Isolation and Structures of Haterumadioxins A and B, Cytotoxic Endoperoxides from the Okinawan Sponge Plakortis lita

Cytotoxic endoperoxides, haterumadioxins A (1) and B (2), were isolated from the Okinawan sponge Plakortis lita. Their structures were determined by spectroscopic analysis. The absolute stereostructure of 1 was determined by degradation reactions and the modified Mosher's method. Haterumadioxins showed significant cytotoxicity against 38 human cancer cell lines.