In vitro antioxidant and free radical scavenging activity of Cyperus rotundus

Cyperus rotundus (Family Cyperaceae) is used both as a functional food and as a drug. In this study, the antioxidative potential of a hydroalcoholic extract of C. rotundus (CRE) was evaluated by various antioxidant assays, including antioxidant capacity by the phosphomolybdenum method, total antioxidant activity in linoleic acid emulsion systems, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, hydroxyl radicals, and nitric oxide (NO) scavenging. We further evaluated the reducing potential of the extract as well as Fe2+/ascorbate-induced lipid peroxidation in rat liver homogenate. These various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene, tocopherol, L-ascorbic acid, and catechin. Total phenolic and flavonoid content of CRE was also determined by a colorimetric method. The extract exhibited high reduction capability and powerful free radical scavenging, especially against DPPH and superoxide anions as well as a moderate effect on NO. CRE also showed inhibited lipid peroxidation in rat liver homogenate induced by Fe2+/ascorbate and prevented deoxyribose degradation in both non-site-specific and site-specific assays showing the hydroxyl radical scavenging and metal chelating activity of the hydroalcoholic extract. Moreover, the peroxidation inhibiting activity of CRE was demonstrated in the linoleic acid emulsion system. These results clearly established the antioxidative potency of C. rotundus, which may account for some of the medical claims attributed to this plant.