Antimicrobial activity of Bauhinia tomentosa and Bauhinia vahlii roots

The hexane, ethylacetate and methanol extracts from Bauhinia tomentosa and Bauhinia vahlii roots were tested for their antimicrobial activity against Gram-positive bacteria (four strains), Gram-negative bacteria (three strains) and three fungi strains using microdilution methods, for the determination of minimal inhibition concentration (MIC) and the minimal microbicidal concentration (MMC). The MIC values of hexane extracts of B. tomentosa and B. vahlii roots were more than 250 μg/ml. The MIC values of ethylacetate and methanol extracts of B. tomentosa roots varied from 7.81 to 31.25 μg/ml and 31.25 to 62.50 μg/ml, respectively. The MIC values of ethylacetate and methanol extracts of B. vahlii roots varied from 15.63 to 62.5 μg/ml and 62.5 to 250 μg/ml, respectively. MMC values obtained are two times greater than the corresponding MIC values. The activities of ethylacetate extracts are attributed to the presence of flavonoids and that of methanol extracts are attributed to the presence of tannins.