Phomopsichin A-D; Four New Chromone Derivatives from Mangrove Endophytic Fungus Phomopsis sp. 33.

Four new chromone derivatives, phomopsichins A-D (-), along with a known compound, phomoxanthone A (), were isolated from the fermentation products of mangrove endophytic fungus sp. 33#. Their structures were elucidated based on comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction or theoretical calculations of electronic circular dichroism (ECD). They feature a tricyclic framework, in which a dihydropyran ring is fused with the chromone ring. Compounds - showed weak inhibitory activities on acetylcholinesterase as well as α-glucosidase, weak radical scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as OH, and weak antimicrobial activities. Compounds - showed no cytotoxic activity against MDA-MB-435 breast cancer cells. Their other bioactivities are worthy of further study, considering their unique molecular structures.