Prota 11(1): Medicinal plants/Plantes médicinales 1
Repert. Spec. Nov. Regni Veg. 12: 298 (1913).
Caesalpiniaceae (Leguminosae - Caesalpinioideae).
Ordeal tree (En). Mucaráti (Po).
Origin and geographic distribution
Erythrophleum africanum occurs in much of tropical Africa, from Senegal east to Sudan, and south throughout Central Africa, Kenya, Tanzania and southern Africa to Transvaal.
In Ghana a mouth wash for relieving toothache is made from the bark of Erythrophleum africanum. In Zimbabwe an infusion of the bark is drunk to treat stomach-ache or dysmenorrhoea. The bark steeped in water is applied externally and internally to cure cardiac diseases and epilepsy. In Namibia the powdered root bark mixed with urine is applied to the skin to treat leprosy. A hot water extract from pounded roots is drunk to induce vomiting in case of poisoning and as a cure for insanity. Inhaling the smoke of burning leaves is said to relieve pain. A paste of root bark is applied to the skin to cure scabies. The bark has been used as an ordeal poison in Tanzania, Malawi and Zimbabwe.
The timber of Erythrophleum africanum and several other Erythrophleum species is marketed under the trade name ‘missanda’. It is used for furniture, heavy and light construction, posts, poles and tool handles. The wood is used as firewood and to make good-quality charcoal, useful in iron working. Cuttings are used to establish living fences. The gum from the bark is used to make baskets water proof and to fix arrow heads and hoe and axe handles. In Zambia the foliage is reportedly used as a fodder but sources from several other countries report that it is toxic and that cattle are kept away from it.
The complex alkaloids of Erythrophleum spp. are esters of tricyclic diterpene acids, and 2 main types exist: dimethylaminoethylesters and monomethylaminoethylesters ( nor-alkaloids). In addition, compounds have been found in which the amine link is replaced by an amide link, but it is not clear whether these are natural compounds or artefacts. The bark of Erythrophleum africanum contains erythrophlamine, norcassamidine, norerythrophlamide and norerythrostachamide. The alkaloid content of the bark ranges from 0.04% to 0.6%. The alkaloids have similar cardiotonic, anaesthetic and diuretic properties as those from other Erythrophleum spp.
The bark contains the flavone 2, 3-dihydroxymyricetin that colours violet after addition of magnesium powder and a few drops of hydrochloric acid. This reaction allows it to be distinguished from the bark of Erythrophleum suaveolens (Guill. & Perr.) Brenan, which colours orange after treatment because of the presence of luteolin.
The wood is red-brown, heavy, hard and very durable and is resistant to termites, powder-post beetles and marine borers.
Adulterations and substitutes
Erythrophleum alkaloids have similar pharmacological activities as digitoxine and ouabain.
Small tree up to 15 m tall; bole straight and cylindrical, up to 120 cm in diameter; crown spreading, fairly dense; young parts very variable hairy. Leaves alternate, bipinnately compound with (2–)3–4 pairs of opposite pinnae; stipules minute; petiole 3.5–5.5 cm long, rachis 3–15 cm long; leaflets alternate, 8–17 per pinna, elliptical or ovate, up to 6.5 cm × 3.5 cm, base asymmetrical, apex obtuse to rounded. Inflorescence an axillary or terminal panicle consisting of spike-like racemes up to 10 cm long, often shortly hairy. Flowers bisexual, regular, 5-merous, white to yellowish green; pedicel c. 1 mm long, hairy; calyx c. 2.5 mm long, tube about as long as lobes; petals narrowly obovate, up to 4 mm × 1 mm; stamens 10, free, up to 8 mm long; ovary superior, long woolly hairy, 1-celled, stigma broadly peltate. Fruit a flat, straight, dehiscent pod, elliptical in outline, 5–19 cm × 2–4.5 cm, base rounded, apex rounded or tapering, thick leathery, pendulous, 3–4-seeded. Seeds ovoid, compressed, c. 12 mm × 10 mm × 4 mm.
Erythrophleum comprises about 10 species, 4 or 5 of which occur in continental Africa, 1 in Madagascar, 3 in eastern Asia, and 1 in Australia. The genus is one of the few Caesalpiniaceae reported to contain alkaloids. The areas of distribution of Erythrophleum africanum and Erythrophleum suaveolens largely overlap and the 2 species share many uses and properties and therefore confusion is quite likely. The results of earlier pharmacological work are blurred by doubtful identifications. The 2 species differ in ecology, a number of morphological characteristics and the alkaloid profile of the bark. Nodulation and vesicular-arbuscular mycorrhizae were observed in the roots of Erythrophleum africanum. The rhizobium involved in nodulation probably belongs to the genus Bradyrhizobium.
Erythrophleum africanum is common in deciduous woodland, and is absent from riparian woodlands and the dry savanna of the Sahel. It occurs at 600–1400 m altitude, and resists bushfires.
Erythrophleum africanum can be grown from seed, but wildlings are used as well. Coppicing and pollarding are recommended management practices for Erythrophleum africanum in Zambia but coppicing often gives poor results.
Genetic resources and breeding
Erythrophleum africanum is widespread and not commercially exploited on a large scale. There is no reason to assume it will become threatened in the near future.
The huge variation in alkaloid contents of Erythrophleum africanum bark warrants caution in medicinal use. Morphological and pharmacological studies could yield a better understanding of the variation in this species.
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Correct citation of this article:
Kawanga, V., 2006. Erythrophleum africanum (Welw. ex Benth.) Harms. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
obtained from P. Ekpe NSBP
obtained from P. Ekpe NSBP
obtained from P. Ekpe NSBP
young fruits and leafy branch
obtained from P. Ekpe NSBP