FLAVONES FROM THE LEAVES OF YUNNAN LOCAL SUN CURED TOBACCO AND THEIR CYTOTOXICITY

摘要

Two new flavones, 4',7-dimethoxy-6-hydroxy-8-isobutyrylflavone (1), 4',7-dimethoxy-6-hydroxy-8- [(E)-3 -hydroxy-2-methylprop-1 -eny1] flavone (2), together with four known flavones (3-6) were isolated from the leaves of Yunnan local sun cured tobacco. Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1-6 were screened for the cytotoxic activity in a panel of human cancer cell lines, including NB4, A549, SHSY5Y, PC3, and MCF7. Compound 2 exhibited high cytotoxicity for A549 and SHSY5Y cells with IC50 values of 1.6 and 2.8 mu M, respectively. The other compounds also exhibited cytotoxicity with IC50 values in the range of 4.3 9.5 mu M, respectively.