A New Kavalactone Dimer from Piper methysticum

A new kavalactone dimer, named kavalactone A (1), and three known compounds, desmethoxyyangonin (2), yangonin (3), and 11-methoxyyangonin (4), were isolated from the leaves of Piper methysticum (kava). Their structures were determined by spectroscopic methods, mainly 1D and 2D NMR and mass spectrpscopic data. Primary bioassays showed that compound 3 had very strong cytotoxicity against A549 and NCI-H460 Cells with IC50 values of 13.6 and 13.7 μg/mL, respectively, compound 2 had moderate cytotoxicity against A549 and NCI-H460 cells (with IC50 values of 35.8 and 37.6 μg/mL, respectively), and compounds 1 and 4 had very weak cytotoxicity against A549 and NCI-H460 cells.