In vitro antimicrobial, antioxidant and cytotoxic properties of Streptomyces lavendulae strain SCA5

Background: Actinomycetes are Gram-positive, often filamentous, bacteria known for their unsurpassed capacity for the production of secondary metabolites with diverse biological activities. The aim of the present study was to evaluate the antimicrobial, cytotoxic and antioxidant properties of Streptomyces lavendulae strain SCA5. Results: The ethyl acetate extract of SCA5 broth (EA-SCA5) showed antimicrobial activity with MIC value of 31.25 mu g/ml. EA-SCA5 showed good antioxidant potential by scavenging 2, 2-diphenyl-picrylhydrazyl (DPPH) (IC50 507.61 +/- 0.66 mu g/ml), hydroxyl radical (IC50 617.84 +/- 0.57 mu g/ml), nitric oxide (IC50 730.92 +/- 0.81 mu g/ml) and superoxide anion radical (IC50 864.71 +/- 1.15 mu g/ml). The EA-SCA5 also showed strong suppressive effect on rat liver lipid peroxidation (IC50 838.83 +/- 1.18 mu g/ml). The total phenolic content of SCA5 was 577.12 mg of GAE equivalents/gram extract. EA-SCA5 exhibited cytotoxic activity on A549 adenocarcinoma lung cancer cell line. It showed 84.9% activity at 500 mu g/ml with IC50 value of 200 mu g/ml. The gas chromatography mass spectrometry (GC-MS) analysis revealed the presence of one major bioactive compound actinomycin C2. Conclusions: The results of this study indicate that the EA-SCA5 could be probed further for isolating some medically useful compounds.