Characterization of Antioxidant Activity of Twenty Selected Medicinal Plants Growing in North-Western Himalaya

In search of new sources of antioxidant compounds, the antioxidant activities of 20 selected medicinal plants were determined using ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays, and the total phenolic contents of these plants were measured by Folin-Ciocalteu method. Plants were extracted by the traditional method, boiling in water and also in methanol. Significant and linear correlation between antioxidant activity and phenolic content was observed in both aqueous (R²_FRAP = 0.8889; R²_DPPH = 0.8271) and methanol (R²_FRAP = 0.9109; R²_DPPH = 0.8932) extracts. Phenolic compounds are thus major contributor of antioxidant activities of these plants. Comparison of extraction efficiency of the two methods revealed that the methanol method extracted phenolic compounds efficiently, and antioxidant activity of extract was higher. Medicinal plants Syzygium cumini, Ocimum sanctum, Picrorhiza kurroa, Cinnamomum camphora and Cinnamomum tamala showed highest antioxidant activities and thus could be potential rich sources of natural antioxidants.