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

ABSTRACT An unrevealed dihydroflavone‐monoterpene conjugate ( 1 ), 2 unrevealed kavalactones ( 2 and 3 , including 1 with an uncommon side chain), and 13 previously identified compounds ( 4–16 ) were extracted from Alpinia katsumadai Hayata seeds. The two‐dimensional structures of the new compounds were authenticated utilizing HRESIMS as well as NMR spectral analysis, whereas 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 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. Compounds 3 and 4 demonstrated antiproliferative activity with IC 50 ranges of 3.94–21.78 µM, whereas the other compounds exhibited no significant cytotoxicity.