Isolation and characterization of marine actinomycetes – bioprospecting for antimicrobial, antioxidant and anticancer properties

Abstract The novel therapeutic agents are frequently produced from marine actinomycetes and are still being explored due to their vast diversity. In this research, we isolated five marine actinomycetes (BN01, BN12, BN13, BN14 and GB15) from the soil sediments of the coastal region of Chennai, Tamil Nadu, India. The morphological and physicochemical properties of the isolates were characterized. The 16S rRNA sequencing analysis showed that the isolates were belonging to two genera namely Streptomyces and Saccharopolyspora. The extracellular crude secondary metabolites were extracted from the culture filtrate of all the marine actinomycetes isolated and tested for the antimicrobial, antioxidant and anticancer potential adopting standard methods. The results revealed that the extracts of the isolates BN01, BN14, and GB15 exhibited antimicrobial activity against M. luteus, E. coli, and S. aureus, with the maximum zone of inhibition of 19 mm, 21 mm, and 27 mm respectively, at the concentration of 10 mg/mL. The extract of the isolate BN12 showed excellent radical scavenging activity of 97.75 % at the concentration of 60 µg/mL and has the half-maximal inhibitory concentration (IC50) of 8.66 µg/mL. The anticancer activity results showed that the extract of the isolate BN12 had better inhibitory activity against the MCF 7 cell line with the IC50 value of 261.01 µg/µL.