Studies on cancer chemoprevention by traditional folk medicines XXV. Inhibitory effect of isoliquiritigenin on azoxymethane-induced murine colon aberrant crypt focus formation and carcinogenesis.

Isoliquiritigenin is a natural pigment with the simple chalcone structure, 4,2',4'-trihydroxychalcone. The effect of this compound on azoxymethane (AOM)-induced colonic aberrant crypt focus and tumor formation in ddY mice was examined. Administration of 15 ppm of isoliquiritigenin in drinking water, significantly suppressed AOM-induced aberrant crypt focus formation (p<0.01), with an inhibitory ratio of 37.3%. Isoliquiritigenin also inhibited AOM-induced colon carcinogenesis by administration in a mixed diet. The average number of tumors was 14.6+/-8.9 items in the control group and were 7.3+/-7.3, 3.9+/-5.6, 4.7+/-6.5 items in the 10, 100 and 250 ppm in the isoliquiritigenin treated groups, respectively. In histopathological studies, the tumors were identified as adenoma and adenocarcinoma, however, significant differences were not observed between the control group and isoliquiritigenin treated groups. These results indicated that isoliquiritigenin might be a potential chemopreventive agent against colon cancer.