New polyhydroxy cucurbitane-type triterpenoids from the tubers of Hemsleya chinensis and their cytotoxic activities.

Phytochemical investigation of the 95 % ethanol extract of the tubers of Hemsleya chinensis led to the isolation of five previously undescribed cucurbitane-type triterpenoids (1-5, named hemslyencins G-K), along with five known analogues (6-10). The structures of these compounds were elucidated through comprehensive spectroscopic analysis (UV, IR, HR-ESI-MS, 1D and 2D NMR data). Compounds 1, 2, 7, 9, and 10 are characterized as 24‑oxygenated cucurbitane-type triterpenoids, were rarely found in the genus Hemsleya. The cytotoxic activities of 1-10 were evaluated against MCF-7, HCT-116, HeLa, and HepG2 cancer cell lines, in which compounds 1 and 8-10 exhibited significant cytotoxic activities with the value of 0.382-13.77 μM. Further mechanism studies displayed that compound 1 dose-dependently induced apoptosis and caused G0/G1 phase cell cycle arrest in MCF-7 cells.