A study of the nutritional and medicinal values of Moringa oleifera leaves from sub-Saharan Africa: Ghana, Rwanda, Senegal and Zambia

Moringa oleifera is an important multipurpose tropical tree under-recognized for its nutritional and medicinal properties. Leaves of M. oleifera collected from the sub-Saharan African countries of Ghana, Rwanda, Senegal and Zambia were analyzed for their nutritional value and bioactivity by UV-Vis spectrophotometry and HPLC coupled with UV and MS detectors. Moringa leaves were found to provide low amounts of vitamin C (0.351 ± 0.046 to 0.749 ± 0.014 mg/100g DW (DW)) as determined using UV spectrophotometry. Using LC/MS, We identified α- and γ- tocopherols, α- and β- carotenes, six analogues of chlorogenic acid including 4 caffeoylquinic acids and 2 coumaroylquinic acids (structural and/or spatial isomers), and chlorogenic acid was used as the standard to estimate the amount of these six phenolic acids. Chlorogenic acid was used as the standard to estimate the amount of these six cumulative isomers by LC/MS. Additionally, in Moringa leaves we detected one sample containing as many as 12 flavonoids including quercetin and kaempferol glycosides with malonyl, acetyl and succinoyl acylations, among which; quercetin and kaempferol glucosides and glucoside malonates are the major constituents based on analysis of their UV and MS data. Using LC/UV/MS, the quercetin and kaempferol aglycones of quercetin and kaempferol in acidic hydrolyzed extracts were successfully separated within 10 min and individually quantitated. A total of 25 samples were assayed for the chlorogenic acid isomers analogs (0.181 to 0.414 mg/100 g DW), tocopherols (7.1 to 116 mg/100 g DW), carotenoids (4.49 to 45.94 mg/100 g DW) and flavonoids (0.179 to 1.643 % g DW). The concentrations of these phytochemicals varied according to the environment, country of collection, genetics, and variety of Moringa oleifera. The nutritional and natural products characterization of Moringa conducted in this study show that the leaves of this plant can contribute significantly to the daily recommended allowance needed for many vitamins and mineral needs as well as serve as a rich source of polyphenols, confirming the importance and role that Moringa can play to improve the health and nutrition particularly in malnourished populations.M.S.Includes bibliographical references (p. 102-113)