Hitoyol A and B, Two Norsesquiterpenoids from the Basidiomycete Coprinopsis cinerea

Hitoyol A ( 1 ), an unprecedented norsesquiterpenoid with an exo -tricyclo[5.2.1.0 2,6 ]decane skeleton, was isolated from the culture broth of Basidiomycete Coprinopsis cinerea along with a novel skeletal hitoyol B ( 2 ) containing 4-cyclopentene-1,3-dione. Their structures and absolute configurations were analyzed by single-crystal X-ray diffraction and electronic circular dichroism spectroscopic methods. Compound 1 is possibly biosynthesized through decarboxylation-induced cyclization of lagopodin B, a known cuparene-type sesquiterpenoid. Compound 2 showed weak antimalarial activity with an IC 50 of 59 μM.