摘要Objective: To investigate the antioxidant activity of marine actinobacteria. Methods: The content of total phenolics, the level of antioxidant potential by DPPH radical scavenging activity, metal chelating activity, FRAP method, β carotene assay and NO scavenging activity in extract were determined. Results: In all the methods the extract exhibited good scavenging activity except NO scavenging activity. The IC50 values of marine actinobacteria extract on DPPH radical were found to be 41.09 μg/mL. The zone of color retention was 12 mm in β-carotene bleaching assay. DNA protective efficiency of the extracts was also studied using UV- photolysed H2O2-driven oxidative damage to pBR322. HPLC analysis identified some of the major phenolic compounds in extracts, which might be responsible for the antioxidant potential and cyto-protection. It showed a 100% cytotoxic effect in brine shrimp lethality assay within 10 mins. The novel actinobacteria was identified as Streptomyces LK-3 (JF710608) through 16S rDNA Sequencing. Conclusions: The results obtained suggest that the extracts bear anti-cancer metabolites and could be considered as a potential source for anti-cancer drug development.