Hypermongones A–J, Rare Methylated Polycyclic Polyprenylated Acylphloroglucinols from the Flowers of Hypericum monogynum

Hypermongones A–J (1–10), rare methylated polycyclic polyprenylated acylphloroglucinol derivatives, together with three known simple acylphloroglucinols (11–13) as their plausible biogenetic precursors, were identified from the flowers of Hypericum monogynum. The structures of 1–10 were elucidated by analysis of their 1D and 2D NMR spectroscopic data; the absolute configuration of their polycyclic skeleton was determined by the electronic circular dichroism exciton chirality method and was subsequently confirmed by an X-ray diffraction study of 1. The evaluation of their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide-induced RAW264.7 cells revealed that compound 7 exhibited significant NO inhibition activity, with an IC50 value of 9.5 μM.