African spiderflower (Gynandropsis gynandra)

African spiderflower (Gynandropsis gynandra L.) is an tropical annual herb mainly used as a vegetable in Africa and Asia. It is grazed by different classes of livestock and wild games. The seeds are eaten by birds and the oilseed meal can be used as a feed (Chweya et al., 1997).

Morphology

Gynandropsis gynandra is an erect annual herb, 50-100 cm tall that can reach 150 cm high under favorable conditions. It is strongly branched and the stem is densely glandular. African spiderflower is taprooted with few secondary roots. The leaves are alternate, petiolated (2-10 cm long), palmately compound with (3–) 5 (–7) leaflets. The leaflets are almost sessile, obovate to elliptical or lanceolate, 2–10 cm × 1–4 cm, cuneate at the base, rounded to obtuse, acute or acuminate at apex, finely toothed on the margins and sparsely to distinctly hairy. The inflorescence is a showy terminal raceme up to 30 cm long. The flowers are bisexual, white or tinged with purple encompassing 4 sepals, 4 elliptical to obovate, 1.5 cm long petals, and 6 conspicuous purple stamens. The fruits are long narrow, cylindrical and dehiscent capsules up to 12 cm long × 1 cm broad and they contain many seeds. The seeds are subglobose, 1–1.5 mm in diameter, grey to black, irregularly ribbed (Mnzava et al., 2004; Chweya et al., 1997).

Uses

Gynandropsis gynandra is primarily used as a leafy vegetable. The tender leaves, young shoots and occasionally flowers are eaten boiled as potherb, relish, stew or side dish. The leaves are used fresh or dried. Their bitterness can be alleviated by discarding the cooking water, by cooking them with milk of with other leafy vegetables such as cowpea, amaranth (Amaranthus blitum) or nightshade (Solanum nigrum) leaves, or by adding peanut butter to improve the flavour. In Kenya, a survey of two rural communities in 2013 showed that it was ranked as the most preferred traditional vegetable by 48% of the respondents (Onyango et al., 2013). To make dried powder, the leaves are blanched, made into small balls and sun- or air-dried that are stored up to a year and then soaked prior to cooking. In Thailand, it is consumed fermented in a product called "paksian-dong" (Mishra et al., 2011). Camels, cattle, sheep and goats graze Gynandropsis gynandra in the wild (Chweya et al., 1997).

Various parts of Gynandropsis gynandra have uses in ethnomedicine. The plant is used as an insect repellent, protecting neighbouring plants like cabbage and French beans from pests like diamond back moth larvae or thrips. Seeds are eaten by birds and can be ground to make a mustard-like condiment. The seed oil is valuable for its polyunsaturated fatty acids. The cake resulting from oil extraction could be fed to livestock (Chweya et al., 1997).