Antioxidant and Free Radical Scavenging Activities of Zingiberofficinale
The present study was carried out to evaluate the antioxidant and free radical scavenging activity of ethanolic extract of ZingiberofficinaleRhizomes (Zingiberaceae) in various systems. DPPH radical, superoxide anion radical, nitric oxide radical and hydroxyl radicalscavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of ethanolic extract increased in a dose dependent manner. About 50,100, 250 and 500 μg of ethanol extract of Zingiberofficinale(EZO) showed 61.44,66.25, 72.01 and 76.85% inhibition respectively on peroxidation of linoleic acid emulsion. Like antioxidant activity, the effect of EZO on reducing power increases in a dose dependentmanner. In DPPH radical scavenging assay the IC50 value of the extract was found to be 168.09μg/ml. EZO was found to inhibit the nitric oxide radicals generated from sodiumnitroprusside. The IC50 value was found to be 83.365 μg/ml, whereas the IC50 value of curcumin was 20.34 μg/ml. Moreover, the EZO was found to scavenge the superoxide generated byPMS/NADH-NBT system. EZO was also found to inhibit the hydroxyl radical generated byFenton's reaction, where the IC50 value of EZO 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 EZO. The amounts of total phenolic compounds were also determined in this study. Theresults obtained in the present study indicate that the EZO can be a potential source of naturalantioxidant.