Inhibitory effects of 2-hydroxy chalcone and other flavonoids on human cancer cell-proliferation.

The effect of thirty-one flavonoids on monolayer HeLa cell proliferation was studied and their structure activity relationship was rationalised. The flavones, flavonols and chalcones possessing the C2,3-double bond were the most potent cytotoxic groups of compounds. The IC50 values for 2-hydroxy chalcone (the most potent flavonoid) and the cytotoxic drug colchicine, were 8 muM and < 0.1 muM, respectively. Whilst colchicine was able to inhibit the incorporation of [C-14] thymidine, uridine and leucine into HeLa cells, 2-hydroxy chalcone inhibited the incorporation of the two nucleotides, but not the amino acid. This indicates that the mode of action of 2-hydroxy chalcone and colchicine are different.