Physiological and antioxidant potential of important medicinal plants i.e. Cassia fistula, Terminalia arjuna and Azadirachta indica were determined. The radical scavenging activity of extracts was evaluated using 2, 2-diphenyl-1-picryhydrazyl (DPPH) assay and The total phenolic content was determined by following Folin-Ciocalteau assay. In the results different plants showed different activities, in the case of Chlorophyll a (Chl a) and chlorophyll b (Chl b) maximum recorded in Azadirachta indica and Terminalia arjuna respectively while minimum in Cassia fistula. In case of carotenoid and protein contents were found maximum in Cassia fistula and minimum in Terminalia arjuna. Antioxidant activity i.e., DPPH and total phenolic contents were found maximum in Terminalia arjuna and minimum in Cassia fistula. These finding indicated that the Terminalia arjuna have most potent antioxidant potential as comparison with other two species. The present study reveals that the selected plants would exert beneficial effects by virtue of their antioxidant activity and could be harnessed as drug formulation.