Monoterpenoid acylphloroglucinols from Hypericum hengshanense W. T. Wang with antiproliferative activities

Hypericum species (Hypericaceae) are a group of important plants with medicinal, edible, and ornamental values. A phytochemical study on the whole plants of H. hengshanense W. T. Wang, a species endemic to China, led to the isolation and elucidation of 25 monoterpenoid acylphloroglucinols (MAPs). Among them, 10 are undescribed compounds, namely hyphengshanols A–D, (+)-empetrilatinol A, (−)-empetrilatinol B, (−)-hyperjovinol A, (9 S ,2′ S )-dauphinol F, and (8 R ,2′ S )-empetrikathiforin. In addition, the absolute configurations of other six compounds were firstly determined in the current study. The structures were established by ultraviolet (UV), high resolution electrospray ionization mass spectrum (HR-ESI-MS), and nuclear magnetic resonance spectroscopy (NMR) data. The absolute configurations were determined by experimental and calculated electronic circular dichroism (ECD) data analyses. Cytotoxicity assays on five human cell lines HL-60, A549, SMMC-7721, MDA-MB-231, and SW480 revealed that 16 compounds exhibited broad-spectrum antiproliferative activities with IC 50 ranging from 7.54 to 45.70 μM. Ten undescribed monoterpenoid acylphloroglucinols and 15 known analogs were isolated and identified, including six pairs of stereoisomers. Their cytotoxicity against five cancer cell lines was evaluated. • MAPs were isolated from Hypericum hengshanense including 10 undescribed ones. • The absolute configurations of 16 MAPs were determined by ECD calculations. • Six pairs of stereoisomers were separated via chiral-phase HPLC. • Sixteen isolates showed cytotoxicity against five cancer cell lines.