In vitro antimicrobial and antioxidant activities of bark extracts of <i>Bauhinia purpurea</i>

Abstract

Bark extracts of Bauhinia purpurea were phytochemically analyzed and evaluated for antimicrobial and antioxidant activities. The phytochemical analysis of the bark extracts revealed the presence of alkaloids, flavonoids, steroids, saponins, triterpenes and carbohydrates. While most of them were present in methanolic and aqueous extracts, one or a few of them were present in other solvent extracts. Among different solvent extracts, aqueous extract exhibited a broad spectrum of antimicrobial activity. It showed strong antibacterial activity against Gram positive bacterial strains like Bacillus subtilis, Staphylococcus aureus and Gram negative strains like Escherichia coli and Klebsiella pneumonia and antifungal activity against Candida albicans. While methanolic extract showed moderate to strong antibacterial activity against B. subtilis, E. coli and K. pneumonia, the extracts of hexane, chloroform and ethyl acetate did not show any anti bacterial or antifungal activity against the tested fungal and bacterial strains. Antioxidant activity of the bark extracts were evaluated in terms of inhibition of free radicals by 2, 2’-diphenly-1-picrylhydrazyl (DPPH). Aqueous extract followed by methanolic extract exhibited strong to moderate antioxidant activity. The antioxidant property and antimicrobial activity of the extracts of B. purpurea against the tested microbial strains therefore, supports that there is scientific basis for their utilization in traditional medicine for wound healing and also in treatment of some infectious diseases.

Key words: Bauhinia purpurea, phytochemical analysis, antimicrobial activity, antioxidant property.