Prota 11(1): Medicinal plants/Plantes médicinales 1
Peters, Naturw. Reise Mossambique, Vol. 6, Botanik 1: 237 (1861).
Solanum renschii Vatke (1882), Solanum kwebense N.E.Br. ex C.H.Wright (1906).
Origin and geographic distribution
Solanum tettense occurs from Ethiopia and Somalia south throughout East Africa and southern Africa.
In Kenya a root extract is drunk to cure typhus and abdominal pain. In Zimbabwe a root extract is drunk or pulverized root is mixed with food to cure diarrhoea. The preparation and use of arrow poison made from the roots is practised by bushmen in Namibia. Samburu warriors of Kenya used to take the plant as a drug.
The fruit of Solanum tettense contains calystegines, which are nortropane alkaloids with glycosidase inhibitory activity. Calystegine A3 selectively inhibits the rat liver β-glucosidase activity. Calystegines are found in many species of the families Convolvulaceae and Solanaceae.
Accidental feeding on Solanum tettense causes disorders in cattle (crazy cow syndrome) characterized by epileptic-like attacks. The poison acts on the central nervous system and the functions of the cerebellum, but does not cause fatal poisoning.
Perennial herb or shrub up to 3(–4) m tall; stems with many pale yellow prickles 1–5 mm long and stellate hairs. Leaves alternate, simple; stipules absent; petiole 0.5–4 cm long, rarely with prickles; blade lanceolate to ovate or ovate-elliptical, 1.5–14 cm × 0.5–8 cm, base unequal, rounded to cuneate, apex obtuse to acute, margin entire to wavy. Inflorescence a lateral cyme, few- to many-flowered. Flowers bisexual, regular, 4–5(–7)-merous; calyx bell- or cup-shaped, 2.5–6 mm long, lobes lanceolate to broadly obovate; corolla rotate, up to 2 cm in diameter, blue, violet, purple or rarely white; stamens alternate with corolla lobes, filaments up to 1.5 mm long, anthers lanceolate, 4 –7 mm long, opening with apical pores; ovary superior, up to 1.5 mm in diameter, style 5–11 mm long. Fruit a globose, soft berry 5–10 mm in diameter, glabrous, yellowish brown, deep red when ripe, many-seeded. Seeds ovoid, compressed, 2.5–4 mm in diameter, pale yellow or creamy. Seedling with epigeal germination; cotyledons thin, leafy.
Solanum comprises about 1000 species and has a cosmopolitan distribution, except in boreal, alpine and aquatic habitats. About 110 species are found in tropical Africa. The principal centre of diversity is located in Central and South America, with secondary centres in Africa and Australia. Solanum has been subdivided into 7 subgenera and numerous sections and series. Solanum tettense is a polymorphic species and 2 varieties are distinguished, based on differences in hairiness. It is placed in the Solanum giganteum group of the section Oliganthes of subgenus Leptostemonum, a group of about 10 species, all of them restricted to sub-Saharan Africa. Two other species of this group have medicinal uses in tropical Africa.
Solanum giganteum Jacq. has a disjunct montane distribution in Africa and is also known from tropical Asia, Australia and South America. In East Africa the woolly hairy underside of the leaves is used to clean wounds and the glabrous upper side is used to dress wounds. The fruits are edible but bitter and are used to treat throat ulcers and to curdle milk. In Uganda powdered dry leaves are added to bath water to overcome sleeplessness. In India Solanum giganteum is planted as a shade tree.
Solanum goetzei Dammer occurs from Kenya southwards to Zambia and Mozambique. In Kenya a hot poultice of pounded leaves is used to reduce swellings and to draw out abscesses.
Solanum somalense Franch. occurs in eastern Ethiopia, Somalia and Kenya,. Its classification in subgenus Leptostemonum and especially in the section Oliganthes is disputed. In Somalia the fruit ash is applied to wounds to promote healing.
Solanum tettense occurs in woodland, wooded grassland and thickets. In miombo woodland it grows on termite mounds and is also found along streams and in rocky areas. It thrives under both moist and semi-arid conditions, up to 1600 m altitude.
Genetic resources and breeding
As Solanum tettense is widespread and not heavily exploited, there appears to be no threat of genetic erosion.
Solanum tettense does not have medicinal uses or properties that make it likely that its importance will develop beyond the present local medicinal uses.
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Correct citation of this article:
Bosch, C.H., 2008. Solanum tettense Klotzsch. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.