Evaluation of Bauhinia variegata L. bark fractions for in vitro antioxidant potential and protective effect against H2O2-induced oxidative damage to pBR322 DNA

Abstract

Bauhinia variegata L. (Fabaceae) is widely used in Indian traditional medicine. The present study was undertaken to evaluate the protective effect of different fractions from the crude methanolic extract of B. variegata L. bark against free radicals and H2O2-induced oxidative damage to pBR322 DNA. 80% methanol extract (MEB) of the bark was fractionated into non-polar fractions, including hexane (HEB), chloroform (CFB) fractions and Polar fractions, including n-butanol (NBB), ethyl acetate (EAB) and remaining extract (REB). The extact/fractions were analysed for total phenolic and flavonoid content and antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power assays while the genoprotective activity was assessed using DNA nicking assay. The polar fractions, MEB, EAB, NBB and REB showed greater antioxidant activity (EC50 44.07, 58.09, 69.68 and 51.81 μg/ml, respectively) in comparison to non-polar fractions. However, all the fractions effectively protected pBR322 plasmid DNA from the H2O2 induced damage. The phytochemical analysis of the polar fractions revealed them to be rich in the phenolic/flavonoid content and that significant correlation existed between phenolic/flavonoid content and antioxidant activity. Our studies showed that the phytoconstituents of B. variegata harbour the potential to combat various free-radicals and need further investigation. © 2011 Academic Journals.