Antioxidant Activity of Polyphenolic RichMoringa oleifera Lam. Extracts in Food Systems

Abstract

Moringa oleifera Lam. has long been used in traditional medicine and for culinary purposes. This study aimed at determining the phenolic content as well as the antioxidative properties of leaf and pod extracts of M. oleifera Lam. in vitro and in mayonnaise and bulk sunflower oil. The methanolic leaf and pod extracts (MLE and MPE) had the highest phenolic content and exhibited the highest antioxidant activities in the Ferric Reducing Antioxidant Potential (FRAP) assay (1,298 ± 4.1 μmol Fe [II]/g fresh weight) compared with the aqueous extracts. Moreover, MLE was the most effective free radical scavenger and metal chelator in the deoxyribose and iron chelation assays, respectively. The antioxidant efficacy of MLE and MPE at 0.2 and 0.4% was compared with that of butylated hydroxytoluene (0.02%) in bulk sunflower oil and mayonnaise. The peroxide and conjugated diene values showed that the extracts effectively protected both systems. MLE at 0.4% exhibited the most potent antioxidant effect. Practical Applications Reactive oxygen species, generated by lipid oxidation, can compromise the safety of foods resulting in harmful effects on human health. There is much interest in natural antioxidants as an effective means to retard oxidative changes in foods due to toxicological concerns associated with synthetic antioxidants. M. oleifera L. is currently underutilized as a food plant despite scientific evidence of its nutritional quality and health benefits mainly ascribed to the presence of antioxidant phytochemicals. This study was aimed at determining the phenolic content and the in vitro antioxidant properties of M. oleifera leaf and pod extracts. The effect of the extracts on oxidative stability in mayonnaise and bulk sunflower oil was also evaluated. Results show that this food plant represents an untapped potential that could be used as a source of natural food additives to retard oxidative damage in various food systems and thus prolonging the shelf life of lipid-bearing foods.