flowers occur in panicles, with inflorescences 30 to 60 cm long. It has a slightly bulbous base. The whole plant gives a characteristic lemon odor when broken. It is a perennial, and the propagation is from the clones. 28,33

Habitat and Distribution — The plant requires a warm climate with plenty of sunshine. It is cultivated in Tanzania, Kenya, and the Malagasy Republic.

Ethnomedicinal Uses — Lemongrass is used primarily as a weak infusion in the form of teas used for fevers and jaundice. Extracts of the plant are also dispensed as a diuretic, emmenagogue, diaphoretic, stomachic, carminative, tonic, antirheumatic, and antidiarrheal. 440 The essential oil is used extensively in perfumery.

Constituents — Lemongrass yields up to 0.7% of volatile oil, which consists mainly of citral, a terpene aldehyde. Other constituents of the oil include geraniol, nerol, furfural, citronellal, methyleptenone, and myrcene, 425,494 as well as the triterpenes cymbopogone and cymbopogonol. 495,496

Pharmacological Studies — A decoction of the leaves has been shown to possess hypotensive and diuretic effects in the rat. 497 The essential oil showed antibacterial activity in vitro, and the activity is attributed to its geraniol and neral content. 498 The oil is believed to have a mild depressant effect on the CNS and analgesic and antipyretic activities. But, recent laboratory evaluation of the plant failed to observe any effects on body temperature, gastrointestinal motility, or the CNS. 499 Extracts of the plant appear to be devoid of any toxicity 500 and were not found to cause either hematological or cellular alterations or mutagenic or embryonic toxicity. 501,502

Cynara Scolymus

Botanical Name — Cynara cardunculus subsp. flavescens Wiklund.

Synonym — C. cardunculus spp. scolymus (L.) Hegi

Family — Compositae

Common Names — Globe artichoke, leaf artichoke, artichaut (Fr.)

African Names — Arabic: kharsuf.

Description — Cynara is a small herbaceous and thorny plant, about 1.5 m in height. The leaves are alternate, deeply dentate, with almost pinnatified whitish capitulum of tall purple flowers that are in turn subtended by thick and imbricate bracts. The crude drug consists of the fresh, thickened lower parts of the involucre bracts and the receptacle of thistle-like flowers of the plant. 436 They are usually greenish or purplish, with the intact bract showing involucre scales enlarged at the base with a short, sharp spine arising from the notched apex. It has a soft and enlarged receptacle that forms a cushion-like mass. The plant has a faint characteristic odor and a peculiar taste.

Habitat and Distribution — Artichoke is a Mediterranean plant. It is cultivated in North Africa and in some subtropical regions of the continent.

Ethnomedicinal Uses — The African Pharmacopoeia 436 listed the plant for the treatment of liver dysfunction and as a diuretic and antiatherosclerotic. It imparts a sweet taste to food and can be used as a sugar substitute for diabetics.

Constituents — It contains chlorogenic acids, cyanarin, and sesquiterpenes. 229 The plant also contains a mixture of polyphenolic compounds, proteins, and inulin.

Cyperus Esculentus

Botanical Name — Cyperus esculentus L.

Synonyms — Cyperus spp. (34 synonyms, subspecies, and varieties); Chlorocyperu saureus (K.Richt.) Palla ex Kneuck.; Chlorocyperus phymatodes (Muhl.) Palla; Pterocyperu sesculentus (L.) Opiz; Pycreus esculentus (L.) Hayek.

Related Species — Cyperus rotundus L.

Family — Cyperaceae

Common Names — Tiger nut, yellow nutsedge, chufa flatsedge; earth-almond, grass nut, rushnut, souchet sultan

African Names — Igbo (Nigeria): aki-awusa; Hausa (Nigeria): ayah, haya; Afrikaans (Namibia): geeluintjie, hoenderuitjie, uintjie; Afrikaans (South Africa): geeluitjie, hoenderuintjie, patrysuitjie; Damara/Nama (Namibia): !han; Khukh (Namibia): !hanni; Otjiherero (Namibia): okatjako; Shona (southern Africa): chufa; Shona (Zimbabwe): pfende; Mozambique: chimbwe-chimbwe; Zulu (South Africa): indawo, insikane; Dioula: tchoro toro; Bambara: nton togon; Malinke: toki

Description — Tiger nut is an annual or perennial herb, cespitose or not, rhizomatous or not, stoloniferous or not. Roots are fibrous, principally adventitious. Stems (culms) usually are trigonous, occasionally serrated, rarely compressed, usually solid, rarely hollow or septate. Leaves are basal or cauline, alternate, usually 3-ranked, rarely 2-ranked or multiranked, with bases forming cylindrical sheaths enclosing the stem; margins are usually fused; the junction of sheaths and blades often is with adaxial flaps of tissue or fringes of hair (ligules); blades frequently are absent from some basal leaves, rarely from cauline leaves, and when present are divergent or ascending, flat, folded, plicate, rolled, or terete, linear, venation parallel. Primary inflorescences (spikelets) have a shortened axis; glumaceous bracts (scales) are 1-many, spirally arranged, sometimes 2-ranked, usually appressed or ascending; scales usually are all fertile, each subtending a single flower, sometimes proximal or distal scales are empty; lateral spikes often are with basal, usually empty, usually 2-keeled scale (prophyll); occasionally, prophyll subtending and enclosing rachilla, bearing 1 pistillate, sometimes (0–) 3 staminate flowers and empty scales. Secondary inflorescences panicles are often modified to corymbs, pseudoumbel, cyme (anthela), raceme, spike, or capitulum (head), rarely single spike, usually subtended by foliaceous or, less frequently, glumaceous bracts; secondary inflorescences sometimes simulating spikelets. Flowers are hypogynous, bisexual in most genera; perianth is absent or with (1–) 3–6 (–30) bristles or scales, usually falling off with fruit; stamens usually (1–) 3, rarely more, usually distinct; anthers are basifixed; pistils are 1, 2–3 (–4)-carpellate, fused, locule 1; style is undivided or branches 2–3 (–4); stigma sometimes is papillate. Fruits are achenes, usually trigonous or biconvex; pericarps are thin (except in Scleria). 1140

Habitat and Distribution — Tiger nut is a perennial tuber or nut found in the wild and cultivated in drier parts of the continent. It has been cultivated since the fourth millennium BC in Egypt and for several centuries in other parts of North Africa and southern Europe. The plant can grow in light (sandy), medium (loamy), and heavy (clay) soils and prefers acid, neutral, and basic (alkaline) soils. It cannot grow in the shade. It requires moist or wet soil.

Ethnomedicinal Uses — The spherical underground tubers, with their sweet nutty flavor, are consumed fresh, dried, and in roasted forms. Fresh tubers are also soaked in water and processed to yield a refreshing milk-like beverage in northern Nigeria and Namibia. In Spain, the nutritional drink is called Horchata de chufa. It is fermented in many parts of West Africa to produce an alcoholic drink. The oil, which is rich in oleic (65.55%), palmitic (16.32%), and linoleic (12.13%) acids, is produced commercially in the Valencia region of Spain as a substitute for olive oil, a nutraceutical agent, and a major ingredient for high-quality cosmetics. According to the online encyclopedia Wikipedia, 1138 tiger nuts have excellent nutritional qualities, with a fat composition similar to olives and a rich mineral content, especially phosphorus and potassium. Since the oil has a predominance of UFAs (82%) against only 18 saturated fatty acids, it is useful as a dietary supplement for people with high cholesterol. It can also be used to replace milk in the diet of people intolerant to lactose to a certain extent. Its ethnomedical use is for the treatment of stomach and bowel disorders and inflammatory diseases.

Constituents — Tiger nut contains carbohydrates, flavonoids, minerals, phytosterols, tocopherols, tocotrienols, and various nutrients. The oil is composed of 7 major TAG (triacylglycerol) classes, with C54:3 (29.00%) and C52:2 (27.82%) dominating. Oleoyl chain primarily occupies both sn-1/3 (52.68%) and sn-2 (77.62%) positions in the tiger nut oil. It has a total tocol content of 120.10 μg/g, dominated by α-tocopherol (86.73 μg/g) and β-tocopherol (33.37 μg/g). The total 4-desmethylsterol content is 986 μg/g, dominated by β-sitosterol (517.25 μg/g) and stigmasterol (225.25 μg/g). 503

Pharmacological Studies — Most of the biological studies on tiger nut have been on its nutritional properties. The rhizomes are used for chewing; in preparing the white, jelly-like, tiger nut milk recommended as a substitute for dairy milk; and in therapeutic diets for diabetes, hypercholesterolemia, and chronic indigestion. Because of its high content of vitamin E, it helps slow the aging of body cells. In cosmetics preparations, it improves the elasticity of the skin and reduces skin wrinkles. 504 The related Cyperus rotundus has been evaluated for its antibacterial, anti-inflammatory, antidiabetic, and antioxidant activities with positive results. 505

Cytisus Scoparius

Botanical Name — Cytisus scoparius (L.) Link

Synonyms — Sarothanmus scoparius (L.) Koch., S. vulgaris Wim., Spartium scorpariium

Family — Leguminosae

Common Names — Broom, Scotch broom. Irish broom, broom tops, besom, scorparium, and several other names

Description — Cytisus is a tall deciduous shrub with ridged stems. The leaves are yellow, with three obviate leaflets at the base and single sessile and lanceolate leaves at the top. The upper parts of the stems bear five prominent longitudinal ridges. Cytisus is a perennial herb with a bitter taste. The flowering tops are the plant part used medicinally.

Habitat and Distribution — Broom is a European herb that has been introduced to the semitropical regions of the continent. It is cultivated in South Africa as a garden plant.

Ethnomedicinal Uses — It is employed as a diuretic and in the treatment of mild hypertension. A decoction of the leaves is used with lime for chest complaints.

Constituents — Cytisus contains quinolizidine alkaloids, flavonoids, phenylethylamines, lectins, and monoterpenes. The major compounds isolated from the plant include the alkaloids sparteine, lupanine, isosparteine, ammoderine, and related derivatives; 506,507 tyramine, epinine, salsolidine, and related phenylethylamines; 507 genistein, quercetin, and their glycosides; 123,508 and caffeic and p-coumaric acids. 509 The seeds contain lectins, 510 and the volatile oil yields eugenol, phenol, cresols, isovaleric acid, benzoic acid, and benzylalcohol, as well as cis-3-hexen-1-ol and 1-octen-3-ol. 509

Pharmacological Studies — Cytisus exerts a plethora of pharmacological activity due to its several constituents. It has a slowing effect on pathologically accelerated stimuli arising in the atrium, reduces increased irritability in the conduction system, and regulates the heart rhythm, simultaneously improving venous return. 511 It does not have any activity on the failing myocardium and therefore is not considered a digitaloid.

One of the active principles, sparteine, has a curare-like effect on peripheral nerves, which depresses respiration; it reduces the conductivity of cardiac muscle, and it is oxytocic. 512 Oxytyramine, a phenylethylamine found in the plant, has been shown to be a vasoconstrictor. 511

Broom is a diuretic and cathartic and has been used for the treatment of tumors. 508 Other alkaloids present in Cytisus, especially sarothamine and genistein, also inhibit conduction. The flavonoids, which co-occur with these alkaloids, have been reported to have a beneficial effect on myocardial function and the initiation of cardiac impulses. 512

Sparteine exhibits genetic polymorphism in its in vivo oxidation profile, and care must be taken to determine the appropriate dose for people from differing backgrounds. Sparteine polymorphism has been observed among the various racial groups. 513515 The drug is effectively inhibited by quinidine administration. 515

Clinical Properties — Oral preparations of Cytisus are used in the treatment of persistent arrhythmias or extrasystoles. It is indicated for long-term treatment of persistent postinfectious myocarditis with arrhythmia and to prevent a tendency for extrasystoles. The drug is also not effective for the treatment of absolute arrhythmia or paroxysmal tachycardia. 511 The plant has also been used as an antioxidant and as a hepatoprotective agent. The extract inhibited the toxicity of CCl4 in rats in a dose-dependent manner, and the activity of the extract at a dose of 500 mg/kg was comparable to the standard drug silymarin (25 mg/kg) in the protection of the liver from oxidative stress. 512

Toxicity and Adverse Effects — Cytisus, when taken in low doses, is relatively nontoxic, but at higher doses the drug causes drowsiness, visual disturbances, and congestion in the head. Sparteine intoxication produces marked bradycardia. Another member of the genus Cytisus, C. laburnum (actually belonging to the genus Laburnum), is very toxic and should not be used for the preparation of drugs.

Datura

The Datura species D. stramonium, D. metel, and D. fastuosa are widely distributed in Africa. For medicinal purposes, the distinction between the three species is not considered important since they all yield the pharmacologically important tropane alkaloids hyoscine, atropine, and hyoscamine. In some books, D. metel is considered synonymous with D. fastuosa and D. innoxia. As indicated in the following discussions, only the variety alba of D. fastuosa is synonymous with D. metel; the black variety of the former appears to be a distinct species and is often confused with Vernonia amygdalina.

Datura Metel

Botanical Name — Datura metel Linn.

Synonyms — D. fastuosa L. var. alba (Nees) C.B.Cl., Brugmansia waymannii Paxton., Stramonium datura Noronha

Family — Solanaceae

Common Names — Hairy thorn apple, metel

African Names — Arabic: oshb daturah; Ashanti: aweawu; Hausa: zak’ani, haukata yaro; Fulani: manga jidde; Igbo: myaramuo; Malinke: kidi ganian; Swahili: mnanaa, mnawha, muranha; Twi: kwasea-dua; Wolof: homhom bug or. Hompay bu gor; Yoruba: apikan

Description — D. metel can be differentiated from D. stramonium by its somewhat brownish color, with entire margins and differences in venation and trichomes. The seeds are light brown in color and ear-shaped; they resemble D. stramonium in the internal structures but can be distinguished by their larger size and more flattened structure. It possesses the disagreeable odor and taste of D. stramonium. The morphological differentiation of the species can be established from the microscopic characteristic of the powdered flowers. 517

Habitat and Distribution — This is a deciduous forest shrub, also found in rich savanna. The plant is distributed throughout the continent. It is often found in wastelands in many parts of West Africa.

Ethnomedicinal Uses — Most parts of the plant are employed in traditional medicine throughout the continent. It is used as a weak decoction for fevers and as an anthelmintic, insecticide, and instillation for eye diseases The leaves are used in Senegal and Guinea as an application for inflammatory swellings, rheumatism, 6 and general body pains. The plant is recognized as a deliriant and is often added to locally brewed beer and palm wine to stupefy victims with the intent to rob them. The Fulani use the leaves and sometimes the seeds in the preparation of a tonic used to drug youths to enable them to withstand the ordeal of the Sharo contest of manhood.

The constituents and pharmacology described are as described for D. stramonium.

Datura Stramonium

 

Botanical Name — Datura stramonium L.

Synonyms — D. tatula L., Stramonium vulgatum Gaertn.

Family — Solanaceae

Common Names — Green thorn-apple, apple of Peru, devil’s apple, devil’s trumpet, jimsonweed

African Names — Ga: blofo ngme-tsho; Krobo: wasiwakwe; Malinke: kidi ganian; Serere (Senegal): ndohar; Shona: chohwa; Sotho: lethsowe, lethsowi, letjoi, mphufi; Tonga: zaba-zaba; Twi: ahwenee, mmfora; Xhosa: umhlavutha; Yoruba: apikan; Zulu: iloqi, iyoli

Description — This is a herbaceous annual up to 1 m high. It has many branches, which gives it a dense appearance. The dried leaves are grayish green in color; they are brittle, twisted, and often broken. The leaves are variable, 8–25 cm long and 7–17 cm wide; they are shortly petiolate, ovate, or triangular-ovate in shape; they are acuminate at the apex and have a sinuate-dentate margin. The fresh leaf is somewhat dagger shaped. A microscopic description of the leaf is included in the work of Trease and Evans. 220 The flowers are white, with streaks of purple appearing sometimes on the ribs and tips of the corolla lobes. They are solitary in the axils and point upward. The plant produces round, greenish fruits or capsules that enclose black, flat, reticulated, kidney-shaped seeds. The plant has a bitter, saline taste with a disagreeable odor when fresh, but the dried plant has a tea-like odor. 28

Habitat and Distribution — This plant grows wild in most parts of the continent and is often found around village homes and on abandoned farmlands and poorly maintained parks.

Ethnomedicinal Uses — The leaf extract is an ingredient in remedies for cough and chest complaints. The crushed leaves or seeds are mixed with palm oil and applied to severe cases of insect bites and stings and also on inflammations to allay the pain. The seeds are sometimes used as an insecticide. 77 The leaves are used in the form of cigarettes or pulverized and burned as an inhalant for the treatment of asthma.

Constituents — The plant is a known source of tropane alkaloids hyoscyamine, atropine, and scopolamine. The total alkaloid yield has been estimated to be between 0.06% and 0.50%. The young leaves contain mainly scopolamine, whereas hyoscyamine is the major constituent of the mature leaves. In addition to these alkaloids, the plant contains other minor tropane derivatives, as well as chlorogenic acid and lectins. The seeds contain up to 30% fixed oil and about 0.2% alkaloids.

Pharmacological Studies — The drug is valued in clinical medicine as a cholinergic agent. The alkaloids of Datura are used as a spasmolytic, antiasthmatic, and anticholinergic. The drug has been employed in proprietary products for the treatment of excessive salivation in Parkinson’s disease.

In high doses, Datura induces strong hypnosis. Hyoscine, also known as scopolamine, in therapeutic doses causes CNS depression, manifesting as drowsiness, amnesia, fatigue, and dreamless sleep with a marked reduction in rapid eye movement (REM). Scopolamine is frequently misused by law enforcement agencies in the preparation of the so-called truth serum. Scopolamine is employed as an adjunct to anesthetic agents or for preanesthetic medication. Datura leaves are incorporated into “cigars” smoked as a euphoria-inducing substance and frequently abused. Hepatonephrotoxicity has been reported with Sudanese D. stramonium administered to rats. 518

Dichrostachys Cinerea

Botanical Name — Dichrostachys cinerea (Linn.) Wight et Arn.

Synonyms — D. glomerata (Forsk.) Chiov., Cailliea glomerata (Forssk.) J.F. Macbr., Desmanthu mutans (Pers.) DC., Mimosa bicolor Bacleex DC.

Family — Leguminosae

African Names — Hausa: dundu; Igbo: ami ogwu; Yoruba: kara

Description — Dichrostachys cinerea is a thorny shrub, growing up to 8 m in some places. The bark is brown, peeling off in strips. The twigs and young leaves are densely hairy. The leaves are tripinnate, from 5 to 10 cm long and with 8–15 pairs of pinnae, with each pinna being up to 4 cm long and sharing a rod-like gland with the opposite pinna. Each pinna bears 10–25 pairs of short, narrow, crowded leaflets. The spines often bear leaves. The inflorescence consists of densely crowded, stalkless, white-pink, or mauve filaments, borne in the axils of the leaves, on stalks about 4 cm long. The sterile flowers are borne below the fertile ones, each of which has yellow stamens. Flowering occurs from February to May and then in July (Agoha). The flowers are faintly fragrant and have been used as ornamentals.

The fruits occur, November–January, as smooth, flat pods, in clusters at the ends of thick stalks. Each pod is about 2.5–7 cm long, becoming folded or twisted with age, and eventually forming a more or less compact head. 77

Habitat and Distribution — It is found in savanna and low shrublands, often in thickets. It is distributed throughout the tropical parts of the continent. In the north, it grows up to Sudan, and in the south, it extends into South Africa.

Ethnomedicinal Uses — The root bark is used in North Africa as a weak decoction for the treatment of venereal diseases and leprosy. The scraped stem bark is pounded and macerated in cold water, spices and lime juice are added, and the mixture is given both for dysentery and for worms. An infusion of the root is administered as a postpartum tonic. The fresh leaves are applied externally for the treatment of abscesses and various inflammatory conditions. A hot decoction of the leaves is inhaled to relieve sore throat.

Decoction of the roots or stem is used for stomachache and constipation and as an anthelmintic in Ivory Coast. The roots are applied after chewing to snakebites and scorpion stings.

Drimia Altissima

Botanical Name — Drimia altissima L.

Synonyms — Urginea altissima, Scilla altissima, Idothea altissima (L.f.) Kuntze., Ornithogalum altissimum L.f.

Family — Asparagaceae

Common Name — African squill

General Notes — The drug, known in commerce as the white squill, consists of the dried sliced bulbs of D. maritime from which the membraneous outer scales have been removed. 220 Squill has a long history of use in medicine: The earlier Greek and Egyptian physicians used various forms of squill as therapeutic agents. An oxymel of squills was part of an Arabic prescription, and a vinegar of squill was used by Dioscorides, the Greek physician.

Squill occurs in two varieties, the white and the red squill. The white variety is employed in medicine, and the red squill is used mainly for the preparation of rat poison. The African squills U. indica (Roxb.) Kunth and U. altissima L. Bak. are used in folk medicine in Nigeria but are not official pharmaceutical products or articles of international trade. 437,519

Description — Squills occur as bulbs that are pear shaped and 15–30 cm in diameter. They are yellow with white, translucent strips of varied lengths (usually 1–5 cm), with a bitter and acrid taste. The drug is very hygroscopic, and if powdered drug is not well stored, it turns into a solid moldy mass.

Constituents — The plant contains a mixture of cardiotonic glycosides based on the scillaridin skeleton. A crystalline glycoside, scillaren A, and an amorphous mixture called scillaren B occur in the various squills. Scillaren A, which is the major component, is very labile and is easily hydrolyzed by acid or enzyme (scillarenase) to yield the genin and sugars. Hydrolysis with scillarenase yields proscillaridin A. Squill also contains other minor glycosides, quercetin derivatives, and kaempferol polyglycosides. 224

Pharmacological Studies — Proscillaridin has cardiotonic properties resembling those of strophanthin. The glycosides are poorly absorbed from the gastrointestinal tract, and they are of short-acting duration. The drug is easily eliminated from the system and is noncumulative. In binding experiments on plasma membranes derived from several types of isolated and cultivated endothelial cells, it was observed that the order of binding of the cardiac glycosides and the genins to the cells was as low as follows: proscillaridin A > ouabain > digoxin > gastrophanthidin > digoxigenin. 520 A study of the pharmacological activity of the reduced proscillaridins in papillary muscles isolated from guinea pig heart has shown that hydrogenated products retained the positive inotropic effect of the parent drug. The compounds bufa-4,20-dienolide, bufa-4,20(22)-dienolide, 2OR-bufo-4-enolide (Ph4-R), 2OS-bufa-4-enolide (PH4-S), and chola-4-enoate exhibited the fastest onset of action but lower potency. The concentrations at which half the maximum inotropic effect was observed were consistently lower for the reduced compounds than the parent drug at less than one-tenth the time taken by proscillaridins in some cases. A dose of 11.9 mg/kg of bufa-4,20-dienolide was administered intravenously by bolus injection into guinea pigs and did not cause arrhythmias. 521 If these effects are reproducible in animals, then the reduced proscillaridins will offer many therapeutic advantages over other cardiac glycosides.

Clinical Properties — The drug is indicated for the treatment of all forms of mild-to-medium-severe heart failure. It is administered both orally and intravenously. Many proprietary preparations containing the whole herb as tablets and “teas” are available in Europe, as well as preparations incorporating the pure compound or the processed extract. Semisynthetic derivatives, especially proscillaridin 4′-methyl ether and methylepoxyproscillaridin, are also used as therapeutic agents. In an evaluation of the hemodynamic effect of methyl-epoxyproscillaridin on six patients with latent cardiac insufficiency, it was observed that the compound caused an increase in stroke volume and the systolic blood pressures both at rest and under ergometer exercise. 522 During physical exercise, the heart rate decreased significantly, and the cardiac output was increased.

The drug is also used in the preparation of expectorants; in small doses, it causes mild gastric irritations that initiate a reflex secretion from the bronchioles. 119

Toxicity — The main side effect of urginea overdose is vomiting. Excessive high doses may cause cardiac toxicity, but death due to proscillaridin intoxication is not common. The drug is eliminated rapidly from the body and is unlikely to accumulate to toxic levels without warning symptoms. In radioimmunoassay determination of proscillaridin given orally to beagle dogs, it was rapidly absorbed, exhibiting plasma maximum concentrations of 2.06 mg/ml at 20 min. The plasma level subsequently declined biophysically with half-lives of 0.6 and 25.4 h. 523

Echinacea Purpurea

 

Botanical Name — Echinacea purpurea (L.) Moench.

Synonyms — Echinacea intermedia Lindl. ex Paxton., Helichroa purpurea (L.) Raf., Rudbeckia purpurea L.

Family — Compositae

Common Names — Purple coneflower, E. angustifolia (D.C) Heller = coneflower, E. pallida (Nutt) Britt. = black Sampson

Description — Echinacea is available in the market as roots or rhizomes, which are often twisted with longitudinal furrows. It is grayish green in appearance, and the transverse section reveals it is yellowish and porous with black patches. It is a slightly aromatic, has a somewhat sweet taste at first, then bitter, and leaves an aftertaste that gives the tongue a peculiar tingling sensation. Although the individual species are botanically very distinct, the drug is treated as one product since the major difference lies in the quantity and type of the minor metabolites. Moreover, much confusion exists regarding the species specificity in some of the published data.

Habitat and Distribution — The plant is indigenous to North America, from which it has been introduced as a cultivated medicinal plant in parts of northern and eastern Africa.

Constituents — Polysaccharides, mainly heteroxylans and norrhamanogalactans, have been isolated from the genus. 524 A triglycoside of a caffeic acid derivative, called echinacoside, has been found present in E. angustifolia, but not in E. purpurea; some alkanes and flavonoids were also found in the species. 525 The essential oil contains caryophyllene, germacrene D, methyl-p-hydroxycinnamate, and humulene. 526,529 The dried roots of E. pallida yielded polyacetylenes that were absent in the fresh plant material, and it has been suggested that these polyacetylenes could be artifacts generated during storage of the drug. 527,528 Other constituents found in Echinacea include unsaturated isobutyl amides (e.g., echinacin), the alkaloids tussilagine and isotussilagine, a labdane derivative, and vanillin linolenic acid derivatives. 123 It has been observed that commercial samples of the drug are sometimes adulterated with American feverfew (Parthenium intergrifolium L.), and some of the compounds reported from commercial samples, especially the sesquiterpene esters, may be due to the adulterant. 123,531

The immunostimulant activity of Echinacea appears to have been known to earlier scientists since as early as 1831 the German scientist Dierbach was said to have indicated its use as an immunostimulant and for healing damaged skin tissues. A modern account of its immunostimulant activity was given by Wagner and his colleagues, 529 who showed the polysaccharide fraction of the aqueous extract of the plant possessed in vitro and in vivo immunostimulant activity. In the carbon clearance test in mice, it was shown that the oral administration of the drug enhanced phagocytosis; also, in the in vitro granulocyte assay, it stimulated phagocytosis. The lipophilic fractions of the extract were more active than the polar fractions. 530 It has also been shown that an acidic arabinogalactan with molecular weight of 75,000, isolated from cell cultures of E. purpurea, was effective in activating to produce TNF-α, interleukin 1 (IL-1), and interferon β2. 531 It does appear from the report that the acidic arabinogalactans were more active than neutral arabinogalactan. It was also found that although arabinogalactan possessed immunostimulant activity, it neither activated B cells nor induced the T cells to produce IL-2, interferon B2, or interferon γ, but it did induce a slight increase in T-cell proliferation. 531 The purified polysaccharides from the cell cultures of the plant were effective in protecting mice against the lethal effects of infections with one predominantly macrophage-dependent and one predominantly granulocyte-dependent pathogen, Listeria monocytogenes and Candida albicans, respectively. 532

Clinical Properties — Echinacea species are employed in clinical medicine as anti-inflammatory agents and as immunostimulants. 533,534 It has been shown that a single dose of the drug per week as a therapeutic adjuvant is adequate for the production of phagocytosis, as evidenced by lymphokine production and assay using [ 3 H]-thymidine incorporation and a skin test with antigen. 534 The drug is marketed all over Europe as an ingredient in several proprietary anti-infective drugs. Esberotox N and Echinichin, two of the most common brands, have been shown to be most useful in phagocytosis-dependent metabolism and therapy. 535

Extracts of the plant are known to inhibit the production of hyaluronidase and thereby help to localize the infection and stop it from spreading to other parts of the blood. 535 In vitro studies showed inhibitory activity against Trichomonas vaginalis, 536 which supports its use in topical preparations such as ointments, poultices, and vaginal pessaries. Other uses of Echinacea include those for antiviral, vulnerary, and alterative activities; for septicemia; for the treatment of upper respiratory tract infections such as tonsillitis and pharyngitis; and for boils and carbuncles. 540 The drug has also been useful in combination therapy for outpatients with inoperable advanced hepatocellular carcinomas. 537

In Nigeria, a locally cultivated Echinacea is used in combination with Garcinia kola seed extract as an immune booster and antioxidant and as a remedy for flu.

Elaeis Guineensis

Botanical Name — Elaeis guineensis Jacq.

Synonyms — Elaeis nigrescens A. Chev., Elaeis virescens A. Chev., Palma oleosa Mill.

Family — Arecaceae

Common Names — Oil palm, palm tree, king palm (Elaeis guineensis var. idolatrica) (English), palmier a huile (French)

African Names — Bambara: m’te; Bini: udin; Hausa: kauku, kwakwa: Igbo: nkwu; Nupe: zukunnu: Swahili: mawese (palm oil); Tivi: irile; Urhobo: orien; Yoruba: ope, eyin

Description — The oil palm is a straight stemmed tree up to 22 m high, with several prominent foliar scars, which increase with the age of the plant. The leaves are dark brown, about 7 m smaller than those of Raphia palm, spiny at the base. The leaves gather at the top to form an umbrella-like canopy. Male and female inflorescences are borne at the axils of the leaves, with the male flowers being clusters of spikes, while the female flowers are in large stalkless heads. The fruits occur as ovoid drupes, with fibrous and oily mesocarp; they are bright red when ripe, appearing in a cluster ranging from 3 to 10 kg. The seed, enclosed in a hard endocarp, contains an oily white albumen. 13

Habitat and Distribution — It is spontaneous in secondary forests and as a derived crop in savanna and high forests. It is widely cultivated throughout the tropical forest regions. It is a major crop in Ghana, Nigeria, Togo, Ivory Coast, Uganda, Tanzania, and Kenya.

Ethnomedicinal Uses — Elaeis guineensis is one of the plants that is central to the lives of traditional societies in West Africa. All parts of the plant are useful: The wood is used as frames for buildings, the sap is fermented into palm wine, and the oil from the mesocarp and the seeds are used for cooking and for making soaps, creams, and other cosmetics.

The fresh sap is used as a laxative, and the partially fermented palm wine is administered to nursing mothers to improve lactation. Soap prepared with ash from the palm fruit husk is used for treating infections. A root decoction is used in Nigeria for headache; the pulverized roots are added to drinks for gonorrhea and menorrhagia and as a cure for bronchitis. 9 The leaf extract and the juice from young petioles are applied to fresh wounds. The fruit mesocarp oil and palm kernel oil (PKO) are administered as a poison antidote and are used externally with several other herbs as a lotion for skin diseases. PKO is applied to convulsant children to regulate their body temperature.

Constituents — The mesocarp yields a yellow-to-red oil known as palm oil, which has a very balanced fatty acid composition: 51% saturated fatty acids, 38% monounsaturated fatty acids, and 11% polyunsaturated fatty acids. The major saturated fatty acid is 38–44% palmitic acid (C16:0) and 4–5% stearic acid (C18:0). Oleic acid (C18:1) represents 39–44% and linoleic acid (C18:2) 10–12% of the UFAs. It has been observed that the fatty acid composition in palm oil is quite remarkable, with the structure of the fatty acids on the triglyceride backbone in which the majority (87%) of the UFAs are situated in the sn-2 position, whereas the saturated fatty acids are mostly in the sn-1 and sn-3 positions. 538 Normally, the sn-2 position monoacylglycerols are readily absorbed in the intestine. This unique structure in the palm oil triglyceride backbone therefore ensures that the UFAs in the sn-2 position are mostly absorbed from the intestine and that the saturated fatty acids in the sn-1 and sn-3 positions ensure stability and protection against oxidation. In addition, it contains, among other things, glycerides of fatty acids with high molecular weights, including oleic acid (40–50%) and myristic acid (1–5%). The oil is rich in carotenoids (including vitamin A and β-carotene) and sterols. Raw unprocessed palm oil normally contains 500–700 ppm carotenoids, of which 35% is α-and 56% is β-carotene. The refined red palm olein, however, contains 513 ppm carotene, of which 44% is α- and 33.3% is β-carotene. Red palm oil contains high levels of provitamin E (600–1000 ppm), with 78–82% being tocotrienols and 18–22% tocopherols. 539 It also elaborates the following phytonutrients: sterols (60–620 ppm), squalene (200–500 ppm), coenzyme Q10 (10–80 ppm), glycolipids (1000–3000 ppm), and triterpene alcohol (40–80 ppm). The kernel yields an oil (PKO) that is pale yellow to colorless and comprised of the following glycerides of fatty acid: lauric acid (50% of total fatty acids), myristic acid (15% of total fatty acids), oleic acid (15% of total fatty acids), and traces of linoleic acid and stearic acid.

Pharmacological Studies — Natural carotenes obtained from palm oil have been shown to suppress the promoting stage of two-stage carcinogenesis of mouse skin and also inhibit the proliferation of human malignant tumor cells, such as neuroblastoma GOTO cells, stomach cancer HGC-27 cells, and pancreatic cancer PANC-1 cells. 540 The bright red nonsolid palm oil has strong antioxidant activity. Tocotrienols found in red palm oil are 40–60 times more potent than tocopherols as antioxidants. Red palm oil also has the highest content of tocotrienols of all edible oils, with rich bran oil as the only other edible oil that comes close, with just less than a third of the levels contained in red palm oil. 541

The extract of the leaves has been evaluated for possible antioxidant activities by 2,2-diphenyl-β-picrylhydrazyl free radical scavenging activity (DPPH), xanthine oxidase inhibition (XOI), nitric oxide scavenging activity (NOS), and hydrogen peroxide scavenging activity (HPSA) assays. It was found that the extract exhibited antioxidant activity with an IC50 value of 814 g/mL in the DPPH radical scavenging method, 534.04 μg/mL in the NOS assay, 37.48 μg/mL in XOI, and 1052.02 μg/ mL by the HPSA method based on the concentrations tested. 542

PKO obtained from the seeds is used as a lubricant and emollient for damaged skin and as a suppository base. The soap prepared from the palm husk ash possesses antimicrobial properties.

Embelia Schimperi

Botanical Name — Embelia schimperi Vatke

Synonyms — E. abyssinica Bak., Pattara pellucida Hiern

Family — Primulaceae

African Names — Kiru: gezi, Masai: os sumategi; Zulu: ibinini

Description — The plant is a climber with rough stems and conical protuberances. The fruits occur as globular, reddish-brown berries, with a small projection at the apex. 77

Ethnomedicinal Uses — The leaves are used as a food vegetable in East Africa, especially in Uganda. A decoction of the stem bark is used in Nigeria as an antispasmodic. The fruit is used by the Masai and Chagga as an anthelmintic. A related species, E. kraussi Harv., is used by the Zulu as a taeniacide. In East Africa, both the roots and stem bark are used for the same purpose. Watt and Breyer-Brandwijk indicated that various species of the genus are employed as an anthelmintic, and the berries are articles of commerce in markets in many parts of the region. 79 The Asian species E. ribes has long been used in Indian medicine as a carminative, anthelmintic, stimulant, and alterative. 175

Constituents — It contains about 6–7% of the active component embelin (2,5-dihydroxy-3-lauryl-p-benzoquinone) and also several naphthaquinones, resinoids, tannins, and an alkaloid christembine. The plant also yields a toxalbumin. The yield of the active compound embelin is reported to be higher in this species than in the Asian species E. ribes. 78

Pharmacological Studies — Controlled clinical studies have showed that the alcoholic and aqueous extracts of Embelia were very effective against ascarides. 543 The active constituent embelin and its derivatives (such as isobutyl-embelin and n-hexylaminoembelin) were active against the parasites Paramphistomum cervi, Trichus ovis, Oesophagostomum columbianum, and Dipylidium camimum at low concentrations within a contact period of 30 min. 544 The diimines were found to be inactive. 544 Embelin has also been investigated as an antifertility agent because of its remarkable properties of preventing implantation without being blastotoxic and also its estrogenic and progestogenic activity. 545,546

Toxicity — The plant may be toxic due to the toxalbumin content. Proper processing is essential to detoxify the extract.

Emilia Sonchifolia

Botanical Name — Emilia sonchifolia DC.

Synonyms — Cacalia sonchifolia Hort. ex L., Crassocephalum sonchifolium (L.) Less., Gynura ecalyculata DC.

Family — Compositae

African Names — Igbo: nti-ele; Swahili: mchekacheka; Yoruba: odundun-odo

Description — This is a straggling herb up to 90 cm tall, common in farmlands and open places in the forest, especially along paths and roadsides. The leaves, alternately arranged on the stem and branches, are 10 cm long and 5–7 cm broad and somewhat triangular in shape. They are deeply and irregularly lobed and clasp to the stem. The flowers are small (about 1.3 cm long and 7 mm in diameter), pinkish, and cylindrical in shape. They occur singly or sometimes in small clusters in the axils of the leaves or at the ends of the stem and branches. Emilia produces small, hairy achenes about 3 mm long. 77

Habitat and Distribution — It is a forest plant, distributed throughout western, central, and southeast Africa. The related species E. sagittata is common in the West Coast.

Ethnomedicinal Uses — In West Africa, the plant is employed as a leaf decoction for fevers. The juice from the crushed leaves is instilled in the eyes for the treatment of conjunctivitis. The leaves are used as an occasional vegetable for their laxative activity or eaten cooked in soup or fresh in salad as a health food. Infants are bathed with the decoction for the prevention of high fever and convulsions. It has also been used as an ingredient for the preparation of anti-inflammatory and wound-healing remedies.

Constituents — The flowers contain flavonoids, while alkaloids and phytosterols have been isolated from the whole plant. The major constituents include kaempherol-3-d-galactoside, quercitrin, quercetin, rutin, ursolic acid, senkirkine, doronine, β-sitosterol, and stigmasterol.

Pharmacological Studies — Emilia possesses antioxidant and anti-inflammatory properties. Fresh juice and methanolic extract of the leaves were found to be potent inhibitors of hydroxyl radical formation and superoxide radical generation in vitro. 547 The methanolic extract inhibited the carrageenan-induced edema in rats. 548 It has also been found to be cytotoxic to DL, Ehrlich ascites carcinoma (EAC), and mouse lung fibroblast (L-929) cells, but not toxic to normal human lymphocytes, under in vitro conditions. Oral administration of the extract (100 mg/kg body weight) to mice reduced the development of both solid and ascites tumors and increased the life span of these tumor-bearing mice. The same methanol extract inhibited DNA synthesis, as shown from a reduction in tritiated thymidine incorporation into DL cells in vitro. 549

Emilia sonchifolia exhibited pronounced opioid-mediated antinociceptive activity action in mice. At test doses of 100 and 300 mg/kg p.o., Emilia extract clearly demonstrated antinociceptive activity in all tests. The extract had a stronger antinociceptive effect than morphine. Administration of the opioid receptor antagonist naloxone completely inhibited the antinociceptive effect induced by the extract (100 mg/kg). 550 This effect is indicative of the biochemical rationale for the probable use of Emilia in the treatment of inflammatory hyperalgesic disorders.

Entada Abyssinica

 

Botanical Name — Entada abyssinica Steud. ex A. Rich

Synonyms — Pusaetha abyssinica (Steud. ex. A. Rich.) Kuntze, Entadopsis abyssinica (Steud. ex A. Rich.) Gilb. & Bout.

Family — Leguminosae

African Names — Ashanti: ekur, sankwituri; Bron: sankasaa, kuboya; Dagbani: chienchienga, zuguli-kukui; Igbo: angara-miri; Rwanda: umusange, umusangasange; Kinyamawezi: mfutambula; Kirangi: ijwekwe; Kizinza: musangisangi; Kibende: mubunda; Kirangi: mwulamvula; Kiluguru: mvulamvula; Kihene: mugelagela; Kinyaturu: mumbu; Musagaruzi Nandi: katutet; Sebei: musiembu, masiembet; Kakamega: musamba; Bemba: mulalatanga, mulalatete; Kaonde: mukumbwangombe; Lozi: fumbwamusowo; Lunda: muzenze; Nyanja: chisekele, chongololo; Tonga: musenzenze, mumnyele; Yoruba: gbengbe

Description — Entada abyssinica is a deciduous tree, 3–10 m high with flat, spreading crown. The bark is slightly fissured and flakes off in irregular patches; the bark is gray to reddish in color, with a pink slash with streaks of red; branchlets are pendulous, glabrous, or sometimes pubescent. The leaves are alternate, bipinnate, with stipules absent; pinnae are 1–22 pairs, leaflets are 15–55 pairs, mostly linear-oblong, 3–14 mm long, 1–4 mm wide, with apex rounded to slightly obtuse and slightly mucronate, appressed pubescent above and below or sometimes glabrous above, rarely entirely glabrous; petiole is glandular. Inflorescence is 1–4 axillary racemes 7–16 cm long (including the 0.4- to 1.5-cm peduncle). It produces cream-white, sweet-scented flowers; the fruits are large flat legumes, 15–39 cm long, 3–9 cm wide, subcoraceous, straight or nearly so, with no apparent seed segments. The seeds are oval, flat, 10–13 mm long, and 8–10 mm wide with splitting between each seed, leaving the pod-rim and forming a wing to the seeds. 9,33

Habitat and Distribution — The plant occurs widely throughout the savanna belt of tropical Africa. It adapts to a variety of soils, from loams to clay loams and sometimes friable clays over laterite at altitudes from 60 to 2290 m. The mean annual rainfall is between 500 and 1270 mm. It has been located in Ghana, Benin, Mali, Guinea, Sierra Leone, Ivory Coast, Burkina Faso, Togo, Nigeria, Cameroon, Central African Republic, Zaire, Rwanda, Burundi, Sudan, Ethiopia, Angola, Uganda, Tanzania, Mozambique, Malawi, Zambia, and Zimbabwe.

Ethnomedicinal Uses — Entada has been used in southern Africa for the treatment of severe bronchitis and persistent coughs. A decoction of the roots is administered to alleviate arthritic pains. 482 According to Matt and Breyer-Brandjwik, 79 the plant is used in the treatment of miscarriage; the leaf is used against fever and abdominal pain. The juice of the bark and of the cambium has been used as an ordeal poison instilled under the eyelid. A weak solution prepared with roasted seeds has been applied for eye inflammation. It is used in East Africa for sleeping sickness and malaria. In Burundi, Entada (Umusange) is burned, and the smoke is inhaled for the treatment of severe headache.

Constituents — The root contains saponins and an alkaloid. Rotenone has been reported from the species. 551

Pharmacological Studies — The leaf infusion at a 1:1000 concentration has been shown to be lethal to the goldfish Carrasius auratus after a 12-h exposure but not toxic to guinea pig at doses of up to 5 g/kg. 551 The defatted methanolic extract has been evaluated for anti-inflammatory activity in acute and chronic models of inflammation. The extract (50–200 mg/kg p.o.) exhibited dose-dependent and significant inhibition of both the carrageenan-induced rat paw edema and granuloma tissue formation in rats. The extract (50–200 mg/kg p.o.) was also found to inhibit the acetic acid-induced vascular permeability in a dose-dependent fashion in mice. 552

Bioassay-guided fractionation of the dichloromethane root bark extract of the plant led to the isolation of a diastereoisomer of the clerodane-type diterpene kolavenol with a trypanocidal activity of IC50 value of 2.5 μg/ml (8.6 μM) against Trypanosoma brucei rhodesiense, the causative agent of the acute form of human African trypanosomiasis. 553

Erythrina Senegalensis

 

Botanical Name — Erythrina senegalensis DC

Synonyms — Chirocalyx latifolius Walp., Duchassaingia senegalensis (DC.) Hassk.

Family — Leguminosae

Common Names — Coral flower, parrot tree

African Names — Bini: eranigbonyakehi; Efik: edeng; Hausa: majiriya; Igbo: echichi; Masai: al oboni; Ndebele: umkawana, ummpumbuluku; Shona: munyanyudza; Yoruba; ologun sheshe; Tiv: showoh

Description — Erythrina senegalensis is a medium-size shrubby tree, 3–4.5 m high but sometimes growing up to 15 m in height and 1.5 m in girth, and prickly. The bark is very rough and fissured, becoming remarkably so in old trees. It has crooked branches with an irregular crown; the thorns on the old wood are slightly curved, with thick woody bases. The slash is yellowish, turning brown on exposure to air. The leaves are rather variable in shape and size, with three leaflets 15 × 10 cm, with the central leaflet the largest. They are usually lanceolate to broadly ovate, glabrous, and sometimes with prickles on the midrib. The flowers are produced September–January in slender racemes up to 30 cm long and scarlet, but they turn black over time. The petals are about 2.5–5 cm long, and when leafless, are folded very flat so that the stamens are hidden. The pods are about 12 cm long and irregularly constricted but usually between seeds; the seeds are red, glossy, with a white hilium about 0.6 cm long. 8,28,33

Habitat and Distribution — The species is a common savanna tree, occurring on the banks of streams and sometimes planted for its medicinal properties. It is distributed from Senegal to Cameroon and also grows in Kenya, Tanzania, Zimbabwe, and Ethiopia.

Ethnomedicinal Uses — The root infusion is used in Nigeria as a toothache remedy and in the Ivory Coast for venereal diseases. The stem bark is employed extensively in traditional medicine, and several trees in homesteads are often stripped of the barks. The aqueous extract of the bark is used for the treatment of jaundice in northern Nigeria; an infusion mixed with lime and pepper is administered for venereal diseases. A decoction of the bark has been used for the treatment of bronchial infections, coughs, and throat inflammation. The pounded bark and leaves are used in soups to treat female infertility. Extract of the bark is given to women during childbirth; in Guinea, it is administered after delivery, whereas in Nigeria it is given to women during labor to ease pain. The wood is reputed to be an aphrodisiac. In central Africa, infusion of the bark and roots is used as an enema for fevers, inflammation, and stomachache.

Constituents — The plant yields alkaloids with curariform activity, collectively known as Erythrina alkaloids. The major ones include α- and β-erythroidine, erysodine, erysovine, erysotrine, and erysopine. Over 30 alkaloids have been recorded from the genus, and in E. senengalensis, erysodine represents 50% of the total alkaloids. 78,554

Pharmacological Studies — The Erythrina alkaloids have been extensively evaluated for their curarizing effects. Earlier studies showed that, based on grams of frog curarized per gram of seed, the species has a value of 20,000 versus 44,000 IU for the related E. sigmoidea. 555 The alkaloids, which have the advantage of being active when taken orally, have been found useful as muscle relaxants in a number of clinical applications, such as for the control of convulsions; as an adjunct to general anesthesia, especially to relax muscles of the abdominal wall; and in electroconvulsive therapy. 428,556 The mechanism of action of the Erythrina alkaloids is similar to that of curare, the paralyzing effect being due to synaptic blockage of the nervous impulse traveling toward the skeletal muscle, without CNS involvement. Unlike curare, which is excreted in the urine, alkaloids of Erythrina are excreted in various ways, and the paralyzing effect is useful in various surgical procedures in which temporary muscular relaxation is required. β-Erythroidine has been shown to compete with acetylcholine, and its curare-like effect is inhibited if quaternization of the nitrogen in its molecule is modified.

It has been shown that a relationship exists between the structure of Erythrina alkaloids and their biological activities, with the sulfoacetic esters of erysovine and erysopine, as well as erysothiovine and erysothiopine, consistently more active than the free bases; 557 the quaternary bases are, however, of shorter duration. Other activities of the alkaloids include CNS depression, neuromuscular blocking, anticonvulsant activity, and hydrocholerectic effects. 428,558,561

Eucalyptus Globulus

Botanical Name — Eucalyptus globulus Labill.

Synonyms — Eucalyptus abbreviata Blakely & Jacobs., Eucalyptus acervula Hook. f., Eucalyptus cannonii R.T. Baker

Family — Myrtaceae

Common Names — Eucalyptus leaf, blue gum tree (E), eucalyptus (F)

African Names — Arabic: kafur; Hausa: Igbo: nkwu-ishi; Swahili: mti- ulaya

Description — They are very tall trees with straight trunks that often have white peeling bark; sometimes, they attain a height of up to 100 m. The leaves are orbicular, with a bluish or silvery surface, and exude a fragrance when crushed; they measure about 230 cm in length and 4 cm in width and are ensiform, acute, entire, coriaceous, brittle, and punctate. The inflorescence is umbellate with white flowers. The plant produces capsular fruits. It has an agreeable and aromatic odor, and the taste is aromatic, pungent, and slightly bitter.

Habitat and Distribution — This is a subtropical plant that originated from New South Wales and Queensland but was introduced in Africa as a cultivated crop. This and related species, such as E. citriodora, E. divans, and Eismithii, are cultivated in many parts of the continent, especially in well-drained subtropical and Mediterranean regions.

Ethnomedicinal Uses — The leaves of Eucalyptus are employed as a remedy for colds. They are also ingredients in the potherb used as steam therapy for malaria.

Constituents — The plant contains up to 3% volatile oil, the major constituents of which are cineole, together with tannin, a bitter principle, and resin. The oil also contains (+)-a-pinene, phellandrene, geraniol, alkyl aldehydes, methyl cinnamate, and a variety of terpenes.

Pharmacological Studies — The essential oil has been found to possess antimicrobial (including antitubercular) activity. 559,560 The plant is listed in the Martindale Extra Pharmacopoeia for catarrh and as a rubefacient. 205

Toxicity — Side effects of excessive eucalyptus consumption include nausea, vomiting, dizziness, muscular weakness, and a feeling of suffocation. Fatality due to severe poisoning is known. 205

Euphorbia (Milkweeds)

Three species of Euphorbia are common in Nigeria: E. desmondi and E. kamerunica, which are medium-size trees, and E. hirta, a small herb. Other species are described in specialized textbooks of economic botany; they include E. aegyptiaca, E. balsamifera, E. convolvuloides, and E. lateriflora. The three species mentioned first are all considered important, but E. hirta is by far the most widely used in the preparation of traditional remedies. There is little problem in differentiating E. hirta from the other two species, although E. hirta is practically indistinguishable from E. convolvuloides. Since in traditional medicine both plants are not distinguished in their use, the drug euphorbia should apply to both E. hirta and E. convolvuloides. All the species produce irritant milky sap.

Euphorbia Hirta

Botanical Name — Euphorbia hirta Linn. Syn. E. pilulifera

Synonyms — Chamaesyce gemella (Lag.) Small., Desmonema hirta (L.) Raf., Ditritea hirta (L.) Raf., Tithymalus pilulifer (L.) Moench

Family — Euphorbiaceae

Common Names — Asthma herb, malomen, Australian asthma herb, malomay

African Names — Hausa: nonan kurchiya; Igbo: udani; Yoruba: ege-ile, emi-ile; Efik: etinkeniekpo; Bini: asen-uloko; Tivi: mbasombol mange; Bari: like babe

Description — Euphorbia hirta is a herb that grows to about 20–30 cm, with more or less erect branches, spreading from a near-erect base and bearing yellowish hairs. The leaves are opposite and in pairs, arising from somewhat swollen nodes. They measure about 4.5 cm long and 1.5 cm broad; they are ovate to rhomboid, unequal sided at the base, and serrulate. 136 The flowers are stalked globose clusters. The fruits occur as single stalked capsules.

Habitat and Distribution — Euphorbia hirta is widespread and common throughout the continent.

Ethnomedicinal Uses — An aqueous decoction of the plant is used for the treatment of acute enteritis and dysentery. The latex is instilled into the eye for the treatment of conjunctivitis. The plant has a reputation as a remedy for bronchitis and asthma, and it is listed in the (British) Martindale Extra Pharmacopoeia 205 (pp. 599–560) for the treatment of coughs and asthma in the form of a liquid extract or tincture. Other uses include those for increased lactation, as a tonic anthelmintic, for treatment of wounds and tumors, and as an anticonvulsant, mild sedative, and antimicrobial agent. The plant is slightly narcotic.

Constituents — The latex contains I-inositol, pyrogallic, and catechuic tannins and an alkaloid xanthorhamnine. 78 Taxerol, friedelin, β-sitosterol, myricyl alcohol, ellagic acid, and hentriacontane have been isolated from the stem extracts. 561 A number of amino acids and ellagic gallic, chlorogenic, and caffeic acids have been reported as occurring with the flavonoids kaempferol, quercitol, and quercitrin in the plant. 561 Arthur indicated the presence of hydrogen cyanide and a triterpenoid in the herb. 562 For the constituents and uses of the Asian species, please consult the work of Perry. 226

Pharmacological Studies — It has been shown that the plant contains two active principles, one exerting a spasmodic or histamine-potentiating activity and the other an antispasmodic property. 563 The antispasmodic principle was identified as shikimic acid and the contracting principle as choline by EI Naggar and his colleagues; they also isolated iso-inositol, glucose, and sucrose. 564 An alcoholic extract of the aerial parts of this herb, containing shikimic acid, produced relaxation of the guinea pig ileum and was used in the treatment of asthma, hay fever, bronchitis, and other respiratory conditions. The extract showed an antispasmodic effect on the smooth muscles of mice and guinea pigs and was effective in clinical trials for the treatment of amebic dysentery. 565 A single oral treatment appeared to be long lasting and produced remissions in 83% of the cases treated for up to 6 months. The hypoglycemic activity of the plant and its antiprotozoal effects have been reported. 566 The alcohol extract also showed activity against leukemia virus in mice. A maximum dose of 1 g/kg p.o.has been recorded as tolerated by mice.

The drug appears to be well tolerated and was a proprietary product in both Europe and the United States. 78 The processed extract was reported to be 20 times more active than the crude extract when tested against Entamoeba histolytica. It does appear that the activity of Euphorbia is due to a wide range of compounds rather than a single isolate; it is therefore necessary to intensify efforts at the purification of the extracts along the lines suggested by Ndir and Pousset. 567 Euphorbia was previously accorded official status (B.P.C. 1954, Indian P.C., N.F. 1939) and was withdrawn because of reports of toxicity.

Garcinia Kola

 

Botanical Name — Garcinia kola Heckel

Synonyms — Garcinia akawaensis Spirlet., Garcinia bergheana Spirlet

Family — Clusiaceae

Common Names — Bitter kola, false kola, male cola

African Names — Bini: edun; Efik: efiari; Ibibio: efiat; Igbo: akilu, aki-inu, adi, akara-inu, ogolu; Ijaw: okan

Description — Garcinia kola is a medium-size tree, but sometimes grows up to 12 m tall and 1.5 m wide. It is a spreading tree with a dense and heavy crown; the bole is straight; the bark is greenish brown, thick, and smooth. It has broad leaves, 5–10 cm long, elongated elliptic to broadly elliptic, acute or shortly acuminate, cuneate, leathery, with very distinct resinous canals. It has 10 pairs of lateral veins that run parallel to the margin but not forming a marginal nerve; the midrib is prominent at the underside; the stalk is stout, finely hairy in young leaves, and about 8 mm long. 168 It bears male and female flowers separately, usually December–March and May–August. Female flowers are yellow and fleshy, globose, 1.5 cm wide; male flowers are smaller but with more prominent stamens (4 bundles), 4 sepals, and 4 greenish-white petals. It produces characteristic large fruits (6 cm in diameter), with the size and color of an orange, containing 2–4 brown seeds embedded in an orange-color pulp. 9

Habitat and Distribution — It is found in moist forests and cultivated in homesteads. It is distributed throughout West and Central Africa and has been located in Sierra Leone, Ghana, Nigeria, Cameroon, and Congo.

Ethnomedicinal Uses — It is used extensively in traditional medicine for the treatment of various diseases. The drug is chewed in southern Nigeria and parts of West Africa as a masticatory, in spite of its very bitter taste. The stem bark is used as a purgative, and the powdered bark is used for the treatment of malignant tumors. The sap is used for parasitic skin diseases. The latex (gum) is used internally for gonorrhea treatment and applied externally to fresh wounds. The twigs of G. kola can be used as tapers, and the roots yield the favorite bitter chew sticks sold in small bundles in local markets in West Africa. The seeds are used to prevent or relieve colic, cure head or chest colds, and relieve cough. The seeds are chewed as an aphrodisiac and the dried nuts for dysentery treatment. The seeds are also used in the treatment of diabetes, bronchitis, and throat infections. The plant has been employed in the treatment of liver disorders. 568 The peeled stem and twigs are cut into small pieces and placed into a bottle of local gin, which is allowed to “mature” over a couple of days for drinking as an aphrodisiac. The alcohol is replenished several times until the resultant infusion becomes colorless.

Constituents — G. kola and other members of the genus are known to elaborate a complex mixture of phenolic compounds, including biflavonoids, xanthones, and benzophenones. 569571 The most important constituents of the plant include the antimicrobial benzophenone, kolanone, 572 and biflavonoids based on eridictoyl/taxifolin moiety GB1, GB2, GB3, kolaflavanone, and garciniflavanone. 573,574 The seeds also contain the chromanols garcinoic acid and garcinal and their derivatives, as well as tocotrienol. 575

Pharmacological Studies — G. kola has been shown to possess remarkable antihepatotoxic activity against a variety of experimental hepatotoxins, including carbon tetrachloride, 2-acetylaminofluorene, paracetamol, and galactosamine, 576581 and protection against the accumulation of heavy metals in the liver. 582 Chronic ingestion of G. kola seeds caused inhibition of gastrointestinal motility and weight reduction and prevented castor oil-induced diarrhea in rats. 583 Other activities of the biflavonoid mixture include those involving anti-inflammatory, antimicrobial, antidiabetic, and antiviral properties. 584586 The antiviral activity is quite broad and showed remarkable inhibitory effects against a variety of viruses, including Punta Toro and Pichinde viruses, sandfly fever, influenza A, Venezuelan equine encephalomyelitis, and ebola. The IC50 values are in the range of 7.2–32/μg/ml with an MTC of more than 320 μg/ml. 587

The seed extract and the dried powder have been formulated into various dosage forms, including tablets, lozenges, creams, vials, and toothpaste. 588 The biflavonoids also possess antidiabetic activity and inhibited the activity of rat lens aldose reductase. 589 Examination of the liver, kidney, and duodenum of rats fed a diet containing 10% (w/w) dry powdered seeds of G. kola for 6 weeks has been reported as revealing some histological alterations in these organs. 465 Studies indicated a possible role in the treatment of dermatological disorders associated with melanin hyperpigmentation. The methanol extract and a Garcinia biflavonoid displayed inhibitory activity (>60%) against tyrosinase (E:C:1.14.18.1), the rate-limiting enzyme in melanin synthesis. 590

Kolaviron, the mixture of biflavonoids, benzophenones, and chromanols, as well as other phenolic compounds in G. kola, possesses strong antioxidant activities. Several reports on the experimental validation of the antioxidant properties of Garcinia are due essentially to kolaviron. An evaluation of the antioxidant properties of garcinoic acid (structurally similar to vitamin E) and its congeners, including investigation of the structure-antioxidative activity relationships, identified a semisynthetic derivative with antioxidant activity that was 18.7 times stronger than dl-a-tocopherol. 591 The aqueous extract showed antidiabetic activity in hyperglycemic rats. 592 At a concentration of 200 mg/kg body weight, over a period of 21 days, the extract significantly (p < 0.05) decreased the blood glucose level and increased the activity of SOD (p < 0.05) and that of malondialdehyde (MDA) (p < 0.05). The extract, however, had no significant effect (p > 0.05) on the activity of CAT.

The clinical outcome observations on the phytomedicines prepared from the standardized whole seeds or extracts of G. kola seem to support the laboratory findings reported and the use of the plant as an adaptogen. Its bronchodilatory effect has been evaluated with a clinical study of 19 male adults. The only respiratory parameter changed by 15 g of G. kola was a peak expiratory flow rate, indicating a mild bronchodilatory effect. 593 Observational studies at the International Centre for Ethnomedicine and Drug Development (InterCEDD) Nsukka (Nigeria) indicated potential application as a remedy for colic in dysentery, liver disorders, upper respiratory infections, asthma, cough, sore throat, laryngitis, arthritis, menstrual and intestinal cramps, and headache. Topical uses awaiting clinical validation include its use as a wound dressing, as an antiparasitic lotion, and in oral hygiene (as a chewing stick). The possible clinical uses for Garcinia based on the analysis of the studies include its use as an antiviral, antihepatotoxic, and immune booster in cases of flu and liver and respiratory diseases, as antioxidant, and in the management of diabetes.

Toxicity — No serious adverse effects have been reported following the consumption of Garcinia. In response to the public health concern in West Africa about the long-term use of Garcinia and in view of the presence of a complex mixture of phenol compounds in Garcinia kola seed, investigators at the University of Ibadan’s (Nigeria) College of Medicine evaluated the hepatic, testicular, and spermatozoa antioxidant status in rats chronically treated with Garcinia kola seed. It was observed that long-term treatment with Garcinia kola had no adverse effect on the spermatozoa characteristics but significantly elevated testosterone concentration when compared to the control group. Improvement of antioxidant systems was accompanied by a significant decrease in MDA level in the liver, testes, and spermatozoa of Garcinia kola-treated rats. Histological observation revealed that chronic administration of Garcinia kola had no effect on the liver and testes at all doses when compared with the control. 594

Glycyrrhiza Glabra

 

Botanical Name — Glycyrrhiza glabra L.

Synonyms — Glycyrrhiza glabra L. var. typica Reg. et Herd., Liquiritia officinalis Moench.

Family — Leguminosae

Common Names — Liquorice (E), reglisse, bois dous, racine douce, herbe aux tanneura (F)

African Names — Arabic: irksos

Description — Glycyrrhiza glabra is a perennial herb or subshrub, 1–2 m tall, with long, highly developed stolongerous roots. The leaves are compound alternate imparipinnate from 9 to 17 leaflets. It produces flat pods of 2 × 6 mm. Three varieties of C. glabra are known in commerce: C. glabra L. var. typica Reg. et Herd., G. glabra var. glandulifera Wald. et kit, and C. glabra var. vislacea.

Habitat and Distribution — The plant is a temperate crop, cultivated in the arid regions around the Mediterranean basin of North Africa and parts of southeastern countries.

Ethnomedicinal Uses — In North Africa, the plant is used mainly as a cough remedy and to prevent extreme thirst in desert areas. In southern and eastern Africa, it is used as a remedy for appendicitis and pulmonary tuberculosis and as a lotion for eye diseases. 79

Constituents — The principal constituents of liquorice are glycyrrhizin and oleanane triterpene glycosides, also known as glycyrrhizinic or glycyrrhizic acid. The aglycone is glycyrrgetinic acid (or glycyrrhitic acid). Co-occurring with glycyrrhizin are the terpenes liquiritic acid, glycyrrhetol, glabrolide, and 28-hydroxyglycyrrhizinic acid. 595,596 The plant also contains flavonoids, including liquiritin, rhamnoliquiritin, licoflavone, licoisoflavones A and B, licoisoflavonone, glabrol, glyzarin, formononetin, and liquiritigenin. 597,598 Chalcones, such as lichochalcones A and B, liquiritigenin, licuraside, and echinatin, have been isolated from liquorice. 599 Other constituents include glucose, amino acids, and volatile oil consisting of fenchone, linalone, furfuryl alcohol, and benzaldehyde. 123

Pharmacological Studies — Liquorice has been employed in the treatment of a variety of illnesses and the pharmacological properties ascribed to the drug reflect the varied uses and heterogeneous nature of the constituents. The plant drug is an effective anti-inflammatory agent, demulcent, expectorant, antitussive, spasmolytic, antiviral, immunostimulant, and therapeutic agent in the treatment of adrenocortical insufficiency. It is difficult to select any of these actions as the most important property of liquorice, although the focus in this section is on the anti-inflammatory activity of the drug; references are made to some of its other pharmacological and biochemical properties. Its potential use for treatment of human acquired immune deficiency syndrome (AIDS) and its antiviral properties are subjects of ongoing research.

Glycyrrhizin and its aglycone, glycyrrhetinic acid, have been shown to possess remarkable anti-inflammatory activity. 600,601 It inhibited edema induced by formaldehyde and carrageenan, as well as activity against cotton pellet granuloma, granuloma pouch, and tuberculin reaction in BCGsensitized guinea pig. 600 In the carrageenan-induced edema model, an ED25 of 30 mg/kg for glycyrrhetic acid was reported. It was also found to have an inhibitory effect on mononuclear leukocyte migration in dextran shown to inhibit both the COX and 5-LOX pathways in AA metabolism. 602 In AA-induced mouse ear edema, it was found that the hemiphthalate derivatives were more active than the parent compound, and the effect appears to be due to a direct anti-inflammatory action rather than modulation of steroid-mediated antiphlogistic activity through secondary formation of a reactive protein. 603 Inoue and his colleagues have demonstrated a similar effect on 12-0-tetradeconoylphorbol-13-acetate (TPA)-induced ear edema. 604 Glycyrrhizin is also an effective antiallergic agent. The aglycone has been shown to inhibit almost completely the dexamethasone-induced increase in both the histamine content and histidine decarboxylase activity of cultured mastocytoma P-815 cells at a dose of [ 3 H]dexamethasone binding to the cytoplasmic receptor, but it inhibited the release of histamine from antigen-stimulated rat mast cells and intensified the inhibitory activity induced by dexamethasone. It also inhibited antigen-induced release and incorporation of [3H]dexamethasone AA in immunized rat mast cells. 605

The anti-inflammatory activity of Glycyrrhiza is not due to the triterpenoid constituents alone. The chalcones licochalcone A (2-methoxy-4,4-dihydroxy-5-,7-dimethylallylchalcone) and licochalcone B (2-methoxy-3,4,4-tri-hydroxychalcone) at concentrations of 10–3 to 10–6 M, inhibited calcium ionophore A23187-induced LTB4 and LTC4 formation in human PMN leukocytes. 606 It has previously been shown that the nonglycyrrhetinic acid-containing (but flavonoid-rich) fraction of liquorice had anti-inflammatory activity, especially AN antigastric effect that is independent of that attributed to the terpenoids. 607 An IC50 of 4.6 × 10–7 was reported for licochalcone A in the leukotriene inhibition assay, and 4.2 × 10–6 M of licochalcone was required for the same purpose. The two chalcones also increased the cyclic AMP level in human PMNs at concentrations of 10–4 to 10–3 M and induced by calcium ion ionomycine dose dependently, in the presence of 1 mM Ca2+ or 1 mM EGTA (ethylenglycol-bis(β-aminoethylether)-N,N′-tetraacetic acid). 229 In addition to the anti-inflammatory activity of glycyrrhiza, most of the other therapeutic applications associated with the drug have been confirmed by the results of laboratory and clinical studies. 608,611 In essential hypertension, glycyrrhizin caused a marked reduction in elevated plasma renin activity, with a concomitant reduction in serum potassium concentration and plasma aldosterone.

The antitussive properties have been evaluated using the water-extracted (WE) polymeric fraction of Glycyrrhiza glabra. This arabinogalactan protein-enriched fraction, 85% or more of which becomes precipitated with Yariv reagent, consisted mainly of 3- and 3,6-linked galactopyranosyl and 5- and 3,5-linked arabinofuranosyl residues. Per oral administration of this polymer in a dose of 50 mg/kg body weight decreased the number of citric acid-induced cough efforts in guinea pigs more effectively than codeine. It did not induce significant change in the values of specific airway resistance or provoke any observable adverse effects. 609

The cardioprotective effect of Glycyrrhiza glabra against ischemia-reperfusion (I-R) injury induced by ligation of the left anterior descending coronary artery (LADCA) in rats has been reported. 610 Ligation of the LADCA for 45 min followed by 60 min of reperfusion has induced significant (p < 0.05) heart dysfunction as evidenced by a significant (p < 0.05) decrease in mean arterial pressure (MAP), heart rate (HR), and contractility; (+)LVdP/dtmax and relaxation; and (−)LVdP/dtmax along with increased left ventricular end diastolic pressure (LVEDP). Ligation induced I-R injury also significantly (p < 0.05) decreased myocyte injury enzymes, creatine phosphokinase-MB (CK-MB) isoenzyme, and lactate dehydrogenase (LDH) as well as antioxidant enzymes; and SOD, CAT, and glutathione peroxidase (GSH-Px). Furthermore, I-R injury also induced lipid peroxidation, as evidenced by significant (p < 0.05) increase in malondialdehyde (MDA) formation and histological perturbations concomitant to depletion of GSH from the heart. However, pretreatment with G. glabra significantly (p < 0.05) prevented the depletion of the antioxidant enzymes; SOD, CAT, GSH-Px, and myocyte injury marker enzymes; CK-MB isoenzyme and LDH. Pretreatment with G. glabra also prevented GSH depletion and inhibited lipid peroxidation in the heart. In addition to improving biochemical indices of myocardial function, G. glabra significantly (p < 0.05) reinstated MAP, HR, (±)LVdP/dtmax and attenuated an abrupt rise in LVEDP. Histopathological preservation evidenced by reduced infiltration of cells and myonecrosis depicted the myocardial salvaging effect of G. glabra. These findings suggest the cardioprotective potential of G. glabra against myocardial infarction by amelioration of oxidative stress and favorable modulation of cardiac function.

Clinical Properties — Clinical reports on glycyrrhizin, its aglycone, or any of the semisynthetic derivatives are usually listed under the generic name of carbenoxolone, which is actually the name of the semisynthetic succinic acid ester of 18-glycyrrhetic acid. Clinical studies have shown that liquorice exerts an inhibitory activity against prostaglandin and thromboxane synthesis in humans. 611 The drug is used as oral tablets at a dose of 5–10 g or is incorporated into tropical preparations for the treatment of skin diseases. Liquorice roots are used in Japan and China in the treatment of allergic inflammation and atopic dermatitis. 606 Its deoxycorticosterone effects have led to its use in the treatment of rheumatoid arthritis, Addison’s disease, and various inflammatory conditions. It is a major ingredient in the Japanese Kampo drugs and features in nearly every Kampo prescription included in recent reviews. 612 In the drug preparation called Shakuya-du-kanzo-to (Tj-68), glycyrrhiza root and peony root are used in equal proportions in the treatment of inflammation and hyperandrogenism. Other clinical uses of glycyrrhiza, including the treatment of gastric ulcer, cancer, and AIDS, are discussed elsewhere in related texts on phytotherapy. Its use for the treatment of ulcer may be due partly to its effect on adhesion of harmful organisms to gut. It has been shown that an aqueous extract (1 mg/ml) of Glycyrrhiza glabra significantly inhibited the adhesion of Helicobacter pylori to human stomach tissue. 609 This effect was related to the polysaccharides isolated from the extract, with one purified acidic fraction (0.25 SPB) as the main active polymer. Purified polysaccharides did not exhibit direct cytotoxic effects against Helicobacter pylori and did not influence hemagglutination. In addition, raw polysaccharides from Glycyrrhiza glabra were shown to have strong antiadhesive effects against Porphyromonas gingivalis. 1078

Pharmacokinetics — Glycyrrhizin is well absorbed in the gastrointestinal tract. A clinical evaluation with human volunteers 234 used the enzyme immunoantibody technique to measure the disposition of the compound and its aglycone. 600 It was found that the time required for maximum serum concentration of glycyrrhizin was less than 4 h after oral administration of a decoction of liquorice containing 133 mg of glycyrrhizin. Most of the drug was eliminated from the blood in the majority of the cases within 72 h. The aglycone reached a maximum serum concentration at about 24 h, and in two of the five cases, the glycyrrhetic acid was still detected in the blood after 96 h. It was interesting to note from the study that in the two clinical cases with symptoms of pseudoaldosteronism by liquorice, glycyrrhetic acid levels were up to 70–80 mg/ml, whereas the serum levels of the glycosides were comparatively low. It is probable that pseudoaldosteronism is restricted to the use of the aglycone and not the glycoside.

Glycyrrhizin has been shown to bind with intracellular and serum-binding proteins. In rabbits, the inhibitor constant values for glucocorticoid receptor binding (dissociation constant of 1.0 nmol/l) in the liver cytosol were found to be 2.0 nmol/l for glycyrrhizin and 1.7 nmol/l for glycyrrhetic acid, and for the mineralocorticoid receptor binding (dissociation constant = 1.1 nmol/l) in the livercytosol, they were 3.5 nmol/l for glycyrrhetinic acid and 3.0 nmol/l for glycyrrhizin. 614 It follows that the activity of glycyrrhizin is due, at least in part, to its effect on glucocorticoid and mineralocorticoid receptors. The compounds did not show any significant effect on estrogen receptors or serum sex hormone-binding globulin. 614

Glycyrrhetinic acid hydrogen succinate (GAHS) as the disodium salt has been found to be well absorbed by nasal instillation, and it was also observed that nasal absorption of insulin was greatly enhanced by the presence of 1% GAHS. 615

Toxicity and Adverse Reactions — Liquorice is well tolerated, and not many serious side effects have been reported when used within normal therapeutic dosage ranges. Most of the adverse reactions are due to hypersensitivity to liquorice, and the few cases of toxicity have been associated with excessive doses. Epstein and his colleagues reported a case of a woman who consumed 30 to 40 g of liquorice daily for 9 months as a starving diet to control her obesity. Her serum potassium level fell to about 1–6 mEq/l, and her urine was dark brown and contained myoglobin. She was reported as lethargic, with dulled reflexes, and had flaccid weakness. She also suffered from sodium retention, which resulted in hypertension, and high aldosterone levels. 616 Cumming et al. have also reported another case of a patient who, after taking as little as 150 mg glycyrrhetic acid per week, showed symptoms of hypokalemia (1.2 mmol/l) and flaccid quadriplegia. 617

It is believed that the observed pseudoaldosteronism associated with glycyrrhizin intoxication is due to the inhibitory effect of liquorice on 11β-hydroxysteroid dehydrogenase. The results of clinical and laboratory experiments supported this conclusion. 618

Gnetum Africanum

Botanical Name — Gnetum africanum Welw.

Synonym — Thoa africana (Welw.) Doweld

Related Species — Gnetum buchholzianum Engl.

Family — Gnetaceae

Common Names — Gnetum, eru

African Names — Efik (Nigeria): áfàng; Ibibio: afang; Igbo: okazi, ; Yala (Ogoja, Nigeria): eruru; Yoruba: àjáàbalè, ajakobale

Description — Gnetum is a dioecious liana up to 10 m long but sometimes longer; it grows in the wild in West and Central Africa; branches are somewhat thickened at the nodes, glabrous. Leaves are decussately opposite, sometimes in whorls of 3, and simple; stipules are absent; the petiole is up to 1 cm long and canaliculate above; the blade is ovate-oblong to elliptical-oblong, rarely lanceolate, 5–14 × 2–5 cm, with base attenuate, apex abruptly acuminate, obtuse, or minutely apiculate, entire, thick-papery, glabrous, pale green above, paler beneath, with 3–6 pairs of strongly curved lateral veins looped near the margin. Inflorescence occurs in an unbranched catkin, axillary or terminal on a short branch, solitary but male inflorescences at the apex of branches and often in groups of 3, up to 8 cm long, jointed, with a peduncle 1–1.5 cm long, with a pair of scale-like, triangular bracts; male inflorescence occurs with slender internodes and whorls of flowers at nodes; female inflorescence has slightly turbinate internodes and 2–3 flowers at each node. Flowers are small, about 2 mm long, with moniliform hairs at the base and an envelope; male flowers have a tubular envelope and exerted staminal column bearing 2 anthers; female flowers have a copular envelope and naked, sessile ovule. Seed, resembling a drupe, is orange-red when ripe and ellipsoid, 10–15 × 4–8 mm, and enclosed in the fleshy envelope. 1140

Ethnomedicinal Uses — Both species are used as a vegetable, eaten raw or cooked in soups and salads. The aerial parts have been used in traditional medicine for the treatment of diabetes, piles, and high blood pressure; as medicine against enlarged spleen and sore throat; and as a purgative. In the Central African Republic, the leaves are eaten to treat nausea and as an antidote to arrow poison made from Periploca nigrescens Afzel. In Cameroon, the leaves are chewed to mitigate the effects of drunkenness, and they are taken as an enema against constipation and to ease childbirth. They are also used to treat boils and fungal infections on the fingers. 1140

Constituents — Gnetum leaves contain C-glycosylflavones, 2″-xylosylisoswertisin and 2″-glucosylisoswertisin. Perhaps of chemotaxanomic importance is the presence of 2″-O-rhamnoylisoswertisin and apigenin-7-hesperidoside and the absence of vitexin and 2″-O-glycosylvitexin in Gnetum africanum. 619 Stilbenes, as well as their dimeric, polymeric, and hydroxylated derivatives, have been isolated from some G. africanum and other Gnetum species.

Pharmacological Studies — Most of the studies on eru are on its nutritional properties. It has been shown that extracts of the leaf of Gnetum africanum induced vaginal openings and increased weights of the uterine muscle in a manner similar to the effect of repeated administration of estrogen to immature female rats. The uterine muscle enlargement suggests the antifertility potential of the popular vegetable in the female reductive system of rats. 620 However, the result on rats may not correlate directly to human use. The antioxidant quality of Gnetum has been evaluated by the determination of lag time, concentration of polyphenol that will inhibit 50% of oxidation of LDL plus very low-density lipoprotein (VLDL) (IC50) and phenol antioxidant index (PAOXI). It was observed that both hydrolyzed and nonhydrolyzed extracts were better antioxidants than vitamin E in the inhibition of copper-mediated LDL-plus-VLDL oxidation. 621 This observation is interesting in view of the reported presence of the antioxidant compound resveratrol and stilbenes in Gnetum. 622,623

Agriculture — Gnetum is still collected from wild species. But, trial cultivations have begun in Cameroon, Nigeria, and Benin Republic. The main problem is that the plant in its natural habitat seems to prefer shaded forest canopies. In experiments in Cameroon, propagation by seed was difficult because the seed is slow to sprout, with germination taking 1 year or more. Perhaps the seeds need pretreatment, such as passing through the intestines of a bird, fruit bat, squirrel, or other animal, before they germinate. Seed is normally found only in the tree canopy. Seed collection is thus far from easy, a further reason why eru is hardly cultivated. 1140 Experimental cultivation using leafy stem cuttings have produced encouraging results.

Commerce — Even with the little work done on the chemistry and pharmacology of eru, there is already a high demand for this highly priced and much prized vegetable. With its remarkable antioxidant profile and reputed nutrient properties, the current trade within the West and Central African zone will likely expand. The major limitation remains the scarcity of the plant in the wild.

Gongronema Latifolium

 

Botanical Name — Gongronema latifolium Benth

Synonyms — Marsdenia latifolia (Benth.) K.Schum., Marsdenia glabriflora Benth., Marsdenia leonensis Benth., Marsdenia racemosa K.Schum.

Related Species — Gongronema angolense (N.E.Br.) Bullock

Family — Apocynaceae (Asclepiadaceae)

Common Names — Bush buck, tafel boom

African Names — Igbo (Nigeria): utazi; Yoruba (Nigeria): arokeke; Ghana: aborode, akam, nsurogya

Description — Gongronema is a small genus comprising five species in Africa, much resembling Dregea, APG has assigned the subject species G. latifolium as a member of the genus Marsdenia. The name Gongronema, however, is used here for ease of cross-reference with earlier information on this medicinally important plant. It is a weak climbing plant with a soft and fibrous stem. The stem is green with little swollen internodes. Both the stem and leafy stalk produce milky latex when cut. The leaves are cordate at the base and a little pointed at the apex. The leaves are smooth. The flowers are cream, and the fruits are ovoid in shape. When dried, they split to expose woolly materials.

Habitat and Distribution — Gongronema is widespread in tropical Africa and occurs from Senegal east to Chad and south to DR Congo.

Ethnomedicinal Uses — Gongronema latifolium is widely used in West Africa for medicinal and nutritional purposes. It has a sharp-bitter and sweet taste and is widely used as a leafy vegetable and as a spice for sauces, soups, and salads. Leaves of Gongronema are used as a bitter tonic to treat loss of appetite and for management of diabetes. It is also used for hypertension and cholesterol control. An infusion of the aerial parts is taken to treat cough, intestinal worms, dysentery, dyspepsia, and malaria. It is taken with lime as a purge to treat colic and stomachache in Sierra Leone. The pulverized leaves are applied as an embrocation in Senegal and Ghana on the joints of small children to help them walk. The boiled fruits in soup are eaten as a laxative. In Nigeria, a leafy stem infusion is taken as a cleansing purge by Muslims during Ramadan. The latex is applied to teeth affected by caries. It is also taken for controlling weight gain in lactating women and overall health management. Asthma patients chew fresh leaves to relieve wheezing. A cold maceration of the roots is also taken as a remedy for asthma. A decoction of the roots, combined with other plant species, is taken to treat sickle-cell anemia. A maceration of the leaves in alcohol is taken to treat bilharzia and viral hepatitis and as a general antimicrobial agent. 1140

Constituents — The leaves contain preganane glycosides, 17β-marsdenin derivatives, β-sitosterol, lupenyl cinnamate, lupenyl acetate, lupeol, essential oils, and saponins. The main components of the essential oil from the leaves are linalool (19.5%), (E)-phytol (15.3%), and aromadendrene hydrate (9.8%). The fixed oil contains saturated (50.2%) and unsaturated (39.4%) fatty acids. Palmitic acid accounts for 36% of the total fatty acid content; minor saturated fatty acids are stearic acid (4.6%), behenic acid (3.7%), and arachidic acid (2.8%). The main UFA is linoleic acid (31.1%), followed by oleic acid (7.1%) and linolenic acid (7.1%). The nutritional composition of the dry leaves is crude protein (9.8–27.2%), lipid extract (6.1%), ash (5.8–11.6%), crude fiber (8.7–10.8%), tannin (0.3%), and nitrogen-free extractives (44.3%). The composition of minerals per 100 g dry matter is K 244.8–332.1 mg, Na 110–113 mg, Ca 115.4–154 mg, P 125.5–326.9 mg, Fe 7.8 mg, Zn 13.4 mg, Pb 0.2 mg, Cu 2.3–43.5 mg, Mg 53.8 mg, Cd 0.1 mg, Co 115.9 mg, oxalate 70 mg, and ascorbic acid 187.1 mg. The major essential amino acids are leucine, valine, phenylalanine, aspartic acid, glutamic acid, and glycine. 1140

Pharmacological Studies — Several laboratory studies have demonstrated the possible antidiabetic activity of Gongronema. Different alcoholic leaf extracts showed promising hypoglycemic and antihyperglycemic activities in a dose-dependent way on normal and alloxan-induced or STZ-induced diabetic rabbits. 1140,624626 An ethanolic leaf extract possessed significant antilipid peroxidative activities. In a small clinical trial, the blood glucose concentration of healthy humans was determined after consumption of the leaves and showed a significant reduction in blood glucose level. Leaf extracts also showed antioxidant, anti-inflammatory, hepatoprotective, antiplasmodial, antiasthmatic, antisickling, antiulcer, analgesic, antipyretic, gastrointestinal relaxing, laxative, and stomachic activities. The antimicrobial activity of essential oil and extracts of Gongronema has been demonstrated on bacterial isolates from the bloodstream of patients infected with HIV. 627 The leaf extract has also been shown to be protective against acetaminophen hepatic toxicity in Wistar rats. 628

Toxicity — Gongronema is considered a nontoxic vegetable. An oral toxicity test on rats gave an LD50 of 1450.5 mg/kg, and an intraperitoneal injection in mice gave an LD50 of 1678.6 mg/kg.

Agriculture — The herb is cultivated in gardens and homestead farms in Nigeria and other parts of West Africa. It can be propagated by seed or softwood, semihardwood, and hardwood cuttings. Fresh seeds have a germination rate of up to 85% at 25–29°C. Cold storage for a brief period improves seed germination. When seeds from green-yellow follicles are matured enough to germinate, they can be stored for a longer period than seeds from yellow follicles. Softwood stem cuttings have better shoot and root development during the wet season, whereas semihardwood and hardwood cuttings perform better during the dry season. 1140

Commerce — A relatively modest trade in Gongronema occurs throughout West Africa but mainly for its use as a bitter vegetable and spice. Its importance as a dietary supplement is based on pharmacological activities, including hypoglycemic, antioxidant, anti-inflammatory, hepatoprotective, antiplasmodial, antiasthmatic, antisickling, antiulcer, analgesic, and antipyretic activities.

Formulation and Dosage Forms — Gongronema is an ingredient in two commercial products: Physogen Tea (for diabetes by Neimeth Pharmaceuticals) and a general bitter tonic by InterCEDD Health Products. Gongronema has also been used experimentally with positive results to replace hops as a bitter principle in brewing beer.

Griffonia Simplicifolia

 

Botanical Name — Griffonia simplicifolia (DC.) Baill

Synonyms — Bandeiraea simplicifolia (DC.) Benth., Schotia simplicifolia M. Vahl ex DC.

Family — Leguminosae

Common Names — Griffonia

African Names — West Africa: atooto, gbobgotri, kajya, kanya, kwakuo-aboto

Description — Griffonia simplicifolia is a woody climbing shrub native to West and Central Africa. It grows to about 3 m and bears greenish flowers followed by black pods. Leaves alternate and are simple, glabrous; stipules are triangular, 1 mm long, soon falling; the petiole is up to 1.5 cm long; the blade is ovate, 6–12 × 3–6 cm, with the base rounded to cordate, apex rounded to short-acuminate, 3(–5) veined from the base, with reticulate veins prominent on both sides. Inflorescence is an axillary, pyramidal raceme 5–20 cm long; bracts and bracteoles are triangular, very small, and persistent. Flowers are bisexual, almost regular, and 5-merous; the pedicel is 3–4 mm long; the receptacle is urn shaped, 1–1.5 cm long, and pale green; the calyx tube is 12–15 mm long, orange, with triangular lobes and up to 2 mm long; petals are almost equal, elliptical, 10–12 mm long, fleshy, greenish, and sparsely short-hairy on the margin; stamens 6 have filaments filiform, up to 2 cm long; the ovary is superior, about 4 mm long, stiped, with a style 1–2 mm long, persistent, stigma small. Fruit is an oblique-cylindrical pod about 8 × 4 cm, the stipe is 1–1.5 cm long, inflated, leathery, and 1–4 seeded. 1140

Habitat and Distribution — Griffonia simplicifolia is native to West Africa and parts of Central Africa. It grows in grass savanna, in coastal plains on termite mounds, in scrub thickets, in secondary and disturbed forest, and along the margins of primary forest and old farms.

Ethnomedicinal Use — The peeled stems and roots are used as chewing sticks and in Ghana also beaten into fibers to yield chewing sponges, a popular means of tooth cleaning. The leaf extract is used for kidney diseases and migraine and as an aphrodisiac. It is also used as eyedrops to cure inflamed eyes. Aerial parts have been used for wound dressing, as an enema for erectile dysfunction, for vomiting, and for mental disorders. The pulp is used in Côte d’Ivoire, Ghana, and Nigeria for the treatment of syphilitic sores. A decoction of stems and leaves is taken as a purgative to treat constipation and is used externally as an antiseptic wash to treat suppurating wounds. Stems and stem bark are made into a paste that is applied to decaying teeth, and a paste made from the leaves is applied to burns. In Nigeria, an extract from the powdered roots has been used to treat sickle-cell anemia. The leaves are used in the production of palm wine and give the wine a bitter taste. Sap that exudes from cut stems can be drunk to quench thirst. In Ghana, the roots are chewed and dried to produce a white powder that is used by women to powder their faces. The leaves are highly valued as animal feed and are said to stimulate reproduction.

Constituents — The leaves of Griffonia simplicifolia contain volatile oil, 5-hydroxy-L-tryptophan (5-HTP), indole-3-acetyl-aspartic acid, 5-hydroxy idole-3-acetic acid (5-HIAA), 5-hydroxytryptamine (5-HT; = serotonin, 0.1–0.2%), and coumarone. The seeds contain very high levels of 5-HTP, up to 18%. The cyanoglucoside lithospermoside (= griffonin) has been isolated from the roots, and it is believed to be the active ingredient against sickle-cell anemia.

Pharmacology — Griffonia is valued for the high content of 5-HTP in the leaves and seeds. In humans, 5-HTP increases the synthesis of serotonin in the CNS and has been shown to be effective in treating a wide variety of conditions, including depression, fibromyalgia, obesity, chronic headaches, and insomnia. 5-HTP is poisonous to insects, for instance, bruchids (Callosobruchus maculatus). 1140 The potential of Griffonia in the treatment of anxiety states has been evaluated in laboratory animals. Griffonia simplicifolia seed extract was shown to exert an anxiolytic-like effect in rats. Griffonia simplicifolia seed extract, dosed at 1, 5, 10, and 25 mg/kg, was orally administered in rats, which were submitted to the dark-light test and open-field test 60 min after the treatment. In the dark-light test, the administration of the extract at the doses of 10 and 25 mg/kg was able to significantly increase the time spent in the light compartment (p < 0.05). In the open-field test, the extract dosed at 5, 10, and 25 mg/kg induced an antitigmotactic effect, as indicated by a significant increase of time spent in the central area of the open field (p < 0.01). 629

In the sexual behavior of SD male rats, acute treatment significantly increased mount latency (at any dosage), intromission and ejaculation latencies (at 100 mg/kg), and postejaculatory interval (at 50 and 100 mg/kg). It was also found that subchronic treatment failed to exert a significant influence on copulatory behavior. The daily administration of the extract dosed at 50 and 100 mg/ kg for 9 days significantly reduced food intake and body weight. 629 However, a single administration of G. simplicifolia significantly reduced lordosis response and increased rejection behavior in female rats treated with the highest dose, while it did not influence proceptive behaviors. On the other hand, the subchronic administration of the extract significantly reduced proceptivity but not receptivity and increased rejection behavior. It was found that all tested dosages were able to markedly decrease food intake and body weight after a 9-day treatment. Taken together, the present results, possibly ascribed to increased levels of 5-hydroxytryptamine x(5-HT) in the brain, suggest a cautious administration of the plant extract owing to its negative influence on female sexual behavior. 629

Several clinical studies have established the value of Griffonia and 5-HTP in the management of depression. 1141 It has been observed that G. simplicifolia extracts direct modulation of the serotonergic system and have a clinically demonstrable value for the treatment of psychological suffering associated with unreciprocated romantic love. 630

Commerce — The seed of Griffonia simplicifolia is exported to Europe from Ghana, Côte d’Ivoire, Nigeria, and Cameroon. Exports from Ghana account for more than 60% of the global market for the unprocessed seeds as an industrial source of 5-HTP. The annual export to Western Europe was about 120 tonnes in 2010 at a wholesale price of US$15 per kg.

Agriculture — Griffonia is still collected mostly from the wild. Domestication efforts have met limited success. In productivity trials, wildlings were successfully used as planting material; this is impractical at a larger scale. Use of stem cuttings has not been successful. Seed propagation gave poor results, and different seed treatments did not improve germination.

Harpagophytum Procumbens

 

Botanical Name — Harpagophytum procumbens DC.

Related Species — Harpagophytum zeyheri Decne.

Family — Pedaliaceae

Common Names — Devil’s claw, grapple plant.

African Names — Twana: Kanako

Description — It has a characteristic large, hooked, claw-like fruit. It derives its name from the translation of the German name Teufelskralle, which means devil’s claw. At the beginning of the rainy season, the larger nodular roots produce young shoots that lie flat on the ground, growing up to 1.5 m in length. The tuber is up to 6 cm in diameter with a yellowish-brown longitudinally striated bark. It produces bright red flowers that rise rather abruptly from the leaf axils. It is the tuber that is used in the preparation of popular African antirheumatic teas. Harpagophytum is available in commerce as circular or fan-shaped pieces; it has an astringent taste and is odorless.

Habitat and Distribution — It grows in savanna and deciduous forests. It is a native of southern Africa, where it is cultivated as a drug plant.

Ethnomedicinal Uses — The tuber of the plant is used for a variety of purposes in southern Africa. An infusion of the tubers is used for the relief of fever and for blood disease. 79 It is administered to pregnant women in doses of about 0.25 g three times a day to relieve pain and in postpartum medication at lower doses. It is a general analgesic and an ointment for sprains, sores, and boils. The drug has been used as a bitter tonic and a digestive aid. Grapple plant is dispensed as an anti-inflammatory agent and is administered both orally and topically for various inflammatory conditions. The fresh tubers are applied as an ointment on women to facilitate labor.

Constituents — Devil’s claw yields a variety of compounds, including the glycosides of the flavonoids kaempferol and luteolin, and chlorogenic and cinnamic acids. 631 It also contains iridoid glycosides such as procumbide, harpagide, and harpagoside, 632,633 as well as a quinone, harpagoquinone; terpenes ursolic and oleanolic acid derivatives and esters; and stachyose and other sugars. 471,631

Pharmacological Studies — The anti-inflammatory activity has been investigated in vivo in a rat pore edema test; it was shown to inhibit the inflammation caused by a variety of agents. 634 The antirheumatic and antiphlogistic properties are comparable to those of pyrazole derivatives, 511 and the analgesic effect has been equated with that of phenylbutazone. 475 It has no spasmolytic or antidiuretic properties. Grapple plant is used as a bitter tonic, and it is reported to have 6000 or more bitterness equivalence to that of gentian root.

The extracts have been shown to cause a reduction in arterial blood pressure in rats, a decrease in heart rate in rabbits, and a protective effect against arrhythmias caused by adrenalin, chloroform, and calcium chloride. 471,635 The secondary storage roots or tubers are used for the preparation of the medicinal extract. In summary, scientific studies revealed that H. procumbens exhibits analgesic, antioxidant, antidiabetic, antiepileptic, antimicrobial, and antimalarial activities. 636 Iridoid glycosides and phenylpropanoid glycosides have been the focus of phytochemical investigations as the biological activity has been ascribed to the iridoid glycosides (such as harpagoside and harpagide), which are common in nature and are known to possess anti-inflammatory activity. It has been shown, however, that the hydrolyzed products of harpagoside and harpagide have more pronounced anti-inflammatory activity when compared to the unhydrolyzed compounds. 1093

Clinical Applications — Harpagophytum extracts have been used by Africans for a long time in the treatment of rheumatic diseases and gastrointestinal disorders. It was introduced into Europe as an herbal tea for the same purpose by a German farmer, G. H. Mehnert. Grapple plant tea is indicated in the treatment rheumatic diseases, especially arthritis and low back pain due to spondylosis. Good results have been reported in the use of the drug for the treatment of rheumatoid arthritis, neuralgia, and headaches. The drug has also been found effective in the treatment of diseases of the upper duodenum with pancreatic involvement, as well as for improvement of enterohepatic circulation and bile acid activation. 490 Clinical evaluation of patients with hypercholesterolemia indicated a marked reduction in blood cholesterol and neutral fatty levels. The drug was therefore found to be beneficial for the treatment of elderly patients with rheumatic complaints, obesity, and hyperlipidemia. The plant is available in Europe as medicinal teas for oral administration, in ampoules for parenteral medication, and as an ointment for external use.

The effects of the crude methanol extract, harpagoside, and harpogide on some smooth muscles in vitro have been studied by Occhiuta et al. 637 It was suggested that harpagoside and other constituents interfere with the mechanism that regulates the influx of calcium in the cells. In Langendorff preparations of rat heart, hyperkinetic ventricular arrhythmias (HVAs) induced by an ischemic perfusion were prevented by extract of H. procumbens and harpagoside in a dose-dependent manner. 638

The major problem with the use of Harpagophytum is that of availability, and many of the products currently marketed in Europe are derived from Scrophularia nodose and Verbascum thapsiforme, which are said to contain the iridoids harpagoside and harpagide. It should be noted that the activity of the grapple plant has not been specifically linked to any of its constituents. The use of the so-called active constituents must be considered with caution. It has been reported that when the constituents deemed to be the biologically active compounds were isolated, the efficacy was lower than that of the whole extract. This means that it is likely that the whole plant is necessary, and all the constituents may be working in synergy to exert the observed pharmacological effects.

Toxicity and Contraindication — Harpagophytum is reported to have some oxytocic properties and should not be taken during pregnancy. 639

Heliotropium Indicum

Botanical Name — Heliotropium indicum L.

Synonyms — Eliopia riparia Raf., Tiaridium indicum (L.) Lehm.

Common Names — Indian heliotrope, turnsole, Cock’s comb

Family — Boraginaceae

African Names — Hausa: kalkaashin korama; Yoruba: agogo-igun

Description — It has a characteristic long terminal, brush-like inflorescence of stalkless, whitish flowers. It is a small herb, about 1 m long. The leaves are oval in shape, about 10 cm long and 7 cm wide, shortly pointed at the apex and rounded or very slightly wedge shaped at the base. The leaf surface is raised between the veins, with saw-edged margins. The fruits consists of two cells, about 8 mm in diameter. 77

Ethnomedicinal Uses — The plant is a major ingredient for the preparation of agbo, a Yoruba traditional remedy. It is employed as an alcoholic extract for the treatment of venereal diseases. In East Africa, the roots are either boiled or pounded and soaked in water and the extract drunk 2–3 times a day for the treatment of yaws. 378 An infusion of the plant is used as an eye lotion and for application to cleanse ulcers. The leaf juice is administered orally as a vermifuge. It is given as an enema and applied mixed with emollient clay to arrest abortion. 77 A related species, H. subulatum, is used in postpartum medication. A topical preparation with castor oil is applied to stings, poisonous bites, and skin eruptions.

Constituents — The genus contains pyrrolizidine alkaloids. The principal alkaloids include europine, heliotrine, lasiocarpine, and 5′-acetyleuropine, 640 as well as 7-angelylheliotrine, 9-angelolretronecine, and its N-oxide.

Pharmacological Studies — The alkaloids possess antimicrobial 641,642 and antitumor properties. 643 The pyrollizidine alkaloids from Heliotropium are very toxic and have been associated with the veno-occlusive disease of the herbal tea. 644 The compounds are excreted through the milk in lactating animals, and their presence in milk has been identified as posing a potential toxicity hazard to neonates. 645

Hibiscus Sabdariffa — Bissap, Zobo

 

Botanical Name — Hibiscus sabdariffa L.

Synonyms — Abelmoschus cruentus (Bertol.) Walp., Furcaria sabdariffa Ulbr., Hibiscus cruentus Bertol., Hibiscus fraternus L., Hibiscus gossypifolius Mill., Hibiscus palmatilobus Baill., Sabdariffa rubra Kostel

Related Species — Hibiscus acetosella Welw. ex Hiern, Hibiscus rosa-sinensis, Hibiscus cannabinus L.

Family — Malvaceae

Common Names — Roselle, red sorrel, zobo, Jamaican sorrel, Indian sorrel, bissap, karkadeh, hibiscus flower

African Names — Hausa: abin kan iyaka, zobo; Igbo: okworo-ozo; Yoruba: amukan; Swahili: ufuta, ufuta dume

Description — The shrub is erect, slightly branched with a smooth or slightly hispid plant that can grow up to 4 m in height. The stem is glabrous to sparsely pubescent, sometimes sparsely prickly, green or reddish. It has lobed leaves and big yellow flowers with a purple center. The epicalyx and calyx are fleshy and succulent, bright red and persistent. The fleshy calyx is situated at the base of the flowers and is about 1.5–2 cm wide and on maturity of the fruit becomes enlarged to 3–3.5 cm. The plant takes about 6 months to mature, and it is harvested at the fruiting stage. Hibiscus flower, as the harvested product is called, is edible with a sweet-sour taste.

Habitat and Distribution — Hibiscus sabdariffa originated from Africa, where it may have been domesticated in Sudan and northern Nigeria about 6000 years ago, first for its seed and later for leaf and calyx production. However, apparently truly wild plants of Hibiscus sabdariffa have been collected in Ghana, Niger, Nigeria, and Angola. It is believed that the vegetable types were introduced to India and the Americas in the seventeenth century. Selection for fiber production took place in Asia, where cultivation is reported from the beginning of the twentieth century (e.g., in India, Sri Lanka, Thailand, Malaysia, and Java). Roselle is now found throughout the tropics. In tropical Africa, it is especially common in the savanna region of West and Central Africa. It is often found as an escape from cultivation. 1140

Ethnomedicinal Uses — Zobo is used throughout West and North Africa as a vegetable and a tonic for the improvement of general body function, blood circulation, and hypertension. Leaves are used as a gargle for cough, toothache, and throat inflammation. It is reported as providing good relief for coughs, biliousness, and symptoms of plethora. The flowers are applied in wound dressing. The root is effective for application to abscesses and bronchitis. Calyces are used to produce a beverage, which serves as a blood tonic and for high blood pressure. Whole dried aerial parts have been used for sexual asthenia, cough, peristalsis, toothache, boils, bronchitis, and conjuctivitis; as a poultice, diuretic, mouthwash, and laxative; and to ease childbirth.

Constituents — Many chemical constituents have been isolated from the calyx and flowers of roselle. These include alkaloids, ascorbic acid, β-carotene, anisaldehyde, arachidic acid, citric acid, malic acid, tartaric acid, glycine, betaine, trigonelline; anthocyanins as cyanidin-3-rutinoside, delphinidin, delphinidin-3-glucoxyloside (also known ashibiscin, the major anthocyanin in H. sabdariffa flowers), delphinidin-3-monoglucoside, cyanidin-3-monoglucoside, cyanidin-3-sambubioside, cyanidin-3,5-diglucoside; the flavonols glycosideshibiscetin-3-monoglucoside, gossypetin-3-glucoside, gossypetin-7-glucoside, gossypetin-8-glucoside, and sabdaritrin; quercetin, protocatechuic acid (PCA), pectin, polysaccharides, mucopolysaccharides, stearic acid, and wax. 646,647 The phytosterols campasterol, stigmasterol, ergosterol, β-sitosterol, and α-spinasterol have been reported from the seed oil. 23 The petals yielded 65% (dry weight) of mucilage, which on hydrolysis gave galactose, galacturonic acid, and rhamnose. In addition to these compounds, Hibiscus sabdariffa extract (HSE) contains complex polyphenolic acids (1.7% dry weight), flavonoids (1.43% dry weight), and anthocyanins (2.5% dry weight).

Pharmacological Studies — The various biological activities associated with Hibiscus sabdariffa can be related to the compounds found in the shrub. These molecules are bioactive in several biological models and responsible for the pharmacological effects presented by the extracts of this species. Various antioxidant constituents are found in the calyx and flower petals of roselle, such as hibiscus anthocyanins (HAs), quercetin, ascorbic acid, steroid glycosides (such as β-sitosteroid glycoside), and PCA.

It has antispasmodic, anthelminthic, and bactericidal properties. The antihypertensive and cardioprotective effects of tea made from roselle calyces have been demonstrated in various animal tests and in a few clinical tests. The phenolic compound PCA isolated from roselle flowers showed antioxidant, antitumor, and hepatoprotective activities. It has been demonstrated to be an efficacious agent in inhibiting the carcinogenic action of various chemicals in different tissues, such as diethylnitrosamine in the liver, 4-nitroquinoline-1-oxide in the oral cavity, azoxymethane in the colon, N-methyl-N-nitrosourea in glandular stomach tissue, and N-butyl-N-(4-hydroxybutyl)nitrosamine in the bladder, in murine models. PCA also shows mild cytotoxicity to PC14 and MKN45 human tumor cell lines and induces apoptosis in human leukemia HL-60 cells by means of the reduction of retinoblastoma protein phosphorylation and Bcl-2 expression. Thus, PCA may play a role in dietary chemoprevention.

Hibiscus exacts have been shown to lower serum cholesterol in men and women in a dose-dependent manner. In a clinical study, 42 volunteers were observed over a period of 4 weeks. The volunteers ranged from 18 to 75 years old with cholesterol levels of 175 to 327 mg/dl. Subjects were randomly assigned to three groups: group I (1 capsule of HSE during each meal), group II (2 capsules), and group III (3 capsules). Serum cholesterol levels were determined at baseline before the study commenced and at 2 and 4 weeks of the treatment period. In general, taking HSE led to a significant decrease in serum cholesterol level in subjects from groups I and II after 4 weeks. After HSE had been administered for 2 weeks, serum cholesterol levels were found to be lower in all groups (p < 0.05 for groups I–III) compared with baseline values by 7.8% to 8.2%. A similar response was observed, a reduction in serum cholesterol level by 8.3% to 14.4%, after 4 weeks of taking the supplement. It is important to note that the serum cholesterol level for 71% of group II volunteers was significantly lowered, with a mean reduction of 12% (p < 0.05). The authors concluded that a dosage of 2 capsules of HSE (with a meal) for 1 month can significantly lower the serum cholesterol level. The observation of lowered serum cholesterol in these subjects suggests that HSE may be effective in hypercholesterolemic patients. 648 This clinical study validated an earlier result from feeding experiments in hypercholestrolemic rats. 649

In another clinical study, HSE was shown to possess a significant uricosuric effect. 650 The study involved a human model with 9 subjects with no history of renal stones (nonrenal stone, NS) and 9 with a history of renal stones (RS) was used in this study. A cup of tea made from 1.5 g of dry roselle calyces was provided to subjects twice daily (morning and evening) for 15 days. A clotted blood and two consecutive 24-h urine samples were collected from each subject three times: (1) at baseline (control), (2) on days 14 and 15 during the tea-drinking period, and (3) 15 days after the tea drinking was stopped (washout). Serum and 24-h urinary samples were analyzed for uric acid and other chemical compositions related to urinary stone risk factors. The results when analyzed showed that serum parameters were within normal ranges and similar between the two groups of subjects and among the three periods. Vis-à-vis the urinary parameters, most of the baseline values for both groups were similar. After taking the tea, the trend was an increase in oxalate and citrate in both groups and uric acid excretion and clearance in the NS group. In the RS group, both uric acid excretion and clearance were significantly increased (p < 0.01). When the fractional excretion of uric acid (FEUa) was calculated, the values were clearly increased in both the NS and RS groups after the intake of tea and returned to baseline values in the washout period. These changes were more clearly observed when the data for each subject were presented individually. 651

The antihypertensive activity of HSE has been demonstrated in several human and animal studies. Ajay et al. established the probable mechanisms to explain the pharmacological basis of the observed clinical hypotensive activity of HSE. 652 The study observed the effects of a crude methanolic extract of the calyces of HSE on vascular reactivity in isolated aortas from SHRs. HSE relaxed, concentration dependently, aortic rings precontracted with KCl (high K+, 80 mM) and phenylephrine (PE, 1 μM), with a greater potency against the α1-adrenergic receptor agonist. The relaxant effect of HSE was partly dependent on the presence of a functional endothelium as the action was significantly reduced in endothelium-denuded aortic rings. Pretreatment with atropine (1 μM), L-NAME (10 μM), or methylene blue (10 μM), but not indomethacin (10 μM), significantly blocked the relaxant effects of HSE. Endothelium-dependent and -independent relaxations induced by acetylcholine and sodium nitroprusside, respectively, were significantly enhanced in aortic rings pretreated with HSE when compared to those observed in control aortic rings. The results thus demonstrated that HSE has a vasodilator effect in the isolated aortic rings of hypertensive rats. These effects are probably mediated through the endothelium-derived NO-cGMP-relaxant pathway and inhibition of calcium (Ca2+) influx into vascular smooth muscle cells. 652

Toxicity — The aerial parts of roselle, zobo, or hibiscus flower have been used as a safe tea substitute and a nutraceutical for centuries without any manifest toxicity. With the popularity of HS as a long-term food-medicine for the management of elevated blood pressure and hypercholesterolemia, it became necessary to investigate any possible toxicity in acute animal models and cohort long-term studies in human subjects. One such study was aimed at assessment of the potential adverse effects of HSE on sperm morphology and testicular ultrastructure of albino mice. Thirty adult male albino mice were divided into three equal groups and were given (a) distilled water, (b) cold Hibiscus aqueous extract, or (c) boiled Hibiscus aqueous extract. Hibiscus extract was administered orally daily for 4 weeks in a dose of 200 mg/kg body weight/mouse. Twenty-four hours after the last treatment, mice were decapitated, and the testes and epididymides were excised and processed for transmission electron microscopy to assess ultrastructural and sperm abnormalities. The results clearly demonstrated that aqueous extracts from dried calyx of H. sabdariffa, either cold or boiled, altered normal sperm morphology and testicular ultrastructure and adversely influenced the male reproductive fertility in albino mice. 653 Another toxicity study on experimental animals evaluated the effect of HS on rat liver enzymes and indicated possible hepatotoxicity of prolonged use of HSE. 654 These finding, although not easily transferable to the human situation, tend to suggest that Hibiscus extract may pose some human risk on prolonged use at high doses. It is interesting to observe that a later study actually indicated that HSE displayed antihepatotoxic activity when tested against azathioprine-induced acute liver damage. 655

Commerce — Hibiscus sabdariffa still remains a grossly underutilized plant. It is an important industrial crop for its fibers, and the demand for roselle fiber is likely to increase as a result of the rising interest in natural, biodegradable fibers. It has a global market as a colorant for herbal teas. Its rising profile and application as a nutraceutical agent makes it a commercially dependable crop. This multipurpose crop provides farmers with food and cash income when other vegetables have become scarce. Processing generates additional family income, from which women benefit in particular. Use of roselle as a vegetable or as a beverage should be promoted through research to improve cultivars, husbandry, and postharvest technologies. Applying rigorous quality standards for grading, processing, and packaging will boost competitiveness in the international market. The current market price for HS in the international market is US$2350–2450 metric ton/cost, insurance and freight (MT/CIF).

Agriculture — The seedlings for cultivation are collected during thinning, the period of vegetative growth when the plants are 6–8 weeks old; branches of about 50 cm long are picked two or three times. Calyces are harvested manually 2–3 weeks after flowering, usually 4–6 months after sowing, before the fruit has dried and dehisced. Regular picking prolongs flowering. The calyces are dried in the shade. When harvested for fiber, stems are cut before flowering, 4–5 months after planting. Fiber quality declines rapidly after the start of flowering. A single roselle plant may yield as many as 250 calyces, or 1–1.5 kg fresh weight. In Africa, average yields are much lower and variable because of environmental conditions and extensive management. Sudan reports an average yield of dry calyces of 93 kg/ha. In Senegal, maximum production of calyx on a dry weight basis is 500 kg/ha. Average fiber yields from roselle are 1.5–2.5 t/ha, depending on cultivar and management. India reported an average yield of 1.9 t/ha for 1997–2001. Reported seed yields ranged from 200 to 1500 kg/ha. 1140

Hilleria Latifolia

Botanical Name — Hilleria latifolia H. Watt.

Synonyms — Hilleria elastica Vell., Mohlana latifolia (Lam.) Moq., Rivina latifolia Lam.

Family — Phytolaccaceae

African Names — Igbo: aka-ato; Yoruba: ago

Description — This is a slender herb up to 1 m tall. The leaves are oval in shape, slightly elongated toward the apex, about 15 cm long and 6 cm broad. The surface is covered with numerous short lines of crystals. There are six prominent lateral veins on either side of the midrib. The leafstalk is long and covered with stiff hairs in the upper side. It has small pinkish or whitish flowers, borne on terminal long common stalks of up to 12 cm long, which are unclustered by the leaves. There are no petals; the sepals and stamens are 4 each, with one very short style. It produces more or less globose, smooth, and reddish fruits, about 2 mm in diameter and net veined. 77

Habitat and Distribution — It is a lowland rainforest plant and prefers rich clay soil where its presence is believed to indicate soils suitable for growing cocoa. 77

Ethnomedicinal Uses — The decoction of the leaves and twigs is used in Ghana for the treatment of jaundice; it is also used as a steam bath for the same purpose. The herb is boiled alone or in palm oil soup and drunk as a remedy for guinea worms and urethral discharges.

Constituents — There is no isolation work reported on this species. Preliminary phytochemical spot tests showed the presence of saponins and flavonoids.

Pharmacological Studies — An extract of the plant was found effective in vitro against Onchocera-volvulus filaroidea adults and microfilariae. 656

Holarrhena Floribunda

 

Botanical Name — Holarrhena floribunda (G.Don) Dur. et Schinz.

Synonyms — Holarrhena Africa A. DC., Holarrhena wulsbergii stapf., Rondeletia floribunda G. Don.

Family — Apocynaceae

Common Names — Holarrhena (English, French)

African Names — Arabic: ola-ina; Bambara: fufu, nofo, kedan; Pehul: indama, taraki; Sukuma: mweriweri; Yoruba: ako-ire, are-ibeji, areno, isai

Description — This is a big tree, reaching 15 m high and 1 m in girth. The bark is gray, smooth, with a pale brown slash and yielding copious latex. The leaves are small and lanceolate, 8–12 cm long and 4–6 cm broad; it is glabrous below, with 8–12 pairs of prominent lateral nerves, which fade close to the margin, and displaying a close network of veins between. It produces white, scented flowers. The plant bears linear cylindrical follicles hanging in pairs reaching 60 cm in length and enclosing flattened seeds with numerous brownish silky hairs (ca. 5 cm long) in a tuft at the apex. 9,164

Habitat and Distribution — It is found in the drier forest regions and fringing savanna forests. The plant is distributed from the Republic of Guinea to Angola.

Ethnomedicinal Uses — The bark macerated in palm wine is used in the treatment of dysentery and fever. 6 The leaf, bark, and roots are used in many parts of the continent as a remedy for malaria. A root decoction of the plant is used alone or in a mixture with other herbs for the treatment of female sterility. Various parts of the plant are employed in the preparation of topical medications for skin infections. It has also been used as an ingredient in a steam bath for malaria and fevers.

In eastern and southern Africa, the bark is dispensed as a febrifuge and as a tonic. 18 The root is boiled in milk and used to wash boys entering puberty and as a remedy for snakebite and for treatment of venereal disease. 654

Constituents — Holarrhena contains about 0.1% alkaloid of the glucosteroid type, including conessine, durchine, holacurtenin, and holacurtin. 78 The stem bark alkaloids are derived from pregnane. 657 The plant also contains nonsteroidal alkaloid, triacanthine, and phenolic acids and the flavonoids kaempferol and quercetin. 658

Pharmacological Studies — The alkaloidal fractions of the plant reduced intestinal amebiasis in rats and hepatic amebiasis in hamsters. Conessine and kurchamine have been shown to be the active constituents of this species. 78 A clinical trial of conessine on patients with intestinal and hepatic amebiasis gave results that were comparable to those of emetine. 659661 The steroidal alkaloids found in the plants also possess hypotensive, local anesthetic, and spasmolytic activity. Some of them are cardiotoxic.

The nonsteroidal alkaloid triacanthine has hypotensive activity, as well as cardiotonic, vasodilatory, antispasmodic, and analeptic characteristics. 662 The compound has been shown to act on experimental anemia in rats, probably due to its stimulation of erythropoiesis. 657 The Holarrhena alkaloids also exhibit diuretic activity and cause sodium retention. 663

Toxicity — The use of connessine in the treatment of dysentery has been discontinued due to its systemic toxicity. The compound is, however, applied externally in the treatment of Trichomonas vaginalis and urethritis. 664 The side effects are mainly neurological complications during therapy and include delirium, agitation, sleeplessness, vertigo, and anxiety. 78

Hoslundia Opposita

 

Botanical Name — Hoslundia opposita Vahl

Synonyms — Clerodendrum micranthum Gilli., Micranthes menthoides Bertol., Orthosiphon physocalycinus A.Rich.

Family — Lamiaceae

African Names — Igbo: oke-ota; Yoruba: anikan-gbiju

Description — This is a medium-size, tender shrub, up to 5 m high. The leaves are oval in shape, about 10 cm long and 4 cm broad. They are broadly lanceolate, pointed at the apex, wedge shaped at the base. They are usually oppositely arranged at the nodes, but some nodes carry 3 leaves, with saw-edged margins. It bears tiny white flowers, usually many on multibranched terminal stalks. The calyx tube is cylindrical, about 3 mm long, with 5 equal pointed tips, and hairy. The corolla is tubular, about 5 mm long, 2 lipped (lips equal in length); one of the lips is hooded, and the other is 3 lobed. There are 2 stamens and 1 style, all projecting from the corolla tube. It produces round, yellowish or orange berries. 9

Habitat and Distribution — It inhabits open forest areas and is distributed throughout the forest regions of the continent.

Ethnomedicinal Uses — The boiled leaves are used for the treatment of constipation. The infusion of the whole herb is used to treat convulsions in children. The crushed flowers and leaves are used as lotion for skin diseases, and the juice of the fresh leaves is applied topically to wounds. The leaves together with those of Ocimum are applied topically as an antidote for snakebite. The plant materials are also mixed and burned with the head of a freshly killed snake, and the ash is used for snake bite. 7 The twigs and leafy stem tips are used in the preparation of a remedy for epilepsy, vertigo, and conjunctivitis. The powdered roots are ingredients of a popular sore lotion in Ivory Coast and Burkina Faso. Decoction of the root is administered in Tanzania for colds, sore throats, and oral wounds and in Ivory Coast, Ghana, and Burkina Faso for the treatment of abdominal pains. The Shambala use the plant for the treatment of liver diseases, for cough and pains in the chest, fever, hookworm, stomach disorders, and wound healing and for the treatment of mental disturbance. 79 The volatile oil is known in Uganda as Kamyuyu oil and is used extensively in traditional medicine as an anti-infective agent.

Constituents — The plant yields sweet-smelling volatile oil, 665 which consists mainly of diterpenes, sesquiterpenes, and sesquiterpene alcohols. 666

Pharmacological Studies — The root bark extract has been shown to possess moderate activity against the multidrug-resistant KI strain of the malaria parasite, Plasmodium falciparum. 466 The petroleum showed the greatest activity with IC50 in the 5- to 9-μg/ml range. The methanol extract possesses antibacterial 667 and anticoagulant activities. 668 The plant has been shown to be effective as an external application for the treatment of herpes zoster. 457

Toxicity — There is one report on possible toxicity of the plant. 669

Hybanthus Enneaspermus

 

Botanical Name — Hybanthus enneaspermus F. von Muell.

Synonyms — Calceolaria enneasperma (L.) Kuntze., Ionidium rhabdospermum Hochst., Polygala frutescens Burm. f. ex DC., Solea enneasperma Spreng., Viola guineensis Schumach. & Thonn.

Family — Violaceae

African Names — Igbo: usolala-ocha; Tuareg (Arab): alwaas; Yoruba: abi-were

Description — This an erect herb, up to 50 cm, usually with one or more vertical branches arising from the base and a slightly ribbed stem. The leaves are opposite or alternate on the stem and branches and are broadly lanceolate or long and narrow, with a sharply pointed apex; they are 4–7 cm long and 0.5–1 cm broad. They have very distinct lateral veins and toothed margins. The plant produces small lilac or bluish flowers with 5 tiny sepals and a corolla of one large (usually colored) petal and two tiny (whitish) ones. The flowers are borne solitary in the axils of the leaves, on long stalks. The fruits occur as tiny 6-seeded capsules crowned with persistent styles. 77

Habitat and Distribution — It grows wild in deciduous forests.

Ethnomedicinal Uses — The leaves are used for the preparation of a remedy for irregular bowel movement. The plant is used to garnish the food of pregnant women, especially before childbirth and after delivery as a general tonic. It is a common ingredient in Yoruba agbo infusions for young children.

Irvingia Gabonensis

Botanical Name — Irvingia gabonensis (Aubry-Lecomte ex O’Rorke) Baill.

Synonyms — Irvingia barteri Hook.f., Irvingia caerulea Tiegh., Irvingia duparquetii Tiegh., Irvingia erecta Tiegh., Irvingia griffonii Tiegh., Irvingia hookeriana Tiegh., Irvingia platycarpa Tiegh., Irvingia tenuifolia Hook.f.; Irvingia velutina Tiegh.; Mangifera gabonensis Aubry-Lecomte ex O’Rorke.

Related Species — Irvingia wombolu Vermoesen (APG = Irvingia tenuinucleata Tiegh.), Irvingia excelsa Mildbr.

Family — Irvingiaceae

Common Names — African bush mango, dika bread, dika bread tree, dika nut, wild mango, sweet bush mango, ogbono

African Names — Igbo: ugiri, ogbono, Odika; Yoruba: apon, oro; Hausa: biri, goron; Cameroon: etima; Gabon: oba; Ivory Coast: odika, ogbono, sioko; Sierra Leone: bobo; Zaire: meba, mueba

Description — The genus Irvingia comprises 7 species, 6 occurring in tropical Africa. Two of the species, Irvingia gabonensis (ugiri) and Irvingia wombolu (APG = Irvingia tenuinucleata Tiegh.), are closely related and difficult to distinguish from each other. Irvingia gabonensis has edible fruit pulp, while that of Irvingia wombolu (adoh) is bitter and inedible. The seeds from both species are used as soup thickeners in West Africa. Both species are called bush mango, but Irvingia gabonensis is referred to as rainy season bush mango, and Irvingia wombolu is called dry season bush mango to reflect their respective fruiting periods. They can also be differentiated in commerce as sweet bush mango for I. gabonensis and bitter bush mango for I. wambolu.

Sweet African bush mango is a small-to-large tree, up to 40 m tall; the bole is generally straight, up to 100 cm in diameter, with buttresses up to 3 m high; outer bark is smooth to scaly, gray to yellow-gray, and inner bark is yellow and fibrous; the crown is spherical or taller than wide and dense. Leaves are alternate, simple, and entire; stipules are up to 4 cm long, unequal, and forming a cone protecting the bud, caducous, leaving an annular scar on the branches; the petiole is up to 5 mm long; the blade is elliptical, 4.5–8 × 2–4 cm, the base is cuneate, the apex is acute or indistinctly acuminate, thinly leathery, and pinnately veined. Inflorescence occurs as an axillary panicle up to 9 cm long. Flowers are bisexual, regular, 5-merous, and small; the pedicel is up to 5 mm long; sepals are free, 1–1.5 mm long; petals are free, 3–4 mm long, and yellowish white; stamens are 10, inserted below the disk, free, equal, with filaments 4–5 mm long; the disk is 1.5 mm in diameter, bright yellow, nectariferous; the ovary is superior, 2 celled, with a style 1–2 mm long. Fruit is an ellipsoid to cylindrical drupe, occasionally nearly spherical, slightly laterally compressed, 4–6.5 × 4–6.5 × 3.5–6 cm, smooth, green when ripe; pulp is bright orange, soft, juicy, sweet to slightly bitter, with a few weak fibers, stone woody, 1 seeded. Seed usually is 2.5–4 × 1.5–2.5 × about 1 cm in size. 1140

Habitat and Distribution — Three centers of genetic diversity in Irvingia gabonensis have been identified to be southern Cameroon, southeastern Nigeria, and central Gabon. Irvingia gabonensis prefers moist lowland tropical forest below 1000 m altitude and with annual rainfall of 1500–3000 mm and mean annual temperatures of 25–32°C. Irvingia gabonensis is better adapted to acid ultisols in high-rainfall areas than to less-acidic alfisols; it prefers well-drained sites. Often, 2–3 trees grow together, and in some areas it is reported to be gregarious. The plant is indigenous to the humid forest zone of the Gulf of Guinea from western Nigeria east to the Central African Republic and south to Cabinda (Angola) and the westernmost part of DR Congo; it has also been found in São Tomé et Príncipe. The presence of Irvingia gabonensis is often associated with former human habitation. The bigger Irvingia species, Irvingia excelsa Mildbr., is somewhat restricted to the rain forest of Cameroon and Gabon, while Irvingia robur Mildbr. and Irvingia smithii Hook.f. are found co-occurring with I. gabonensis throughout the region.

Ethnomedicinal Uses — All parts of the plant are used in traditional medicine. The seeds are used as soup thickeners in West Africa. An edible oil is extracted from the seed that is also used in cooking. The fruit of Irvingia gabonensis is juicy and sweet, is eaten fresh like mango, and makes a refreshing tonic drink. Unlike the fruit pulp of most other Irvingia spp., which is bitter, the pulp of ugiri has been used for the preparation of juice, jelly, jam, and wine and can be fermented sometimes to yield an alcoholic beverage. The seed is used for the preparation of a very slimy soup given to nursing mothers to prevent postpartum weight gain. Dika fat is solid at ambient temperatures and has been used as a substitute for cocoa butter in beverages and in cosmetics. The stem bark has been used for dysentery. It is used to increase male fertility and for yellow fever, scabies, and skin diseases. The plant has been used in Laos for the treatment of liver diseases, gonorrhea, body pain, gastrointestinal diseases, diarrhea, edema, male sexual dysfunction, and toothache.

Constituents — Irvingia is valued for its edible seeds and fruit pulp. The seeds yield fat (40–75 g/100 g), called dika fat, which consists of lauric acid (20–59%), myristic acid (33–70%), palmitic acid (2%), stearic acid (1%), and oleic acid (1–11%). The nutritive value of the kernels per 100 g edible portion is water 4 g, energy 2918 kJ (697 kcal), protein 8.5 g, fat 67 g, carbohydrate 15 g, Ca 120 mg, Fe 3.4 mg, thiamin 0.22 mg, riboflavin 0.08 mg, and niacin 0.5 mg. 1 The pulp yields about 75% juice, which is rich in vitamin C, and wine produced from it was found to be of good color, mouthfeel, flavor, and general acceptability. The pulp contains zingiberene and α-curcumene, ethyl and methyl esters of cinnamic acid, and dodecanal and decanol, which are the main flavor components and are responsible for imparting spicy-earthy, fruity, and wine-yeast flavor notes. The nutritive value of the fruit pulp per 100 g edible portion is water 81 g, energy 255 kJ (61 kcal), protein 0.9 g, fat 0.2 g, carbohydrate 15.7 g, Ca 20 mg, P 40 mg, Fe 1.8 mg, and ascorbic acid 7.4 mg. 1140

Pharmacological Studies — The stem bark was found to have analgesic effects in tests with mice. Aqueous extracts of the leaves have caused a reduction in intestinal motility in test animals. A nutritional evaluation related to the performances of growth and the analysis of increasing amounts of dika nut fat (0, 5.1%, 7.34%, and 13.48%) in young Wistar rats has shown that increasing amounts of dietary Irvingia gabonensis fat was in correlation with the rising of myristic acid (23.53% to 58.86%), modified cholesterol metabolism, and increased the concentration of HDL cholesterol without any change in the quantity of LDL receptor. 670 Clinical observational studies in humans have also shown that addition of a supplement of 4 g/day of “dika bread” to the diet of patients with type 2 diabetes for 1 month reduced plasma glucose and lipid levels. There was remarkable reduction in the LDL plus VLDL cholesterol and triglyceride levels, while the levels of beneficial HDL cholesterol increased. The three ATPases of the erythrocyte membrane of the diabetic patients were significantly lower than in normal subjects. 671 The use of African bush mango for treatment of obesity has been established by several laboratory and clinical studies. 672,673 In a double-blind, randomized study involving 40 subjects (mean age 42.4 years), 28 subjects received Irvingia gabonensis (1.05 g three times a day for 1 month), while 12 were on placebo and the same schedule. During the 1-month study period, all subjects were on a normocaloric diet evaluated every week by a dietetic record book. At the end, the mean body weight of the I. gabonensis group had decreased by 5.26% ± 2.37% (p < 0.0001) and that of the placebo group by 1.32% ± 0.41% (p < 0.02). The difference observed between the IG and the placebo groups was significant (p < 0.01). The obese patients under Irvingia gabonensis treatment also had a significant decrease of total cholesterol, LDL cholesterol, and triglycerides and an increase of HDL cholesterol. On the other hand, the placebo group did not manifest any changes in blood lipid components. 1149

The male fertility enhancement of Irvingia has been evaluated in a study in which hormonal parameters of male guinea pigs were investigated and compared with that of Proviron using an enzyme immunoassay method, which was done by reaction of antibody with serum testosterone and testosterone label, magnetic solid phase separation, and color development step. The aqueous extract of the seeds (50–400 mg/kg) caused a statistically significant increase (p < 0.05 analysis of variance [ANOVA]) of testosterone in male guinea pigs, from 2.70 ± 0.26 ng/ml to 3.10 ± 0.42 ng/ml on day 7 and to 3.30 ± 0.48 ng/ml on the 28th day of the administration of the extracts. The highest increase was 3.30 ± 0.48 ng/mL, obtained after 28 days of treatment. These effects were similar to those of Proviron, which were 2.80 ± 0.28 ng/ml and 3.00 ± 0.41 ng/ml on the 7th and 28th day of treatment, respectively. 674

The extracts of the leaves and roots showed significant antimicrobial activities that were found comparable to those of gentamicin and tioconazole used as controls. 675 The mutagenicity of dika nut as evaluated by Ames assay, in vitro and in vivo chromosomal aberration test, and in vivo micronucleus assay did not reveal any genotoxicity of the extract. The results of a subchronic toxicity study suggested the no observed adverse effect level (NOAEL) for I. gabonensis extract (IGOB131) was greater than 2500 mg/kg/day, the highest dose tested. 676

Commerce — Kernels of Irvingia gabonensis are valuable articles of trade domestically and between countries in West and Central Africa. There has been a recent increase in demand due to international trade because of its use in the preparation of an effective weight loss dietary supplement. Domestication of this species offers great opportunity for the sustainability of production. A few plantations exist in Nigeria and Cameroon, but these are hardly sufficient to meet the growing demand and have resulted in substitutes from Asia and fake products containing ordinary mango. International Centre for Research in Agroforestry (ICRAF), cited in Ladipo, 677 reported that in 1975 the market for kernel products was worth in the region of US$50 million. The market has been growing since then. The global trade on raw dika nuts and products was estimated at about US$165 million in 2010.

Agriculture — Irvingia gabonensis has a slow growth on planting but gradually picks up. It is mainly propagated by seed. Germination of Irvingia gabonensis seeds takes more than 14 days, and they should first be extracted from the fruit and dried for at least 2 days. A germination rate of 80% can be reached in this way. Methods of vegetative propagation through rooting of leafy stem cuttings under mist have been developed, and micropropagation, grafting, and marcotting experiments have yielded good results. Preliminary results showed that plants from bush mango marcotts can fruit 2–2.5 years after transplanting.

Formulation and Dosage Forms — Proprietary formulations of Irvingia are available in Europe and America mainly for the treatment of obesity. These are usually dried extracts of the seeds in capsules and tablets. The total seed powder is produced by InterCEDD Health Products (Nigeria) in cubes for cooking as soup thickeners and for the management of diabetes. Local production of the dika wine is limited to parts of western Cameroon and eastern Nigeria.

Jateorhiza Palmata

Botanical Name — Jateorhiza palmata Miers

Synonyms — Cocculus palmatus D.C., Menispermum palmatum Lam.

Family — Menispermaceae

Common Names — Calumba

African Names — Lindi (Konde): roamwa; Yoruba: agbihu, atutu

Description — The plant is a climber. The root possesses a thick bark and a depressed center, with a grayish-brown surface. The fracture is short and mealy, and the transverse section is yellowish with vascular bundles in radiating lines. It is very bitter and mucilaginous, with a slight odor. 9,28,77

Habitat and Distribution — The plant grows in rich alluvial soil. It is distributed in East Africa, Malagasy, and parts of the West Coast. It is cultivated as a medicinal plant in Kenya, Ghana, Tanzania, Malagasy, and Mauritius. A related species, J. macrantha Ecell & Mendonca, is distributed from southern Nigeria to Gabon and Rwanda.

Ethnomedicinal Uses — The root bark is used as a general tonic. The whole herb, especially the leaves, yields a pleasant bitter and stomachic. It is used extensively in traditional medicine, especially for the preparation of remedies for hypertension, bronchial infections, and male impotence. In East Africa, the plant is reputed to be an effective dysentery remedy. The root decotion is used in the treatment of fevers (probably malaria) and as an anthelmintic.

Constituents — The plant elaborates a complex mixture of isoquinoline alkaloids, of which the major ones include palmatine, columbamine, jatrorrhine, and bisjatrorrhizine. It also contains bitter terpene-dilactones, such as calumbin and dihydronaphthalene (chasmanthin and palmanin). Thymol is a major component of the volatile oil. The sapogenins diosgenin and kryptogenin occur in low quantities.

Pharmacological Studies — Palmatine has hypotensive, antimalarial, and uterine stimulant activity. Jatrorrhizine is hypotensive, sedative, and antifungal. 123 The extract possesses antimicrobial activity. The drug is official in many countries as a bitter flavoring agent; it is listed in Japanese, Portuguese, and Spanish pharmacopoeias and in the Martindale Extra Pharmacopoeias. 205

Jatropha

Three species of Jatropha, J. curcas Linn., J. gossypiifolia L., and J. podagarica Hook, are common in Africa. They are believed to have been introduced to West Africa by the Portuguese. J. curcas is by far the most widely used species in traditional medicine, although the others are more available to investigators because of their use as ornamental plants and as hedges. No chemotaxonomic delimitation has been reported, and the species appear to have similar uses in folk medicine, the same chemical constituents, and similar pharmacological activity. A distinct differentiation can be effected by the macroscopic examination of the leaves and the variations in the dominant colors of the flowers. J. curcas has yellowish-green flowers; J. gossypiifolia Linn has deep red purple flowers and in lax cymes; and J. podagrica has dark red flowers and in congested cymes. The profile mainly concerns J. curcas, but references are made to the other species as appropriate.

Jatropha Curcas

 

Botanical Name — Jatropha curcas Linn.

Synonyms — Castiglionia lobata Ruiz & Pav., Curcas adansonii Endl., Manihot curcas (L.) Crantz., Ricinus americanus Mill.

Family — Euphorbiaceae

Common Names — Physic nut, termite nut, Barbados nut, fig nut

African Names — Hausa: bini da zugu, chi ni da zugu; Fulani: jkwolkwelaje; Bwari: kwotewi; Bini: oru-ebo; Igbo: ololu-idu, uru-eekpa, elu, and more; Efik: eto-mkpa; Anang: mbubok; Ibibio: eto-mkpo; Yoruba: botuje, lapalapa, seluju, polopolo, and more; for other Yoruba district names, see the work of Gbile. 678

Description — This is a shrub or small tree growing up to 6 m high with viscid milky sap, which sometimes is reddish and gummy. The leaves are 5 lobed or sometimes entire, openly cordate at the base, with small stipules and undulating margins, 15 cm long and broad. It flowers April– May; yellowish-green, the male and female flowers are borne at different times of the same inflorescence; petals are 6–7 mm long. The fruits occur as long, black subspherical capsules, scarcely lobed, 2.5–4 cm long, and containing about three blackish oil-rich seeds, about 2 cm long. 9

Habitat and Distribution — It is a widespread tropical plant and cultivated as an ornamental tree throughout the continent.

Ethnomedicinal Uses — The leaf decoction is used as a lactagogue, rubefacient, and suppurative. A mixture of the leaf decoction and lime juice is used for fevers and convulsions and as an anthelmintic. The ash from the burnt leaf is applied to guinea worm sore, and it is believed to be able to draw out the worm. An infusion of the young leaf shoots (at a dose of 2 cigarette tins, i.e., ca. 200 g three times a day) is used for most “urinary complaints”. 266

The stem and twigs are used to arrest bleeding and for toothache, eye inflammation, and wound healing. The latex is used on carious teeth and to help children’s teeth erupt. 7 The root decoction is used for the treatment of gonorrhea. The powdered root bark is used as dressing for wounds and sores. The latex is mixed with salt as a tooth cleanser and mouthwash. 266 An infusion of the root is indicated for rheumatism, dyspepsia, diarrhea, and incontinence. The root pulp is mixed with xylopia fruits for the treatment of dysentery.

The seed yields a strong purgative, “Pulza oil” or “Pinhen oil ” which is applied externally in cases of itch and herpes and is also rubefacient. Roasted seeds are mixed with pepper and shea butter for the treatment of guinea worm infestation. Preparations containing the seeds of Jatropha have been used for remedies for dropsy, gout, tumors, syphilis, and parasitic skin infestation and as an abortifacient. Every part of the plant is used as an ingredient in the preparation of a variety of other remedies. The seeds are considered poisonous, and their use as a purgative has been abandoned.

Constituents — The seeds contain 50% of a fixed oil and a mucilage, which consists of xylose, galactose, rhamnose, and galacturonic acid, and a toxalbumin, curcin. 679 The shell has been found to contain traces of glycosides. The nondrying fixed oil in the seed of J. curcas consists mainly of glycerides of stearic, palmitic, myristic, oleanolic, and curcanoleic acid. 79 The flavonoids vitexin and isovitexin have been isolated from J. curcas growing in India. 680 Cyanic acid has been detected in the fruits, roots, and bark. 79 The stem of J. podagrica yields tetramethylprazine. 681 The genus contains diterpenes.

Pharmacological Studies — The purgative activity of the seeds and leaves has been investigated. 79,682 The purgative activity of the oil (0.3–0.6 ml) has been shown to be greater than that of castor oil but less than the activity of croton oil. 683 The fruits and seed isolates possess contraceptive activity. 684 The ethanol extract has shown activity against P388 lymphocytic leukemia. 685 The latex of J. multifida showed activity on human complement activation and on PMN leukocyte activation. 686 The extract of J. gossypiifolia exhibited in vitro activity against Plasmodium falciparum. 687 Jatrophone, a diterpene isolated from J. elliptica at concentrations of 1–300 μM, caused a concentration-dependent relaxation effect against acetylcholine (Ach)-oxytocin and KCl-induced uterine sustained contraction. 688 The observed effect was not modified by phorbol ester, forskolin, MIX, TMB-8, and W-7. The diterpenes from J. curcas have been found not to induce mutation in Salmonella typhimurium TA98 and TA100. 689

Toxicity — Jatropha is a very toxic plant and should be considered dangerous as a drug, especially if taken in fresh preparations without boiling. The seed contains curcin, a toxalbumin, and an uncharacterized toxic protein. Jatropha poisoning is characterized by nausea, followed by acute abdominal pain, vomiting, and diarrhea. These symptoms occur within 1 h of the ingestion of the drug. Fatalities are rare except in very high doses, when depression, syncope, and coma may occur. Cases of toxicity due to accidental ingestion of the plant by children are common. In one reported case involving two children aged 3 and 5 years, the clinical syndrome observed included restlessness, severe vomiting, and dehydration. 690 In another case, eight children who accidentally ingested the seeds of the plant also exhibited the same clinical syndrome of nausea, vomiting, and diarrhea, and five of the patients needed intravenous rehydration. 691

The seed oil has been shown to contain tumor promoters. 692 The diterpenes, mainly phorbol esters found in oil, are believed to be responsible for the tumor-promoting activity. 693 The main use of Jatropha currently is in the industrial production of biodiesel from the oil. 694

Khaya Senegalensis

 

Botanical Name — Khaya senegalensis (Desr.) A. Juss.

Synonym — Swietenia senegalensis Desr.

Family — Meliaceae

Common Names — African mahogany, Senegal mahogany, cail cedrat, dry zone mahogany

African Names — Ashanti: kuntunkuri; Biron: korobaa; Dagarti (Mampridi, Moshi, Nankani, Wala): koko, koka; Fulani: dalehi; Hausa: mdachi; Igbo: ono; Itsekiri: okpe; Kanuri: kagam; Tiv: ha; Yoruba: ogonwo

Description — Khaya senegalensis is a tall evergreen tree, 15–30 m high, up to 3 m in diameter, with a clean bole 8–16 m, dark gray bark, with small, thin, reddish-tinged scales. The slash is dark pink to crimson, exuding a red bitter sap. The plant is recognized by its round evergreen crown of dark shining foliage. Leaves are pinnate, alternate, compound, and without stipules. The leaflets are 3–4 in number, rarely 5–7, usually in opposite pairs, oblong to narrowly oblong-elliptic, 4–12 cm long, 2–5 cm wide, apex acute to shortly acuminate, base rounded, margins entire, pale green, and with 4–8 pairs of lateral nerves. The flowers, about 4 mm long, are borne individually in conspicuous panicles, with pale green sepals, cream petals, and a bright red disk beneath the (4-celled) ovary. It produces a characteristic, almost spherical, woody capsule, 4–6 cm in diameter, opening by 4 valves from the apex. Six or more seeds are contained in a cell, broadly transversely ellipsoid to flat, about 25 mm long, 18 mm wide, with margins narrowly winged. The wood is valued as a savanna mahogany, although of an inferior quality to the wood of K. ivorensis. 9

Habitat and Distribution — The species is found in the savanna woodland and riverine forests. It occurs from West Africa to the Sudan and has been found growing in Gambia, Mali, Guinea, Senegal, Guinea Bissau, Sierra Leone, Ivory Coast, Ghana, Togo, Benin, Niger, Nigeria, and Cameroun. It is also found in Chad, Sudan, Uganda, and Central African Republic.

Ethnomedicinal Uses — Khaya is used extensively in West Africa as a bitter tonic and a fever remedy. Its name, Quiquiona du Senegal, in Francophone West Africa, is attributed to its use in the treatment of malaria. It is also used as a vermifuge, taeniacide, and antimicrobial agent for the treatment of venereal diseases. The crushed bark and seeds have been employed as an emmenagogue. The drug is highly valued in traditional veterinary practice: For the treatment of cattle suffering from liver fluke, an infusion made by steeping the bark in a mixture of brine and water is given as a draught and as a dressing for ulcers on camels, horses, and donkeys; decoction of the bark is administered to horses for internal ailments associated with mucous diarrhea.

Constituents — The plant yields limonoids, of which the major ones include khivorin, 7-ketokhivorin, 3-deacetylkhivorin, 3-deacetyl-7-ketokhivorin, 7-ketogedunin, methyl anglensate, methyl-6-hydroxy anglensate, mexicanolide, 6-hydroxymexicanolide, 7-deacetyl-7-oxo-gedunin, 6-deoxyswietenolide esters, and khayasin. 695697 The bark contains a bitter principle called “calicedrin” in commerce, which contains triterpenes with a lactone or epoxide function and a furan ring. Similar principles also occur in K. ivorensis. 698,699 The coumarones scopoletin, aesculetin, and scoparone have been shown to be constituents of the bark, while the fruits yield scopoletin. 700

Pharmacological Studies — The crude aqueous alcohol extracts of the stem bark possess sedative and reduced locomotor activity, as well as CNS depressant activity in mice. The coumarones found in the plant have been associated with analgesic, antipyretic, and moderate anticonvulsant action. 701,702 Earlier studies of the bitter “principle” caliderin showed that when injected through the subcutaneous or intraperitoneal routes, it produces a significant lowering of temperature in experimental hyperthermic animals. 703,704 Extracts of the plant were found to be antimicrobial at very low concentrations. 273

Kigelia Africana

 

Botanical Name — Kigelia africana (Lam.) Benth.

Synonyms — Kigelia pinnata (Jacq.) DC.; Kigelia aethiopica Decne., Bignonia africana Lam., Crescentia pinnata Jacq., Tanaecium pinnatum (Jacq.) Willd.; 30 other synonyms and subspecies

Family — Bignoniaceae

Common Names — Sausage tree, cucumber tree

African Names — The sausage tree is found throughout tropical Africa, and there are local names for the plant among the several hundred tribes. The following list gives only a selection of the common names: Afrikaans (South Africa): worsboom; Swahili: mvungunya, mwegea, mwicha, mranaa; Igbo (Nigeria): uturukpa, iteni, amo-ibi, uturu-bein, izhi, umu-aji, okpe sera, oke ogisi; IjoIzon (Nigeria): ogirizi; Twi (Ghana): nufuten, nufoten, nufutsen; Fante (Ghana): etua, etua, nufutsen, (e-) nufutsen; Yoruba (Nigeria): orara, pandoro, orora, uyan, epo amayan; Edo (Nigeria): ugbongbon, usuonbon, ugbongbon, usuonbon; Hausa (Nigeria): hantsar giiwaa, noonon giiwaa; FulaniFulfulde (Nigeria): jirlaare (fruit), jirlahi; Tiv (Nigeria): tyembegh, tyambeg; Manding-Bambara (Senegal): sidiamba; Wolof (Senegal): dobale, dabal, diambal, dabole, dombale; Zulu (South Africa): umBongothi, umZingulu, unbongothi, unfongothi, umvunguta, umzingula, ibele-ndlovu, umVongothi; Swazi (Southern Africa): umVongotsi; Taita (Kenya): mwaisina; Somali (Somalia): bukural, bukror, berde, saad, sag; Luo (Uganda): jago; Ngakarimojong (Uganda): edodoi; Lunde (Zambia): muvunguvungu; Lunyul (Uganda): mujungwe; Luo (Kenya): yago; Luo (Uganda): jago; Lusoga (Uganda): muvunjudza; Maa (Kenya): oldarpoi, ortarboi; Maasai (Tanzania): ol darboi, ol darboi; Ngoni (Zambia): muvungula; Nguu (Tanzania): mvungwe; Mbukushu (Namibia): ghuvunguvungu, ghuvenguvungu; Malinke (Gambia): sanjubaha, limbi; Malinke (Guinea): limbi lamban, dindon; Malinke (Ivory Coast): lamban, lemba, limbi; Malinke (Mali): dindon, limbi, tudo

Description — Kigelia comprises a polymorphous species. It is extremely variable in habit and leaf morphology, which has led to the distinction of up to 10 separate species and many synonyms. Kigelia africana is a small- to medium-size semideciduous tree, up to 25 m in height. The bark is gray and smooth at first, peeling on older trees. It can be as thick as 6 mm on a 15-cm branch. The wood is pale brown or yellowish, undifferentiated, and not prone to cracking. The tree is evergreen where rainfall occurs throughout the year, but deciduous where there is a long dry season.

The leaves are opposite or whorled, usually in whorls of 3–4, usually crowded toward the apex of branches, imparipinnate, up to 60 cm long; stipules are absent; petiole is up to 15 cm long and rachis up to 25 cm long; leaflets are 5–13, with lateral ones subopposite, subsessile except rounded to cuneate, more or less asymmetrical, apex rounded or retuse to broadly tapering, margin entire, serrate, toothed or wavy, papery to leathery, glabrous to more or less hairy at both surfaces, with 6–13 pairs of lateral veins. Inflorescence is a terminal, pendulous, very lax panicle, up to 100 cm long, with a long peduncle. Flowers are bisexual and very large; pedicel is up to 11 cm long, upcurved at the tip; the calyx is shortly tubular to campanulate, 2–4.5 cm long, suddenly widening and incurving upward, with limb 2-lipped, the superior lip 2-lobed, the lower one 3-lobed and recurved, lobes are rounded, at first yellowish, later becoming reddish to purplish with darker streaks; stamens 4, didynamous, adnate to the corolla tube, 4–7.5 cm long, staminode 1; disk annular, thick; ovary superior, 1 celled, up to 1.5 cm long, with 2 parietal placentas, style filiform, up to 7 cm long. The fruit is a large, sausage-like, pendulous berry up to 100 × 18 cm, with a peduncle up to 100 cm long, indehiscent, wall woody, surface heavily marked by lenticels, and gray-brown when mature. The fruit pulp is fibrous and pulpy and contains numerous seeds.

Habitat and Distribution — Kigelia is widely distributed throughout tropical Africa, particularly in the drier regions. It is a very resilient plant.

Ethnomedicinal Uses — The plant is used in traditional medicine for various purposes, including chronic constipation, fainting, anemia, sickle-cell anemia, epilepsy, respiratory ailments, hepatic and cardiac disorders, and nutritional illnesses such as kwashiorkor, rickets, wasting, and weakness. The fruit is used for edema, cancer, rheumatism, snakebites, fevers, malaria, and syphilis, and an alcoholic beverage similar to beer is also made from it. 1138 The unripe fresh fruit is considered poisonous and strongly purgative and is used internally only in small doses. It can be prepared for consumption by drying, roasting, or fermentation. The leaves and stem bark have been used for dysentery, constipation, wound dressing, boils, and fevers. The leaves are sometimes used to prepare a general tonic for improved health and growth. The stem bark decoction has been used as an aphrodisiac and for the treatment of kidney diseases, solar keratosis, diarrhea, coughs, and inflammation. The bark and leaves are decocted and administered as an abortifacient. Sexual complaints such as infertility, poor libido, sexual asthenia, and impotence are treated with medicines containing the fruits, roots, or leaves. 1 The root is a remedy for boils, sore throat, constipation, and tapeworm infestation. 705

Kigelia is also used in the treatment of skin diseases and in traditional cosmetics preparations as a skin lightening agent, to reduce wrinkles, and to promote smooth skin. In Nigeria, the ground fresh or dried fruits are formed into a paste and rubbed on the breast to treat “cancer” of the breast or abscess. 706 In some parts of Africa, it is considered a sacred plant and is used in religious rituals.

Constituents — The sausage tree elaborates a complex mixture of secondary plant metabolites, including iridoids, naphthoquinones, phenylpropanoids and phyenylethanoid derivatives, coumarins, lignans, flavonoids, fatty acids, and steroids. The fruits have been shown to contain the following iridoids: jiofuran, jioglutolide, 1-dehydroxy-3,4-dihydroaucubigenin, des-p-hydroxybenzoyl kisasagenol B, ajugol, verminoside, 6-trans-caffeoyl ajugol, 7-hydroxy viteoid II, 7-hydroxy eucommic acid, 7-hydroxy-10-deoxyeucommiol, and 10-deoxyeucommiol. 707 The major iridoids found in the root bark and stem bark of K. africana are specioside, verminoside, and minecoside. 708 The major flavonoid components of the leaves and fruits are luteolin and quercetin. They also contain the phenolic acids 4-hydroxy cinnamic acid, ferulic acid, and caffeic acid.

Pharmacological Studies — Extracts of Kigelia and isolated compounds have been shown to possess antibacterial, antifungal, antineoplastic, analgesic and anti-inflammatory, antimalarial, antiprotozoal, antidiarrheal, and CNS stimulant activities. 709 Bioassay-guided fractionation and separation of K. africana led to the isolation of norviburtinal and isopinnatal, which are partially responsible for the antineoplastic effect of the plant. Norviburtinal showed a much greater cytotoxic effect but showed little selectivity toward melanoma cell lines. Isopinnatal displayed slightly greater cytotoxic activity against the melanoma cell lines, but its high cytotoxicity against the noncancer fibroblasts indicates that it probably has a general cytotoxic effect that precludes it from being considered as a lead molecule for novel anticancer agents. It is interesting to note that the crude extract of Kigelia had a lower IC50 value than the isolated compounds alone, which suggests that several compounds are working together synergistically to give the observed antineoplastic effect. 710,711

The short-term effects of Kigelia africana fruit extract (KAFE) on cisplatin-induced testicular histomorphometric changes in SD rats have been investigated. 712 It was found that cisplatin treatment caused over 37.5% mortality of SD rats. Qualitative histological assessment showed no deleterious changes following treatment with KAFE alone or as a pretreatment with cisplatin. KAFE posttreatment resulted in focal vacuolar changes in the seminiferous tubules (STs) of the SD rats. Cisplatin treatment negatively affected the histoarchitecture of these STs, with massive loss of spermatogenic cells. There was also a significant reduction in testicular weight/volume, ST diameter, and cross-sectional areas (p < 0.001), but KAFE positively improved these parameters. KAFE alone and as prophylaxis significantly increased body weight, serum testosterone, and follicle-stimulating hormone (p < 0.001). It showed a significant elevation in CAT activity, decline in MDA, and upregulation of GSH levels (p < 0.001). These parameters were negatively affected by cisplatin treatment. It was suggested that the cytoprotection against cisplatin-induced testicular damage by KAFE is likely via an antioxidant modulatory pathway and also the possibility that KAFE may possess an androgen-stimulating property. 712

The extracts from the fruits have been shown to possess remarkable antidiabetic properties. In STZ-induced diabetic Wistar rats, daily oral treatment with the methanolic extract of K. africana flowers and standard drug for 21 days significantly reduced blood glucose, serum cholesterol, and triglyceride levels. The HDL cholesterol level was improved (p < 0.01) compared to the diabetic control group. Iridoids isolated from Kigelia have been evaluated for a GLUT4 translocation modulatory effect in skeletal muscle cells. 7-Hydroxy eucommiol and three related iridoid glycosides showed significant stimulation of GLUT4 translocation to the cell surface in skeletal muscle cells without any adverse effect on cell viability. The effect of these four compounds was concentration dependent and comparable to the standard drug rosiglitazone. These findings indicate that constituents of K. africana may provide leads for the therapeutics for insulin resistance and diabetes. 713

The anti-inflammatory and analgesic properties of the extracts of Kigelia africana have been shown to be comparable to those of synthetic anti-inflammatory agents and analgesics. Supercritical CO2 extracts of Kigelia have been shown to be more effective than indomethacin (a potent synthetic anti-inflammatory agent) when evaluated against two anti-inflammatory assays, the inhibition of “oxidative burst” on human neutrophils and inhibition of COX-2. 714 The methanol extract of the flowers exhibited significant (p < 0.01) anti-inflammatory and analgesic activities with doses of 100, 200, and 400 mg/kg in rats and mice, respectively. 715 The plant extracts and the constituent compounds showed significant antioxidant activity and a potent effect against Trypanosoma brucei brucei, T.b. rhodensiensis, and Entamoeba histolytica. In the E. histolytica studies, it was found that when tested against the HK-9 strain, verminoside had twofold the antiamoebic activity of metronidazole, the standard antiamoebic drug, while specioside showed comparable activity with metronidazole. 716

In cosmetics, extracts of the plant have been evaluated for their ability to heal damaged skin and for the treatment of various dermatological conditions. A topical preparation containing the fruit extract is used to remove sunspots on the face and hands, “solar keratosis.” Several patents have been granted for the use of Kigelia extracts as antiwrinkling agents and for skin lightening and general skin rejuvenation. The fruit extract is useful to develop the bust and the stability of breast collagen fibers.

Commerce — Kigelia is not yet a major article of trade in most countries in Africa. In Nigeria, it is sold mainly in the local herb market for the preparation of a remedy for enlarged breasts. Most exports are for the cosmetic industry and are limited to a few tons per annum. Greater demand is envisaged because of the increasing scientific data that tend to support the traditional uses of the plant.

Agriculture — Kigelia is sometimes grown as an ornamental plant. Experimental cultivation as a commercial medicinal plant has been successful.

Formulations and Dosage Forms — Kigelia has been incorporated in skin creams, shampoos, and scalp applications as a cosmeceutical agent because of its beneficial effect on skin elasticity, reduction of wrinkles and skin blemishes, tightening of the delicate skin around the eyes, antimelanoma property, and repair of sun-induced skin damage.

Lawsonia Inermis

Botanical Name — Lawsonia inermis L.

Synonyms — Lawsonia alba Lam., Rotantha combretoides Baker., Alcanna spinosa Gaertn.

Common Names — Henna, Cypress shrub, Egyptian pivet, alkanna

Family — Lythraceae

African Names — Arabic: enah; Bambara: jabi; Hausa: lalle: Igbo: uhie inine; Swahili: mhina; Yoruba: laali

Description — A slender shrub or small tree. The branchlets are spiny when old. The leaves are simple, oppositely arranged, with short pointed apex, about 1.3–2.5 cm long and 2 cm broad. The flowers are creamy white, sweet scented; they are borne on common, leafy bracts. The petals are crisped, stamens 4–8. The fruits are globular, about 5 mm in diameter. 9,28

Habitat and Distribution — The herb is used for the treatment of skin infections. The powdered dry leaves are an ingredient in the preparation of local cosmetics. The herb is soaked in water to which a little lime has been added and applied for tinting the hands, feet, and nails. It is applied topically by the Hausas of northern Nigeria to control perspiration. The leaves and roots are believed to have properties that stimulate menstrual discharges and are also anthelmintic. The root is employed in North Africa in the treatment of hysteria and general malaise.

Constituents — Naphthoquinones such as lawsone, a 2-hydroxy-1, 4-naphthoquinone, are the major constituents of the leaves. The plant also contains resins and hennatannin. The plant is noted as a source of dye for hair, hands, and feet and as a cosmetic colorant.

Pharmacological Studies — An extractive from the plant has strong antimicrobial activity, which has been evaluated as comparable to the antibiotic activity of sulfonamides and penicillin. 717 Lawson exhibits slight antihemorrhagic properties. The compound also has emmenagogic and oxytocic properties. 662 The herb possesses significant in vivo activity against the growth of tubercle bacilli from sputum and Mycobacterium tuberculosis H37R at very low dose, 718 6 μg/ml for the in vitro study and 5 mg/kg in the in vivo assay. The stem bark extract is fungitoxic to 13 ringworm fungi, and the activity was not affected by autoclaving, high temperature, or prolonged storage. 691

Lepidium Sativum

Botanical Name — Lepidium sativum L.

Synonyms — Arabis chinensis Rottlerex Wight., Cardamon sativum (L.) Fourr., Nasturtium crispum Medik., Thlaspi sativum (L.) Crantz.

Family — Brassicaceae

Common Name — Garden cress

African Names — Hausa: lafsur; Soto: umatholisa; Zulu: umathoyisa

Description — This is an annual herb, erect, smooth, with distinguished leaf size and shape. The majority of the leaves are deeply lobed with linear segments. It has small white flowers borne on common stalks. The fruits are ellipsoid, compressed, notched at the top, and slightly winged toward the apex and enclose oval-shaped brown or red seeds. Three varieties of the herb (red, white, and black) exist.

Ethnomedicinal Uses — The whole herb, especially the seeds, is used for the treatment of bacterial and fungal infections. The soaked seeds, which are mucilaginous, are valued as a remedy for diarrhea and dysentery and externally as a liniment and for dressing sores in camels and horses. The soup is used in the treatment of bronchitis and cough and as a poison antidote. A related species, L. myriocarpum Sond, is used as a vegetable for cooking. 79

Constituents — Lepidium leaves yield about 0.12% volatile oil, known as cress oil. The major constituents of the oil are phenylacetonitrile and aromatic isothiocyanates. The seeds also contain similar compounds. Alkaloids, terpenes, and saponins are present in the herb.

Pharmacological Studies — The volatile oil has been shown to inhibit the growth of Bacillus subtilis and Staphylococcus aureus. 719 The active constituents, the benzyisothiocyanates, were excreted intact in the urine within an hour of ingestion. The herb also exerts antitoxic activity. 720 It has been shown to be a good model for the assay of phytotoxic compounds. 721 A member of the genus, L. capitatum, has been effective as a postcoital contraceptive. 722

Lonchocarpus Cyanescens

 

Botanical Name — Lonchocarpus cyanescens (Schum. & Thonn.) Benth.

Synonyms — Robinia cyanescens Schum. & Thonn., Philenoptera cyanescens (Schum. & Thonn.) Roberty.

Family — Leguminosae

Common Names — Indigo vine, West African wild indigo

African Names — Ashanti: dwira; Bafo (and Blong): mutely; Balando: mubakote; Basa: weechu; Bini: ebelu; Ewe: avantime, adzudzu; Fulani: talakiri; Hausa: talaki; Igbo: anunu; Tiv: suru; Twi (and Ga): akase; Yoruba: elu

Description — This is a shrub or small tree, sometimes woody climber, 5–7 m high and about 50 cm in girth. The stem is brown or yellow, and the branchlets are silky when young. The leaves are pinnate, occur in 4–5 pairs, are ovate or elliptic, 30 × 12 cm, with 5 pairs of prominent lateral veins. The leaves turn blue-green on drying and yield the popular indigo dye. The flowers are reddish or bluish white, sweet scented, and occur in panicles between May and June. The fruits are 30 × 20 cm and occur as flat pods, indehiscent, and enclose 1–5 seeds. The fruits turn bluish black on drying. 9

Habitat and Distribution — The plant grows in fringe, deciduous, and savanna forests. It occurs from Guinea to Cameroon.

Ethnomedicinal Uses — The main use of indigo vine is in the preparation of local embrocation for sprains and for healing of yaws. The leaves are also used as a poultice for ulcers and as dressing for skin diseases. In Ivory Coast, women have been reported as using a decoction of the roots and leafy stems as postpartum medication. 9 The leaves have been used as ingredients for the preparation of stomachic in Ghana and as treatment for leprosy and cataract in Sierra Leone. 9 The stem bark and roots have been employed as a general tonic and remedy for fevers. The leaf decoction has also been used for venereal diseases and semen insufficiency. 266

Constituents — It contains the insecticide rotenone. Glycyrrhetinic acid and related oleanolic acid derivatives have been shown to be present in the plant. 723 Flavonoids and pterocarpans have also been reported from a related species, P. laxiflorus. 724

Pharmacological Studies — Extracts of L. cyanescens have been shown to reduce carrageenan-induced rat paw edema, as well as adjuvant-induced polyarthritis in rat. 725

Lonchocarpus Sericeus

Botanical Name — Lonchocarpus sericeus (Poir.) Kunth.

Synonyms — Robinea sericea Poir., Derris sericea (Poir.) Ducke

Family — Leguminosae

Common Name — Senegal lilac

African Names — Ashsnti: totoro; Igbo: njassi; Sefwi: boma; Twi: jwandwoananin, ofefrae, osantewa; Wassaw: dukaw; Yoruba: ipapo

Description — This is a shrub but often grows to a medium-size tree, about 12–15 m high and 1.2–1.4 m girth, sometimes branching near the base. In poor soils, usually by the roadside, it occurs as a struggling shrub less than 5 m high. It has a smooth, grayish bark, with a yellowish-brown slash with reddish tints. The twigs and young shoots are covered with brownish velvety hairs. Leaves are pinnate, with 3–5 (sometimes 7) pairs of opposite leaflets 6–14 cm long, 3–9 cm wide, increasing in size toward the terminal leaflet, ovate-elliptic or elliptic, apex shortly or bluntly acuminate, base rounded to broadly cuneate or subcordate, margins entire or slightly wavy, glabrous above, pubescent below, midrib prominent below, and lateral nerves in 6–10 pairs. It produces pale purple or lilac color flowers, with a broadly cup-shaped calyx, 5 mm long and densely hairy. The flowers are borne December–February and April–July. The fruits occur as flattened indehiscent pods, clustered, persistent, about 12 cm long and 1 cm wide, irregularly constricted between the seeds and more or less twisted, both ends acute with thickened margins. The pods encapsulate oblong kidney-shaped, reddish-brown seeds, about 7 mm long and 5 mm wide. 28,33

Habitat and Distribution — The species grow in coastal savanna woodland and in fringe and transition forests. Due to the ease in generating the plant from the seeds and the ability to withstand fairly long periods of drought, it is planted as a shade tree in many parts of tropical Africa. The plant has been located in many countries in West Africa, including Cameroon, Ghana, Nigeria, Senegal, Gambia, Guinea Bissau, Guinea, Sierra Leone, Ivory Coast, and Benin.

Ethnomedicinal Uses — Extract of the bark is used in Nigeria as a stomachic and a laxative. An external application prepared from the stem bark is employed in the treatment of convulsion and backache, and the lotion is applied for parasitic skin conditions and eruptions. 78

Constituents — Lonchocarpus is a source of the insecticide rotenone. A compound named lonchocarpine, 5-hydroxy-2,2-dimetyl-3-chromen-6-yl-strylylcetone, has been shown to be a component of the roots, seeds, and leaves of this species. 726 Other constituents of the plants include quercetin, rutin, p-coumaric acid, and β-sitosterol, as well as isoflavonoids and pterocarpans. 78,727,728

Pharmacological Studies — A resin that occurs in the seeds and the fruit is considered to be a violent poison. 729 The extract has insecticidal action due to its rotenone content.

Mallotus Oppositifolius

Botanical Name — Mallotus oppositifolius Geisel. Muell. Arg.

Synonyms — Acalyphadentata Schumach. & Thonn., Claoxylon cordifolium Benth., Croton oppositifolius Geiseler., Echinus oppositifolius (Geiseler) Baill., Ricinocarpus dentatus (Schumach. & Thonn.) Kuntze., Rottlera dentata Baill.

Family — Euphorbiaceae

Common Names — The name Kamala, camala, or Glandulae rottlerae in official monographs refers to the trichomes and glands from the fruits of Mallotus phillipinensis.

African Names — Hausa: kafar; Igbo: okpokirinya; Yoruba: eja

Description — This is a shrub up to 13.5 cm long and 2.5–10 cm wide. The leaves are oval in shape and long stalked. The apex is shortly pointed, and the base is more or less heart shaped. There are 3 main veins from the base. The lower sides of the leaves are densely dotted with glands. The lateral veins end in small glands at the leaf margins. The margins are slightly toothed. The stalks are 2.5–5 cm long. It produces tiny, white, fragrant flowers, borne on slender common stalks at the end of the twigs or in the axils of the leaves. The fruits are produced throughout the year, deeply lobed, 3 celled, about 5 mm in diameter, and covered with glandular hairs. The hairs and glands covering the fruit are easily rubbed out, sifted, and made to float on water as a red motile powder.

Habitat and Distribution — It grows in old farms, in secondary forests, and thickets. It thrives also in savanna vegetation. The drug is native to East Africa, India, and Arabia. In Africa, it is distributed almost throughout the continent.

Ethnomedicinal Uses — The whole herb is used for the treatment of dysentery and as a vermifuge. The stem is chewed to fibrous brush and used as chew sticks for teeth cleaning. The fresh leaves are crushed and applied to fresh cuts to stop bleeding. The leaf juice has been used as nasal drops for headache. Irvine indicated that the leaves of the plant are used with those of Trema, Bandeirae, and Dalium guineense in Akropong and Akwapim (Ghana) for urinary disorders during pregnancy. 9

Constituents — Kamala consists of a red pigment, isoallorottlerin; the yellow component methylene-bis-methylphloroacetophenone, and other phloroglucinol derivatives, such as rottlerin and isorottlerin, as well as two compounds, kamalins I and II of undetermined structure. 730,731 The fruit contains terpenes, flavonoids, chalcones, and saponins. 732734 Five hydrolyzable tannins 735 and cytotoxic phloroglucinol 736 have been reported from the bark of M. japonicas. Cytotoxic chromene derivatives have been isolated from the pericarp of the same species. 737

Pharmacological Studies — Kamala is a purgative and taeniafuge and has been employed in India and many parts of the world for the treatment of tapeworm infestation. Both the alcoholic and dithylether extracts of the fruit showed taenicidal action in vitro and in vivo. 733 The drug has been found to possess antifertility activity when tested in rats and guinea pigs, and this action has been attributed to the presence of rottlerin. 738 Other derivatives of crude Kamala extract have hypoglycemic, antibacterial, antispasmodic, and antitumor activity against human epidermoid carcinoma of nasopharynx in tissue culture and sarcoma 180 in the mouse. 737 In clinical medicine, Kamala is also applied topically as an ointment for ringworm, scabies, herpes, and other parasitic skin diseases.

Manniophyton Flavum

Botanical Name — Manniophyton flavum Muell. Arg.

Synonym — M. africanum Muell. Arg.

Family — Euphorbiaceae

African Names — Bini: ebumen; Igbo: ege; Mano: fei, fai; Mende: njuli

Description — This is a hairy wood climbing plant or a straggly shrub; the young stems are pithy or hollow, and the branchlets are covered with brown stinging hairs. It has polymorphous leaves, mainly entire, often 2–5 lobed, and asymmetrical with caudate base, with parallel tertiary nerves and covered on both surfaces with prickly stellate hairs. It is up to 25 cm long and about the same size in breadth. The flowers are small and occur in clusters on the common stalks. Male and female flowers are separate, up to 25 cm long. There are between 10 and 20 stamens in a flower. The female panicles are smaller than the male ones. It produces 3-lobed capsules, 2–5 cm long, almost rounded with raised ribs.

Habitat and Distribution — This is a rainforest plant, found mainly in mixed deciduous and evergreen forests. It is distributed from Sudan to Tanzania and occurs in the West Coast up to Sierra Leone.

Ethnomedicinal Uses — The main use of the plant in many parts of the continent is in the treatment of skin infections. The seed oil, which is rich in iodine, is applied externally for yaws. The bark and stem are chewed as a remedy for cough. A decoction of the leafy twigs and roots is drunk as a medicine for stomachache and for gonorrhea. A fresh decoction is used for treating snakebite and scorpion stings.

Massularia Acuminata

 

Botanical Name — Massularia acuminata (D.Don) Bullock ex Hoyle

Synonym — Randia acuminata (Benth)

Family — Rubiaceae

Common Name — Chewing stick tree

African Names — Igbo: atu-uhie; Yoruba: pako-ijebu, orin-ijebu

Description — Massularia is a medium-size shrub or small tree, growing up to 5 m high. The leaves are large, practically stalkless, elliptic-oblanceolate, acuminate, almost glabrous, papery, and subsessile. The flowers, usually red, are borne in short axillary cymes and appear around January. The fruits are 5 cm long, narrowly ovoid, beaked, and yellow-white in color.

Habitat and Distribution — It is a tropical plant, found usually in undergrowth of closed moist forests. It is distributed from Sierra Leone to Zaire. Related species grow in the East Coast.

Ethnomedicinal Uses — The stems are prized as chewing sticks in southern Nigeria. The pulped roots are employed as an enema for dysentery and as an aphrodisiac. The juice from the incised fruits is used as eyedrops in Sierra Leone. 9 The pulped leaves are used externally as liniment for lumbago and muscular pains. 739 The stem is believed to be an aphrodisiac, and it is sold in Nigerian cities for this purpose.

Constituents — Preliminary phytochemical tests on the stem bark and roots of the plant (in the author’s laboratory) showed the presence of alkaloids, saponins, and polyphenolics. The aqueous extract of the stem contained alkaloids (0.22%), saponins (1.18%), anthraquinones (0.048%), flavonoids (0.032%), tannins (0.75%), and phenolics (0.066%). 740

Pharmacological Studies — It has been shown to possess significant antimicrobial activity against oral pathogens associated with orodental infections, 741 including Bacteroides gingivalis and B. melaninogenicus. 742 The aqueous extract of the plant has an MIC of 0.5 and 2 μg/ml against Bacteroides gingivalis and B. melaninogenicus, respectively. 746 The adherence of Streptococcus mutants to the surfaces of the teeth was effectively inhibited by a 1% concentration of the aqueous extract of Massularia. 743

The possible effect of Massularia on male reproductive system has been investigated in laboratory animals. Extracts of the stem at various doses (20–1000 mg/kg) produced a significant increase (p < 0.05) in testes–body weight ratio, testicular protein, glycogen, sialic acid, cholesterol, testosterone, and luteinizing and follicle-stimulating hormone concentrations of male rats throughout the period of administration. The testicular gamma glutamyl transferase activities were decreased significantly (p < 0.05) after the first dose and were sustained throughout the experimental period. 744

Matricaria Recutita

Botanical Name — Matricaria recutita L.

Synonyms — M. chamomilla L., M. suaveolens L.

Family — Compositae

Common Names — Matricaria flowers, German or Hungarian chamomile flowers

African Names — Arabic: bahboonig; Xhosa: msolo

Description — The flowers of Matricaria can be differentiated from those of the English chamomile by their hollow receptacle, which is devoid of paleae. The capitulum spreads out to 10–17 mm in diameter and consists of an involucre, up to 20 marginal ligulate florets, and many central tubular florets. Comparatively, Matricaria has smaller flower heads than chamomile. It has a bitter and aromatic taste, but the odor is usually weaker than that of Roman chamomile.

Habitat and Distribution — The plant is largely a Mediterranean crop, but grows well in North Africa and cooler regions of southern and eastern Africa.

Ethnomedicinal Uses — African chamomile is reputed as an herbal tea and is dispensed as a sedative, carminative, antiseptic, analgesic, antispasmodic, and anti-inflammatory. It has been used for the treatment of gout, indigestion, diarrhea, and insomnia and in pediatric practice for infantile convulsions, colic, and teething pains. 123

Constituents — It yields a pleasant-smelling volatile oil, with the sequiterpene α-bisabolol composing up to 50%. The volatile oil content is about 2% of the dry weight of the flowers. Other components of the volatile oil include chamazulene, guiazuline, farnescene, α-bisablol derivatives, and matricine. 744,745 The plant also contains flavonoids apigenin, luteolin, patuletin, and quercetin and related glycosides. 746 Coumarins, spiroethers, and polysaccharides have been shown to be present in Matricaria.

At least four chemotypes of the drugs can be distinguished depending on the composition of the oil: chemotypes with or without chamazulene (European origin); those with α-bisabolol (Portuguese and Spanish origin); those with α-bisaboloxide A (African, Bulgarian, and Turkish origin); and those with α-bisaboloxide B (Argentine origin). 747

Pharmacological Studies — Extracts and tincture of the plant have been shown to possess many and varied pharmacological properties due to its many biologically active compounds. It appears that the anti-inflammatory activity is the predominant effect of Matricaria extract when applied externally, and smooth muscle–relaxing effects predominate when taken internally. The azulenes of both species of chamomile have been shown to be antiallergenic and anti-inflammatory. 748 One of its major constituents, α-bisabolol, has been shown to have anti-inflammatory, antibacterial, antimycotic, and ulcer-protective properties. 744 In experimental animals, the compound was also found to inhibit ulcer development induced by indomethacin, stress, and ethanol and reduced the healing times for ulcers induced by chemical stress or heat coagulation. 749 Natural (-)-α-bisabolol has been shown to be more effective than the synthetic racemic bisabolol in healing burns; it also decreases the temperature of skin exposed to UV light. 744,745 Bisabolol has a spasmolytic activity comparable to that of papaverine. 583 Other constituents of Matricaria with spasmolytic activity include apigenin (2–5 times the activity of papaverine), apiin, patuletin, α-bisaboloxide A and B, and the cis-spiroethers (10 times as active as papaverine). The wound-healing property of the drug is aided by the immunostimulating activity of the polysaccharides, which activate macrophages and B lymphocytes. 750 In a comparative evaluation, Matricaria ointment (Kamillosan) was found to be more effective in experimentally induced toxic contact dermatitis than the ointment base or 0.1% hydrocortisone acetate ointment; the topical preparation was assayed by a profilometry determination of the structural changes of the epidermal surface. 751

Toxicity — The drug has low toxicity. The acute LD50 of the volatile oil is approximately 15 ml/kg in rats and mice. The teas prepared from pollen-laden flower heads cause contact dermatitis and anaphylaxis on hypersensitive individuals. 752,753 Sensitivity to Matricaria has been ascribed to type I immunoglobulin E (IgE)-mediated immunologic response, and persons suffering from pollen-induced hay fever are particularly susceptible. 754 Cross-reactivity has been demonstrated among chamomile tea extract and the pollens of Matricaria, Ambrosia trifida (giant ragweed), and Artemisia vulgaris (mugworth) using an ELISA (enzyme-linked immunosorbent assay) inhibition study. 758

Maytenus Buchananii

Botanical Name — Maytenus buchananii (Loes.) Wilczek

Synonyms — Gymnosporia buchananii Loes., Maytenus ovata (Walp.) Loes. var. ovata

Family — Celastraceae

African Names — Digo: mudziadzyah; Katenga: mukululubishia; Rwanda: umutukuza, urutka; Shona (Zambia): mutumbwishia; Kindembo (Zaire): musoma; Musaka (Zaire): umushubi; Kitabwa (Zaire): mubamba ngoma, mumpulukuswa, pulukusva; Kiluba (Zaire): musonga, sombo; Kinyaruanda (Zaire): umusakara, umutakaza

Description — This is a glabrous woody shrub or small evergreen tree 2–12 m high, with paired spines up to 2.8 mm long. It has a fairly hard slash, with the inner bark of large stems red with a thin, bright yellow layer just under the outer gray surface; small stems have pink slash without a yellow layer. The leaves are simple, petiolate, and spirally arranged. The lamina is elliptic or elliptic-oblong to ovate, oblanceolate, or suborbicular, 1–1.7 m long, 0.8–8 cm wide, apex obtuse to rounded or rarely acute to shortly acuminate, especially when young, with lateral nerves and sense reticulate venation more prominent below than above. It has solitary inflorescence, with axillary, dichasial, or monochasial cymes, 0.5–2.3 cm long; whitish puberulous; peticels 2–5 mm long, articulated in the lower half. The flowers are whitish, usually cream colored, 3–25 per cyme, about 2.5 mm in diameter; the petals are oblong, with margins ciliolate to more or less entire. The sepals are lanceolate to triangular, 0.5–1.25 mm long, apex acute to subacute, margins ciliolate. It produces long, pale green to reddish fruits enclosing 2–3 shiny red seeds partly embedded in fleshy white or pale yellow aril. 9,28,33

Habitat and Distribution — It is a native to the well-watered savanna regions of the continent. It is a light-demanding tree of open lowland, riverine forests, and forest margins. It occurs on a wide range of soils, including sandy, larval, and limestone soils; acid soils are preferred. The plant is distributed mainly in southeast Africa, including Kenya, Tanzania, Zimbabwe, and Ethiopia. The species also grows in Nigeria, Ghana, Cameroon, Gabon, Fernando Po, Central African Republic, Rwanda, Burundi, South Sudan, Uganda, Malawi, Mozambique, and Zambia.

Ethnomedicinal Uses — The powdered bark is reputed as a Moshi remedy for wounds, ulcers, and boils. In Togo, a leaf decoction was used for the treatment of mouth infections and wounds and is still used in folk medicine in West Africa as a mouthwash for mouth ulcers and toothache. The related species, M. senegalensis (Lam.) Excell (the confetti tree), is also used in traditional medicine; the chipped roots are added to beer and used in Zambia as an aphrodisiac. 227 The roots, which are slightly bitter, are also mildly laxative and are used in various parts of tropical Africa for gastrointestinal troubles, especially dysentery, 9 and a poultice of the green leaves has been used to dress sores in Tanzania. 755

Constituents — The plant contains the antileukemic ansa macrolides maytansine, originally isolated from M. seratta collected from Ethiopia, 756 and maytanbutine. 757,758 The genus also yields the spermidine alkaloids celacinnine and cellallocinine 759,760 and the nicotinoyl sesquiterpene alkaloids maytoline and maytolidine, catechin, PACs, and phenoldienone triterpenes. 761

Pharmacological Studies — The main pharmacological activity of this genus is its remarkable antitumor activity. The compound has been extensively studied as a part of the drug development program of the Division of Cancer Treatment, National Institutes of Health, Bethesda, Maryland. The ansa macrolides have shown significant activity against various animal tumors, including B-16 melanoma, lymphatic lymphoma, and carcinosarcoma. Cytotoxic activity appears to be caused by inhibition of the proper formation of the mitotic spindle and thus cessation of cell division. 762 Various side effects were observed in the phase I human studies, including gastrointestinal, hepatic, and neurological disorders. Adverse reactions such as nausea, vomiting, diarrhea, and lethargy have been reported as being dose limiting. 763 Reviews containing reports of the development of maytansine are available. 764,765

Merremia Angustifolia

Botanical Name — Merremia angustifolia Hall. f.

Synonyms — Convolvulus oligodontus Baker., Ipomoea angustifolia Jacq., Xenostegia tridentata (L.) D.F. Austin & Staples

Family — Convolvulaceae

African Names — Hausa: yimbururu; Yoruba: atewegbore, abiarunum

Description — This is a prostrate or climbing herb. It has narrow leaves, alternately arranged on the stem, about 3 cm long, pointed, almost lanceolate and lobed at the base. The stalks are very short. The flowers are yellow in color, funnel like, and about 8 mm long, with 5 persistent sepals and a corolla with 5 lobes. The 5 stamens are attached to the base of the corolla tube. It yields small rounded fruits. 77

Habitat and Distribution — It grows mainly in secondary forests and savanna. The plant has been located in the Jos and Kaduna areas of Nigeria, and in the southern part of the continent, it has been collected from Kenya, Zimbabwe, and Botswana.

Ethnomedicinal Uses — The boiled tuber is used in southeastern Nigeria as a fever remedy. In West Africa, a decoction of the plant together with native carbonate of soda (natron) is administered as a remedy for gonorrhea. The root is eaten with bran to acquire prolonged immunity against scorpion sting.

Mitragyna Ciliata

Botanical Name — Mitragyna ciliata Aubr. & Pell.

Synonyms — Adina ledermanni K. Krause, Mitragyna ledermanni (K. Krause) Risd.

Family — Rubiaceae

Common Names — Poplar (Liberia), African linden (M. stipulosa)

African Names — Bini: eben; Efik: uwen; Igbo: uburu; Kimbundu: mulangu; Mzima: baya; Shambala: mlombelombe; Twi (Wassaw): subaha; Yoruba: abura

Description — Mitragyna ciliata is an evergreen tree that grows up to 30 m high or more and about 1 m in diameter, with cylindrical, straight bole and clear branches for up to 20 m or more, rarely buttressed. The bark is grayish brown with flat, thin scales; the slash is cream yellow with a pinkish under layer that turns brown on exposure and is thick and fibrous. The crown is small, compact, and irregular. It bears red leaves when young. Mature leaves are large, simple, opposite, petiolate with large, conspicuous interpetiolate stipules; the petiole is 1.5–4 cm long, with stipules ovate-elliptic to obovate, 4–10 cm long, 3–7 cm wide, tomentose; the blade is broadly elliptic to suborbicular, 10–65 cm long, 8–44 cm wide, with apex rounded or obtuse, base truncate to cuneate, margins slightly wavy, medium green above, pale below, glabrous except a tuft of hairs in the leaf axils; midrib and 7–12 pairs of lateral nerves prominent below. It flowers in March and November and produces white flowers that are hermaphrodite, 5–7 merous, with each flower surrounded by up to about 15 wedge-shaped bracts about 4 mm long, with the bract ciliate at the apex. The fruits occur in June and July, and heads are up to 2.3 cm in diameter, with many amphora-shaped capsules 5–8 mm long with numerous seeds, 1.5 mm long, flat, and slightly winged. 9

Habitat and Distribution — This species, as well as M. inermis, M.stipulosa, and about four other related species, is indigenous to the continent. The subject species grows in freshwater swamps in closed rain forests. It is common in narrow fringing belts along streams in high forest areas, grass plains, and low-lying swampy areas of deciduous and evergreen rain forests. It has been found in swampy areas at high altitudes (e.g., at 500 m at Udi plateau in Nigeria and at 600 m at Vane in Ghana). It is also present along riverine forests within the savanna. The plant is distributed throughout the coastal regions of West Africa, in Sierra Leone, Liberia, Ivory Coast, Ghana, Nigeria, Cameroon, and Equatorial Guinea and in Zaire, Congo Republic, Angola, Tanzania, and some parts of southern Africa.

Ethnomedicinal Uses — The bark and the leaves are used in West Africa for the treatment of bacterial infections, especially gonorrhea and dysentery. In Cameroon and parts of Central Africa Republic, the bark boiled with Capsicum (pepper) seeds and those of piper guineense is reputed to be a remedy for chest complaints. It is listed by Walker as an ingredient with the bark infusion of Coula edulis, Isolana letestui, and Berteria fistulosa with an extract of the leaves of Alchornea cordifolia in a remedy used by the Bupunus to cure sterility in women. 198 A major use of Mitragyna species in Africa is as a febrifuge and for the treatment of malaria. A decoction of the stem bark mixed with Garcinia kola seed extract is used in southeastern Nigeria for the treatment of African sleeping sickness.

Pharmacological Studies — The Mitragyna alkaloids have been shown to possess pharmacological activities resembling those attributed to the crude drug in traditional medicine. The oxindoles rhynchophylline, mitraversine, and mitraphylline have been shown to have antihypertensive and local anesthetic activity and to decrease the rhythm of the heart. 78 Mitragynine has been credited with analgesic properties equivalent to those of codeine but without any of the side effects of the opiate; 33 the compound is also reported as being hallucinogenic. 766 The alkaloids possess antiprotozoal activity and strong stimulatory action on the contractility of intestine and uterine muscles. 767

Mollugo Nudicaulis

 

Botanical Name — Mollugo nudicaulis Lam.

Synonym — Lampetia nudicaulis (Lam.) Raf.

Family — Molluginaceae

Common Name — Daisy-leaved chickweed

African Name — Hausa: narba

Description — Mollugo is an erect weed and is small, rarely exceeding 30 cm in height. The leaves are long oval in shape, widening toward the apex and rounded, and the base is wedge shaped. The leaves form a rosette on the ground. The flowers are whitish green, small, and borne on long, terminal, thin stalks of many ascending branches. The fruits occur as small capsules with many warty seeds. 13

Habitat and Distribution — This occurs in deciduous forests and is distributed from Sierra Leone to South Africa.

Ethnomedicinal Uses — The whole herb is used as a cough remedy and is reputed to be effective in the treatment of whooping cough. The leaves are macerated in water to which some lime juice has been added and drunk as a worm expeller.

Constituents — The plant is rich in flavonoids and related phenolic compounds. It also contains CNGs, terpenes, and saponins. The total phenolic content (TPC) of the methanolic and aqueous extracts of leaves was 47.01 ± 0.8 and 46.4 ± 0.05 mg/100 g, respectively. The total flavonoid content (TFC) from the methanolic and aqueous extracts of leaves has been estimated to be 41.3 ± 0.04 and 36.2 ± 0.01 mg/100 g, respectively. 768

Pharmacological Studies — The methanolic and aqueous extracts of the leaves have been shown to possess significant antioxidant properties, with IC50 values of DPPH radical scavenging as 48 and 190 μg/ml, respectively. In the 2,2-azinobis-3-ethylbenzo-thiazoline-6-sulfonate (ABTS) radical scavenging assay, the IC50 values for the methanolic and aqueous extracts were 83 and 198.3 μg/ ml, respectively. The same extracts were found to have antimicrobial activities against Pseudomonas aeruginosa, Proteus sp., Streptococcus sp., and Entrobacter sp. 1113 The plant has shown a protective effect against acute liver injury induced by perchloroethylene in experimental rats. 769

Mondia Whitei

 

Botanical Name — Mondia whitei (Hook.f.) Skeels

Synonym — Chlorocodon whitei Hook.f.

Related Species — Mondia ecornuta (N.E. Br.) Bullock.

Family — Apocynaceae

Common Names — White’s ginger, tonic root (Eng.)

African Names — Angola: mundondo, mudondo; Cissongo (Central African Republic): mundondo, bondo, molo busio; Ngwaka (DR Congo): nlondo, kimbiolongwa, kumba; Lugware (DR Congo): ubasangbwandiya, gatimba; Tshiluba (DR Congo): mujimbaye; Fula (Guinea, Guinea Bissau): lacadje; Kenya: mkombela; Malawi: citumbulo; Zulu: umondi, mundi, mindi; Uganda: sedando omutona; Shona (Zimbabwe): mungurawu.

Description — According to a description provided by the South Africa National Biodiversity Institute, Mondia whitei is a perennial, woody, rather robust and vigorous climber that grows from a large tuberous rootstock. The roots are aromatic and apparently taste like ginger or liquorice and have an aroma reminding one of vanilla. The leaves are attractive, large (100–300 × 50–150 mm), opposite, with a deeply notched heart-shaped base and stalks that are 30–55 mm long. The stipules are well developed and consist of frilly teeth. The flowers are borne in branched inflorescences. They are large and relatively short lived (die after 3–4 days). The reddish-purple corolla lobes are ±14 mm long and usually have a green margin. Plants flower from October to March in the southern and from May to August in the northern distribution areas of the species. The large fruits (75–100 × 44 mm) are almost woody and contain many seeds. 770 Because the plant grows as a climber with the basal portion of the stem usually leafless, the leaves and flowers mainly appear in the canopy of the supporting vegetation and are thus rarely noticed.

Habitat and Distribution — M. whitei is native to Africa, and it is considered endemic in almost all African regions with the exception of the northern part of the continent. Mondia occurs mainly in moist-to-wet forests. It is found in vegetation types that range from swamp forest, swampy shrubby grassland, and riverine forest to disturbed forest, at altitudes from sea level to 1800 m. In West Africa, the species is commonly found in Guinea, Ghana, and Nigeria; in the Central Africa region, it occurs in Cameroon, Gabon, and DR Congo; in East Africa, it is found in Kenya, Tanzania, and Uganda; and in southern Africa, it occurs in South Africa, Malawi, Angola, Mozambique, and Zimbabwe.

Ethnomedicinal Uses — Mondia roots have a slightly bitter taste at first but a sweet aftertaste and a pleasant vanilla odor and are used to make a tonic beverage similar to ginger beer. The young roots are sweet in taste and are less valued. It is used as an appetite stimulant and for indigestion, anorexia, and stress. In West Africa, the roots are brewed in alcohol to make an energizing drink for wedding parties. Mondia can be used as a tea. The plant is reputed to be an effective aphrodisiac and is valued as a medicine for the treatment of chronic male sexual erectile dysfunction and impotence. It has been used as a general anodyne and for the treatment of hypertension, stroke, anemia, asthma, hangover, mastitis, and allergies; it is also taken to improve sleep, enhance urination, and ease birth pains, and for use as a mouth freshener and toothbrush and for the treatment of fits in children. 94

Constituents — The plant has been shown to contain a potent tyrosinase inhibitor, 2-hydroxy-4-methoxybenzaldehyde, (−)-loliolide, isovanillin, coumarins, and coumarinolignan, as well as chlorinated coumarinolignan. Mondia elaborates a mixture of triperpenes, flavonoids, reducing sugars, and tannins. Nutritional analysis indicated that Mondia is rich in minerals and vitamins. The yields of the various nutrients, roots and leaves, respectively, are as follows (mg/g): potassium (11.34, 32.05); sodium (5.61, 24); magnesium (1.40, 2.83); calcium (3.08, 8.25); iron (0.20, 0.43); zinc (0.03, 0.07); copper (0.003, 0.06); manganese (0.64, 0.05); cadmium and lead (trace, trace); crude protein (4.35, 21.8); beta-carotene (0.004, 0.022); thiamine (0.78, 3.70); niacin (0.52, 8.15); riboflavin (0.62, 2.45); fructose (0.008, 0.015); xylose (9.17, 18.70); and glucose (2.40, 9.0).

Pharmacological Studies — Some of the biological activities associated with Mondia have been evaluated in a number of scientific studies to validate some of the traditional uses. The studies include biological assays on the aphrodisiac, antimicrobial, anti-inflammatory, antityrosinase, and antioxidant activities. The aphrodisiac efficacy of M. whitei roots has been established in various animal studies. 771,772 The extracts displayed significant inhibition of tyrosinase, and this property could account for its observed cytotoxicity against certain types of cancer in vitro. The methanol extract has also been shown to possess in vitro antioxidant activity 773 and an anti-inflammatory property, as evidenced by the remarkable inhibition (>80%) of COX-1 enzyme. 774 The ethanol leaf extract showed moderate antidepressant activity in vitro in the serotonin reuptake transport (SERT) assay. 775 Bioguided isolation identified the presence of (−)-loliolide in the active fraction with an IC50 of 977 μM. The extract had significant in vivo activity in both the tail suspension test (TST) and forced swim test (FST), and locomotor activity tests. 776

Commerce — Mondia is widely traded in most parts of the continent for its aphrodisiac properties and the treatment of male erectile dysfunction. Because it is not usually traded across borders, not much information is available on the volume of trade or harvest of the species. The fresh roots are sold for US$7–12/kg. In East Africa, the wholesale price for the whole plant is US$0.20–0.30/ kg, and it retails for more than US$2/kg. In Nigeria, small pieces (0.01–0.02 m in diameter and up to 0.4 m in length) of the roots are sold by street vendors for US$0.20 each.

Agriculture — This species is easily cultivated from seed. Seeds are collected as the fruit starts to split open, with the seeds picked off from their parachute-like tuft of hairs before it opens. The seeds are best sown fresh, but they can be stored for about a year under normal room conditions. Wood ash from a fire is mixed with the seed to prevent attack by insects. The plant, however, is largely harvested from the wild. The root is the plant part used most in traditional medicine, and studies of M. whitei have also focused on the root/root bark extracts, which is an indication of the high stress on the underground plant part. The plant is seriously threatened by overharvesting. There have been proposals on the possibility of sustainable harvesting of the species from the wild.

Monodora Myristica

Botanical Name — Monodora myristica (Gaertn.) Dunal

Synonyms — Monodora borealis Scott-Elliot., Monodora claessensii DeWild., Annona myristica Gaertn.

Family — Annonaceae

Common Name — Calabash nutmeg

African Names — Hausa: gujiya’dan miwa; Igbo: churu, efuru; Yoruba: abo lakoshe, arigho, eyinaghose

Description — Monodora myristica is an ornamental tree up to 30 m high, with dense foliage and spreading crown. The stem is fluted; the bark is fissured geometrically; the outer bark is thin and dark brown; and the inner bark is light brown above and pale cream beneath. The sapwood is soft, white, and slowly turns pinkish after slashing. The stem is aromatic. The leaves are elliptic, sometimes becoming wider at the apex, about 14–15 cm long and 5–14 cm broad, arranged alternately. The apex is shortly pointed, and the base is rounded or slightly caudate. The leaves display up to 20 pairs of prominent lateral veins and parallel secondary nerves. It flowers from September to April, at the time of the appearance of new leaves. The fruits are large, fragrant, and pendant, hanging on very long stalks with a crinkly bract about 2.5 cm long near the end of the stalk. Sepals are about 4 cm long, spotted with red, and with wavy edges and crisped. There are 6 petals, the outer ones, about 10 cm long, are brightly yellow in color and with dark red marks on the edge and toward the end. The inner petals are subtriangular, dull cream yellow, with red spots in the inner side.

The fruits are produced April–September, are about 15 cm in diameter, green, round, and are woody, suspended in a long stalk. The pulp is white and contains numerous seeds about 2.5 cm long.

Ethnomedicinal Uses — The seeds yield a colorless volatile oil with a pleasant taste and odor and are used as condiments for soup and added into snuffs as a flavoring agent. The seeds are also used to treat migraine (external application on the forehead) and as a stomachic and mixed with palm oil as a stimulant. 77 A pomade is made from the pulverized seeds fried in oil and the powder is used to treat guinea worms and other sores. 77 A related species, M. tenuifolia is used as an anthelmintic and in Yoruba traditional medicine for the treatment of toothache.

Constituents — The plant contains volatile oils, alkaloids belonging to the benzyltetrahydroisoquinoline group, prenylated indoles, diterpenes, and sesquiterpenes. A related species, Monodora brevipes, yields the proaporphine alkaloids crotsparine and stepharine, 3-formylindole, the sesquiterpene (-)-α-cadinol and the monoterpene lα,6βdihydroxy-4α-p-menth-2-ene, and clerodane diterpenes. 777

Pharmacological Studies — The essential oils and extracts of M. myristica are known to possess antimicrobial properties. The antibacterial and antifungal activities have been evaluated against some microorganisms. 778 In the in vitro assay against Mycobacterium tuberculosis, methanolic extract of the seeds showed both mycobacteristatic (IC50 = 512 μg/ml) and mycobactericidal (IC50 = 1024 μg/ml) activities on two strains of the organism tested. 779

Morinda Longiflora

Botanical Name — Morinda longiflora G. Don

Synonyms — Morinda longiflora var. breviloba DeWild.

Family — Rubiaceae

African Names — Fulani: kodudu; Mende: wawe, leve rokbeni; Mano: gie gbindi; Wolof: rambeul; Yoruba (Oyo): oju-olgbo

Description — Morinda longiflora is a climbing shrub common up to 6 m high. The leaves are simple, oval-elliptic, pointed at the apex, and rounded at the base. They are smooth and shiny and oppositely arranged on the stem and branches. It has white, sweet-scented flowers, borne on terminal heads, about 5 cm long and up to 3 cm broad. The fruits occur as crowded berries, about 5 cm across, flat sided, and joined together by means of the persistent calyx on each section. They mature to an attractive orange color. 9,33

Habitat and Distribution — M. longiflora occurs in the lowland forest areas. It is abundant in the West Coast and is found also in Zaire, Tanzania, and Zambia.

Ethnomedicinal Uses — A decoction of the leaves and fruits is taken for colic and constipation caused by worms. A lotion for craw-craw (scabies) is made from the leaves. It is not used for the treatment of fevers or malaria as is M. lucida, discussed next. It is also used as a systemic anthelmintic.

Morinda Lucida

Botanical Name — Morinda lucida Benth

Related Species — M. citrifolia Chev

Family — Rubiaceae

Common Name — Brimstone tree

African Names — Bambara: sangongo; Bondoukou: alongua; Ewe: amake; Ho: maticki; Kimbundu: ngole; Nzima: sema; Twi: konkroma, ope-asi-akwa; Umbundu: ngongouve; Yoruba: oruwo, owuru

Description — Morinda lucida is a medium-size tree up to 15 m high. It has characteristic yellow wood, from which it derived its name “brimstone tree.” It has slender branchlets and a dense crown. The leaves are broadly elliptical to broadly ovate, acuminate, and entire, about 20 × 15 cm. The base is rounded to broadly cuneate and often dark purplish or black when dry. It produces white flowers January–July and September–October. It fruits March–April. 9,28,33

Habitat and Distribution — The species occurs in fringe forests and flooded areas. Sometimes, it takes over secondary clearings in rain forests. It is distributed from Burkina Faso to Zaire, Angola, Kenya, and Tanzania.

Ethnomedicinal Uses — The leaves are used in the preparation of fever teas, which are used not only for the treatment of malaria but also as a general febrifuge and analgesic. All parts of the plant are used as a laxative. A weak decoction of the stem bark is administered for the treatment of severe jaundice, often characterized by hemoglobinuria and hematuria. The treatment induces vomiting, diarrhea, and diuresis, and cure is determined from the clearance of yellow coloration of the urine.

The extract of the leaves and stem bark has been recommended for the prevention and treatment of hypertension and its cerebral complications. 780 It has also been employed for the treatment of dysentery. 78

Constituents — The plant contains tannins, methylanthraquinones, and heterosides. 78

Pharmacological Studies — The use of the plant in the treatment of jaundice has been validated by controlled studies. 781 The extract of the leaf and stem bark has been shown to possess strong but short-acting antihypertensive activity. 785 This therapeutic activity may be due to its pronounced diuretic and tranquilizing properties. Due to its apparent lack of acute toxicity, the drug is recommended for chronic treatment of hypertension and in cases requiring high doses or frequent medication to arrest elevated blood pressure. 782

The anthraquinone fraction has been shown to possess molluscicidal properties, and the activity may be due to oruwacin. 783 Aqueous alcohol extract of the leaves showed significant activity against Trypanosoma brucei infection in mice at a dose of 1000 mg/kg given intraperitoneally. 784 The LD50 was calculated to be 2000 mg/kg. The extract was also found to possess purgative activity. 785 The leaf extract demonstrated significant schizonticidal activity against Plasmodium berghei in mice. 786,787 The lyophilized aqueous extract of roots of M. citrifolia showed a significant, dose-related, central analgesic activity in the writhing and hot plate tests. 788 The activity was antagonized by naloxone. The extract caused sedation on the experimental animals at high doses, as evidenced by the decrease of all behavioral parameters in the two-compartment test, the light/dark choice situation test, and the staircase test, as well as the induction of sleep. 793 At the doses tested, the extract did not show any acute toxicity.

Morinda induced relaxation of vascular smooth muscle, which occurs via endothelium-dependent and -independent mechanisms, the former of which involves the NO-cGMP pathway. 789 At a concentration of 0.25–9.0 mg/ml, the extract of Morinda lucida elicited vasorelaxation in noradrenalineprecontracted rings. This relaxation response was partially attenuated by removal of the endothelium and completely inhibited by pretreatment of rings with L-NAME and methylene blue. 790

Moringa Oleifera

Botanical Name — Moringa oleifera Lam.

Synonyms — M. pterogosperma Gaerthn., Hyperanthera moringa (L.) Vahl., Guilandina moringa L.

Family — Moringaceae

Common Names — Oil of Ben tree, horseradish tree, Ben aile (French)

African Names — Arabic: habbah ghaliah; Ewe: babatsi; Hausa: zongallagandi, danga; Igbo: okwe-beke (okwe-oyibo); Yoruba: ewe igbale

Description — Moringa oleifera is a small deciduous tree about 8 m high, with pale gray bark and soft wood. It has a crooked stem that often is forked near the base. The twigs and young shoots are densely hairy. The leaves are tripinnate, usually with 6 pairs of pinnae, large, and alternately arranged on the stem. Secondary and tertiary leaflets are oppositely arranged, dark green above and pale green below the surface, with variable shapes and sizes but mostly obovate. The flowers are small, sweet scented, and borne on loose axillary common stalks up to 15 cm long, cream colored, with unequal petals that are usually larger than the sepals; the latter are 5, pale green, up to 1.2 cm long, and finely hairy. The fruits are 3 angled, pod-like, up to 45 cm long and 1.3 cm broad, slightly constricted at intervals, gradually tapering to a tip, containing rows of blackish, rounded, oily seeds, each of which has 3 papery wings. 77

Habitat and Distribution — It is a tropical plant, cultivated in parts of the continent but probably native to Morocco, Egypt, and Tunisia.

Ethnomedicinal Uses — Moringa leaves and young pods are used as vegetables and added to soups and salads to aid digestion and to stimulate appetite. The infusion of the root bark is dispensed for venereal infections and the treatment of fevers. The kernel yields clear, sweet oil that is applied externally as a counterirritant like mustard. 7 The pounded root mixed with salt is used as a poultice for inflammatory swellings. The tree is planted on graves to keep away hyenas, and its branches are used in the preparation of a charm against witches. The seeds are used in Sudan and other parts of North Africa for water purification. In East Africa, the seeds are used in the induction of abortion.

In India, the root is used as a stimulant in paralytic syndrome and for the treatment of epilepsy, nervous disorders, hysteria, and spasmolysis, as well as for a cardiac circulatory tonic. 82 In India, the plant is cited for the treatment of diseases of the liver, spleen, and articular pains; the tender leaves are indicated for scurvy and catarrh and given to children suffering from flatulence. 170

Constituents — The leaves are rich in amino acids, including aspartic acid, glutamic acid, serine, glycine, threonine, α-alanine, valine, leucine, isoleucine, histidine, lysine, cysteine, methionine, arginine, and tryptophan. 791 The flowers and the fruits also contain amino acids. 792 The root bark yields the sulfurated amino bases moringinine and spirochine, as well as benzylamine and glucotropaeline. 82 The seeds contain an almost-colorless fixed oil, known in commerce as Beni or Moringa oil. The oil consists of a 60% liquid olein fraction and 40% solid fat. The major constituents of the oil are oleic acid (65%), stearic acid (10.8%), behenic acid (8.9%), myristic acid (7.3%), palmitic acid (4.2%), and lignoacetic acid (3.0%). 170,793 The stem bark has been shown to contain sterols and terpenes, 794 as well as 4-hydroxymellin, vanillin, β-sitosterol, β-sitosterone, and octacosanoic acid. 795 The roasted seeds contain 4-α-L-rhamnosyloxyphenylacetonitrile, 4-hdroxyphenylacetamide. 796

Pharmacological Studies — The juice from the leaves and stem bark showed antibacterial and antitubercular activity, 797,798 and root bark extract showed antiviral effect against vaccinia virus 799 and anti-inflammatory and analgesic activity (Kapoor). Ethanol extract of the whole plant demonstrated significant cytotoxic activity against human epidermoid carcinoma of the nasopharynx in tissue culture and in vivo activity against P388 leukemia in mice. 800 Moringinine has been shown to exhibit sympathomimetic activity similar to that of adrenalin. 82 The compound has cardiac stimulant activity, as well as peripheral vasoconstriction and elevation of blood pressure. It has a depressive action on smooth muscle fibers, relaxes the bronchioles, and inhibits the tone and movement of the intestine in rabbits and guinea pigs. 801

Two complex benzylisothiocyanates found in the root, pterospermine and anthomine, possess strong antimicrobial activity; the latter is also active against cholera vibrion. 78 Spirochine at a dose of 0.035 g/kg accelerates and amplifies the heartbeat in humans, and at an elevated dose of 0.35 g/ kg, the compound exhibits an opposite effect. 78 The compound produces generalized paralysis of the CNS and possesses antimicrobial activity. 802

The plant has remarkable antifertility properties. The oral administration of an aqueous extract of the root has estrogenic, antiestrogenic, progestational, and antiprogestational effects. 803 It was shown that the extract progressively increased the uterine wet weight of bilaterally ovariectomized rats. The estrogenic activity was supported by stimulation of uterine histoarchitecture. In 50% of the rats tested, a dose of 600 mg/kg of the extract interfered with the formation of deciduoma, which is indicative of antiprogestational activity, although the same dose failed to induce a decidual response in the traumatized uterus of ovarectomized rats. 804 Treatment of rats with the extract caused an enlargement of lumen, and luminal epithelium remained unstimulated; the uterus was nondematous; in the control group, the glandular cells showed hypertrophy, and in the endometrium the leukocytic infiltration was increased. The antifertility activity of the plant could therefore be due to the non-receptive state of the uterus throughout the treatment period. 804 The biochemical and physiological alterations in the genital tract of female cyclic rats following administration of aqueous extract of the plant have been investigated. It was observed that after administration of the drug, there was an initial stimulation of the uterine structures and metaplasmic changes in the cervical epithelium, and considerable cornification in the vaginal epithelium was provoked. These effects were followed later by significant inhibition in the histoarchitecture and changes in some biochemical parameters. 805

The aqueous extract of the seeds, which is used for water purification in Sudan, has been shown to effect a turbidity reduction of 80–90.5% and concomitant reduction in the bacterial count after 1–2 h of treatment, with the bacteria concentrated in the coagulated sediment. 806 Moringa should be regarded as consisting of three distinct herbs: the highly nutritional leaves, the seeds, and the aerial parts.

Many scientific and clinical studies have provided much evidence to support the use of the leaves as dietary supplements for the treatment of hyperlipidemia, hypertension, diabetes, and diseases due to oxidative stress, anemia, and chronic arthritis. A traditional herbal formulation that contains Moringa oleifera leaves, Bidens pilosa, and sodium chloride is used in Côte d’Ivoire with positive results for the treatment of high blood pressure. The herbal supplement at doses of 5 × 10−8 to 5 × 10−2 mg/kg caused a dose-dependent hypotension. The herbal supplement elicited drops in blood pressure ranging between 7.14% ± 4% and 100% ± 7.5%, compared to normal blood pressure of rabbits. The 50% effective dose of herbal supplement was 3.95 × 10−4 mg/kg, which was similar to the hypotension induced by acetylcholine, the one caused by herbal supplement at a dose of 3.95 × 10−4 mg/kg in rabbit was progressively inhibited by atropine dosed between 5 × 10−4 and 5 × 10−2 mg/kg. The percentage drop of recorded blood pressure ranged from 50.3% ± 1.87% to 3.71% ± 1.09% compared to the normal blood pressure value. In the presence of atropine, the herbal supplement effect was partially inhibited. The same increasing doses of herbal supplement reduced significantly the increase of blood pressure induced by adrenaline dosed at 4.76 × 10−4 mg/kg from 89.3% ± 2.19% to 1.19% ± 0.59%. 790

Mucuna Pruriens

 

Botanical Name — Mucuna pruriens (L.) DC.

Synonyms — Carpopogon pruriens (L.) Roxb., Dolichos pruriens L., Mucuna aterrima (Piper & Tracy) Merr., Mucuna axillaris Baker, Mucuna cochinchiniensis (Lour.) A. Chev., Mucuna nivea (Roxb.) Wight & Arn., Mucuna prurita (L.) Hook., Stizolobium pruritum (Wight) Piper, plus 5 others

Related Species — Mucuna pruriens var. hirsuta (Wight & Arn.) Wilmot-Dear, Mucuna pruriens var. pruriens (L.) DC., Mucuna pruriens var. utilis (Wall. ex Wight) L.H. Bailey

Family — Leguminosae

Common Names — Lacuna bean, bengal velvet bean, black velvet bean, buffalo bean, hell fire bean, itchy bean

African Names — Igala (Nigeria): inyelekpe; Igbo (Nigeria): ukpo; Kiswahili: upupu; Malawi: chitedze; Yoruba: yerepe or warapa; Madagascar: aga

Description — The plant consists of three related species, noted for the extreme itchiness they produce on contact, particularly with the young foliage and the seed pods. They differ significantly in their morphological characteristics. Detailed descriptions of the three species are available in PROTA. 1140 The subject species, Mucuna pruriens (L.) DC, according to the description in Wikipedia, 1138 is an annual climbing shrub with long vines that can reach over 15 m in length. The young plant is almost completely covered with fuzzy hairs, but when older, it is almost completely free of hairs. The leaves are tripinnate, ovate, reverse ovate, rhombus shaped, or widely ovate. The sides of the leaves are often heavily grooved, and the tips are pointy. In young plants, both sides of the leaves have hairs. The stems of the leaflets are 2 to 3 mm long. Additional adjacent leaves are present and are about 5 mm long.

The flower heads take the form of axially arrayed panicles. They are 15 to 32 cm long and have 2 or 3 or many flowers. The accompanying leaves are about 12.5 mm long; the flower stand axes are from 2.5 to 5 mm. The bell is 7.5 to 9 mm long and silky. The sepals are longer or of the same length as the shuttles. The crown is purplish or white. The flag is 1.5 mm long. The wings are 2.5 to 3.8 cm long. In the fruit-ripening stage, a 4- to 13-cm long, 1- to 2-cm wide, unwinged, leguminous fruit develops. There is a ridge along the length of the fruit. The husk is very hairy and carries up to 7 seeds. The seeds are flattened uniform ellipsoids, 1 to 1.9 cm long, 0.8 to 1.3 cm wide, and 4 to 6.5 cm thick. The hilium, the base of the funiculus (connection between placenta and plant seeds), is surrounded by a significant arillus (fleshy seed shell). It bears white, lavender, or purple flowers. Its seed pods are about 10 cm long and are covered in loose orange hairs that cause a severe itch if they come in contact with skin. The seeds are shiny black or brown drift seeds.

Habitat and Distribution — It is found occurring naturally in tropical parts of Africa, Asia, and Caribbean.

Ethnomedicinal Uses — Mucuna seeds are used in traditional medicine mainly for the treatment of diabetes and male sexual dysfunction and as a soup thickener for general weakness. The pod hairs mixed with syrup, molasses, or honey are taken as an anthelminthic and anti-inflammatory. Boiled seeds are occasionally eaten as a pulse and boiled immature pods and young leaves as vegetables. It enjoys a reputation as a potent aphrodisiac and source of vitamins and minerals.

Constituents — Mucuna pruriens seeds contain protein (15–30%), amino acids, fixed oils (8%), calcium, fiber, and vitamins. Two important nonprotein amino acids are found in the seed and in smaller amounts in the stems and leaves: L-dopa (L-3.4-dihydroxyphenylalanine), from which dopamine, an important medicine to relieve the effects of Parkinson’s disease, is prepared, and DMP (N-dimethyltryptamine), which has hallucinogenic properties. The L-dopa content varies from 1.6% to 3.3% and is sufficiently high both as a phytomedicinal and for commercial extraction of the active constituent. The seed also contains a number of alkaloids, the most important of which are mucunaine, prurienine, and serotine. The stinging hairs of velvet bean, used as an anthelmintic, contain a pruritogenic, proteolytic enzyme and granular matter, tannic acid, and resin. 1140 The concentration of L-dopa in the defatted Mucuna meal was greatly increased when extracted by supercritical carbon dioxide, performed in a laboratory-scale unit at 40°C and 60°C over the pressure range 150 to 250 bar. A constant flow rate of CO2 close to 3 ml/min was maintained. This finding is industrially useful in the production of L-dopa from Mucuna without the problem associated with residual solvent after extraction of plant materials for clinical use. 807

Pharmacological Studies — The chemical compounds responsible for the itch are the protein mucunain and serotonin. The seed powder of Mucuna pruriens has been clinically assessed in several studies for its application in the treatment of Parkinson’s disease. 808,809 The clinical effects of Mucuna seed powder and levodopa (L-dopa) pharmacokinetics were evaluated following two different doses of mucuna preparation and were compared with standard L-dopa/carbidopa (LD/ CD). In the study, 8 patients with Parkinson’s disease with a short duration L-dopa response and on period dyskinesias completed a randomized, controlled, double-blind, crossover trial. Patients were challenged with single doses of 200/50 mg LD/CD and 15 and 30 g of mucuna preparation in randomized order at weekly intervals. L-dopa pharmacokinetics were determined, and the Unified Parkinson’s Disease Rating Scale and tapping speed were obtained at baseline and repeatedly during the 4 h following drug ingestion. Dyskinesias were assessed using modified AIMS and Goetz scales. The 30-g mucuna preparation when compared with standard LD/CD, led to a considerably faster onset of effect (34.6 vs. 68.5 min; p = 0.021), reflected in shorter latencies to peak L-dopa plasma concentrations. Mean on time was 21.9% (37 min) longer with 30 g mucuna than with LD/ CD (p = 0.021); peak L-dopa plasma concentrations were 110% higher, and the area under the plasma concentration-versus-time curve (area under curve) was 165.3% larger (p = 0.012). No significant differences in dyskinesias or tolerability occurred. These findings suggest that the rapid onset of action and longer on time without concomitant increase in dyskinesias on mucuna seed powder formulation indicate that this natural source of L-dopa might possess advantages over conventional L-dopa preparations in the long-term management of Parkinson’s disease. 808

The antidiabetic activity has been established in a rat model. Chronic administration of the alcoholic extract of Mucuna pruriens seeds resulted in a significant dose-dependent reduction in the blood glucose level (p < 0.001). Acute toxicity studies indicated that the extract was relatively safe at low doses; although some adverse reactions were observed at higher doses (8–32 mg/kg body weight), no death was recorded. Furthermore, oral administration of M. pruriens seed extract also significantly reduced the weight loss associated with diabetes. 810 In another study, the effect of ethanolic seed extract of M. pruriens on mitochondrial dysfunction and the DNA damage in hyper-glycemic rat epididymal spermatozoa was investigated. 811 Significant reduction in the sperm count, motility, and viability and a significant increase in the number of abnormal sperm in STZ compared to the control group was observed. STZ rat sperm showed a significant increase in lipid peroxidation (LPO) and DNA damage. Both the enzymic and nonenzymic antioxidants were decreased; mitochondiral membrane potential (MMP) and the mitochondrial functions were severely affected in STZ group. The diabetic rats supplemented with M. pruriens showed a remarkable recovery in antioxidant levels and reduced LPO with well-preserved sperm DNA. The MMP and mitochondrial function test were also preserved in STZ plus Mucuna pruriens (MP) rat sperm. The findings clearly demonstrated the potency of M. pruriens to reduce the diabetic-induced sperm damage induced by oxidative stress. It is inferred from these results that a similar mechanism may account for the effect of Mucuna in humans. 811

Agriculture — Propagation of Mucuna pruriens is mostly by seed. The seed requires no scarification, but dry seed requires soaking in water for 24 h. The germination rate of fresh seed is 90–100%, declining with time. Seed stored in a cool dry place remained viable for about 2 years, but seed stored in a sealed jar for 3 months lost its viability. Germination takes 4–7 days. It is cultivated more for its soil fertility benefits than as a medicinal plant. In India and other parts of Asia, the plant is cultivated commercially.

Commerce — Mucuna is a major commodity in international medicinal plant trade, but it is neither cultivated on a large scale nor exported in any significant manner in the continent. Annual world seed production has been estimated to be 900,000 t. Small quantities exported from Cameroon in 2011 were sold at US$2.5 per kg.

Myristica Fragrans

Botanical Name — Myristica fragrans Houtt.

Synonyms — M. moschata., M. officinalis L.

Family — Myristiaceae

Common Names — Nutmeg tree, muscadier (Fr.)

African Names — Arabic: goz el-tieb; Igbo: ehuru; Swahili; kungu; Yoruba: abolakose, ariwo

Description — Nutmeg is the dried kernel of the seed, while mace is the dried outer covering or aril. Myristica fragrans is a dioecious evergreen tree, growing up to 60 feet, but most are about 40 feet high, with grayish-black bark, which is longitudinally fissured in old trees. The leaves are elliptic or oblong-lanceolate, and coriaceous, and the flowers occur as umbellate cymes. The yellow fruits, with fleshy pericarp, are 6 to 9 cm long, glabrous, and usually drooping. The seeds are pale brown, about 3 cm long and 2 cm broad, with a reticulate surface patterned with grooves, lines, and specks. The seed has a characteristic aroma and bitter taste.

Habitat and Distribution — It grows in humid tropical forest regions and is widely cultivated throughout the continent.

Ethnomedicinal Uses — The essential oil is used as a carminative and applied externally for rheumatism. 82 It is used in soaps as a postpartum medication.

Constituents — Nutmeg contains about 10% volatile oil composed of linene and camphene as the major constituents, and the minor constituents include myristicin, safrole, elemicin, terpeneol, cymene, α-thujene, γ-terpinene, linalool, eugenol, isoeugenol, methyleugenol, and several minor terpenoids. The plant also yields up to 40% fixed oil, proteins, and diarypropanoids, as well as elimicin and safrol. 812

Pharmacological Studies — The drug is a mild hypnotic agent, and the component responsible for this activity is myristicin. The drug is an inhibitor of prostaglandins and related endochemicals produced by the human colon 813815 and has also been found to decrease prostaglandin levels in the rat. 816 It has carminative, spasmolytic, antiemetic, or oxygenic activity and has been used clinically for the treatment of a variety of stomach disorders, including nausea, flatulence, indigestion, and diarrhea, especially diarrhea secondary to thyroid medullary carcinoma. The drug has platelet aggregation inhibition activity, associated with the eugenol and isoeugenol content. 817 The hypnotic effect does not appear to be manifest when nutmeg is used as a culinary spice.

Toxicology — High doses of nutmeg are highly hypnotic and toxic. Reported adverse effects include hypothermia, giddiness, nausea, weak pulses, and general feeling of heaviness in the chest and lower abdomen. 608 It also causes tachycardia, and the oil decreases fertility in rats. 818 One of the constituents of nutmeg, safrole, has been found to be carcinogenic in mice. 819

Nuclea Latifolia

Botanical Name — Sarcocephalus latifolius (Sm.) E. A. Bruce

Synonyms — N. esculentus (Afz. ex Sab.) Merrill, Sarcocephalus esculentus Afz., S. sasandrae Chev., S. samucinus Schum., S. russegeri Kotschy ex Schweinf.

Family — Rubiaceae

Common Names — African peach, Guinea peach, doundake, country fig

African Names — Ashanti: kusia, kankanu (Ejura); Bron: hwene hwenti; Ewe: nyimo; Fanti: ekusiawa

Description — Nuclea latifolia is a straggling or scandent shrub or small spreading tree, usually about 7 m high but growing up to 35 m in closed forests. The leaves, 17 × 12 cm, are glabrous, obvate, sharply acuminate, with a darker upper surface. The stipules are broad, ovate, and persistent. The flowers are sweet scented, large, and fleshy. The fruits are red, fleshy, and shallow pitted, with numerous embedded seeds surrounded by edible, sweetly acrid pulp.

Habitat and Distribution — The species is essentially a savanna plant. It has been found in savanna forests and fringe tropical forests from Senegal to Zaire. The related species N. diderrichii Merrill is restricted to deciduous and evergreen forests. 9

Ethnomedicinal Uses — The genus is used in Nigeria and neighboring countries for the preparation of tonics and fever medicine. The soot is used as chewing sticks and for the treatment of toothache, caries, and septic mouth. An aqueous decoction of the root bark has been used as a malaria remedy. The dried fruit is used in the treatment of dysentery and piles, but the fresh fruit, when taken in excess, causes diarrhea. The stem bark has been used as a homeostatic, analgesic, anthelmintic, and diuretic. A lotion made from the stem bark is effective in the treatment of complex skin disease resembling cutaneous leishmaniasis.

Constituents — Nuclea contains several indole-quinolizidine alkaloids and glycoalkaloids. 820,821 The major ones include angustine, angustoline, angustifoline, nauclefine, and naucletine. 822824

Pharmacological Studies — An aqueous extract of the leaves and stem bark collected from Nigeria has been shown to lower the rectal temperature of the guinea pig for several hours when the drug was administered intraperitoneally. 825 The hypothermic activity has also been demonstrated in dogs, and the extract further produced a sudden decrease of the carotid pressure followed by the opposite effect, as well as vasoconstriction. 825 Extracts of the leaves and bark possessed cardiac activity, 826 and the leaf extract showed anticancer activity against transplantable sarcoma 180 tumors and against Lewis carcinoma. 827 An alkaloidal isolate from the roots has been found to be anticholinergic and relaxed smooth muscles. 828 Extracts of the plant exhibited molluscicidal activity against laboratory-reared Lymnea natalensis. 829

Neostenanthera Myristifolia

Botanical Name — Neostenanthera myristifolia (Oliv.) Excell

Synonym — Stenanthera myristifolia Engl. et Diels.

Family — Annonaceae

African Name — Bini (Edo): uyenghen eze

Description — Neostenanthera myristifolia is a shrub or small tree about 10 m high. The stem is slender, the bark is grayish-brown, and the slash is whitish. Sometimes, it is stilt rooted. The twigs and young leaves are usually covered with small hairs but become smooth with age. The leaves are simple, oblong-elliptic, 10–30 cm long and 5–10 cm broad, with a short apex that tapers to a tip. There are about 12 pairs of lateral nerves. The flowers are greenish at first, turn yellow later, and are borne on slender, short, and hairy stalks. It produces egg-shaped fruits, which appear from May to July; 13,81 they are about 1.3 cm long and attached to stalks through individual shorter stalks.

Habitat and Distribution — This is a forest tree and occurs in Liberia, Ghana, Gabon, and probably Nigeria and Cameroon.

Ethnomedicinal Uses — The dried and pulverized leaves are used like snuff for treating tumors of the nose. A related species, N. hamata, is used as a vermifuge in Liberia.

Ocimum

Many members of the genus Ocimum are used for the preparation of remedies in African traditional medicine. The most important ones include O. basilicum, O. gratissimum, O. canum, and O. suave. All four species are used as a febrifuge, and some are used as food flavors. They all yield volatile oils, but the oils differ significantly in their chemical compositions.

Ocimum Basilicum

 

Botanical name Ocimum basilicum Linn.

Synonyms — O. viride Willd., O. guineense Schum. et Thonn.

Family — Lamiaceae.

Common Names — Fever plant, fever leaf, fever plant of Sierra Leone, tea bush

African Names — Ashanti: nunum, onunum; Bini: ihiri eziza, aramogho; Ewe: debeshui, beblosi; Hausa: dai doya ta gida; Igbo: nchu-anwu; Efik: ntion; Malinke: su-guen-fira; Mandingo: sisejambo; Mende: kumoi, kumwi; Timme: e-b’ onto, o-gbonto; Yoruba: efinrin

Description — This is an erect, small shrub with many branches, usually not more than 1 m high. The leaves are simple, lanceolate to oblong, up to 9 cm long and 4.5 cm broad, with cuneate or unequal-sided base and toothed margins. They are sparsely hairy on the undersurface and pitted with glands. The veins are slightly hairy. The herbs have an aromatic smell when crushed. The flowers are creamy white or yellowish and appear in paniculate racemes about 12 cm long. The calyx is small and 2 lipped; the upper lip is broadly oval in shape with a tiny short point. The lower lip is oblong and toothed, and the petals combine to form a lipped tube. The fruits occur as small 4-lobed capsules. 28

Habitat and Distribution — It occurs in deciduous forests and savanna. It is commonly found around village huts and gardens and is cultivated for its medicinal uses and as a food flavor.

Ethnomedicinal Uses — The whole herb is used throughout West Africa as a febrifuge and as an ingredient of many malaria remedies. The crushed leaves are instilled into the eye as a treatment for conjunctivitis. The oil from the leaves is regarded as highly antiseptic and has been applied for the dressing of wounds, as a mouth gargle, and to prevent postpartum sepsis. The leaves are used in Nigeria as a stomachache and catarrh remedy 266 and as a general tonic and antidiarrheal. The oil is used in many parts of West Africa to prevent mosquito bites. The oil mixed with alcohol is applied as a lotion for skin infections and taken internally for bronchitis. An infusion of the leaves, the so-called Ocimum tea or bush tea, is dispensed as a remedy for fever and as a diaphoretic.

The leaves are boiled with those of Spondias and the bark of Funtumia elastica and applied as a treatment for hemorrhoids. The leaves are also applied externally for rheumatic pains and lumbago.

Constituents — The leaves yield a very aromatic volatile oil that consists mainly of thymol (32–65%) and eugenol. The plant also contains xanthones, terpenes, and lactones. The chemical composition of Ocimum gratissimum essential oil varies enormously according to chemotypes: timol, eugenol, or geraniol.

Pharmacological Studies — Thymol isolated from the plant has been shown to be antiseptic, antitussive, and antispasmodic. 830 Some of the observed biological activity of the plant could be due to the presence of xanthones, which have been associated with monoamine oxidase inhibition activity, 831 the tetraoxygenated xanthones with anticonvulsant properties, and the secoiridoids, which possess stimulant and antispasmodic properties. 78 A fraction of the crude extract has been shown to contract guinea pig ileum and rat colon and to raise rat mean arterial blood pressure. 832 The volatile oil exhibited antimicrobial, insect repellent, and anthelmintic activity. 833 Oral and topical formulations of the plant have been evaluated in Nigeria. 833

Ocimum leaf extract is effective in the treatment of malaria 834 and CNS diseases. 835 Evaluation of the CNS activity was done using the open-field and rota-rod tests; sleeping time induced by sodium pentobarbital (PBS; 40 mg/kg i.p.) and anticonvulsant activity against seizures induced by both pentylenetetrazole (pTZ; 85 mg/kg s.c.) and maximal electroshock (MES; 50 mA, 0.11 s) were determined. Essential oils obtained in each season were effective in increasing the sleeping duration, and a preparation obtained in spring was able to protect animals against tonic seizures induced by electroshock. In each season, eugenol and 1,8-cineole were the most abundant compounds, and in spring, the essential oil presented the greatest relative percentage of sesquiterpenes, suggesting that these compounds could explain the differences observed in the biological activity in essential oils obtained in different seasons of the year. 836

Ocimum Suave

Botanical Name — Ocimum suave Willd.

Synonyms — Ocimum trichodon Bak. ex Gürke, Ocimum dalabaense A. Chev.

Family — Lamiaceae

African Names — Kipare: mrumbash, muodo; Kimeru: induka, mnuka; Kirufiji: kifumbazi, manyinyiikwa; Kisambaa: msumbasha, mvumbash; Kiswahili (Kiluguru): kivumbashi; Kiarusha: olmanyinyikwa olemura; Kiluguru: msuameno; Kigogo: iwenya, mzenye, izenhye; Kinyiramba: inengafai, ijembaei, idumbasi; Kinyaturu: lumbasi; Kinyamwezi: ilumbasye; Kihehe: iwenye; Rwanda: umwenya

Description — It is a much-branched herb about 1–4 m high, with ribbed stem and glabrous branchlets. The leaves are simple, oppositely arranged, 3–12 cm long, 1.6 cm wide with ovate to ovate-lanceolate or sometimes lanceolate blade, and bluntly serrated margin. The apex is acuminate, and the base is cuneate. It has terminal inflorescence with simple or paniculate racemes. The flowers are hermaphrodite, borne in whorls, and irregularly shaped. The corolla is a whitish or greenish-yellow tube, about 5 mm long, with a 4-lobed upper lip. The calyx is distinctly hairy, 5–7 mm long, with an oval upper lip, with the lower lip displaying 4 triangular teeth. The herb gives a pleasant aromatic odor when crushed. 33

Habitat and Distribution — Like other members of the genus, Ocimum suave is widely distributed throughout the continent. It is primarily a savanna species, occurring in a wide range of soils at altitudes between 100 and 20,000 m in areas receiving between 500 and 1500 mm or more annual rainfall. The plant is the dominant species in most of eastern and southern Africa. It has been found to occur in Rwanda, Burundi, Ethiopia, Somali, Uganda, Kenya, Botswana, Angola, Namibia, South Africa, Tanzania, Malawi, Zambia, and Zimbabwe. It also occurs in the West Coast and grows well in Sierra Leone, Guinea, Ivory Coast, Nigeria, and Cameroon, as well as in North Yemen and Comoro Island.

Ethnomedicinal Uses — The plant is used as a local application for the relief of nasal congestion; for this purpose, the fresh herb is crushed and sniffed. Extracts of the plant have been used for the treatment of coughs, abdominal pains, and ear and eye inflammation and as a gargle for mouth infections. The FAO monograph 33 of the species reported that a decoction of the root pieces is administered twice a day for barrenness. The drug was also listed for the regulation of menstruation and for the treatment of prolapse of the rectum. The smoke from the burning plant is used as a mosquito repellant. The plant is also used as a charm against evil spirits.

Constituents — O. suave has a high content of volatile oil, which consists mainly of eugenol. 79

Pharmacological Studies — The plant has antimicrobial activity. Other uses are as described for O. gratissimum. Eugenol is used extensively in restorative dentistry as a temporary filling material for root canal. The leaf of O. suave is used to perfume chewing tobacco and snuff. Most of the pharmacological activities described under Ocimum gratissimum L. are applicable to Ocimum suave Willd (Ocimum gratissimum subsp. gratissimum).

Ocimum Sanctum

Ocimum sanctum is a synonym of Ocimum tenuiflorum L. The plant occurs in parts of northern and eastern regions of the continent. The medicinal uses are as indicated for the previously discussed species.

An alcoholic extract and aqueous suspension of the leaves of Ocimum sanctum have been reported as possessing an immunomodulatory effect on an antigenic challenge of Salmonella typhosa and sheep erythrocytes in albino rats. 837 It was found that there was definite stimulation of the humoral immunologic response, as represented by an increase in antibody titer in both the Widal and sheep erythrocyte agglutination tests as well as by a cellular immunologic response represented by E-rosette formation and lymphocytosis. 819

Olea Europaea

Botanical Name — Olea europaea Linn.

Synonyms — Olea pallida Salisb.

Family — Oleaceae

Common Names — Olive tree, olea

Description — The olive tree yields evergreen leaves that are employed for the treatment of hypertension. The plant is native to the Mediterranean region, where it is cultivated both for its valuable oil and for the leaves. It produces edible blue-black fruit (2–3 cm length) that occurs in drupes. The olive tree grows to a great age but seldom exceeds 12 m in height. The leaves are leathery with scale-like hairs on the underside. 838

Ethnomedicinal Uses — The leaves and bark extracts have been used as a remedy for scrofula and intermittent fever, and a weak decoction of the stem is used as a tonic. 79 The fixed oil from the fruits is employed in southern Africa as an astringent for the treatment of diarrhea. Olive oil is a valuable edible oil used as an emollient and as a dietary supplement.

Constituents — The leaf is rich in tannins. A bitter water-soluble glucoside called oleorepein has been shown to be present in the bark, leaves, and fruits. 839 The seed is the source of the commercially important olive oil, which consists of glycerides of oleic acid (70–80%), with the glycerides of palmitic, stearic, and linoleic acids minor components.

Pharmacological Studies — The aqueous extract of the olive leaves has been shown to possess significant hypotensive activity in rats. 840 The antihypertensive activity of olive leaves may be due to the presence of oleuropein. 511 In a work credited to Petkow and Manolow, the drug was found to achieve extended and always reproducible reductions in blood pressure, as well as spasmolytic actions on the smooth musculature. 511 The effects were observed to be less marked in rats than in cats. Extracts of the leaves also exhibited direct relaxant action on smooth muscles, dilated the bronchi, and improved blood circulation. 841

Clinical Application — Weiss 511 recommended olive leaves for labile and medium-severe hypertension. Proprietary preparations are available containing olive leaves, for example, Osvysat (Burger), or in combination with the diuretic hydrochlorothiazide and potassium chloride (Olivyysat compound). A commercial product, Hyperidyst (Vogel and Wber), exists that contains olive leaves, raulwolfia, arnica root, and mistletoe. A daily dose of 100 ml of an infusion of the leaves for 20 to 25 days has been shown to increase the daily urine output by 10% to 15%, with a concomitant decrease in blood uric acid levels and an increase in the urinary uric acid content, without any significant effect on the blood sodium and chloride levels. 842,843

Parkia Biglobosa

 

Botanical Name — Parkia biglobosa (Jacq.) G.Don

Synonyms — Inga biglobosa (Jacq.) Willd, Mimosa biglobosa Jacq., Parkia africana R.Br., Parkia clappertoniana Keay, Parkia intermedia Oliv., Parkia oliveri J.F.Macbr.

Related Species — Parkia bicolor A Chev.

Family — Leguminosae

Common Names — African locust bean, nitta tree, locust bean, monkey cutlass tree

African Names — Yoruba: ewé igba, igiougba, iru; Hausa: dawa dawa, daddawa; Igbo: ogiriawusa; Fufulde (Nigeria): netteh, nerre; Mandinka (Senegal): netto; Wolof: nette, houlle, ouli; Ewe: moti, wati; Bassa: budo; Mina: woti; Malinké: néré; Baoulé: kparalé, kpalé; Fon: arouati; Peuhl: niri

Description — Parkia biglobosa is a medium-size tree up to 30 m tall; taproot is often present, with lateral roots up to 10(–20) m spreading from the bole; the bole is usually straight and robust, cylindrical, up to 130 cm in diameter, often branching low; bark is distinctly longitudinally fissured, often with more or less regular scales between the fissures and is thick, ash gray to grayish brown; slash is fibrous and reddish brown, exuding an amber gum; crown is dense, wide spreading, and umbrella shaped, consisting of heavy branches. Leaves are bipinnate, swollen at the base and therewith an orbicular gland, with 8–16 pairs of pinna, each one composed of 15–35 pairs of leaflets 1 cm long and 2 mm broad. Inflorescence is a pendulous head arranged racemosely; the peduncle is 10–35 cm long, turning salmon-pink and many flowered. Flowers are narrow, red, and 3 cm long; stamens have blackish anthers. Pods are slender, a little flattened, and 30 cm long. Seeds are globose-ovoid and embedded in a yellowish farinaceous fleshy endocarp.

Habitat and Distribution — Parkia biglobosa is a Sudano-Zambezian species present in a belt between 5° N and 15° N, from the Atlantic coast in Senegal to southern Sudan and northern Uganda. The belt is widest in West Africa (maximum 800 km) and narrows to the east. It was probably introduced to São Tomé and Principe.

Ethnomedicinal Uses — The locust bean is used in Africa as a fermented food condiment for seasoning sauces and soups. The use of the fermented beans of African locust bean dates back many centuries and was already described in the fourteenth century. In West Africa, the bark, roots, leaves, flowers, fruits, and seeds are commonly used in traditional medicine to treat a wide diversity of complaints, both internally and externally, sometimes in combination with other medicinal plants. The bark is most important for medicinal uses, followed by the leaves. Medicinal applications include the treatment of malaria; parasitic infections; circulatory system disorders, such as arterial hypertension; and disorders of the respiratory system, digestive system hemorrhages, and dermatosis. 1140 It has also been used for the treatment of measles, chicken pox, and gingivitis and as an anthelmintic. In the savanna and Sahel regions of West Africa, locust bean plays a role in all major rituals, including those associated with birth, baptism, circumcision, marriage, and death.

Constituents — The boiled and fermented seeds contain 35% proteins, 29% lipids, and 16% carbohydrates and have good organoleptic properties and a positive effect on intestinal flora. The seeds are good sources of protein, fat, and calcium but contain a nontoxic oil of variable composition. The seed fatty acids include arachidic, behenic, stearic, oleic, palmitic, and linoleic acids. The fruit pulp contains up to 80% carbohydrate. The bark was found to contain a long-chain ester of trans-ferulic acid, together with an inseparable mixture of long-chain cis-ferulates. In addition, lupeol, 4-O-methylepi-gallocatechin, epi-gallocatechin, epi-catechin 3-O-gallate, and epi-gallocatechin 3-O-gallate were isolated. 841 The bark, leaves, and pod husks are rich in tannins, flavonoids, and coumarins.

Pharmacological Studies — The ethanolic extract of P. biglobosa gave a positive response in the brine shrimp lethality assay (LD50 315.2 μg/ml. This result was reinforced by cytotoxicity assays against tumoral cell cultures NSCLC-N6-L16 human bronchopulmonary carcinoma, IC50 13.0 μg ml; KB human nasopharyngeal cancer, IC50 20.0 μg/ml; and P388 leukemia in mice, IC50 22.4 μg/ ml. 841 The seeds possessed antiplatelet, 844 antioxidant, and antihypertensive activities and showed antisnake venom activity. 845 The hydroalcoholic, ethyl acetate, and butanolic extracts of Parkia biglobosa leaf, which contained mainly PACs and monomeric flavonoids, induced endothelium-dependent NO- and endothelium derived hyperpolarizing factor (EDHF)-mediated relaxation in porcine coronary artery rings. The vasorelaxant activity was dependent on their phenolic content and appears to involve mainly PACs. This finding provides a probable mechanism for the antihypertensive activity of P. biglobosa leaves. 846

Commerce — The fermented seeds of African locust bean, known as soumbala, dawa dawa, netetu, ogiri, iru, afitin, and nététou, serve primarily as a condiment for seasoning sauces and soups. Roasted seeds are used as a coffee substitute known as “Sudan coffee” or “café nègre.” The extract of the stem bark is used in the preparation of a preventive medicine for cattle known as “cure salee.” The African locust bean is therefore highly valued in Africa, and it is an article of trade in many parts of the continent.

Pausinystalia Yohimba

Botanical Name — Pausinystalia johimba (K.Schum.) Pierre ex Beille

Synonyms — Corynanthe yohimba K.Schum., Pausinystalia trillesii Beille, Pausinystalia zenkeri W.Brandt

Family — Rubiaceae

Common Names — Johimbe, yohimba

African Names — Yoruba (Nigeria): idagbon; Duala (Cameroon): djombe-wa

Description — Yohimba is an evergreen, medium-size tree and grows up to 30(–35) m tall; the bole is straight, up to 50(–60) cm in diameter, without buttresses but grooved at the base; the bark is easy to peel off and bitter tasting; the bark surface is longitudinally fissured, with transverse cracks, gray to reddish brown; inner bark is fibrous, pinkish and turns reddish brown on exposure; the crown is compact, with branches in whorls. Leaves appear in whorls of 3 and are simple; stipules are 1.5–2 cm long, glabrous, and caducous; the petiole is up to 5(–8) mm long; the blade is obovate or oblanceolate, (11–)13–47 × 5–17.5(–19) cm; the base is cordate, cuneate, or rounded; the apex is short-acuminate; and the margin is often wavy, glabrous, pinnately veined with (8–)10–20 pairs of lateral veins. Inflorescence is a terminal or axillary panicle 5–21(–30) × 9–15 cm, branched in whorls of 3, with flowers in clusters at the ends of branches; the main axes are glabrous; the peduncle is 0.5–5 cm long with 3 ridges. Flowers are bisexual, regular, and fragrant; the calyx consists of a short tube and triangular or rounded lobes. Pausinystalia johimbe can be distinguished from Pausinystalia macroceras by its larger leaves with shorter or no petioles. In addition, the bark of Pausinystalia johimbe is extremely bitter tasting and is easy to peel off, whereas that of Pausinystalia macroceras is less bitter and difficult to peel off. 1140

Habitat and Distribution — Pausinystalia comprises 5 species and occurs in West and Central Africa. P. johimbe occurs in evergreen lowland forest, in primary as well as secondary forest, and at relatively low densities. It is common in southern Nigeria, Cameroon, Gabon, and Central Africa Republic.

Ethnomedicinal Uses — Yohimbe tree has a reputation as a potent aphrodisiac and for the treatment of male erectile dysfunction. The bark is sold in markets throughout West and Central Africa for the preparation of a general tonic. It has also been used as a local anesthetic, as a hallucinogen, for the treatment of angina, against constipation and intestinal worms, as a performance enhancer for athletes, and to increase the clarity of singers’ voices. In Congo, a bark decoction is drunk for the treatment of pelvic pain and for body pain.

Pharmacological Studies — More than 40 alkaloids have been isolated from Pausinystalia johimbe, including the indole alkaloids yohimbine (10–15%), mesoyohimbine, yohimbinine, corynanthine, alloyohimbine, and ajamalicine. Yohimbine (also known as aphrodine, quebrachine, or corynine) is a selective inhibitor of α-2-adrenergenic receptors. It has hypertensive activity at low doses but is hypotensive at high doses, through vasodilation of peripheral vessels. Yohimbine raises the heart rate and norepinephrine levels. The use of yohimbine as an aphrodisiac is attributed to its dilating effect on the blood vessels of the sexual organs, thus increasing blood supply, while it also provides an enhancement of the reflexes involved in the control of ejaculation. 1140 Tests have shown that treatment with yohimbine indeed results in increased libido and easier ejaculation. The effects of yohimbine on smooth muscles favor tonus and movement of the intestine. It also acts on α-2-adrenergenic receptors of adipocytes, resulting in increased lipolysis. However, double-blind trials on the effectiveness of yohimbine for body weight reduction gave conflicting results, and it is therefore unclear whether yohimbine is effective in reducing body weight.

In normal volunteers, the sympathetic effect of yohimbine occurred at doses of 45 mg or higher, between 60 to 90 min after oral administration, lasting on average 4 to 5 h. Similar effects can be achieved at a very low dose (5.4 mg) in patients with autonomic failure given their denervation hypersensitivity. 847

Toxicity — The crude yohimbe plant is relatively tolerated at the dosage used in traditional medicine and the over 50 over-the-counter products that contain bark of Pausinystalia johimbe. The main active compound, yohimbine, has shown a wide range of adverse effects, including hypertension, mania, bronchospasm, anxiety, agitation, hallucinations, vertigo, stomach problems, headache, and weakness. It may also interact with other prescription drugs, including antidepressants, antihypertensives, and cardiac drugs. People with hypertension, prostate problems, or heart diseases are warned against using yohimbine-based products. Another major compound found in the yohimbe plant, ajamalicine, also has vasodilating activity. Corynanthine closely resembles yohimbine, but is more active as a sympatholytic agent and less toxic. 1140 In acute and chronic (long-term) studies, yohimbine has been found to be relatively free of side effects over the dose range predicted to be effective in erectile dysfunction. At much higher doses, the most frequently observed effects, consistent with the primary pharmacological action of the drug, are elevation of blood pressure, a slight anxiogenic action, and increased frequency of urination. These side effects are all easily reversible on termination of yohimbine therapy. 848,849

Agriculture — The yohimbe tree has not been cultivated to any significant extent in West and Central Africa. Overharvesting due to increased international demand has put the plant under great stress. Various experimental cultivations have been undertaken in Nigeria and Cameroon. It has been shown that P. johimbe is amenable to vegetative propagation through the rooting of leafy stem cuttings using low-cost technology polythene propagators. 850 Using single-mode leafy cuttings, three experiments were investigated in Cameroon, the first with three propagation media (sawdust, 50:50 mixtures of sand and sawdust, and sand alone). Initial observation showed that rooting was best in the mixed medium, but subsequently, cuttings set in the sawdust rooted better than those in sand and the mixture of sand/sawdust. However, there was no significant (p > 0:05) treatment effect on rooting percentage or on the mean number of roots per cutting. Second, three types of auxin at 50 mg per cutting (IAA, indole-3-acetic acid; IBA, indole-3-butyric acid; and NAA, 1-naphthalene acetic acid) were dissolved in 10 ml of alcohol. The control treatment received 10 ml of alcohol only. Significant differences in rooting percentage occurred after 3–4 weeks between the auxin-treated cuttings and the control. Within the same period, IBA-treated cuttings rooted better than those with NAA and IBA. The third experiment involved four leaf areas: 0, 50, 100, and 200 cm 2 . Leafy cuttings rooted better than leafless cuttings after 4–5 weeks, with the 50-cm 2 leaf area the best from week 6. Significantly higher cutting mortality (p < 0:05) occurred for leafless cuttings than for leafy cuttings. 850

Phaseolus Vulgaris

Botanical Name — Phaseolus vulgaris L.

Synonyms — P. communis Pritzel., P. compessus DC.

Family — Leguminosae

Common Names — Bean, kidney bean, navy bean, French bean, haricot (Fr.)

African Names — Arabic: fasolia; Hausa: wake; Igbo: akidi, okwe; Swahili: haragwe, haragi; Yoruba: awuje

Description — It is a twining annual herb, erect or recumbent, with short stems, climbing up a length of 5 m. The leaves are trifoliate, opposite, oval pinnate, and acuminate. It produces whitish flowers with yellow or purple spots. The pods are narrow with a beak at the end and contain seeds of various colors.

Habitat and Distribution — It is a cultivated crop grown in most parts of the world. It does not grow well in an atmosphere with high humidity and in lowland areas, where it is frequently attacked by pests.

Ethnomedicinal Uses — The leaves of the plant are used in the preparations of lotions for external use in the treatment of a variety of skin conditions; a paste made with the crushed bean cake has been applied to cutaneous leishmanial lesions. The bean is eaten as a nutrient during convalescence. Duke 378 listed the plant as used as a carminative, depurative, acne application, digestive, diuretic, emmenagogue, febrifuge, and cardiotonic, among several other uses.

Constituents — The beans are rich in protein and are recognized as a cheap source of proteins. They also contain starch, cyanogenetic glycoside, and a hemaglutin, phaseolitin. The leaves, pods, and beans yield several vitamins and minerals, and enormous variation exists in the ratio of these nutrients in plants from different parts of the world and among different hybrids. The fresh beans have been found to contain estrone, estriol, and 17α-estradiol. 851

Pharmacological Studies — Phaseolin isolated from the beans has fungicidal activity. 227 Aqueous extracts depress the isolated intestine of the rabbit and guinea pig. 852

Toxicity — The plant contains up to 0.008% toxic HCN and the tumor-enhancing phytoglutinin; both constituents are, however, destroyed during cooking. The seeds also contain trypsin and chymotrypsin inhibitors. 378

Physostigma Venenosum

Botanical Name — Physostigma venenosum Balfour

Synonym — Physostigma venonum Balf.

Family — Leguminosae

Common Names — Calabar bean, African ordeal bean, fève de Calabar (F)

African Names — Arabic: shagar lubiyar kalabar; Efik: esere: Igbo: akpi; Yoruba: iso

Description — The plant is a subligneous creeper with smooth climbing stalks, with twining branches climbing to a great height. The leaves are trifoliate, 6 × 10 cm. The pink or purple flowers are borne in axillary racemes. The pods are up to 15 cm long, oblong in shape, and contain a few ellipsoid seeds 3 cm long. The seeds are dark brown in color, extremely hard, and testa smooth in the neighborhood of the grooved hilium, which runs the whole length of the convex side and around one end; where somewhat wrinkled, on the other side of the groove is a well-marked ridge; in the groove are the grayish, papery remains of the funiculus. 9,28

Habitat and Distribution — It is found in the dense rainforest areas of the continent and distributed from Senegal to Zaire.

Ethnomedicinal Uses — The drug is used with other herbs by the Barkwiris in the local treatment of articular rheumatism. An extract of the seeds or a mixture of the seed in palm oil is used for eradicating lice and bugs. In the Ivory Coast, a weak decoction of the seeds is used for edemas.

Constituents — The seeds contain the alkaloids physostigmine (eserine), eseridine, eseramine, physovenine, phytosterol, and starch. They also yield an albumin.

Pharmacological Studies — Physostigmine is used in the treatment of glaucoma as an eye-drop. The compound is a powerful and reversible acetylcholine esterase inhibitor and therefore allows acetylcholine to exert maximal effect on the smooth muscles, glands, and heart. It therefore effectively increases the concentration of acetylcholine at the sites of cholinergic transmission. It exerts its cholinesterase inhibitor effect in both the periphery and CNS. It dilates the blood vessels and has a slowing effect on the heart. It has been found useful as an antidote for toxicity due to strychnine, nicotine, curare, and atropine and as an adjunct in medication for myasthenia gravis. It was formerly used in clinical medicine as a postoperative medication after abdominal surgery to prevent adhesion by stimulation peristalsis.

In modern experimental medicine, physostigmine remains a safe and quite unique agent wherever increase of acetylcholine in the brain is necessary, examples being intoxications with anticholinergic drugs, recovery from anesthesia, and in psychiatry. Physostigmine is being investigated not only for its role in alleviating symptoms of Alzheimer’s disease, but also for its capacity to counteract opiate-induced respiratory depression without abolishing analgesia. 853 Eseroline, the first metabolite of physostigmine, is being investigated for its opioid-like and cholinesterase-inhibiting properties. There is a possible application of physostigmine into spinal liquor for its beneficial effects. 857

Toxicity — Calabar bean has been used in the southeastern region of Nigeria, from where it derived its name, as a ritual plant and ordeal poison. In ancient times, suspected criminals, witches, and people accused of breaking one of the taboos were often forced to drink from a decoction made from the esere seeds. If the accused vomited the poison and lived, the accused was declared innocent, but if guilty, then the verdict of the gods was accepted and the victim was buried without any normal funeral rites. It has a sedative action on the spinal cord, which results in paralysis of the lower limbs and death by asphyxia and, in large doses, concomitant paralysis of the heart. The ordeal trial rationalized that an innocent person was likely to be brave and swallow the decoction in a gulp, which would irritate the stomach and cause vomiting of the drug; the guilty person will be frightened by guilt and would likely drink the poison slowly, with the attendant gastrointestinal absorption and then toxicity. It appears that the elders of the village were aware of the nature of this poison since it featured prominently among the secrets passed on to the initiates of the highly esteemed Ekpe cult and in some male puberty ceremonies. When used as a form of capital punishment or suicide, the whole seed was to be chewed, or the drug could be powdered and administered as an enema. The villagers also understood that burning or boiling of the seeds greatly reduced, if not eliminated, the toxicity.

Picralima Nitida

 

Botanical Name — Picralima nitida (Stapf) Th. & Dur.

Synonyms — P. klaineana Pierre, P. macrocarpa Chev., Tabanaemontana nitida Stapf.

Family — Apocynaceae

Common Name — Akuamma seeds

African Names — Ashanti (Twi): ekuama; Igbo: osi, osu-igwe; Idoma: otosi; Yoruba: erin

Description — The plant is 12–30 m in height and about 0.6–1 m in girth. It has a grayish bark; the slash is yellowish with dark flecks and fibrous, yielding rather scanty latex with other blackish branchlets. The leaves are oblong-lanceolate to broadly oblong-elliptic, shortly acuminate, with the blade rounded to slightly cunneate. They are dark green, leathery, and glossy glabrous. There are numerous parallel nerves, rather faint, with thinner veins between. It produces white flowers, up to 5 cm wide, borne in terminal inflorescence. The entire inflorescence is glabrous; the calyx is about 2.5 cm long, broadly cup shaped at the base with 5 overlapped triangular-ovate lobes. The corolla tube is slender, about 2.5 cm long, showing 5 elliptic corolla lobes. 854 The fruits occur usually in pairs, hanging at the end of a long stalk. They are broadly ovoid, smooth, glabrous, and leaf green in color, turning to yellow or orange when ripe. They vary enormously in size, up to 15 cm long and 10 cm wide and contain numerous seeds (5–10 cm wide) embedded in a pulp. All parts of the plant are very bitter. 7,9

Habitat and Distribution — Picralima occurs in deciduous forests and is widely distributed in tropical Africa, although sparse. It has been located in Ghana, Ivory Coast, Angola, Nigeria, Zaire, Cameroon, and Tanzania.

Ethnomedicinal Uses — Extracts of the leaves, seeds, or stem bark are used in the preparation of various fever and malaria remedies. In Central Africa, it is used for the treatment of primary hypertension, malaria, and jaundice. 855 The crushed seeds are eaten for stomachache and pneumonia. Extracts of the stem bark and seeds are administered for venereal diseases and as a vermifuge. In herbal markets in Ghana, Nigeria, and Ivory Coast, Akuamma seeds, the stem bark, and dried fruit rind are highly prized as antimalarial agents and a remedy for sleeping sickness. The seeds are used in the preparation of a treatment for insanity and related CNS diseases. The root decoction is dispensed as a cure for yellow fever.

Constituents — The plant elaborates a complex mixture of indole and dihyroindole alkaloids, including alstonine, akuammiline, akuammidine, akuammine, Ψ-akuammigine, akuammicine, echitamine, picraline, picratidine, and picraphylline. 856

Pharmacological Studies — Extracts of the plant have been shown to possess local anesthetic, opiate receptor, antihypertensive, and sympatholytic properties. The plant contains several indole alkaloids, of which the major ones include akuammidine, akuammine, and Ψ-akuammigine. The leaves elaborate picraphylline and picraline, among several other indole bases. Akuammidine has a sympatholytic action and a hypotensive effect, which was reported to be weaker than that of yohimbine. 857 The compound also showed strong local anesthetic action, which was found to be three times that of cocaine hydrochloride. 858,859 The aqueous decoction of the bark has been shown to be active against Trypanosoma brucei. 860

The major alkaloids of the fruits of P. nitida have been examined for in vitro activity against drug-resistant and -sensitive strains of Plasmodium falciparum. The alkaloids showed remarkable inhibitory activity against both clones of P. falciparum at IC50 values of 0.08–0.9 μg/ml. Among the compounds tested, those belonging to the picraline-akuammine subgroup showed greatest activity, followed by those of the akuammicine type. The alkaloid echitamine was inactive. 861 The alkaloids also demonstrated strong inhibitory activity against clinical isolates of Leishmania and trypanosomes.

Although the mechanism of action of Picralima is yet to be determined, the drug is presently used as a crude extract in traditional African medicine as an antimalarial and for the control of blood pressure. Alstonine, found in the seeds and fruit rind, has shown antipsychotic-like effects, a putative antipsychotic, which consistently differed from the effects of known drugs in various mouse models. 862,863 Treatment with alstonine was able to prevent MK801-induced working memory deficit, indicating its potential benefit for cognitive deficits now seen as a core symptom in the disease. Corroborating previously reported data, alstonine was also effective in counteracting MK801-induced hyperlocomotion and social interaction deficit. Ritanserin, a 5-HT2A/C receptor antagonist, prevented alstonine’s effects on these three behavioral parameters. Available evidence suggests that 5-HT2A/C receptors are central to the antipsychotic-like effects of alstonine, consistently seen in mouse models relevant to the three dimensions of schizophrenia symptoms. 864

Piper Guineense

 

Botanical Name — Piper guineense Schum. et Thonn.

Common Names — Bush pepper, West African black pepper, Ashanti pepper, Guinea pepper

Family — Piperaceae

African Names — Anang: okurusa; Arab (Shuwa): shitta masoro; Ashanti: soro-wisa; Bambara: niamaku; Bakwari (Bota): indoko; Bakundu (Balondo, Batanga): ndonga; Diola: funkungen; Efik: eti-nkeni; Ewe: kale, asonsa; Fanti: sasima; Fulani: chitta masoro; Hausa: masoro; Igbo: uziza; Kanuri: ngolo imassoro; Malinke: fefe; Mano: za wele; Mende: komasimi, neni; Twi: sesaa, asonsa; Yoruba: iyere, ata iyere

Description — Piper guineense is a slender climber, up to 12 m high, with prominent nodes and clasping roots. The leaves are elliptical in shape, about 15 cm long and 7 cm broad. They are pointed at the apex and rounded and up to 5-nerved at the base. The leaves when crushed have a pleasant aroma. The flowers are small, borne on common stalks as clusters opposite the leaves or at the terminals of the stem and branches. The fruits occur as racemes and are red or red-brown and turn black when dry.

Habitat and Distribution — Piper guineense is found in high forest area; it occupies forest clearings and clings on remaining trees in secondary forests. It is widely distributed.

Ethnomedicinal Uses — The black berries are used as spice to flavor soup. The oil distilled from them is used for perfumery and soap making. The leaves are used to regulate the menstrual cycle and as an ingredient in remedies for female infertility. The weak decoction of the leaves and fresh fruits is used as a cough remedy. The seeds are stomachic and carminative and are indicated especially for gripping stomachaches. 9 The plant is a reputed antibacterial agent, and the roots and fruits are incorporated in preparations for the treatment of infectious diseases. The roots are listed for gonorrhea, bronchitis, syphilis, and colds; the leaves are applied to wounds; and the seeds are dispensed for bronchial infections. The pulverized seeds are used as an insecticide, and the whole fruit is extracted and employed externally as a stimulating ointment or as a counterirritant.

Constituents — Several lignans have been reported from the plant, including aschantine and yangambine. 78 The roots yield piperine, trichostachine, and lignans, and the leaves contain the lignin dihydrocubebin. 865 The essential oil obtained from the berries has been shown to consist mainly of phellandrene, pinene, and limonene. 866,867 A phytochemical analysis of the fruits led to the isolation of several amide piperines, including sylvatine, N-isobutyloctadeca-trans-4-dienamide, Δα,β-dihydropiperlonguminine, Δα,β-dihydropiperine, and trichostachine. 868,869 The plant also contains the pyrrolidine amide wisanidine, pipreidine amides, dihydrowisanine, 870 dihydropiperine, 874 wisanine, 871,872 and N-formyl piperine. 873

Pharmacological Studies — The amides have been shown to possess antimicrobial, anticonvulsant, antihypertensive, sedative, tranquilizing, and insecticidal properties. 874 P. guineense seeds exhibit activity against sickle-cell disorder. The effects have been attributed to the presence of piperine, capsaicin, cubebin, and caryophyllene or closely related compounds in the plant. 874

Toxicity — High doses of the drug have been reported to cause convulsions and hematuria. 875

Poga Oleosa

Botanical Name — Poga oleosa Pierre

Family — Rhizophoraceae

Common Names — Inoi nut, African Brazil nut

African Names — Boki: onyo; Bule: angale; Duala (and Mungo): pobo, povo; Igbo: imono; Efik: inoi; Yoruba: iku

Description — Poga oleosa is a dominant tree up to 33 m high, with a straight and cylindrical stem and occasionally with buttress roots. The bark is gray and fairly smooth, with a thick, brownish, and granular slash. The branchlets are purplish and rough. The leaves are 9–15 cm long and 5–7 cm broad, leathery, smooth, and glossy, with a slight offset tip. The flowers are very small, without stalks, and borne on common stalks on leafless shots. There are 4 sepals and 4 petals; each petal has a saw-edged tip. The stamens are 8 and the styles 4. The fruits are roughly spherical and elongated, 5–6.5 cm long and about 5 cm broad. A rind surrounds a very hard shell, which contains 2–4 seeds. 77

Ethnomedicinal Uses — The kernels are edible and contain proteins and carbohydrates; hence, they are ground and used for cooking and as an emollient. 77 The oil is used with Dorstenia multiradiata as a treatment for psoriasis.

Portulaca Oleracea

 

Botanical Name — Portulaca oleracea Linn.

Synonyms — P. quadrifida Linn.

Common Names — Pursley, pusley, wild purslane, pigweed

Family — Portulacaceae

African Names — Ashanti: adwere; Bambara: missidi kumbare; Efik: efere-makara; Ewe: afiaa, devio-fe ‘ama; Hausa: baba jibji, halshen saniya; Mano: toa p’lo; Malinke: mazahi; Mende: tooge; Wolof: tanguipeta; Xhosa: igwanitsha; Yoruba: papas an; Zulu: amalenyane

Description — Portulaca oleracea is a diffusely branched, prostrate, succulent, short-lived annual herb with bright yellow flowers. The leaves are very fleshy, oval shaped, about 4 cm long and 2 cm broad. They are narrower toward the base and rounded at the apex.

Habitat and Distribution — It is a very common weed found in both cultivated and undisturbed land and is distributed in most parts of the continent.

Ethnomedicinal Uses — An infusion of the plant is used as an anthelmintic for children to expel roundworms and in high doses as an emetic. The crushed plant is applied locally on swellings, bruises, and whitlow to ease pains and cause healing. 77 The pressed juice is instilled in the ears for earache and also applied with cotton lint to carious teeth. The leaf infusion has been reported as a cooling drink, with a mild diuretic effect, and is used as a vegetable for its antiscorbutic properties. The seeds are demulcent, diuretic, and slightly astringent. 136 The plant has been attributed with insecticidal properties. 136

Constituents — Oxalates and noradrenalin have been isolated from the plant. 876 The plant also contains saponins.

Pharmacological Studies — The extract has been shown to possess antidiabetic 877 and muscle relaxant 878 activities. The muscle relaxant effects have been found to be similar to the activity of D-600 and dantrolene when tested against rat hemidiaphragm and frog rectus abdominus, and the mechanism of action has been suggested as probably due to inhibition of transmembrane Ca2+ influx, interference with the Ca-induced and Ca+ release process, or inhibition of the release of intracellular Ca+ from stores in the sarcoplasmic reticulum. 879 Extract of the plant has also produced dose-dependent negative inotropic and chronotropic effects and a pressor response in the rat. 880 It has been argued that the extract may act in part on postsynaptic α-adrenoceptors and by interference with transmembrane calcium influx. 881

A related species, P. grandifolia, has been shown to possess significant anti-HBsAg as determined using the ELISA technique. 881 The water extract of the same species has been found to be antimutagenic. 882

Prunus Africana

 

Botanical Name — Prunus africana (Hook. f.) Kalkman

Synonyms — Pygeum africanum Hook. f.; Pygeum crassifolium Hauman

Family — Rosaceae

Common Names — African stinkwood, African prune, African cherry, bitter almond, iron wood, pygeum, red stinkwood

African Names — Bamileke (Cameroon): alumty; Banso (Cameroon): kirah; Kom (Cameroon): lluo; Oku (Cameroon): vla; Bakweri: wotangue; Kenya: muiri, mueri; Afrikaans: rooistinkhout; Amharic: tikur inchet; Luganda: ngwabuzito, ntasesa; Tanzania: mkomohoyo; Tanzania: mseneo; Uganda: ntasesa; Ganda: entasesa, ngwabuzito; Xhosa: umkakase; Zulu: inyazangoma-elimnyama

Description — Prunus africana is an evergreen tree that is native to the montane regions of sub-Saharan Africa and the Islands of Madagascar, Sao Tome, Fernando Po, and Grande Comore at about 900–3400 m of altitude. The mature tree is up to 25 m high, rarely a shrub 3–5 m tall, or a medium-size tree about 10 m tall; it is much-branched and often pendulous in forest and shorter and with a round crown 10–20 m in diameter in grassland. It requires a moist climate, 900–3400 mm annual rainfall, and is moderately frost tolerant. The bark is dark brown to gray and rugged. Leaves are petiolate; lamina are 4 6–11(15) × 2–4(5·5) cm, elliptic, lanceolate-elliptic, or oblong-lanceolate and glabrous, coriaceous, or subcoriaceous; the apex is obtuse to subacuminate; the base is broadly cuneate to rarely rounded; margins are coarsely crenate-serrate to subentire with dark glandular dots in the incisions (the most proximal gland on one or both margins of the leaf sometimes is conspicuous); the petiole is 1–2 cm long, channeled, and often reddish; stipules are ± linear, 15–20 cm long, and caduceus.

Habitat and Distribution — Prunus africana is a Pan-African montane tree species. It is listed as an endangered species by CITES, but experts believe that the species is not remotely in danger of extinction as long as some montane forest survives somewhere within its enormous range. 1140 It occurs in Cameroon, Congo, Ethiopia, Ghana, Kenya, Madagascar, Malawi, Tanzania, South Africa, Zimbabwe, and other montane zones of the continent. It is commercially collected mainly from Cameroon and Madagascar.

Ethnomedicinal Uses — Pygeum is used in traditional medicine in West and Central Africa for malaria, wound dressing, appetite stimulation, gonorrhea, insanity arrow poison, stomach pain, and kidney disease and as a purgative. The plant came into prominence in the 1990s as an herbal remedy for the treatment of benign prostatic hyperplasia (BPH).

Constituents — The major compounds isolated from Prunus bark include fatty acids (C22– C24), alkanes, alkanols and phytosterols, lauric acid, myristic acid, n-tetracosanol, n-docosanol, ferulic acid, β-sitostenone, β-sitosterol, and ursolic acid. The relative concentration of these compounds in several Prunus bark samples have been used to show an independent evolution of bark metabolism within different phylogeographical lineages, and that the molecular phylogeographic pattern is partly reflected in the variation in concentration of bark constituents. This finding may have important implications for the design of strategies for the sustainable use and conservation of this important African tree species. 883

Pharmacological Studies — Extracts of the African prune tree have been shown by many studies to be effective in the treatment of lower urinary tract symptoms (LUTSs) associated with BPH and obstructed bladder. In anti-inflammatory evaluation, it inhibits production of 5-LOX metabolites in vitro 884 and the fibroblast growth tumor (FGF)- and epidural growth tumor (EGF)-induced proliferation of 3T3 fibroblasts. 885 Two recent clinical trials using P. africanum revealed an approximately 40% reduction in the International Prostate Symptom Score (IPSS) and improvement in the urinary flow rates of approximately 18% over baseline. 886,887 Based on a meta-analysis of 18 clinical trials, Ishani et al. demonstrated that men receiving P. africanum were more than twice as likely to be rated with symptom improvement by their physician compared with men receiving placebo (65% vs. 30%, relative risk [RR] = 2.1). 888

Toxicity — Prunus extracts seem well tolerated in both acute and chronic toxicity studies, at doses of up to 8 mg/kg for the acute single dose in rats and mice, and administration for up to 6 months in rats and mice. 889 Gathumbi et al., however, reported some adverse biochemical and hematological changes in rats given 3.3 mg/kg for 6 days. 1141

Commerce — Prunus is a major article of commerce from Cameroon and Madagascar to Europe and the United States. An attempt by the Plantecam Company to add value to the raw material by establishing a process plant at Mutegene in Cameroon was not sustained. The price of the raw material is US$9.56 kg CIF, and the dried extract sold in Europe is at US$175.84 per kg CIF.

Agriculture — The tree grows at a moderate rate and responds well to cultivation. The seeds cannot be stored; therefore, fresh seeds are used for cultivation. Moist leaves around the seed minimize moisture loss during temporary storage and transport. It is able to withstand severe bark removal to exhibit complete bark regrowth, but poor harvesting of bark may lead to tree death. Sustainable harvesting is done by collecting the bark only from quarters on opposite sides of trees, from about 35 cm above the ground level to the height of the first branch. In this way, it is believed that the bark can be harvested sustainably every 4–5 years. Bark removal induces early flowering. Mean bark yield per tree is 55 kg, ranging from 34 to 74 kg.

Psidium Guajav

 

Botanical Name — Psidium guajava L.

Synonyms — Guaiava pyrigormis Gaertn., Syzygium ellipticum K.Schum. & Lauterb.

Family — Myrtaceae

Common Names — Guava

African Names — Hausa: gwabaa; Efik: woba; Igbo: ugwoba; Yoruba: guafa

Description — It is a large shrub or small tree up to 10 m high. The stem is slender, usually not exceeding 30 cm in width; the bark is brownish, thin, smooth, and often flaking off in small patches. The leaves are oblong, slightly oval shaped, and oppositely arranged on the stem and branches, 5–10 cm long, rarely exceeding 15 cm in length. They are light green in the upper surface and downy and pale green in the lower side. They display prominent nerves in the leaf underside. The flowers are white and occur solitarily or as a few in a cluster in the axils of the leaves. They are about 2.5 cm in diameter, with numerous stamens that are arranged in groups. The fruits are globose or pyriform, yellow, usually 2.5–10 cm long and 2.5–5 cm in diameter, although horticulture varieties with larger fruits are common. They contain many seeds, and the calyx persists in fruit. 33

Habitat and Distribution — The plant is a native of Central America but is found all over Africa in semicultivation.

Ethnomedicinal Uses — The fruits are edible, and the juice is used as a refreshing drink. The major ethnotherapeutic use of the plant is in malaria; for this purpose, its leaves are used as an ingredient in the preparation of fever teas. The leaves are also used as part of the potherb in steam treatment of malaria. A weak infusion of the leaves and tender branches is dispensed for diarrhea and as a tonic in psychiatry.

Constituents — The fruits are rich in vitamins (A and C), iron, calcium, and phosphorus. 81 The essential oil from the leaves has been shown to contain caryophyllene, nerolidiol, β-bisabolene, and β-sitosterol and ursolic, oleanolic, crategolic, and guayavolic acids. 494 The plant also contains leukocyanidins, sterols, and gallic acid in the roots. 494

Pharmacological Studies — The aqueous alcohol extract has been shown to exhibit sedative activity. Oral doses of 188.5, 337, and 1131 mg/kg caused a significant dose-dependent decrease of the motor activity for 90 min after the administration of the extract. 494 In rats, the plant significantly decreased, in a dose-dependent manner, the intestinal transit time. It also showed in vitro antimicrobial activity against Escheria coli, Salmonella typhi, Staphylococcus aureus, Proteus mirabilis, and Shigella dysenteria. 890,891

P. guajava has been evaluated in many laboratory studies to validate its antispasmodic and antimicrobial properties in the treatment of diarrhea and dysentery. It has also been used extensively as a hypoglycemic agent. Literature is available on the ability of guava to exhibit antioxidant, hepato-protective, antiallergic, antimicrobial, antigenotoxic, antiplasmodial, cytotoxic, antispasmodic, cardioactive, anticough, antidiabetic, anti-inflamatory, and antinociceptive activities, which provided scientific rationale for its traditional uses.

Apart from its antihyperglycemic properties, guava may be beneficial for preventing cardiovascular complications associated with diabetes. It has been established that nonenzymatic glycosylation (glycation) between reducing sugar and protein results in the formation of advanced glycation end products (AGEs), which are believed to play an important role in diabetes-associated cardiovascular complications. Thus, agents that inhibit the formation of AGEs are believed to have therapeutic potential against diabetic complications. The antiglycative potential of the ethyl acetate fraction of Psidium guajava has been evaluated by administering the extract to STZ-induced diabetic rats. Daily administration of the extract for a period of 1 month significantly decreased the blood glucose, glycated hemoglobin, and fructosamine levels in a dose-dependent manner. Evaluation of the toxicity markers like SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) revealed the nontoxic nature of the extract. The presence of the cardiac isoform of liver alpha 2 macroglobulin, which is a major protein associated with earlier stages of cardiac hypertrophy, was also evaluated. SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) analysis showed that the level of this protein decreased significantly in extract-treated groups compared to a diabetic control. 892

A wide range of clinical applications has been suggested for the treatment of oxidative stress, infantile rotaviral enteritis, diarrhea, and diabetes. 893 The dried leaves and extracts of the fruits have been formulated as dietary supplements.

Punica Granatum

Botanical Name — Punica granatum L.

Synonym — P. nana L.

Family — Lythraceae

Common Names — Pomegranate tree, grenadier (French)

African Names — Arabic: roumamman-goulnar, rumman, rummani, ximani; Chagga: ngukumaanga; Mpondo: mbona wesilungu; Swahili: mkoma manga

Description — Pomegranate is one of the oldest drugs known. It was mentioned in the Papyrus Ebers of Egypt written in about 1150 BC and was also included in many Ayurvedic texts. Pomegranate of commerce consists of the stem and root of Punica granatum containing at least 0.4% and sometimes 1% of alkaloids, of which the anthelmintic pelletierine tannate is the most important. It is a shrub, which often reaches a height of 2.5 cm, with quadrangular and somewhat thorny stalks. The leaves are lanceolate, 4 to 6 cm. It bears red, solitary flowers 4 cm long. The fruits are spherical and 10 cm in diameter and contain numerous reddish fleshy seeds. The plant is cited in the first edition (Vol. 1) of the African Pharmacopoeia. 436

Ethnomedicinal Uses — The plant has limited use in traditional medicine but is acclaimed as a potent anthelmintic. The plant is an ingredient in the remedy for dysentery and chronic diarrhea. The fruit rind is used in postpartum medication.

Constituents — The most important compound found in the plant used to be the anthelmintic alkaloid pelletierine, which has been isolated from the root, stem bark, and unripe but mature fruits. Other alkaloids found in pomegranate include isopelletierine, pseudopelletierine, and methylisopelletierine. The ellagitannins punicalin, punicalagin, punigluconin, and punicacorteins A, B, C, and D and casuarin are also found in the plant. 894 The rind of pomegranate, which was once used as food flavor and sometimes added as an adulterant to the drug, does not contain the anthelmintic alkaloids but yields gallotannic acid and other phenolic compounds. The presence of phenolic compounds, such as anthocyanin, 895 in the leaves and fruits is considered of immense therapeutic importance. An analysis of P. granatum juice with high-performance liquid chromatography with diode array detection and tandem mass spectrometry analysis with positive and negative electrospray ionization (HPLC-DAD-ESI+/−/MS n ) powered by an ion trap yielded a total of 151 phenolics, consisting of 65 anthocyanin, anthocyanin–flavanol, and flavanol–anthocyanin adducts, including some unusual cyanidin and pelargonidin trihexosides not previously described in natural extracts. Similarly, a total of 86 nonanthocyanin phenolic components were also identified, 39 of them reported for the first time in this juice. 896

Pharmacological Studies — Pelleterine, the active constituent, possesses a specific action on tapeworms but is ineffective against other intestinal parasites. 205 The alkaloids of pomegranate act by causing the tapeworm to relax its grip on the intestinal walls, thereby making it possible to be expelled by cathartics. Pomegranate and its alkaloids are not favored as an anthelminthic due to their toxic effects, muscle cramps, and dizziness. 123 The extract of the flowers and the rind has been shown to possess significant inhibitory activity against many bacteria 897 and some fungi. 898

The modern use of Punica granatum is not because of its anthelmintic principles but its antioxidant activity. Differential solvent extracts of Punica granatum leaves (hexane, dichloromethane, ethyl acetate, ethanol, and methanol) have been evaluated for antioxidant, anti-inflammatory, anticholinesterase, and cytotoxic activities. TPC (8.8–127.3 mg gallic acid equivalent/g dry weight), flavonoids (1.2–76.9 mg quercetin equivalent/g dry weight), tannins (63.7–260.8 mg catechin equivalent/kg dry weight), and anthocyanins (0.41–3.73 mg cyanidin-3-glucoside equivalent/g dry weight) of different extracts were evaluated. The methanolic extract presented a good IC50 by DPPH and ABTS assays (5.62 and 1.31 mg/l, respectively). The strongest 5-LOX, acetylcholinesterase, and butyrylcholinesterase inhibition activities were obtained for the ethanol extract (IC50 values of 6.20, 14.83, and 2.65 mg/l, respectively), and the best cytotoxic activity against MCF-7 cells was obtained for the methanol extract (IC50 = 31 mg/l). Although it is the fruits and juice of P. granatum that are used as pharmaceutical antioxidants, the leaves could be a potential source of the active molecules intended for applications in the pharmaceutical industry. 899

Pycnanthus Angolensis

 

Botanical Name — Pycnanthus angolensis Welw.

Synonym — P. combo Warb.

Family — Myristicaceae

Common Names — False nutmeg tree, African nutmeg, wild nutmeg

African Names — Abe: walele; Bakwari (Duala, Bosamba, Nasamba, Bakoosi): ngosame; Basa: dihin; Bini: moghan; Efik: abakang; Ibibio: abakang; Fanti: edua; Igbo: egwu-noma, egiri oma; Mende: gboyei; Nupe: kpokogi; Nzima: tika; Timme: pompon; Yoruba: akomu

Description — Pycnanthus angolensis is a tall tree, up to 33 m high and about 3 m in girth. The bole is long and straight, cylindrical and without buttress roots. The bark is reddish gray, scaly, and fissured lengthwise. In old trees, the bark flakes off in patches. The slash is reddish and exudes a sticky, honey-colored latex that turns red later. The branches are in two whorls; the twigs and leaves are covered with rust-colored, woolly hairs. The leaves are leathery in texture, with a smooth upper surface; the lower surface is covered with rust-colored hairs, which disappear with age; they are generally riddled with holes caused by insects and are simple, 15–21 cm long and 5–9 cm broad, with nearly parallel margins. They have a short apex and short and heart-shaped base. The midrib is very prominent on the lower surface. The stalk is thick and about 1.5 cm long. The flowers are small, brownish red, in small crowded heads, falling in masses around the base of the tree; male and female are borne at different times; there are irregularly branched common stalks, which may be as long as 7–15 cm. The flower stalks are among the leaves or slightly below them. The fruits are egg shaped or almost round, 2–3 cm long and 1.5–2 cm in diameter. The shells are rather hard and split longitudinally into two valves, exposing solitary seeds with bright red arils, which turn brownish with time. 77

Habitat and Distribution — Pycnanthus angolensis is a lowland rainforest tree common in secondary forests. It is distributed throughout the West Coast, Chad, Ethiopia, and parts of Somalia, Zambia, and Zaire.

Ethnomedicinal Uses — The seeds are aromatic and are used as a soup condiment in many parts of Africa. The seed fat is applied together with the reddish latex on skin diseases. The bark is pounded and drunk with palm wine for loss of appetite. The twigs are sucked to cure sores in the mouth. 77 The root infusion is used with extracts of Cassia occidentalis and guinea grains as an anthelmintic. 9 In Nigeria, the seeds are used for the preparation of mouthwash for the treatment of thrush.

Quassia Africana

Botanical Name — Quassia africana (Baill.) Baill.

Synonym — Simaba africana Baill.

Family — Simaroubaceae

African Names — Calensi: ogama; Pahoin: olon; Iokundu: bolome; Mayumbe: bundi tse, voanda, kadi; Equateur: Yella atomba; Kitalela: okenzu; Yagambi: weko

Description — Quassia africana is a small tree about 3 m high with grayish-green bark and glabrous branches. It bears compound alternate leaves, composed of 2–7 leaflets, a petiole 3–16 cm long, rachis 0–15 cm long, and more or less narrowly constricted at the insertion of the leaflets. The leaflets are opposite, sessile, and lamina obovate or oblong acuminate to obtuse at the apex, coriaceous to papyraceous, with median nerves prominent above and below, and up to 10 pairs of lateral nerves, regularly anastomose. Terminal leaflets are slightly larger than the lateral leaflets. The flowers are borne throughout the year as hermaphrodites, solitary or in fascicles, slender, glabrous, and 5-merous. 32

Habitat and Distribution — The plant occurs in the lowland rain forest of the transition zone from evergreen to semideciduous forest. It is found in southern Sudan, northern Nigeria, Cameroon, Rio Muni, Gabon, Congo, Zaire, and Angola.

Ethnomedicinal Uses — The main use of the species in most of the continent is for the treatment of gastrointestinal disturbances and as a vermifuge. The powdered root is used in the preparation of a remedy for bronchial pneumonia and venereal diseases and for wound dressing, as a febrifuge, and as an anti-inflammatory. An infusion of the leaves is used by the Teke for the treatment of dysmenorrhea.

Constituents — The species has been shown to contain the bitter terpenoid quasinoid lac-tones, nigakilactone A-J, picrasine B, quassin, 14-deoxy-15-(1′-methylbutyryl)-brucein, and neoquassin. 900

Pharmacological Studies — The genus has an established pharmaceutical use as a bitter tonic, 901 as a vermifuge for threadworms, and as a treatment for pediculosis. 205 Quassin is believed to possess insecticidal and amoebicidal properties. 902 Quassinoids from various Brucea species have been shown to have antileukemic 903 and antimalarial properties.

Quillaja Saponaria

Botanical Name — Quillaja saponaria Nolina

Synonyms — Quillaia saponaria Mol., Quillaja poeppigii Walp.

Family — Quillajaceae

Common Names — Soap bark tree, Panama wood, kilaya (Fr.)

African Names — Arabic (Shuwa): kilay

Description — Q. saponaria is a tall tree, growing to about 18 m high. The economically useful bark occurs in flat strips about 1 m long, 20 cm broad, and 3–10 mm thick. 436 The outer surface is yellowish white and smooth. It breaks with a splintery and laminate fracture. The back consists almost entirely of phloem with large crystals of calcium oxalate, which may be seen with the naked eye as glistening. The powdered drug produces an abundant froth when shaken with water and is strongly sternutory. Quillaia bark has a characteristic acrid and astringent taste. 28

Habitat and Distribution — It is a native of the mountainous terrains of Chile, Peru, and Bolivia but has been introduced into other parts of the world, including North African countries. The plant is rather restricted to a high-altitude savanna belt.

Ethnomedicinal Uses — The dried inner bark of Quillaja saponaria and other related species is used in pharmacy as an emulsifying agent. The plant is employed in folk medicine for the treatment of inflammation of the mucous membrane.

Constituents — The plant contains a mixture of saponins known as quillaja-saponin (ca. 10%). The saponins on hydrolysis yield quillaic acid (hydroxygypsogenin) and sugar derivatives. 904 It also contains tannins and calcium oxalate. 123

Pharmacological Studies — Quilla bark is employed in pharmacy as an emulsifying agent. It is also used as an expectorant, as an anti-inflammatory, and as a detergent. 220 The anti-inflammatory and antihypercholestrolemic properties of the saponins in animals have been reported. 904,905

The saponin mixture has been shown to possess immunostimulatory properties, and it is employed in veterinary medicine as an adjuvant for vaccines, particularly against foot-and-mouth disease. 906 The saponin was found to be a powerful adjuvant for the antibody response to strong antigens in the mouse, eliciting both IgG1 and IgG2 antibody and cell-mediated immunity, which may account for its success in experimental vaccines against parasitic protozoal diseases such as malaria, babesiosis, and trypanosomiasis.

The exact mechanism of the immunostimulatory activity of quilla saponins has not been determined. It has been suggested that the surface activity and surface-binding property of the saponins may be important factors in the observed immunostimulant activity. 907,908 The target cell in the immune system to which the saponin activity is directed is believed to be the macrophage or antigen-presenting cell (APC), which is stimulated to release IL-1. It has also been argued that quilla saponin cannot substitute for T-cell helper since the adjuvant activity of saponin for sheep red blood cells (SRBC) in the mouse is abolished by depletion of T lymphocytes. 909 It is likely that the saponins act by promoting the interaction between APCs and T cells; they are, however, considered adjuvant for T-independent antigen and therefore may be able to boost B-cell function directly. 910

Saponins have been shown to form ordered particulate structures of around 35-nm diameter (i.e., about the size of a virus particle) with the surface proteins from enveloped viruses. 911,912 These particulate structures, or immunostimulating complexes (ISCOMs) as they are called, are highly immunogenic and contain very little saponin, thus reducing the required dose for an adjuvant effect. ISCOM vaccines against a number of viruses have been prepared, and it is very possible that quilla saponin may be introduced soon into human medicine. The saponin exhibits immunostimulant activity even when given orally. 913

Rauwolfia Caffra

Botanical Name — Rauvolfia caffra Sond.

Synonyms — Rauvolfia natalensisi Sond., Rauvolfia inebrians K. Schem., Rauvolfia ochrosioides K. Schum., Rauwolfia foetzi Stapf., Rauvolfia obliquinervis Stapf.

Family — Apocynaceae

Common Name — Quinine tree

African Names — Kiswahili: mwembemwitu, mkufi; Kimeru (Kichaegga): msesewe, mseseve, Kisambaa: mweti; Kihehe: muveliveli; Kividuanda: mlolo; Kimassai: oljabokalyan; Kingu: mlengwelengwe; Kiarusha: njavolikalia oltawakalian; Kibende: mtawentwe; Kigogo: mkongo; Kirangi: msumai; Kikuyi: mwerere taveta; Meru: nutu; Bemba (Kaonde, Tonga): mwinbi; Kaonde (Lunda): mototo; Lunda: mutochi; Nyanja: muyesani, mpambamvula, msabua, mvumbamvula, mwimbe

Description — Rauvolfia caffra is a medium-size tree with straight bole; it is slightly buttressed, crown dense, and much branched. It has a light brown or gray bark with irregular fissures. The slash is cream, turning light brown, and exudes a bitter white latex. The leaves are simple, occurring in crowded whorls, 6–32 cm long, and oblanceolate to linear-oblanceolate; the apex is acute or subacuminate, with base cuneate; margins are entire. They are glabrous with a shiny green upper surface and paler below. The veins, about 18–20 pairs, form an irregular open network; the petiole is 0.5–5 cm long. The flowers are bisexual, occurring in much-branched whorl inflorescence; the peduncle is 2–6 cm long, and bracts are minute; flowers are bisexual, 5-merous; pedicels are 1 mm long. The calyx is cup shaped, 1 mm long, with a mouth filled with whitish hairs. The fruits occur as glossy green, subglobose to obovoid drupe, becoming wrinkled and blackish purple, 1–1.5 cm long, 2 cm in diameter if 12 seeded. 33

Habitat and Distribution — Rauwolfia caffra occurs in forests, especially lowland forests, swampy areas, and along rivers and streams in the savanna belt. It prefers loamy sands or sandy clay loam soils of mainly volcanic origin at altitudes between 500 and 2100 m, in areas receiving an annual rainfall between 500 and over 1270 mm. The plant is native to eastern and southern Africa and occurs in Zaire, Uganda, Kenya, Tanzania, Mozambique, Zambia, Malawi, Zimbabwe, and the Republic of South Africa. In the West Coast, the plant is found in Nigeria, Cameroon, and Ghana and can be differentiated from the more predominant R. vomitoria by its larger size, markedly oblanceolate leaves, and larger fruits.

Ethnomedicinal Uses — In East Africa, extracts of the roots are used for the treatment of fevers, insomnia, and palpitation of the heart. The bark has been reported as a remedy for general body swellings, rheumatism, and pneumonia. 478 The stem and root bark have also been dispensed as an ascaricide and the powdered unopened inflorescent as a local application to sores on the legs. 80 An FAO monograph listed other folk uses of the plant, including use as a purgative or an emetic and as a cure for coughs, stitch, and toothache. 33

Constituents — R. caffra yields idole and dihydroindole alkaloids similar to those found in other Rauwolfia species. The species, however, differs from R. vomitoria, R. cumminsii, and R. mombasiana in containing serpentine series of heteroyohimbine alkaloids found in the Asian R. serpentine, as well as the alstonine-type alkaloids found in the previously mentioned African species. The major alkaloids include reserpine, ajmaline, reserpiline, and sarpagine, as well as perakine, peraksine, and ajmaline. 913916

Pharmacological Studies — Rauwolfia alkaloids have been extensively investigated for biological activity, and the activities reported for R. vomitoria alkaloids also hold for this species.

Rauwolfia Vomitoria

 

Botanical Name — Rauvolfia vomitoria Afzel.

Synonyms — Rauwolfia vomitoria Afzel., Rauvolfia congolana De Wild. & T. Durand, Rauvolfia senegambiae A. DC., Rauvolfia pleiosiadica K. Schum., Rauvolfia stuhlmannii K. Schum., Hylacium owariense P. Beauv.

Family — Apocynaceae

Common Names — The swizzle stick, African rauwolfia

African Names — Anyi: baka egbe, ngbe ngbe; Ashanti (Twi, Wassaw): kakapenpen, penpen; Bini: akata; Efik: uto enyin; Igbo: akanta, ekpiri; Swahili: mesesewe; Yoruba: ira-igbo, asofeiyeje

Description — R. vomitoria is a small tree that sometimes grows up to 15 m in height. The genus can be characterized by the occurrence of phloem sclereids, nonarticulated lactiferous tubes, nonseptate fibers, and heterogeneous rays. The stem can be differentiated from the root by the presence of a well-defined central pit and unlignified fibers in the pericyclic region. The bark is gray with a pale brown slash exuding a bitter white latex, which changes slowly to rose color on exposure to air. It has simple, whorled leaves in groups of 4 or 5. The leaves are widely lanceolate and acuminate, with petioles 8–25 cm long and shadowy grooved above. The margins are entire; the base is cuneate, with a shiny green upper surface, and dull medium green below; the midrib is impressed above, and there are 8–16 pairs of major lateral veins. The flowers are borne in threes at the end of the ultimate branches and puberulus; the corolla is creamy white, up to 1 cm long; there are small lobes and 5 sepals, ovate. It bears red solitary or paired drupes, about 6 mm in diameter. It flowers January–June and fruits April–November. 9,28

Habitat and Distribution — It grows in moist lowland forest and well-watered tropical savannas. It is widespread in sub-Saharan Africa, occurring in Sierra Leone, Senegal, Ghana, Cameroon, Nigeria, Gabon, Zaire, Sudan, Tanzania, and Zimbabwe.

Ethnomedicinal Uses — The plant is a common ingredient in traditional medicine, with the dose and method of preparation critical for the various indications. It is boiled with fruits of Xylopia aethiopica to treat convulsions in children. A decoction of the leaves, prepared with leaves of Indigofera macrophylla and Cajanus cajan, and whole herb of Olyra latifolia is used as a remedy for smallpox. An infusion of the leaves is indicated for treatment of constipation and indigestion. The root and stem bark infusion is mixed with Capsicum annum and taken for malaria fever. In southern Nigeria, the root decoction is prepared with ash from palm husk for the treatment of aggressive maniac behavior.

Constituents — Rauwolfia contains more than 40 indole alkaloids, each possessing remarkable pharmacological activities. The alkaloids of Rauwolfia can be grouped into five main types: the yohimbine and its esters, including reserpine; the ajmaline type, which includes compounds with vasoactive properties; the ajmaline-sarpagine series with antiarrthmic dihydroindoles; the anhydronium bases, including the quick-acting hypotensive compound alstonine; and the oxyin-doles and pseudoindoxyls. 917,918 This species contains more reserpine and ajmaline than the Asian species R. serpentine. 919921

Pharmacological Studies — Rauwolfia alkaloids exert their antihypertensive effect by a combination of various biochemical mechanisms. One of the primary modes of action is the depletion of norepinephrine through inhibition of catecholamine storage in postganglionic adrenergic nerve endings. The hypotensive effect is often accompanied by a reduction in heart rate, contraction of the pupils, and stimulation of intestinal peristalsis. 10 Rauwolfia does not cause significant alteration in cardiac output or renal blood flow. The carotid sinus reflex is inhibited, but postural hypotension is rarely observed. 922 The cardiovascular and CNS effects may persist even after withdrawal of the drug.

The sedative and tranquilizing properties of Rauwolfia are believed to be related to depletion of amines in the CNS. It is this secondary activity that informs the use of Rauwolfia in the treatment of chronic anxiety states often associated with the incidence of hypertension. Other pharmacological properties are similar, but not identical, to those described under reserpine.

Clinical Properties — Rauwolfia is undoubtedly the most effective and the most widely used plant antihypertensive agent. The drug exerts its hypotensive effects slowly, but the effects persist for a few weeks. Rauwolfia therapy produces reduction of congestion of the head, vertigo, cardiac oppression, and general restlessness. 10 Although Rauwolfia is very effective in controlling most of the symptomatic manifestations of hypertension, adequate reduction in blood pressure is achieved in only about 40% of mild and 30% of medium-severe cases of hypertension. 10 The drug cannot compete with the more powerful ganglion-blocking agents (such as guanethidine and hexamethonium) in the treatment of severe and malignant hypertension. Rauwolfia is not suitable for such conditions and for cases requiring rapid lowering of the blood pressure.

The drug has been formulated with β-blockers, diuretics, or convallaria glycosides. In summary, the clinical indications of Rauwolfia are as follows:

  1. It is the drug of choice in medium-severe primary hypertension. The drug should be given over a prolonged period, usually up to 6 months and even 1 year.
  2. It is effective as an oral antihypertensive but has slow onset of action. The usual regimen is to begin therapy with small doses followed by a gradual dose increase until there is a reduction in blood pressure or the advent of undesirable side effects, which will necessitate lowering the dose.
  3. For hypertension therapy, it has the advantage of oral administration and is available in many bio-equivalent dosage forms.
  4. Rauwolfia is neither a cure for hypertension nor a prophylaxis for the progression of the disease. At a dose of 2–6 mg of the crude drug in divided doses, Rauwolfia ameliorates most of the subjective symptoms of hypertension.

The drug is available in the following forms:

  1. Powdered Rauwolfia serpentine (U.S. Pharmacopoeia; Indian Pharmacopoeia): This consists of R. serpentine roots reduced to fine or very fine powder and adjusted to contain 0.15% to 0.2% of reserpine-like alkaloids, calculated as reserpine.
  2. Rauwolfia dry extract (Indian Pharmacopoeia): The drug is prepared by percolation of roots of R. serpentine with 90% of alcohol and the percolate concentrated under reduced pressure (<60°C) to yield a soft extract. The product is adsorbed to starch and dried. It is standardized to contain 4% w/w of total Rauwolfia alkaloids; the usual dose is 15 to 16 mg.
  3. Rauwolfia liquid extract (Indian Pharmacopoeia): This is prepared by percolation as in item 2, but no starch is added, and it is not concentrated. The standardized extract contains 1% w/v of the total alkaloids; the dose is 0.2 to 0.5 ml.
  4. Alseroxylon: This is the feebly basic fraction of the alcoholic extract of Rauwolfia containing reserpine rescinnamine and deserpidine. The standardized drug contains at least 5 mg/ml of reserpine-like alkaloids.

Pharmacokinetics — When ingested, Rauwolfia is slow in onset of antihypertensive effects due to the time required (several days) to deplete existing stores of norepinephrine. One week or more may be required to realize the full antihypertensive effect of drug.

Toxicity — Rauwolfia alkaloids are known to cause mental depression, which may persist for several months after the drug has been withdrawn. The drug should be discontinued at the first sign of despondency, early morning insomnia, loss of appetite, impotence, or self-deprecation. Severe cases resulting in maniac depression or suicidal tendencies are extremely rare. The drug is contraindicated in patients with a past history of bronchial asthma or allergy, active peptic ulcer, ulcerative colitis, or pheochromocytoma and in patients receiving electroconvulsive therapy. The safety and efficacy of its use in pregnancy, lactation, and children have not been established. Chronic toxicity and interaction with other drugs are similar to reserpine.

Ricinus Communis

 

Botanical Name — Ricinus communis L.

Synonyms — Ricinus speciosus Burm., Ricinus viridis Willd.

Family — Euphorboraceae

Common Names — Castor oil plant, Palmer Christi (English), ricin (French)

African Names — Arabic: khirwa; Bambara: tomontigi; Hausa: zurma, kula kula, ‘dan kwasare; Igbo: ogiri, ogiri-ugbo; Swahili: mbono, nyonyo; Yoruba: lapa-lapa-adete, lara, ilara, ilarun

Description — It is a shrub up to 3 m high, branchy at the base. The leaves are alternate, dark green or red, on long leafstalks, and palmatilobate with 7 dentate glandular lobes. The male and female flowers are borne separately. The fruits occur as spiny capsules containing 3 arillated seeds. The African Pharmacopoeia described the seeds as rounded, oblong, and somewhat flattened surface from 8 to 12 mm long, 6 to 9 mm wide, and 4 to 8 mm thick. The seed coat, which is thin and brittle, is smooth and glossy, varying in color from grayish brown to gray, and mottled with reddish-brown or black spots and stripes. At one seed extremity there is a prominent and usually pale-colored caruncle, from which the raphe runs along the ventral surface as a distinct line to the other extremity, where it terminates in a raised chalaza. The caruncle can be removed easily, disclosing the hilum beneath as a dark spot. A delicate, silvery white, oily endosperm encloses the embryo with two large, papery cotyledons. 28

Habitat and Distribution — It is indigenous to the tropical regions of the continent and grows wild in East Africa but is now pantropic, cultivated for its oil-bearing seeds. The fermented powdered seeds are used by the Igbo people (Nigeria) as a soup flavor. It is best cultivated as an annual with fresh seeds planted every year.

Ethnomedicinal Uses — The leaf decoction is used as an emmenagogue and as a poultice applied to a lactating woman’s breast to increase milk flow. The crushed leaves are also used as a hot poultice for application to a guinea worm sore. The oil is used as a purgative but is used only in traditional veterinary practice as an excellent remedy for gripes in horses. 266

Constituents — The seeds contain about 50% fixed oil, which consists mainly of glycerides of ricinoleic, isoricinoleic, stearic, and dihydroxystearic acids. The cake left after expression of the oil contains a very poisonous toxalbumin called ricin, the crystalline alkaloid ricinine, a very active lipase, and other enzymes. The seeds also contain some peptides, starch, and mucilaginous substances.

Pharmacological Studies — Castor oil is an effective and safe purgative. The oil is used as a topical application in dermatosis and as a prophylactic in contact dermatitis allergens. Ricin has some antitumor and immune stimulatory properties, and segments of the compounds are being investigated in various laboratories for possible therapeutic application in immune diseases. Castor oil is an excellent vehicle for many pharmaceuticals.

Sabicea Calycina

Botanical Name — Sabicea calycina Benth.

Synonym — Sabicea barteri Wernham

Family — Rubiaceae

African Names — Ashanti: ananse, ananse ntoroma homa; Basa: gor-vah (S. lasiocalyx); Mende: namatei; Yoruba: jiri, ogan-aparo

Description — This is a twining or creeping shrub, up to 6.5 m, often rooting at nodes. The leaves are simple, oppositely arranged on the stem and elliptic-oblong, acuminate, with short, pointed apex, and rounded or heart-shaped base, 5–8 cm long, and 3–4 cm broad; the margins are entire, and the lower surface is thinly covered with soft, long hairs. The flowers are white, with about 12 borne on one head; the heads are on long, upright stalks, emerging from the nodes and enclosed by involucres of many greenish and pinkish leafy bracts. They are about 2.0 cm long, narrowly tubular, with 5 pointed lobes. The shrub produces blue-black berries. 77

Habitat and Distribution — This is found in deciduous and secondary forests, in stream beds and wetlands, and often as sand binder on a sea beach. It is distributed from Sierra Leone to the Congo, Angola, and Zambia.

Ethnomedicinal Uses — Sabiacea is used in southern Nigeria as a laxative and is drunk in palm wine. The ground leaves are applied to the limbs of small children to strengthen their bones and help them walk. The crushed leaves are also applied to cuts and wounds. An infusion of the leaves is believed to be good for memory. A member of the genus, probably S. africana, is used for the treatment of senile dementia. It is an ingredient in the Yoruba agbo medicine.

Salvadora Persica

 

Botanical Name — Salvadora persica Linn.

Synonyms — Embellia grossularia Retz., Galenia asiatica Burm.f.

Family — Salvadoraceae

Common Names — Toothbrush tree, Siwak, Miswak

African Names — Arabic: shiwak; Masai: o, remit; Swahili: msuake, mswaki, musuake

Description — Salvadora persica is a small tree, usually with crooked stem and drooping branches. The leaves are elliptic lanceolate, obtuse, cuneate, or with a rounded base. Flowers are greenish yellow, borne in axillary and terminal lax, clustered toward the tip of the branches, with panicles 5–12 cm long; the corolla is twice as long as the calyx. It produces one-seeded, globose drupes, 3 mm in diameter and red when ripe. 166 It has been observed that the large amount of intraaxillary phloem and the widely spaced, thick-walled fibers in the pericycle of the root allow the spongy wood to be easily crushed by the teeth and softened, if dry, with water. 227 The fiber-like quality of the wood is also aided by the numerous thick-walled vessels and fibers found in the xylem.

Habitat and Distribution — The plant grows in secondary forests and semisavanna. It is found in North Africa and parts of East and Central Africa.

Ethnomedicinal Uses — Salvadora persica has been known as the toothbrush tree for several centuries. 923 It is used widely in Africa, Arabia, and parts of India for cleaning the teeth. Salvadora was mentioned in the Arabian ancient script the Muwashsha (AD 900) as a chewing stick or shiwak. The root bark is considered a remedy for ancyclostomiasis by the Nyamwezi. The Massai employ the paste of the powdered root in a decoction for venereal diseases and for catarrh. In East and Central Africa, the plant is used for oral hygiene and as an ascarifuge.

Constituents — The plant is rich in chlorine, resin, and trimethylamine and has a high ash value of 27.06%. It also contains sulfur, silica, tannins, saponins, and vitamin C. 924 The oil cake from the seeds contains nitrogen (4.8%), potash (2.8%), and phosphoric anhydride (1.05%). 170 One of the major constituents of siwak is benzyl isothiocyanate (BITC), isolated from the roots. 924

Pharmacological Studies — Salvadora has been incorporated into many commercial toothpastes. It possesses antiplaque activity. 925 BITC isolated from Salvadora has virucidal activity against HSV, inhibits the growth and acid production of Streptococcus mutans, and is fungistatic to Candida albicans. In vitro studies of shiwak extracts have also demonstrated some antibacterial activity against certain bacterial species implicated in periodontal disease and dental caries. 926 Clinical studies on saliva showed that using shiwak sticks or rinsing with aqueous shiwak extract has an immediate inhibitory effect on salivary bacteria. 927,928 Among chronic or habitual users, clinical studies have shown some positive effects of siwak on their dental health. 929,930

In a double-blind, randomized, controlled trial, 68 patients with gingivitis were randomly assigned to miswak group and were instructed to use only issued miswak for oral hygiene during the 3-week experimental period. Registration of plaque, gingival inflammation, and plaque samples were taken at baseline and on completion of the study. Plaque samples were analyzed by a DNA-DNA hybridization technique. Miswak significantly reduced dental plaque (p = 0.007) and the composition of subgingival microbiota. Miswak showed an overall effect on dental plaque and gingival inflammation scores. It was suggested that miswak can be used as a dental hygiene method in conjunction with interproximal cleaning aides. 931

Extracts of the leaves are used in the treatment of scurvy for rheumatism and as a decoction in asthma and for a cough. 134 Oil obtained from the flower is a stimulant and laxative and has been used as a carminative, anthelmintic, analgesic, and antimicrobial agent. 166 The effects of prolonged administration of a lyophilized stem decoction of Salvadora persica have been evaluated in diet-induced rat hypercholesterolemia. The preparation was administered for 15 and 30 days (by gavage at a dose of 500 mg/kg in an aqueous vehicle in a volume of 0.5 ml/100 g body weight). Cholesterol, HDL, LDL, and triglyceride plasma levels were assayed. The results showed that the S. persica decoction significantly lowered cholesterol and LDL plasma levels in rats, proving to be more active at 30 days of treatment. The systemic administration of Triton X-100 (surfactant) resulted in a rise in plasma cholesterol and triglyceride levels. The results showed that S. persica decoction was inactive at 18 h after treatment, whereas at 27 h, it was able to reduce cholesterol and LDL plasma levels. The HDL and triglycerides were unchanged however. 932 The anticholesterol activity may be due to the presence of stigmast-5-en-3β-ol isolated from the plant, which has been shown to have antihyperlipidemic and antitumor properties. 933 Miswak also showed antidiabetic activity in animal studies. 934

Sansevieria Liberica

 

Botanical Name — Sansevieria liberica Gérôme & Labroy.

Family — Asparagaceae

Common Names — African bowstring hemp, leopard lily

African Names — Efik: ekono-ekpe; Hausa: mooda; Igbo: ebube-agu; Tswana: mokgotsi (S. cylindrica); Yoruba: ola-koriko

Description — Sansevieria liberica is an erect herb with several stiff, red-edged, elliptic leaves, arising from the rhizome. The leaves are upright, up to 60 cm long and 6–10 cm broad, and transversely marked with dark and light green bands, and the margins are marked with red and white lines. The flowers are white and borne on interrupted common stalks. The fruits are reddish, almost round, about 1.25 cm long. Each fruit contains one seed. 33

Habitat and Distribution — It is commonly found in shady places near streams and rock out-crops. It is common in the savanna regions and grassland. It is distributed from Chad to Morocco, Ethiopia, Kenya, and Tanzania.

Ethnomedicinal Uses — The root decoction is a stimulating tonic and a cough remedy and is also administered for hemorrhoids. The roots are used in Ghana as an abortifacient and administered during labor. The expressed juice of the leaves is dropped in the eyes and ears for infections and inflammation. The leaf juice mixed with the fluid expressed from edible snails is used to relieve teething pain. The fumes from the burning leaves are inhaled to relieve feverish headache and cold. The juice pressed from the leaves or a decoction of the leaves is drunk for the treatment of gonorrhea, earache, and toothache and applied to ulcers, sores, and topically in case of earache and toothache. The fermented rhizomes are eaten to cure malaria. A root decoction is used as a remedy for convulsions. As a fetish plant, it is grown on graves, at shrines, and in compounds. 1140

Constituents — Sansevieria liberica contains phytosterols and their glycosides, amino acids, vitamins, and minerals.

Pharmacological Studies — Sansevieria possesses anti-inflammatory activity in animal studies. It significantly (p < 0.05) inhibited the development of paw edema induced by egg albumen in rats. 935 The extract of the leaves showed positive antidiabetic and antioxidant activities. It also exhibited hypolipidemic, immune-modulating, ocular, hepatorenal, and cardioprotective potentials. 936 It was found that in a dose-dependent manner, it significantly lowered (p < 0.05) ocular MDA content; atherogenic indices; red cell, total white cell, and lymphocyte counts; mean cell hemoglobin concentration; plasma levels of glucose, triglyceride, total, VLDL, LDL, and non-high-density lipoprotein cholesterols; total, conjugated. and unconjugated bilirubin; sodium, urea, and blood urea nitrogen; as well as plasma activities of ALP, alanine, and aspartate transaminases. However, the treatment significantly increased (p < 0.05) hematocrit, hemoglobin concentration, mean cell hemoglobin, mean cell volume, neutrophil and monocyte counts, and plasma levels of HDL cholesterol, potassium, chloride, calcium, bicarbonate, and total protein, ocular ascorbic acid content, and ocular activities of CAT and SOD. 937

The plant possesses in vitro antiplasmodial and anticancer activities.

Sceletium Tortuosum

Botanical Name — Sceletium tortuosum (L.) N.E. Brown

Synonym — Mesembryanthemum tortuosum L.

Family — Aizoaceae

Common Names — Kanna, channa, kana, sceletium

African Names — Khoi-khoi (South Africa): kougoed; San (South Africa): kanna; Afrikaans: kougoed

Description — The plant is described by the South Africa National Biodiversity Institute as a prostrate to scrambling perennial succulent herb. The leaves are imbricate, flat triangular in sectional view, with tips incurved, 30–40 × 10–15 mm, with large bladder cells giving foliage a glistening surface, dying back after flowering to leave skeletal remains; flowers (July–September) are white, pale yellow, pale pink, or salmon and ±20–30 mm in diameter; fruits are 4- to 5-locular, with valve wings.

Habitat and Distribution — The plant occurs in South Africa, where it appears restricted to the western and northern Cape provinces. Eight species of Sceletium are known to exist, but only S. tortuosum is of commercial importance. It can be differentiated by its straight secondary veins, prominent idioblasts, incurved leaf tips, and imbricate leaves.

Ethnomedicinal Uses — The herb is used in traditional medicine by the Khoi-khoi and San peoples of South Africa as a mood enhancer, sedative, and analgesic; for toothache and stomach pains; and as an appetite/thirst suppressant. These properties of kanna were noted and recorded by early settlers at the Cape, who adopted its use for similar purposes. It is also used as a masticatory for social and spiritual purposes. 942

Constituents — Indole alkaloids belonging to the mesembrine group (mesembrenol, mesembranol, mesembrenone, and mesembrine) are the major constituents of Sceletium tortuosum. Three distinct structural types have been isolated and characterized. Mesembrine appears to be most abundant (0.3% leaves and 0.86% stem). Mesembrenone and 4′-O-demethylmesembrenol are also present. Tortuosamine, also isolated from S. tortuosum, represents a second structural type in which the pyrrole ring is opened. Alkaloid levels appear to fluctuate seasonally and may be highest in late spring/early summer; this is the time when plants are traditionally gathered and prepared for use. Investigation of alkaloid ratios and total alkaloid content demonstrated that both are substantially altered by traditional processing methods. Mesembrine and 4′-O-demethylmesembrenol levels were lower in fermented than in unfermented material, while mesembrenone content had doubled during fermentation/ drying. Material crushed and dried at 80°C immediately after collection had similar alkaloid patterns to fermented material. The unfermented material showed high levels of oxalates (3.6–5.1%).

The analysis of the relative concentrations of the mesembrine alkaloids has been useful in the quality control of commercial samples of the plant. 938 Both reversed-phase ultra high-performance liquid chromatography with photodiode array detector (RP-UHPLC PDA) and GC/MS methods have been used for quantitative assessment of mesembrine-type alkaloids in S. tortuosum raw materials and products. 939 The use of nonaqueous capillary electrophoresis coupled to mass spectrometry (NACE-MS) was also found efficient for the separation of complex alkaloid mixtures found in commercial kanna teas. 940

Pharmacological Studies — Sceletium tortuosum has been investigated by many groups to validate its application in the treatment of depression, neurological disorders, and neurodegenerative diseases. 941 The extract has been shown to be a potent blocker in 5-HT transporter binding assays (IC50 4.3 μg/ml) and had powerful inhibitory effects on phosphodiesterase 4 (PDE4) (IC50 8.5 μg/ml), but not other PDEs. No cytotoxic effects were observed. Mesembrine was the most active alkaloid against the 5-HT transporter (Ki 1.4 nM), while mesembrenone was active against the 5-HT transporter and PDE4 (IC50s < 1 μM). The activity of the Sceletium tortuosum extract on the 5-HT transporter and PDE4 provides a probable explanation for the clinical effects of preparations made from this plant. The activities were related to the presence of alkaloids, particularly mesembrine and mesembrenone. 942 A remarkable feature of the activity of S. tortuosum tested is the selectivity of action. Considering that the plant extract will have several components, it is perhaps surprising that the Sceletium extract affected so few sites in the extensive panel of receptors, ion channels, transporters, and enzymes used in the study. Selective serotonin reuptake inhibitors are well known as antidepressants, and PDE4 inhibitors have also attracted considerable attention as potential antidepressants, although the pharmaceutical compounds tested clinically have had dose-limiting side effects of nausea and emesis. 943

Toxicity — Sceletium seems well tolerated in feeding experiments on dogs and cats. In the canine evaluation, milled dry Sceletium tortuosum was given at a dose of 10 mg/kg twice a day to seven healthy beagle dogs as well as one dog with dementia for 6 days. The plant material was mixed into the animals’ food. Pre- and postfeeding observations and blood tests were made, including those for red cell count, hemaglobin, hematocrit, white cell count, platelet count, blood urea nitrogen, creatinine, glucose, glutamic pyruvic transaminase, total cholesterol, and total protein. Holter monitoring of the electrocardiogram (ECG) was done for the duration of the study. No changes in behavior or adverse effects were noted in the healthy dogs. The blood tests showed no abnormality in the hematology, liver and kidney functions, glucose, or lipid metabolism over the 6-day period. No adverse effects were noted in the dog suffering from dementia. Similar results were obtained from the experiments on cats. However, a slight increase in daytime sleep was noted, and in the blood chemistry, a slight decrease of GOT (glutamic oxaloacetic transaminase) and increase of ALP were observed, which were still within normal limits. 944,948

Commerce — The use of S. tortousum alkaloids is the subject of U.S. Patent 6,288,104 by Gericke and Van Wyk, 142 which discloses the use of mesembrine and related compounds, including novel compounds, as serotonin uptake inhibitors and the use of standardized amounts of these compounds in pharmaceutical formulations for use in the management of psychiatric and psychological conditions, including depression, anxiety, drug dependence, bulimia, and obsessive-compulsive disorder. A proprietary product, Zemberin, which contains the standard extract, is being evaluated for use as an antidepressant agent.

Schumanniophyton Magnificum

Botanical Name — Schumanniophyton magnificum (K.Schum) Harms

Synonyms — Tetrastigma magnificum K.Schum

Family — Rubiacea

African Names — Cameroon: abamoto, titimoto; Igbo: akito

Description — Schumanniophyton magnificum is a shrub or tree 4–5 m high with a soft, wooded stem and very large, simple leaves. The leaves are larger at the upper half than at the lower half, about 60–120 cm long and 30–45 cm broad. The flowers are stalkless, large, white or yellow, and occur in dense clusters at the ends of shoots opposite leaves or just above pairs of leaves, subtended by large bracts. The corolla tube is 6–7 cm long, densely hairy, and with 7–10 dagger-shaped lobes, which are up to 2 cm long. The fruits appear around November, almost oval in shape, grayish green in color, and covered with some corky outgrowth. 9

Habitat and Distribution — It is found in lowland rainforest areas in Cameroon, Sierra Leone, southeastern Nigeria (Calabar and Igbogodo), and Ghana.

Ethnomedicinal Uses — A decoction of the bark is used in an enema as a remedy for dysentery. It is used also as a lotion after circumcision. Fresh leaves (cold expression) and stem extracts are used in the treatment of snakebite.

Constituents — The plant yields a mixture of chromone alkaloids, including schummaniophytine, isoschummaniophytine, 945,946 N-methyl schummaniophytine, schumaginine, and schumannificine, 947,948 as well as the related bases trigonelline, rohitukine, and the chromone noreugenin. 949 The n-butanol extract of the root bark of the Cameroonian species has also been shown to contain new chromone glycosides and schummaniofioside A and B. 949

Pharmacological Studies — The polar extracts of the stem possess both in vivo and in vitro activity against cobra cardiotoxin. 950,951 The activity has been attributed to the presence of a chromone alkaloid glycoside schummaniofoside isolated from the stem bark. 952 A nonalkaloidal compound RW12 has also been isolated from the plant with activity against cobra cardiotoxin. 953 The compound, when tested on chick biventer cervices nerve preparation challenged with cobra cardiotoxin, demonstrated anticardiotoxin activity in a dose-dependent manner at a dose range of 0.4 to 1.4 μg/ml, with an ID50 of 0.63 μg/ml. 954 Schummaniofoside and trigonelline have also been shown to exhibit antimicrobial activity. 954

The antiviral activity has been evaluated and its activity against HIV and HSV; the nonpolar fraction of a methanolic extract of the root bark was present in a fraction containing the chromone secondary amine schumannificine. 955 Other chromone alkaloids present in the plant were isolated and tested for inhibition of HIV and HSV infections in C8166 and Vero cells, respectively. Acyl and methyl derivatives were prepared and tested. Of all the compounds tested, schumannificine 1 displayed the greatest activity against HIV, whereas potent anti-HSV activity was observed for a number of its derivatives. The presence of a piperidine ring and unsubstituted hydroxyl groups on the molecules seemed to favor the anti-HIV activity. The anti-HIV activity was considered to be due to irreversible binding to gp120 rather than inhibition of reverse transcriptase or protease. 956

Schwenkia Guineensis

 

Botanical Name — Schwenkia guineensis Schum. & Thonn.

Synonyms — S. Americana L., S. hirta Wright.

Family — Solanaceae

African Names — Hausa: dandana; Yoruba: ale odan

Description — Schwenkia guineensis is a thin, erect, herbaceous weed, with much branched stem, and is up to 50 cm tall. The leaves are oval in shape, about 4 cm long and 2 cm broad; the stalks are sparsely covered with short, soft hairs. It produces greenish or purple flowers, with cylindrical calyx, about 3 mm long and with pointed lobes. The corolla is tubular, cylindrical, and about 8 mm long, narrow, and 5 lobed. The fruits are small, round capsules, about 3 mm long, with 4 protrusions, and they contain many tiny seeds. 77

Ethnomedicinal Uses — The root and stem wood are used as a chewing stick for tooth cleaning and oral hygiene. A decoction of the plant is administered both orally and topically to treat rheumatic pains and swellings. It is used by nursing mothers to prevent neonatal diarrhea and also given to the suckling baby for the same purpose. The pounded whole plant is used as a fish poison. The root extract is used in Ghana as a cough medicine and in Angola for the treatment of chest pains. 78

Constituents — The plant contains a glycoside called schwenkioside, steroidal sapogenins, and traces of alkaloids. 957,958

Pharmacological Studies — The sapogenin isolated from the plant has cardiotonic activity. 958 The compound caused an initial inhibition of toad heart followed by prolonged stimulation. Extracts obtained from various parts of the plant cause hemolysis of red blood cells.