Antifungal and antibacterial activities of Pentanema divaricatum and its active constituent.

The antimicrobial activity of ethanol and chloroform extracts of Pentanema divaricatum Cass. was studied using the conventional disk diffusion method. The extracts' highest antimicrobial activity was observed against Aspergillus niger. Bioassay-guided fractionation of the crude extract by preparative thin layer chromatography (PTLC) showed one antimicrobial fraction which was especially effective against Aspergillus niger. By conventional spectroscopy the active fraction was identified as 4alpha,5alpha-epoxy-10alpha,14H-1-epi-inuviscolide. This compound represented the most potent antimicrobial candidate, with MIC values of <25 microg/disk against A. niger strains and 200 microg/disk against Bacillus cereus and Staphylococcus aureus.