Nutritional quality of some wild leafy vegetables in South Africa

Wild vegetables play an important role in the diet of inhabitants of different parts of the world. Among the wild vegetables of South Africa are Chenopodium album, Sonchus asper, Solanum nigrum and Urtica urens. The leaves of these plants were analysed for their nutritive value, anti-nutritive components and polyphenolic contents. The protein contents of their leaves ranged between 13.25% and 26.44%, while the fibre and mineral (ash) contents were 16.08-23.08% and 13.0-27.75%, respectively. U. urens contained the highest concentrations of calcium, potassium, phosphorus and zinc. A high level of iron was observed in S. asper. These values were found to be comparable with or higher than those of commonly used vegetables such as spinach, lettuce and cabbage. The total phenolic contents ranged between 4.58 and 10.53 mg/g. In terms of anti-nutritional principles, all the vegetables had comparatively lower concentrations of phytate, alkaloids and saponins. Considering the amount of available mineral elements in the vegetables, these plants could be valuable and important contributors to the diets of the people in South Africa.