Preliminary assessment of nutritional value of traditional leafy vegetables in KwaZulu-Natal, South Africa

Abstract

In this report, we present preliminary nutritional data for traditional leafy vegetables collected in Kwa Zulu-Natal, South Africa, including their content of mineral elements (Ca, P, Na, Zn, Mg, Mn and Fe) and antioxidant levels. Twenty vegetables were studied: Amaranthus dubius, Amaranthus hybridus, Amaranthus spinosus, Asystasia gangetica, Bidens pilosa, Centella asiatica, Ceratotheca triloba, Chenopodium album, Cleome monophylla, Cucumis metuliferus, Emex australis, Galinsoga parviflora, Justicia flava, Momordica balsamina, Oxygonum sinuatum, Physalis viscosa, Portulaca oleracea, Senna occidentalis, Solanum nodiflorum and Wahlenbergia undulata. The results of this study provide evidence that these local traditional vegetables, which do not require formal cultivation, could be important contributors to improving the nutritional content of rural and urban people. From this study, it was determined that twelve leafy vegetables, namely A. dubius, A. gangetica, A. hybridus, A. spinosus, C. metuliferus, C. monophylla, C. triloba, G. parviflora, J. flava, M. balsamina, P. viscosa and W. undulata provide mineral concentrations exceeding 1% of plant dry weight and are much higher than typical mineral concentrations in conventional edible leafy vegetables; they are thus recommended for future commercial cultivation. High levels of antioxidant activity (96%) were noticed in J. flava and P. oleraceae.