Sampsoniones A–M, a Unique Family of Caged Polyprenylated Benzoylphloroglucinol Derivatives, from Hypericum sampsonii

Further thorough investigation of the ethanolic extract of the aerial parts of Hypericum sampsonii has yielded sampsoniones K–M which together with the earlier isolated sampsoniones A–J form a unique family of related polyprenylated benzoylphloroglucinol derivatives formed by complex cyclisations of prenyl groups. The structures of these cage compounds have been elucidated by extensive studies of various spectrometric techniques. The 13 metabolites, some of which are bioactive, are probably biosynthesized from a simple common benzoylphloroglucinol precursor.