Akazamicin, a cytotoxic aromatic polyketide from marine-derived Nonomuraea sp.

In our screening program on marine-derived actinomycetes, Nonomuraea sp. AKA32 isolated from deep-sea water collected from a depth of 800 m in Sagami Bay, Japan was found to produce compounds cytotoxic to cancer cells. Activity-guided purification led to the isolation of a new aromatic polyketide, akazamicin (1), along with two known compounds, actinofuranone C (2) and N-formylanthranilic acid (3). Structures of these compounds were elucidated through the interpretation of NMR and MS spectroscopic data. Compounds 1, 2, and 3 displayed cytotoxicity against murine B16 melanoma cell line with the IC50 value of 1.7, 1.2, and 25 mu M, respectively.