Extraction and identification of antibacterial compound from marine Streptomyces sp. VITAK1 isolated from the coast of Andaman and Nicobar Islands, India

Abstract

Marine bacteria are considered as imperative source for novel antibacterial compounds. The marine Streptomyces species was isolated from the sediment sample collected at the coast of Andaman and Nicobar Islands, India and identified as Streptomyces sp. VITAK1. The petroleum ether (PE) extract prepared from the culture supernatant of the isolate was purified by silica gel column chromatography using a mixture of PE and ethyl acetate (1 : 1 vol/vol) as solvent system. The purified compound was identified by using 1H and 13C NMR spectral data and GC-MS based on the similarity index with the reference compounds available in the mass spectra library of National Institute for Standards and Technology as coumarin-6-ol, 3,4-dihydro-4,4,5,7-tetramethyl- (CDTM). The antibacterial activity of the purified compound was tested according to the National Committee for Clinical Laboratory Standards guidelines and it was revealed that the lead compound showed IC50 value ranging from 2.5–40 µg/mL against tested bacterial pathogens. Proteus vulgaris was the most susceptible (IC50: 2.5 µg/mL) to inhibition by CDTM. In addition, the lead compound showed concentration-dependent anticoagulant activity with human blood samples. The results of the study suggest that Streptomyces sp. VITAK1 is the potential source for coumarin type of antibacterial compound.