Prota 11(1): Medicinal plants/Plantes médicinales 1
Apont.: 589 (1859).
Trichodesma hockii De Wild. (1913).
Origin and geographic distribution
Trichodesma ambacense is widespread in East and southern Africa. In West Africa it is reported only from Nigeria, in Central Africa only from Cameroon and south-eastern DR Congo.
In Zimbabwe the woody rhizome of Trichodesma ambacense has multiple medicinal uses. It is applied to incisions made in the skin to treat backache, headache, painful swellings and syphilitic swelling of glands. For swellings caused by oedema, a decoction is applied as a hot compress. For depressed fontanelle, the crushed rhizome is applied and an infusion given to drink. An infusion is drunk to dilate the birth canal. Powdered rhizome is taken orally to cure bilharzia. In DR Congo the leaf ash is applied to corns, and the macerated leaves are used to dye white hair black.
No information is available on the phytochemical or pharmacological properties of Trichodesma ambacense. In other Trichodesma spp. with similar medicinal uses pyrrolizidine alkaloids appear to be the pharmacologically or toxicologically active ingredients.
Perennial, erect herb up to 50(–70) cm tall, usually unbranched. Leaves simple and entire, sessile, lower leaves opposite, upper leaves subopposite or alternate; stipules absent; blade ovate to elliptical, oblanceolate or linear-oblong, 4–7 cm × 0.5–3 cm, exceptionally on sterile shoots up to 16 cm × 5 cm, base cuneate to rounded, apex acute or obtuse. Inflorescence terminal, up to 30 cm long, with up to 9(–12) branches each with up to 8(–12) flowers. Flowers bisexual, regular, 5-merous; calyx lobes ovate, up to 18 mm × 9 mm, enlarging in fruit; corolla 17–25 mm long, tube white or cream, lobes spreading or reflexed, triangular, blue, rarely white. Fruit a single discoid nutlet, c. 13 mm × 8 mm.
In Trichodesma ambacense 2 subspecies are recognized: subsp. ambacense has only been found in Angola, whereas subsp. hockii (De Wild.) Brummitt is found in the rest of the range of the species. Trichodesma physaloides (Fenzl) A.DC. occurs largely in the same area as Trichodesma ambacense, but is absent from Nigeria and extends into South Africa. The former has glabrous stems and pedicels, whereas in the latter these are hairy. Intermediates that are thought to be hybrids do occur. The woody rootstock of Trichodesma physaloides is used in a paste to treat wounds in Zimbabwe, and the powdered rootstock mixed with beer or porridge as an aphrodisiac in Malawi. In Tanzania an infusion made of the peduncles is given to calves that suffer from diarrhoea. In DR Congo the leaves are rubbed on the skin to treat lumbago. Apart from the mention that Trichodesma physaloides contains a toxic alkaloid, nothing appears to have been published on its properties.
Trichodesma ambacense is found in grassland and woodland that is subject to annual burning. Its altitudinal range is 600–1500 m.
Genetic resources and breeding
Trichodesma ambacense is widespread and not threatened with genetic erosion.
In view of its medicinal uses and the apparent lack of knowledge on its pharmacological properties, Trichodesma ambacense and related species deserve more attention in research.
• Brummitt, R.K., 1982. A revision of Trichodesma sect. Friedrichsthalia (Fenzl) A.DC. non Brand (Boraginaceae). Kew Bulletin 37(3): 429–450.
• Gelfand, M., Mavi, S., Drummond, R.B. & Ndemera, B., 1985. The traditional medical practitioner in Zimbabwe: his principles of practice and pharmacopoeia. Mambo Press, Gweru, Zimbabwe. 411 pp.
• Taton, A., 1971. Boraginaceae. In: Flore du Congo, du Ruanda et du Burundi. Spermatophytes. Jardin botanique national de Belgique, Brussels, Belgium. 82 pp.
• Kokwaro, J.O., 1993. Medicinal plants of East Africa. 2nd Edition. Kenya Literature Bureau, Nairobi, Kenya. 401 pp.
• Verdcourt, B., 1991. Boraginaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 125 pp.
Correct citation of this article:
Bosch, C.H., 2006. Trichodesma ambacense Welw. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.