Biyoulactones D and E, meroterpenoids from Hypericum chinense

Two new meroterpenoids, biyoulactones D (1) and E (2), were isolated from the roots of Hypericum chinense, and their structures were elucidated on the basis of spectroscopic data and conformational analysis. Biyoulactones D (1) and E (2) are structurally unique tricyclic meroterpenoids having an octahydroindene ring, a γ-butyrolactone ring, and a β-diketone moiety.