The current study was designed to investigate the effects of
nobiletin (5,6,7,8,3',4'-hexamethoxy flavone) on 2-amino-1-methyl-6-phenylimidazo[4,5-
b]pyridine (
PhIP)-induced prostate and colon
carcinogenesis.
PhIP was administered to 6-wk-old F344 male rats intragastrically (100 mg/kg) twice a wk for 10 wk. The animals were given 0.05%
nobiletin or the basal diet for 50 wk. At the end of the experiment, serum
testosterone,
estrogen, and
leptin did not differ between the 2 groups. The
body weights of
nobiletin-treated rats were significantly higher than controls (P<0.05), and feeding of
nobiletin significantly reduced the relative prostate (P<0.05) and testes (P<0.05) weights as well as the Ki67 labeling index in the normal epithelium in the ventral prostate (P<0.01). The incidence and multiplicity of
adenocarcinomas in
nobiletin-treated ventral prostate were 50% and 36%, respectively, of controls, but the differences were not statistically significant. However,
nobiletin did significantly reduce the total number of colonic
aberrant crypt foci (ACF) compared to the control value (P<0.05).
Nobiletin, therefore, may have potential for
chemoprevention of early changes associated with
carcinogenesis in both the prostate and colon.