Cytotoxic α-pyrone derivatives from Cryptocarya yunnanensis.

Five new α-pyrone derivatives, cryptoyunnanes A - E (1 - 5), together with four known analogues, were isolated from the leaves and twigs of Cryptocarya yunnanensis. Their structures including absolute configurations were elucidated by extensive spectroscopic data and electronic circular dichroism (ECD) analyses. Compounds 4 and 6 showed significant cytotoxicity against A549, HCT-116, MDA-MB-231, PC-3 and HeLa with IC50 values from 2.25 to 8.97 µM. Compounds 1, 2 and 7 also displayed good cytotoxicity against HCT-116, MDA-MB-231 and PC-3 with IC50 values from 1.26 to 8.32 µM. This is the first time to report the isolation and bioactivity evaluation of chemical constituents from C. yunnanensis.