Structurally diverse polyprenylated acylphloroglucinols from Hypericum addingtonii with anti-hepatocellular carcinoma...

Hepatocellular carcinoma (HCC) remains a major cause of cancer-related mortality worldwide. In this study, 40 benzoylated polycyclic polyprenylated acylphloroglucinols (PPAPs), including 11 new compounds, hyperadditionciols A-K (1-11), were isolated from the fruits of Hypericum addingtonii. Compounds 1-40 were classified into bicyclo[3.3.1]nonane, adamantane, homo-adamantane, 1,2-seco, and complex PPAPs. The structures of 1-11 were established by HRESIMS and 1D and 2D NMR spectroscopic analyses, while their stereochemical assignments were supported by single-crystal X-ray diffraction, ECD calculations, and GIAO NMR calculations. Compounds 2, 3, and 5-40 were evaluated for cytotoxicity against HepG2 cells, and selected active compounds were further tested against Huh7 cells, with several PPAPs showing cytotoxicity against both cell lines. Subsequent SPR screening showed that hyperisampsin J (15) directly bound to DEAD-box RNA helicase 5 (DDX5), with a K_D value of 5.02 μM. Molecular docking and a 100 ns molecular dynamics simulation supported the plausibility and stability of the predicted binding mode. Western blot analysis further showed increased DDX5 and decreased p62/sequestosome 1 (SQSTM1) protein levels in HepG2 cells following treatment with 15. These findings expand the chemical diversity of benzoylated PPAPs from H. addingtonii and support further investigation of this class of natural products for their potential anti-HCC activity.