The antioxidant activity and free radical-scavenging capacity of phenolics of raw and dry heated moth bean (Vigna aconitifolia) (Jacq.) Marechal seed extracts

The antioxidative properties and total phenolic contents of Vigna aconitifolia   were examined. The raw and dry heated samples were extracted with 70% acetone and the extracts were freeze-dried. The raw seeds contained higher levels of total phenolics (6.54%) and tannins (1.91%) than the dry heated seeds. The extracts were screened for their potential antioxidant activities using O2-, OH, α,α-diphenyl-β-picrylhydrazyl (DPPH), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), Ferric reducing/antioxidant power (FRAP), linoleic acid emulsion and Fe2+ chelating systems. At 1 mg of extract in the reaction mixture, the superoxide anion radical-scavenging activity was found to be similar in raw and dry heated seed extracts. The DPPH radical and ABTS cation radical scavenging activities were well proved and correlated with the ferric reducing antioxidant capacity of the extracts. Interestingly, both raw and dry heated seed extracts showed the highest hydroxyl radical scavenging activity of 67.3% and 68.5%, respectively, at concentration of 1 mg/g extract. In addition, both extracts exhibited good peroxidation inhibiting activity (54.2% and 58.2%, respectively) against the linoleic acid emulsion system and the values were lower than BHA and Trolox. Fe2+ chelating activity was also detected in both raw and dry heated seed with EDTA equivalent of 0.61 mg and 0.45 mg/g extracts, respectively.