Tetracenoquinocin and 5-Iminoaranciamycin from a Sponge-Derived Streptomyces sp Sp080513GE-26

Two new anthracyclines, tetracenoquinocin (1) and 5-iminoaranciamycin (2), together with the known compounds aranciamycin (3) and antibiotic SM 173B were isolated from the culture of Streptomyces sp. Sp080513GE-26 associated with a marine sponge, Haliclona sp. The structures of 1 and 2 were established on the basis of extensive NMR and MS analyses along with C-13-labeling experiments. The compounds 1-3 were evaluated for cytotoxicity against two cancer cell lines.