10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 4 2013 (October - December) The present investigation was to study the purification and lessThan i greaterThan In vitro lessThan /i greaterThan antioxidant activities of the polysaccharide from green seaweed lessThan i greaterThan Caulerpa racemosa lessThan /i greaterThan . The polysaccharide was isolated and purified from green seaweed lessThan i greaterThan C. racemosa lessThan /i greaterThan by ethanol precipitation and DEAE-cellulose ion exchange chromatography. The chemical analysis of polysaccharide showed carbohydrate content (47.43%), sulfate content (12.86%) and uronic acid content (4.9%). The lessThan i greaterThan In vitro lessThan /i greaterThan antioxidant activity was determined by free radical scavenging assays such as total antioxidant activity (80.24±0.56%), Reducing power assay [(0.243±0.04) - (1.624±0.07)],Hydrogen peroxide assays (77.22±0.67%),DPPH assays (71.42±0.74%), ABTS assays(73.32±1.27%), Hydroxyl assays (68.29±1.03), Superoxide anion assays (66.17±0.77 %) and Nitric oxide radical assay (40.64±1.82%). The antioxidant capacities of the lessThan i greaterThan C. racemosa lessThan /i greaterThan polysaccharides showed potential rich sources of natural antioxidants. S. MAHENDRAN AND S.SARAVANAN Caulerpa racemosa,polysaccharide, DEAE-cellulose, In vitro antioxidant activities. 1214-1227