Prota 2: Vegetables/Légumes
2n = 32
Origin and geographic distribution
Sesamum angolense is found in DR Congo, Rwanda, Burundi, Kenya, Uganda, Tanzania, Malawi, Zambia, Angola, Zimbabwe and Mozambique.
The leaves of Sesamum angolense are collected from the wild, wilted and cooked alone or mixed with beans, peas, groundnuts or amaranth, and served with a staple food. They are sometimes sold on local markets. The cooked leaves form a very slimy product. In Malawi Sesamum angolense is often eaten with bran porridge and is particularly popular with women; the dish is often given to babies and disabled persons.
A decoction or infusion of the leaves or roots is drunk to counteract vomiting, cough, catarrh, constipation, diarrhoea and poisoning, and applied externally to cure wounds and skin diseases such as measles and sores, and to curtail bleeding after tooth removal. Formerly, in Malawi, the leaves were pounded with water and the liquid poured into the eyes and over the ears, nose and mouth to cure smallpox. In Malawi an infusion of the roots is drunk at the time of labour to hasten delivery. An infusion of the leaves in water is also used as a shampoo to oil and straighten the hair and as a substitute for soap. The leaves can also be dried and stored for later use, either whole or powdered.
There is no information on the nutritional composition of Sesamum angolense leaves, but it is probably comparable to that of Sesamum indicum L. (cultivated sesame) leaves, which is per 100 g edible portion: water 85.5 g, energy 188 kJ (45 kcal), protein 3.4 g, fat 0.7 g, carbohydrate 8.6 g, fibre 2.4 g, Ca 77 mg, P 203 mg, riboflavin 0.3 mg (Leung, W.-T.W., Busson, F. & Jardin, C., 1968). The seed of Sesamum angolense yields 24% of a green fixed oil, which contains 9% of the phenylpropanoid sesamin. Although the yield of oil is little more than half that of commercial sesame, the high sesamin content offers opportunities for developing the oil as a synergist to pyrethrin insecticides. The haemostatic properties of the roots are possibly caused by the presence of iridoid glucosides (sesamoside, phlomiol, pulchelloside-I and 6-β-hydroxy-ipolamide) or the phenylpropanoid glycoside verbascoside.
Erect annual or perennial herb up to 3 m tall, bad smelling, with simple or branched, slightly quadrangular stem. Leaves opposite, simple, without stipules, sessile or with short petiole; blade oblong, elliptical to oblanceolate, 2–11 cm × 0.5–4 cm, base cuneate, apex truncate, retuse or acute and usually mucronate, margin entire, more or less inrolled, glabrescent above, white tomentose and densely glandular below. Flowers solitary in leaf axils, bisexual, zygomorphic, 5-merous; calyx campanulate, with lanceolate lobes up to 1 cm × 2 mm, pubescent, persistent in fruit; corolla obliquely campanulate, up to 7 cm long, 2-lipped, pink, red, purple or pale mauve with deeper markings, pubescent; stamens 4, filaments arising from a band of hairs near the base of the corolla tube; disk annular, regular; ovary superior, white-hairy, 2-celled, style filiform, stigma 2-lobed. Fruit a slightly quadrangular capsule 2–3 cm × 5–7 mm, 4 -grooved, gradually narrowed into a flattened short beak, densely pubescent but glabrescent, dehiscing longitudinally, many-seeded. Seeds flattened obconical, c. 2 mm × 1.5 mm, not winged, faintly rugose.
Sesamum comprises about 20 species, most of which are indigenous to tropical Africa. Sesamum angolense belongs to section Aptera, characterized by entire leaves and seeds without wings, together with e.g. Sesamum angustifolium (Oliv.) Engl., Sesamum calycinum Welw. and Sesamum radiatum Thonn. ex Hornem. This section is closely related to the genus Ceratotheca. Sesamum angolense can be recognized easily by its leaves, which are white tomentose below, and its large flowers.
Sesamum angolense is common in grassland, open woodland, roadsides and abandoned fields, on black or red loam soil, at 400–2400 m altitude.
Genetic resources and breeding
Sesamum angolense is widespread and not in danger of genetic erosion.
Sesamum angolense will remain a minor vegetable, of importance when other vegetables are scarce. Its medicinal properties are promising and deserve more attention, in addition to research on the nutritional composition of the leaves. Sesamum angolense with its attractive large flowers frequently visited by bees also has potential as a garden ornamental and bee forage.
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• Leung, W.-T.W., Busson, F. & Jardin, C., 1968. Food composition table for use in Africa. FAO, Rome, Italy. 306 pp.
• Potterat, O., Msonthi, J.D. & Hostettmann, K., 1988. Four iridoid glucosides and a phenylpropanoid glycoside from Sesamum angolense. Phytochemistry 27(8): 2677–2679.
• Tredgold, M.H., 1986. Food plants of Zimbabwe. Mambo Press, Gweru, Zimbabwe.153 pp.
• Watt, J.M. & Breyer-Brandwijk, M.G., 1962. The medicinal and poisonous plants of southern and eastern Africa. 2nd Edition. E. and S. Livingstone, London, United Kingdom. 1457 pp.
Correct citation of this article:
Jansen, P.C.M., 2004. Sesamum angolense Welw. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.