Cytotoxic polyprenylated benzoylphloroglucinol derivatives with an unusualadamantyl skeleton from Hypericum sampsonii (Guttiferae)

[GRAPHICS] The structures of sampsoniones I and J, isolated from the aerial parts of t he Chinese medicinal plant Hypericum sampsonii, have been elucidated by det ailed spectral analysis. They are complex adamantyl derivatives, and sampso nione I is the first polyprenylated benzoylphloroglucinol derivative with t he unique caged tetracyclo[7.3.1.1(3,11).0(3,8)]tetradecane-2,12,14-trione skeleton. Cytotoxic sampsonione I has also been obtained by the biomimetic transformation of sampsonione J.