Maoecrystal Z, a cytotoxic diterpene from Isodon eriocalyx with a unique skeleton

作者:Han Quan Bin; Cheung Susan; Tai Joseph; Qiao Chun Feng; Song Jing Zheng; Tso Ting Fai; Sun Han Dong; Xu Hong Xi*
来源:Organic Letters, 2006, 8(21): 4727-4730.
DOI:10.1021/ol061757j

摘要

A novel diterpene with an unprecedented tetracyclic 6,7:8,15-di-seco-7,20-olide-6,8-cyclo-ent-kaurane skeleton, named maoecrystal Z (1), has been isolated from the leaves of a Chinese medicinal herb, Isodon eriocalyx (Labiatae). Its structure was determined by comprehensive NMR and MS spectroscopic analysis coupled with single-crystal X-ray crystallographic diffraction. Compound 1 exhibited comparable inhibitory effect against human K562 leukemia, MCF7 breast, and A2780 ovarian tumor cells with IC(50) = 2.90, 1.63, and 1.45 mu g/mL and with camptothecin and paclitaxel as the positive controls.