Minerals, trace elements and antioxidant phytochemicals in wild African dark-green leafy vegetables (morogo)

Abstract

Wild African dark-green leafy vegetables (morogo) are an important constituent of the traditional starch-based African diet. Three wild morogo types were sampled from different geographical regions in South Africa to determine their mineral, total polyphenol, total carotenoid and beta-carotene contents. Mineral and trace element compositions were determined using inductively coupled argon plasma mass spectrometry (ICP-MS). Concentrations of total carotenoids and total phenolics were measured by spectrophotometry and beta-carotene concentrations by high performance liquid chromatography (HPLC). In comparison with values reported for commercial spinach and swiss chard, results from the present study indicate relatively high calcium and magnesium concentrations in the wild morogo. Total carotenoid concentrations in the three morogo types were comparable with that of spinach. Beta-carotene concentrations were highest in Amaranthus hybridus, but this value was lower than those reported for other morogo species grown commercially. Concentrations of total phenolics were in the same range as those reported for conventional and commercially-grown non-conventional dark-green leafy vegetables. Results from the present study suggest that readily accessible wild morogo varieties represent inexpensive sources of dietary minerals, trace elements and antioxidant phytochemicals