In vitro activity of 5-(2,4-dimethylbenzyl) pyrrolidin-2-one extracted from marine Streptomyces VITSVK5 spp. against fungal and bacterial human pathogens.

BACKGROUND Pharmacological screening and usage of natural products for the treatment of human diseases has had a long history from traditional medicine to modern drugs. The majority of modern drugs are reported to be mostly from natural products. OBJECTIVE The aim of the present study was to evaluate the inhibitory activity of 5-(2,4-dimethylbenzyl) pyrrolidin-2-one (DMBPO) extracted from marine Streptomyces VITSVK5 spp. isolated from sediment samples collected at Marakkanam coast of Bay of Bengal, India. METHODS The lead compound was isolated by bioactive guided extraction and purified by silica gel column chromatography. Structural elucidation of the lead compound was carried out by using UV, FT-IR, (1)H NMR, (13)C NMR, DEPT and HR-MS spectral data. RESULTS Systematic screening of isolates for antimicrobial activity lead to identification of a potential strain, Streptomyces VITSVK5 spp. (GQ848482). Bioactivity guided extraction yielded a compound DMBPO and its inhibitory activity was tested against selected bacterial and fungal strains. DMBPO showed maximal activity against Escherichia coli with a MIC value of 187 μg/ml, followed by Klebsiella pneumoniae (MIC of 220 μg/ml and 10.3mm zone of inhibition), Staphylococcus aureus (MIC of >1000 μg/ml and 4.4mm zone of inhibition) and Bacillus subtilis (MIC of 850 μg/ml and 2.6mm zone of inhibition). Furthermore, DMBPO was found to be a potent inhibitor of opportunistic fungal pathogens too. It showed a maximum activity against Aspergillus niger with a MIC value of 1 μg/ml and 28 mm zone of inhibition. CONCLUSION The result of this study indicates that DMBPO possess antibiotic activity to selected bacterial and fungal pathogens and exhibited better activity against fungi than bacteria.