Lithocarpinols A and B, a pair of diastereomeric antineoplastic tenellone derivatives from the deep-sea derived fungus Phomopsis lithocarpus FS508

Abstract Lithocarpinols A ( 1 ) and B ( 2 ), a pair of tenellone diastereoisomers with novel fused skeleton were isolated from the deep-sea derived fungus Phomopsis lithocarpus FS508. Their structures were elucidated by comprehensive spectroscopic analyses, X-ray diffraction and quantum molecular calculation. Their plausible biogenetic pathway featured an intriguing carbonyl-ene cyclization. Lithocarpinol A exhibited moderate inhibitory effect against HepG-2 and A549 tumor cell lines with IC 50 values of 9.4 μmol/L and 10.9 μmol/L, respectively.