Flavonoids and Kavalactones Isolated from Seeds of Alpinia katsumadai Hayata. and Their Cytotoxic Activities.

An unrevealed dihydroflavone-monoterpene conjugate (1), two unrevealed kavalactones (2-3, including one with an uncommon side chain), and thirteen previously identified compounds (4-16) were extracted from Alpinia katsumadai Hayata. seeds. The two-dimension structures of the new compounds were authenticated utilizing HRESIMS as well as NMR spectral analysis, while their absolute chiral configurations were ascertained either by correlating the experimental and simulated values of electronic circular dichroism (ECD) patterns or conducting X-ray diffraction experiments. Compounds 2-5, 9, 11, and 14 were assessed for their capacity to impede the growth of cancer cells of A549, HepG2, SGC7901, and SW480 using the MTT assay. Compounds 3 and 4 demonstrated antiproliferative activity with IC50 ranges of 3.94-21.78 μM, whereas the other compounds exhibited no significant cytotoxicity.