Structural elucidation of novel bioactive compound (2-chloro-1-(2-chlorocyclopropyl)-2-(4-nitrophenyl)ethanone) from basidiomycetous fungus Lentinus squarrosulus

While screening for bioactive compounds from macrofungi of Western Ghats of Karnataka, Lentinus squarrosulus a member of polyporaceae was collected and mycelium of the fungus was obtained on potato dextrose agar medium and cultured in a liquid medium (containing 2% glucose, 1% peptone and 2% yeast extract) for 20 days on a rotary shaker for the production of secondary metabolites. The cell free culture fluid (100ml) was subjected to solvent extraction with dichloromethane (100ml) and the extract was evaluated for antimicrobial activity by agar diffusion method and cytotoxic activity of the extract was also determined by MTT and SRB assay on MCF7 cell line. The results revealed that the dichloromethane extract was inhibitory against Escherichia coli, Enterobacter aerogenes, Staphylococcus aureus and Bacillus subtilus and also fungi such as Aspergillus niger, Fusarium solani and Trichoderma harzianum . The extract showed 13-27% cell inhibition at 63-1000 g/ml concentration by MTT and SRB assays on MCF7 cell line. The structural elucidation of the compound by spectroscopic NMR ( 1 H and C 13 ), IR and mass spectrometric analysis confirmed the presence of 2-chloro-1-(2-chlorocyclopropyl)-2-(4-nitrophenyl)ethanone responsible for antimicrobial and cytotoxic activity.