New isohemigossypol related conjugates and caffeoylated oleanane triterpenoids from Hibiscus syriacus roots with anti-senescence modulating activity

Phytochemical investigation of the dried roots of Hibiscus syriacus L. led to the isolation of six previously undescribed compounds, including three rare benzo[1,4]dioxane-fused isohemigossypol conjugates (1–3) and three caffeoylated oleanane-type triterpenoids (4–6), together with 11 known compounds (7–20). Comprehensive spectroscopic analyses, combined with electronic circular dichroism (ECD) calculations, enabled the full structural elucidation of these metabolites and revealed isohemigossypol-derived phenylpropanoid conjugates and caffeoylated oleanane-type triterpenoids. Notably, Cell based screening identified selected compounds that suppressed p16^INK4A (p16) promoter activity, and follow up assays in senescent fibroblasts showed reduced senescence associated readouts, including SASP related cytokine transcripts. These findings highlight H. syriacus as a good source of structural diversity and pharmacological potential for the discovery of previously undescribed anti aging scaffolds.