Prota 2: Vegetables/Légumes
2n = 32
Sesamum calycinum Welw. var. angustifolium (Oliv.) Ihlenf. & Seidenst. (1968).
Wild simsim (En). Mfuta, mlenda mwitu (Sw).
Origin and geographic distribution
Sesamum angustifolium occurs in Kenya, Uganda and Tanzania, but its distribution area may be larger because it is bordered by that of the closely related and very similar Sesamum calycinum Welw., with which it is easily confused.
The leaves and young shoots of Sesamum angustifolium (and also those of Sesamum calycinum) are mostly collected from the wild. As the cooked leaves are mucilaginous they are chopped and cooked together with other ingredients such as other leaf vegetables (e.g. Corchorus), peas and beans to thicken sauces that are eaten with the staple food. The taste is mild to sour and in Uganda it is eaten frequently, but elsewhere it is often considered a famine food. The unpleasant smell of raw chopped leaves mostly disappears with cooking. The leaves and young shoots can be dried and stored for later use.
The seeds produce an edible oil, but they are mostly eaten in a sauce or soup after grinding and heating. In Kenya the plant is fed to cattle, mixed with sweet potatoes to make digestion easier. The mucilage of rubbed leaves in water is used to treat eye troubles, burns, wounds, stomach-ache, diarrhoea in children and to ease labour and delivery. In Tanzania a root decoction is used to treat cough and an infusion of powdered roots is drunk to cure diarrhoea and other intestinal disorders. Crushed leaves are used as a soap substitute, rubbed into the hair when washing it to give it a glossy look, but also to treat baldness. In Tanzania the sticky crushed leaves have been used to trap tsetse flies on cattle, a fresh application giving protection for about 4 hours. The seed oil is used to treat ringworm.
There is no information on the nutritional composition of Sesamum angustifolium 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 angustifolium yields about 30% oil which is pale to dark yellow and odourless. The oil contains 3.7% unsaponifiable matter, of which 16% lignans (sesangolin 3.2%, sesamin 0.3%, sesamolin 0.2%) and 800 mg tocopherols per kg oil.
Erect or spreading, simple or branched herb up to 2 m tall, with grooved, quadrangular, glabrescent stem. Leaves opposite, simple, without stipules, almost sessile; blade linear -lanceolate, 2–12 cm × 0.1–4 cm, base cuneate, apex acute or rounded, margin entire, undulate or sometimes in lower leaves irregularly toothed, thinly pubescent to glabrous above, usually densely glandular below. Flowers solitary in leaf axils, bisexual, zygomorphic, 5-merous; calyx campanulate with lanceolate lobes up to 9 mm long, persistent in fruit; corolla tubular, 2–4 cm long, 2-lipped, pink, red, mauve or purple, often spotted inside, pubescent; stamens 4, filaments arising from a band of hairs in the corolla tube; disk annular; ovary superior, 2-celled, style filiform, stigma 2-lobed. Fruit a narrowly oblong, quadrangular capsule up to 2.5 cm × 4 mm, deeply 4-grooved, apex with a narrow beak up to 3.5 mm long, glabrous to slightly pubescent, dehiscing longitudinally, many-seeded. Seeds c. 1.5 mm × 1 mm, not winged, surface rugose, black.
Sesamum angustifolium belongs to section Aptera, together with e.g. Sesamum angolense Welw., Sesamum calycinum Welw. and Sesamum radiatum Thonn. ex Hornem, and opinions differ about its delimitation. The difference between Sesamum angustifolium and Sesamum calycinum is not always clear. The fruits of Sesamum calycinum are usually broader and its seeds usually larger and have a double fringe.
Sesamum angustifolium is common in roadsides, grassland and as a weed in fields, from sea-level up to 2000 m altitude.
Sesamum angustifolium is mostly collected from the wild, but occasionally cultivated around houses or in fields, and sold at local markets. Propagation is by seed and seedlings are thinned to a spacing of about 20 cm. Young shoots can be harvested about 6 weeks after sowing and if water and soil fertility allow, harvesting can be repeated about 6 times because the plant recovers from the base. When the plant starts flowering and fruiting the shoots become too woody for vegetable use.
Genetic resources and breeding
Sesamum angustifolium is widespread and not in danger of genetic erosion.
In East Africa Sesamum angustifolium is locally an appreciated vegetable, which is occasionally cultivated but also widely available from the wild. Its nutritional composition and medicinal properties deserve further research. Sesamum angustifolium has potential as an attractive garden ornamental.
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Correct citation of this article:
Jansen, P.C.M., 2004. Sesamum angustifolium (Oliv.) Engl. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.