New cucurbitane triterpenoids with cytotoxic activities from Hemsleya penxianensis

Abstract Seven new cucurbitane triterpenoids, Pengxianencins A–G ( 1 – 7 ) including one alkaloid, were isolated from the ethanol extract of the tubers of Hemsleya penxianensis . Their structures were elucidated on the basis of extensive spectroscopic data, including 1D and 2D NMR spectra as well as HR-ESI-MS. The evaluation of inhibition activity against human Hela, MCF-7, and A-549 cell lines showed that compounds 1 , 4 , 6 , 7 have different levels of cytotoxic activities, with IC 50 values ranging from 1.67 to 45.28 μM.