Flavones 1–4 isolated from Kaempferia parviflora were used for structural modification. Sixteen flavonoid derivatives, including four new derivatives, were synthesized and evaluated for cytotoxicity against KB and NCI-H187 cell lines. Flavanones 2a–4a demonstrated higher cytotoxic activity than the parent compounds. Cytotoxicity against KB cell line of oxime 1c was about 7 times higher than the ellipticine standard. Interestingly, ...