Radical Scavenging Activity of Methanol Leaf Extracts of Orthosiphon stamineus.

Abstract

The antioxidant activity of methanol extracts of Orthosiphon stamineus. Benth (Lamiaceae), cultivated in different regions of Malaysia, was determined by measuring the scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and on superoxide anion. The results showed a variation in free-radical and superoxide-anion scavenging activities of the methanol extracts ranging from 62.82 to 92.34% and 53.29 to 75.88%, respectively. Methanol extract was active, and its antioxidative potency was comparable to that of pure quercetin and higher than that of the widely used synthetic antioxidant butylated hydroxylanisole (BHA). The UV and HPLC chromatographic fingerprints of the major phenolics were qualitatively similar for all the methanol leaf extracts of Orthosiphon stamineus. from various locations.