Antimicrobial and Antimycobacterial Activities of Methyl Caffeate Isolated from Solanum torvum Swartz. Fruit

Solanum torvum Swartz. (Solanaceae) fruit is traditionally used for the treatment of bacterial and fungal infections. The methanolic extract was subjected to activity guided fractionation by column chromatography over silica gel. The structure of the compound was elucidated using physical and spectroscopic data. The antimicrobial activity was screened using five Gram-positive bacteria, six Gram-negative bacteria, seven clinical isolates and four fungi. Antimycobacterial activity was screened against two Mycobacterium strains. The zone of inhibition by methyl caffeate ranged from 0 to 22 mm. The lowest minimum inhibitory concentration (MIC) values of methyl caffeate were: 50 mu g/ml against P. vulgaris, 25 mu g/ml against K. pneumoniae (ESBL-3971), 8 mu g/ml against M. tuberculosis (H(37)Rv) and 8 mu g/ml against M. tuberculosis (Rif(R)). Methyl caffeate showed moderate antimicrobial and prominent antimycobacterial activities. Methyl caffeate can be evaluated further for drug development.