Striatoids A-F, Cyathane Diterpenoids with Neurotrophic Activity from Cultures of the Fungus Cyathus striatus

Six new highly oxygenated polycyclic cyathane-xylosides, named striatoids A-F (1-6), were isolated from the cultures of the basidiomycete Cyathus striatus. Their structures were established by comprehensive spectroscopic analysis including 2D NMR (HMBC, HSQC, ROESY, H-1-H-1-COSY) and HRESIMS experiments. Compounds 2 and 3 possess an unusual 15,4'-ether ring system. The isolated compounds dose-dependently enhanced nerve growth factor (NGF)-mediated neurite outgrowth in rat pheochromocytoma (PC-12) cells.