Superoxide radical scavenging activity.The superoxide anion radical was generated by xanthine/xanthine oxidase system. Superoxide radical scavenging activity was performed according tothe method described by Arumugam, Subathra, and Ramesh (2010).In brief, the reaction mixture consisted of 2.70 ml of 40 mmol/lsodium carbonate buffer containing 0.1 mmol/l ethyl-enediaminetetraacetic acid (EDTA) (pH 10.0), 60 ml of 10 mmol/lxanthine in 25 mmol/l sodium hydroxide solution, 30mlof5mg/mlbovine serum albumin (BSA), 30 ml of 2.5 mmol/l nitroblue tetra-zolium (NBT) and 60 ml of extracts. The mixture was kept at room temperature (25C) for 20 min, and after that 120ml of xanthineoxidase (0.04 units/ml) diluted in 50 mmol/l Tris-HCl buffer (pH7.5) was added to start the reaction. The absorbance at 560 nm wasrecorded after 5 min. The solution of 60ml methanol is used asa control. The tests were performed in triplicate. Results areexpressed as percentage of inhibition of superoxide radicals.Percentage of inhibition is calculated using the formula