Abstract
The effects of dietary feeding of two flavonoids, chalcone and 2-hydroxychalcone on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) were investigated in male F344 rats. We also assessed the effects of chalcone and 2-hydroxychalcone on the activities of detoxifying enzymes of glutathione S-transferase (GST) and quinone reductase (QR) in liver and colon. Rats were given subcutaneous injections of AOM (15 mg/kg body weight) once a week for 3 weeks to induce ACF. They also received an experimental diet containing 0.05% chalcone or 0.05% 2-hydroxychalcone for 5 weeks, starting one week before the first dosing of AOM. AOM exposure produced 90 ± 24 ACF/rat at the end of the study (week 5). Dietary administration of chalcone (44 ± 13, 51% reduction, p<0.01) or 2-hydroxychalcone (40 ± 16, 56% reduction, p<0.005) caused significant reduction in the frequency of ACF. Gavage with chalcone or 2-hydroxychalcone significantly elevated liver GST or QR activities in liver and colon. These findings might suggest the possible chemopreventive ability of chalcone and 2-hydroxychalcone, through induction of liver and colon GST and/or QR on colon tumorigenesis.
