Objectives: Free radicals are the important role in causing various kinds of diseases. Free radicals neutralized with the help of antioxidants, so the aimof this study is to find out the antioxidant potential of ethanolic extract of Terminalia catappa Linn. leaves by in vitro models.Methods: The plant material is collected, authenticated, dried, and grind into powder. The powdered plant material is subjected to successivelySoxhlet extraction with a solvent of ethanol. Ethanol extract of leaves were taken and the extract is subjected to reducing power assay, H assay,nitric oxide assay, and 2,2-diphenylpicrylhydrazyl (DPPH) assay by using standardized methods.Results: The results of all the assays proved that the ethanolic extract of T. catappa has an antioxidant potential on a dose-dependent manner. Thehighest percentage of reducing power (78.04%) is recorded at 500 μg/ml, 500 µg/ml have a (56.4%) of scavenging activity, (74.68%) activity ofnitrous oxide production and DPPH percentage of inhibition is (99.6%). The results were compared with the antioxidant activity of standard ascorbicacid.Conclusion: The study proves that the ethanolic extract of T. catappa leaves is a good source of antioxidants, and future medicated world choose thisphytochemical constituent rich plant for their drug preparation after the deepness of research. In all the methods the plant leaves has been found topossess the antioxidant activity. which may be the responsible for various therapeutic properties. The current study showing that T.catappa is havinghigh quantity of phytochemicals and a worthy source of natural antioxidants. Using this kind of herbal medicine we can lead the life with harmlessdrug for harmful illness.Keywords: Terminalia catappa, Reducing power assay, Hydrogen peroxide assay, Nitric oxide assay and 2-2-diphenyl-1-picrylhydrazylassay
