EVALUATION OF IN VITRO ANTIOXIDANT POTENTIAL OF METHANOLIC EXTRACT OF COCCULUS HIRSUTUS (L.) DIELS Mukesh Kumar Meena, Neelam Singh, Vidya Patni Plants are a potential source of natural antioxidants. Antioxidants protect from the potentially damaging oxidative stress, which is a result of an imbalance between the formation of ROS (Reactive oxygen species) and the body antioxidant defense. The present study was directed to investigate the antioxidant activity of methanolic extract of different plant parts of Cocculus hirsutus. The antioxidant activity of the methanolic extracts of in vivo and in vitro plant parts of Cocculus hirsutus was determined on the basis of their scavenging activity of the stable 2, 2- diphenyl- 2-picryl hydrazyl (DPPH) free radical. In the present study, methanolic extracts of the different plant parts and callus of Cocculus hirsutus showed potential free-radical scavenging activity. The methanolic extract of Cocculus hirsutus and Ascorbic acid (standard) showed DPPH free radical scavenging activity in a concentration range of 10-1000 μg/ml and its inhibition ranged from 36.92 - 84.1% and that of standard was 49.68 - 94.60%. Methanolic extracts of callus were found to have maximum IC50 value (151.65 µg/ml) followed by leaf (121.45 µg/ml) and stem (37.83 µg/ml). Standard antioxidant used was Ascorbic acid (1mg/ml) having 24.79 µg/ml IC50 value. The highest DPPH radical scavenging activity was detected in methanolic extract of stem followed by methanolic extract of leaf and callus respectively. These activities are less than that of standard ascorbic acid. The results of DPPH scavenging activity assay in this study indicates that the methanolic extract of stem was potently active than other plant parts of Cocculus hirsutus and the methanolic extract of the study species is effective in scavenging free radicals and has the potential to be powerful antioxidant. International Journal Of Pharmacy 2249-1848 2014-01-23 1 204-207 Copyright (c) Pharma Scholars. All rights reserved 2013