Phytochemical analysis and free-radical scavenging activity of Flemingia strobilifera (Linn) R. Br

The present investigation is to evaluate the antioxidant activity of various extracts of root and leaf of F. strobilifera using different in vitro methods and its phytochemical analysis. The antioxidant activity was studied by DPPH radical scavenging method, nitric oxide radical inhibition assay and scavenging of hydroxyl radical by p-NDA method. Methanolic extract of root and leaf of F. strobilifera showed a very good DPPH radical scavenging activity with low IC50 values of 11.4 μg/ml and 38.0 μg/ml respectively. Butanolic extract of F. strobilifera root showed good nitric oxide radical inhibition activity with IC50 of 150.0 μg/ml in a dose-dependent manner. The methanolic extract of root showed hydroxyl radical scavenging by p-NDA method with IC50 value of 378.33 μg/ml. Subsequent quantification showed the presence of 13.75 and 8.84 % w/w phenolics (calculated as gallic acid), 2.14 and 3.26 % w/w of flavonol in methanol extract of root and leaf of F. strobilifera respectively. The high amount of flavonols and phenolics prompted us to evaluate its antioxidant activity. This study revealed that methanolic extract of F. strobilifera comprise effective potential source of natural antioxidant, which might be helpful in preventing the progress of various oxidative stresses.