Abstract

Marine sediment samples from Machilipatnam (Krishna District, A.P) coast off Bay of Bengal, India were investigated as a source of actinomycetes to screen for the production of novel bioactive compounds. More than 10,000 bioactive compounds have been described from marine actinomycetes, with many different properties, ranging from colour pigments to cytotoxic compounds. The search for cytotoxic compounds is continuing due to the demand for new anticancer drugs. In this work, compound I was isolated from the marine derived actinomycete strain AUBN₁₀/2, obtained from marine sediment samples of Bay of Bengal, India. This was obtained by solvent extraction followed by chromatographic purification. The pure compound I was identified from spectroscopic data which was related to the actinomycin D, it showed a potent cytotoxic activity against cell lines HMO2 (gastric adenocarcinoma) and HePG2 (hepatic carcinoma) in vitro. It also exhibited antimicrobial activities against gram positive and negative bacteria.

Key words: Marine actinomycetes, phenoxazinone chromophore, actinomycin D, cytotoxic compounds, antibacterial activity.

Abbreviation

GI₅₀, Drug concentration causing 50% growth inhibition; LC₅₀,minimum concentration which reduces the initial cell number to half; TGI, drug concentration causing 100% growth inhibition; MIC, minimum inhibitory concentrations; I, purified antibiotic.