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

Hypermongones A–J (<b>1</b>–<b>10</b>), rare methylated polycyclic polyprenylated acylphloroglucinol derivatives, together with three known simple acylphloroglucinols (<b>11</b>–<b>13</b>) as their plausible biogenetic precursors, were identified from the flowers of <i>Hypericum monogynum</i>. The structures of <b>1</b>–<b>10</b> 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 <b>1</b>. The evaluation of their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide-induced RAW264.7 cells revealed that compound <b>7</b> exhibited significant NO inhibition activity, with an IC₅₀ value of 9.5 μM