CYTOTOXIC EFFECT OF BUTEIN ON HUMAN COLON ADENOCARCINOMA CELL-PROLIFERATION

Several classes of plant polyphenols namely, flavonoids, chalcones and coumarins exhibited varying degrees of inhibition on the cell proliferation of human colon adenocarcinoma cell line 220.1. At the highest concentration tested (100 mu M), many of the chalcones showed > 100% growth inhibition and their order of potency was butein > 2'-hydroxychalcone > 2-hydroxychalcone > 2',6'-dihydroxy-4'-methoxychalcone > 2',4-dihydroxychalcone with IC50 values of 1.75, 6.2, 7.5, 17, 23 mu M, respectively. Butein (the most potent chalcone) at 2 mu M concentration inhibited the incorporation of C-14-labelled thymidine, uridine and leucine into the colon cancer cells whilst 5-fluorouracil (5-FU, a chemotherapeutic drug) at 50 mu M concentration could significantly inhibit only the uridine incorporation. The mode of cytotoxic action of butein was different from 5-FU but may be similar to colchicine, a known HeLa cell inhibitor.