Antioxidant activity of Moringa oleifera seed extracts

The present research evaluates the phytochemical and antioxidant activity of Moringa oleifera Lam. seed kernel grown in Bangladesh. M. oleifera seed kernel was extracted with methanol, acetone and water individually. The phytochemical content was evaluated through the determination of total phenolic, total flavonoid and total tannin contents. In vitro antioxidant capacity was determined following four complementary methods: DPPH (2,2-diphenyl-1-picrylhydrazyl, ABTS{2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)}, and NO (nitric oxide) free radical scavenging and reducing power tests. The total phenolic contents 60.99 +/- 0.153, 30.78 +/- 0.101 and 90.97 +/- 0.134mg gallic acid eq./g dry extract, total flavonoids contents 10.13 +/- 0.171, 13.32 +/- 0.101 and 221.76 +/- 0.221mg quercetin eq./g and total tannins contents 97.10 +/- 0.153, 73.91 +/- 0.107 and 21.74 +/- 0.086mg gallicacid eq./g dry extract were found to be present in methanol, acetone and water extracts respectively. Among the three extracts, the water extract exhibited significant activities for scavenging DPPH, ABTS and NO free radicals with EC50 values 36.89 +/- 0.154, 13.20 +/- 0.049 and 217.95 +/- 0.327g/mL respectively against the standard antioxidant compound ascorbic acid and butylated hydroxy anisole. The results of this research revealed that among the three extracts of M. oleifera seed kernel the water extract exhibited significant free radical scavenging activity. Reducing power, total phenolic and total flavonoid contents were also observed to be significant for the water extract. So in contrast of all the results of this study it can be concluded that among the three extracts (methanol, acetone and water) the water extract possessed potent antioxidant activity which support the use of M. oleifera seed kernel as natural antioxidant.