Bioactive Eudesmane sesquiterpenes from Artabotrys hongkongensis Hance

A new naturally occurring trinoreudesmane sesquiterpene, artahongkongol A (1), together with seven known eudesmane sesquiterpenes (2-8), was isolated from the stems and leaves of Artabotrys hongkongensis Hance. Among them, 1 is a rare trinoreudesmane sesquiterpene containing 12 carbon atoms on the carbon skeleton. All known compounds (2-8) were isolated from the genus Artabotrys for the first time. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. All isolated compounds were evaluated for their cytotoxicities against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480 in vitro. Compounds 1-8 showed significant inhibitory effects against various human cancer cell lines with IC₅₀ values ranging from 0.57 to 15.68 μM.