The new sesterterpenoid 6-epi-3-anhydroophiobolin B (1) and six known ophiobolins were isolated fromthe extracts of the fungus Cochliobolus heterostrophus race O. The structure of 6-epi-3-anhydroophiobolinB was deduced from analysis of spectral data and the structural characterization of dehydration anddimerization products. Ophiobolin A (2) showed potent activity in cytotoxicity assays and marginal activityin antimalarial assays.
