Cytotoxic flavonoids from the leaves of Cryptocarya chinensis.

Bioassay-guided fractionation led to the isolation of six new tetrahydroflavanones, cryptochinones A-F (1-6), from the neutral CHCl(3) fraction of Cryptocarya chinensis leaves, together with 14 known compounds (7-20). The structures of these new compounds were determined through spectroscopic analyses, including 2D-NMR, MS, CD, and X-ray crystallographic analysis. Among the isolates, infectocaryone (7) showed cytotoxic activities with IC(50) values of 11.0 and 3.7 μM against NCI-H460 and SF-268 cell lines, respectively, and cryptocaryanone A (9) showed cytotoxic activities with IC(50) values of 5.1, 4.3, and 5.0 μM against MCF-7, NCI-H460, and SF-268 cell lines, respectively.