Anti-cancer and Antibacterial Trioxacarcins with High Anti-malaria Activity from a Marine Streptomycete and their Absolute Stereochemistry

The ethyl acetate extract from the Streptomyces sp. isolate B8652 delivered the trioxacarcins A-C (2a-2c) and additionally three new derivatives designated as trioxacarcins D-F (2d-2f). All trioxacarcins showed high anti-bacterial and some of them high anti-tumor and anti-malaria activity. The structures of the new antibiotics were derived from mass, 1D and 2D NMR spectra and confirmed by comparison of the NMR data with those of known derivatives. The absolute configuration of the trioxacarcins is deduced from the X-ray analysis of gutingimycin (2g) and from the known stereochemistry of the L-trioxacarcinoses A and B.