Lack of chemopreventive effects of lycopene and curcumin on experimental rat prostate carcinogenesis

The chemopreventive efficacy of lycopene and curcumin with regard to prosta te carcinogenesis was investigated using 3,2'-dimethyl-4-aminobiphenol (DMA B)- and 2-amino-1-methylimidazo[4,5-b]pyridine (PhIP)-induced rat ventral p rostate cancer models. Three 60 week experiments with male F344 rats were c arried out, In the first DMAB was given for the first 20 weeks and lycopene or curcumin were administered concomitantly or subsequently at dietary dos es of 15 and 500 p.p.m., respectively. In the second experiment lycopene an d curcumin were given to rats pretreated with DMAB at doses of 5, 15 or 45 p.p.m. or 100 or 500 p.p.m. In the third PhIP was selected as an initiator for prostate carcinogenesis and administered for 20 weeks, Rats were then f ed a diet containing lycopene at a dose of 45 p.p.m. or curcumin at a dose of 500 p.p.m. or both together, Chemopreventive effects of lycopene and cur cumin on development of DMAB-induced ventral prostate carcinomas were obser ved only in the first experiment and no confirmation of inhibition potentia l was obtained in the following studies. Neither summational nor synergisti c chemoprevention was evident. It is concluded from the present data that, overall, neither lycopene nor curcumin can consistently prevent rat prostat e carcinogenesis.