Antioxidant and Free Radical Scavenging Activities of Ervatamia coronaria Stapf. Leaves

The present study was carried out to evaluate the antioxidant and free radical scavenging activity of methanolic extract of Ervatamia coronaria leaves (Apocynaceae) in various systems. DPPH radical, superoxide anion radical, nitric oxide radical and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of methanolic extract increased in a dose dependent manner. About 50, 100, 250 and 500 µg of methanol extract of Ervatamia coronaria (MEEC) showed 61.33, 66.21, 72.04 and 76.83% inhibition respectively on peroxidation of linoleic acid emulsion. Like antioxidant activity, the effect of MEEC on reducing power increases in a dose dependent manner. In DPPH radical scavenging assay the IC₅₀ value of the extract was found to be 167.09 µg/ml. MEEC was found to inhibit the nitric oxide radicals generated from sodium nitroprusside. The IC₅₀ value was found to be 83.375 µg/ml, whereas the IC₅₀ value of curcumin was 20.4 µg/ml. Moreover, the MEEC was found to scavenge the superoxide generated by PMS/NADH-NBT system. MEEC was also found to inhibit the hydroxyl radical generated by Fenton's reaction, where the IC₅₀ value of MEEC was found to be more than 1000 µg/ml and for catechin the IC₅₀ value was found to be 5 µg/ml, which indicates the prooxidant activity of MEEC. The amounts of total phenolic compounds were also determined in this study. The results obtained in the present study indicate that the MEEC can be a potential source of natural antioxidant.