Metabolites from the marine actinobacterium Streptomyces sp. KMM 7210

Abstract

In continuation of the search for biologically active metabolites from marine actinobacteria, we studied the strain Streptomyces sp. KMM 7210 that was isolated from sediment samples of Troits Bay (Poset Gulf, Sea of Japan). Cultivation of this strain in medium consisting of edible potato starch (10 g/L), peptone (2 g/L), yeast extract (2 g/L), CaCO3 (1 g/L), pH 7.7, and distilled water:seawater (1:1) for 6 d at ~20°C produced compounds with cytotoxic activity against sea urchin Strongylocentrotus intermedius embryos. The cultivation liquid (20 L) was centrifuged for 30 min at 500 g. The resulting cells were suspended in distilled H2O (100 mL) and destroyed with cooling by ultrasound for 2 min at 20-second intervals. The suspension of destroyed cells was extracted (3 ) successively with EtOH and acetone. The supernatant was extracted with EtOAc (3 ). The resulting extracts were combined and evaporated to dryness. The dry solid (600 mg) was chromatographed over a column of SiO2 using a gradient of hexane:EtOAc (10:1, 5:1, 2:1, 3:2, 1:1), EtOAc, and EtOAc:EtOH (20:1, 10:1). This produced pure 1 (3 mg), 2 (2 mg), 3 (2.2 mg), and 4 (2.5 mg).