Variation in bioactive compounds and antiradical activity of Moringa oleifera leaves: influence of climatic factors, tree age, and soil parameters

Moringa oleifera Lam. (Moringa) leaves are a significant source of phytochemicals with different bioactivities carrying human health benefits. This study was undertaken to investigate the effects of the tree age, soil physical and chemical parameters, and climatic factors, on the content of gallic acid, total phenolics, total carotenoids, and ascorbic acid and on the antiradical activity (DPPH and ABTS assays) of ethanolic extracts obtained from Moringa freeze-dried leaves. Multivariate data analysis showed that the bioactive compounds measured as reference and the antiradical activity from Moringa leaves presented correlation with climatic factors (precipitation, humidity, and radiation) and with soil nutrients, principally with the K and P contents. Tree age was positively correlated with the total carotenoids contents, and inversely correlated with the ascorbic acid contents. This information offers an understanding on variations in bioactive compounds and antiradical activity in Moringa leaves influenced by climatic factors, soil, and tree age, which may help in the estimation of the antioxidant potential present in the plants during different harvest times.