Discovery of 13,15- nor -polycyclic polyprenylated acylphloroglucinols from Hypericum longistylum with anti-inflammatory activity.

Spihyperglucinols A (1) and B (2), the first 13,15- nor -polycyclic polyprenylated acylphloroglucinols (PPAPs) featuring a 7/6/5 tricyclic ring system based on an unexpected bicyclo[3.2.2]nonane core, along with three new congeners, spihyperglucinols C-E (3-5), were isolated from Hypericum longistylum . Importantly, 1 and 2 displayed potential inhibitory effects on the production of nitric oxide in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, with IC 50 values of (8.70 ± 1.18) and (9.23 ± 1.26) μM, respectively, comparable to the positive control, dexamethasone, with an IC 50 value of (9.76 ± 1.13) μM.