Tricin present in rice and wheat exhibits antigrowth activity in several human cancer cell lines and anti-inflammatory potential. However, the chemopreventive activity has not yet been elucidated in preclinical animal models. This study was designed to determine whether dietary tricin exerts inflammation-associated colon carcinogenesis induced by azoxymethane (AOM) and dextran sulfate sodium (DSS) in mice. Male Crj: CD-1 mice were initiated with a single i.p. injection of AOM (10 mg/kg bw) and followed by a 1-week exposure to DSS (1.5%, w/v) in drinking water to induce colonic neoplasms. They were then given the experimental diet containing 50 or 250 ppm tricin. The experiment was terminated at week 18 to determine the chemopreventive efficacy of tricin. The effects of dietary tricin on the expression of several inflammatory cytokines, including tumor necrosis factor (TNF)-α, were also assayed. Feeding with tricin at both doses significantly inhibited the development of colonic tumors. Dietary tricin also significantly reduced the proliferation index and the numbers of mitoses/anaphase bridging of adenocarcinoma cells. Tricin feeding significantly suppressed the TNF-α expression in the normal appearing crypts. Our findings may suggest a potential use of tricin for clinical trials of colorectal cancer chemoprevention in the inflamed colon.
Keywords: colitis-associate cancer; colorectal cancer; chemoprevention; rice bran; tricin.