Cosmos leaf (Cosmos sulphureus) contains various secondary metabolites such as phenolic, flavonoid, alkaloid, and essential oil; hence it needs to be fractionated to find out the phenolic compound with the greatest potential as an antioxidant. This research study was aimed to know an antioxidant potential of ethyl acetate extract from Cosmos leaves. It was extracted by Soxhlet apparatus. The crude extract was fractionated with ethyl acetate. Ethyl acetate fraction was screened for phytochemical content including identification of phenolic and flavonoids. The antioxidant activity of ethyl acetate fractions were tested qualitatively with Nitric Oxide radical assay. Phytochemical screening test showed that ethyl acetate fraction from Cosmos leaves contain phenolic and flavonoids. Concentration of phenolic content was found to be 0.164mg/ml and flavonoid concentration was found to be 0.169mg/ml. The qualitative analysis of ethyl acetate fractions from Cosmos leaves showed an antioxidant activity. The IC50 value of ethyl acetate fractions and Standard Ascorbic acid were 129.21μg/ml, 13.29μg/ml respectively. The research had shown that the ethyl acetate fraction of the Cosmos leaves have more potential for antioxidant activity, but less as compare to standard Ascorbic acid. Thus this study concluded that, the result might be helpful for treatment of oxidative stress generated diseases.
