Prota 11(1): Medicinal plants/Plantes médicinales 1
Prodr. 8: 370 (1844).
Hazunta coffeoides (Bojer ex A.DC.) Pichon (1948); Hazunta modesta (Baker) Pichon (1948), Hazunta velutina Pichon (1948), Hazunta costata Markgr. (1970).
Origin and geographic distribution
Tabernaemontana coffeoides is endemic to Madagascar, Comoros, Mayotte and Seychelles.
In Madagascar the bitter twig bark of Tabernaemontana coffeoides is chewed to combat fatigue and to suppress hunger. A twig or bark infusion is reputed to promote weight loss as it reduces appetite. The bitter bark is added to alcoholic beverages, some of which are used during circumcision rituals. The bark was formerly used to make string for cloth. In Mayotte, branched twigs were formerly used as an oil-lamp support. In the Comoros the wood is used as firewood.
Tabernaemontana coffeoides contains mainly monomeric indole alkaloids, although some bisindolic alkaloids occur in the leaves as well. The root bark contains most alkaloids (60 g/kg), followed by the stem bark (37 g/kg) and the leaves (22 g/kg). The alkaloids of the root bark, stem bark and leaves consist for up to 50% of vobasine, tabernaemontanine, dregamine, methuenine and silicine (all corynanthean class); small amounts of apparicine (pericalline, aspidospermatan class) are present. Additionally, the alkaloids of the stem bark and root bark contain 12–16% of ibogamine (ibogan class). The leaves also contain many alkaloids of the plumeran class including the pharmacologically active tabersonine. They also contain akuammidine and normacusine B (both corynanthean class), heyneanine (ibogan class) and vincanidine (strychnan class). In addition they contain the dimeric hazuntiphylline ( plumeran-plumeran class) and stemmadenine (conynanthean-plumeran class).
Dregamine shows convulsant and respiration-stimulant activities. It also inhibits muscular fatigue in the same way as ibogaine from Tabernanthe iboga Baill. It has been used in treatments of muscular and nervous asthenia, respiratory depression and type III poliovirus (HPV-3). Tabernaemontanine has a vasodilatory effect and can be used in humans in cases of arteriosclerosis, cerebral trauma and circular irregularities. It shows antibacterial activity against several human pathogenic bacterial strains, and is cytotoxic to human nasopharyngeal epidermoid carcinoma cells in vitro, but is inactive against P-388 lymphocytic leukaemia in mice. Methuenine might be effective in the control of cardiac arrhythmias since it mainly decreases the excitability of depolarized arterial fibres in frogs. It also showed a noncompetitive antagonistic activity against histamine and acetylcholine in guinea-pig ileum. Reserpiline produces hypotension in dogs and cats, but it exerts a tranquilizing action as well. It is about as potent as reserpine, which is commonly used against high blood pressure and it lacks the side effects of reserpine. Normacusine B is sympatholytic and its hypotensive activity is greater than that of reserpine. Akuammidine has hypotensive, skeletal-muscle-relaxant and local-anaesthetic activities. Its local anaesthetic activity is about 3 times as potent as cocaine. At low doses, vincanidine stimulates spontaneous mobility in mice, but at high doses it causes muscular paralysis. It has an emetic effect in dogs. It has significant antibacterial activity against Staphylococcus spp., Micrococcus spp. and Escherichia coli. Stemmadenine increases or decreases blood pressure in vitro and in vivo, depending on the conditions of the experiment. Tabersonine has about a quarter of the hypotensive activity of reserpine, and a spasmolytic effect on the smooth muscle of the intestine. Apparicine also showed strong activity against type III poliovirus, as well as significant cytotoxicity against P-388 lymphocytic leukaemia cell cultures. Apparicine showed opioid activity in opiate receptor studies. Vobasine exhibited little activity in general pharmacological screening tests.
Shrub or small tree up to 7(–10) m tall, repeatedly dichotomously branched, glabrous; trunk up to 10(–20) cm in diameter; bark pale brown. Leaves opposite, simple and entire; ocrea widened into stipules in axils of petioles; petiole 5–25 mm long, slender; blade narrowly elliptical to ovate, 2–15 cm × 1–5(–7) cm, base cuneate, decurrent into the petiole, apex acuminate, pinnately veined with 5–15 pairs of lateral veins. Inflorescence a lax corymb, 2–11 cm long, usually 2 together in the forks of branches, few- to many-flowered; peduncle 1–4.5 cm long, slender. Flowers bisexual, regular, 5-merous, sweet-scented; pedicel 3–14 mm long; sepals almost free, ovate to suborbicular, 1–3 mm long, rather thick; corolla tube cylindrical, 5–15 mm long, pale green, slightly widened around the anthers, inside hairy or glabrous, lobes obliquely oblong or narrowly obovate, 5–13 mm × 1.5–6 mm, undulate, spreading, apex rounded, white; stamens inserted about halfway the corolla tube, included, anthers sessile; ovary superior, ovoid, consisting of 2 separate carpels, style slender, 2–5 mm long, pistil head 1–3 mm long, composed of an obscurely lobed ring, a narrow cylinder and a 2-lobed stigmoid apex. Fruit consisting of 2 separate obliquely ellipsoid follicles, 1–3 cm long, apex obtuse, acute or acuminate, green, 2-valved, 1–10-seeded. Seeds obliquely ellipsoid, 5.5–10 mm long, with longitudinal grooves, densely covered with small warts, brown or dark brown, aril red.
Tabernaemontana comprises about 110 species and is pantropical. About 18 species occur in mainland Africa and 15 in Madagascar, of which Tabernaemontana coffeoides is most widespread. Tabernaemontana coffeoides flowers in Madagascar and the Comoros mainly in October–December; in Madagascar, fruiting is mainly from December–March. In the Seychelles, flowering and fruiting probably occurs throughout the year.
Tabernaemontana ciliata Pichon occurs in northern and north-eastern Madagascar. The latex is poisonous and used as a strong purgative. The bark contains the bisindolic pandicine. Tabernaemontana retusa (Lam.) Palacký is a lowland forest tree of eastern Madagascar. The leaves are applied as an emollient and against lung conditions. The latex is used to prepare bird-lime. The seeds contain the pharmacologically active voaphylline, pachysiphine and tabersonine and the leaves contain 3-oxovoacangine and voacristine. Heyneanine occurs in the leaves, stem bark and root bark, while the root bark also contains ibogamine. Voacangine occurs in the seeds, leaves and stem bark, while coronaridine occurs in the seeds, stem bark and root bark.
Tabernaemontana coffeoides occurs on dunes or rocks, often on limestone, in dry forest, bush or savanna, up to 1300 m altitude.
Genetic resources and breeding
Tabernaemontana coffeoides is not threatened by genetic erosion in Madagascar, but it is threatened in the Comoros and to a lesser extent in the Seychelles, because of habitat loss.
Tabernaemontana coffeoides is very rich in pharmacologically interesting indole alkaloids. This warrants more investigations towards the possible development of Tabernaemontana coffeoides as an important medicinal plant.
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Correct citation of this article:
Schmelzer, G.H., 2006. Tabernaemontana coffeoides Bojer ex A.DC. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.