Rare merosesquiterpenoids from basidiomycete Craterellus odoratus and their inhibition of 11beta-hydroxysteroid dehydrogenases.

Rare merosesquiterpenoids, craterellins A-C (1-3), were isolated from cultures of basidiomycete Craterellus odoratus together with the previously known massarinolin C (4). Structures of 1-3 were elucidated on the basis of extensive spectroscopic analysis. Compounds 1-3 possess a rare, epoxymethylenecyclohexanetriol-bicyclofarnesane sesquiterpene hybrid skeleton. Compounds 1-4 were evaluated for their inhibitory activities against two isozymes of 11beta-hydroxysteroid dehydrogenases (11beta-HSD1 and 11beta-HSD2).