Objective: To characterize and standardize the ethanolic extract of Adhatoda vasica (AV) and evaluate its antioxidant potential in vitro, and to studyits free radical scavenging effect in A549 cell line.Methods: Antioxidant activity of AVE through DPPH, ABTS, superoxide radical scavenging activity, H2O2, NO and Lipid peroxidation assays werecarried out.Results: In A549 cell line, the NO scavenging ability of AVE was analysed through NO production measurement. IC values of ethanolic extract throughDPPH, ABTS, superoxide radical scavenging activity, H2O250, NO and lipid peroxidation assays were found to be 64, 200, 54, 62, 40 and 340 µg/ml,respectively. The reducing power was found to increase in a concentration dependent manner. AVE (1 - 2µg/ml) scavenged NO radicals (11% and28% in comparison to control).Conclusion: The present study showed the ethanolic extract of AV to be a good oxygen radical scavenger and a natural source of antioxidants. AVEshowed significant nitric oxide radical scavenging activity in A549 cell line.Keywords: Adhatoda vasica, Phytochemicals, Flavonoids, Tannins, Antioxidant potential
