Inhibitory effects of fucoxanthin, a natural carotenoid, on N-ethyl-N'-nitro-N-nitrosoguanidine-induced mouse duodenal carcinogenesis.

Fucoxanthin was shown to inhibit chemical carcinogenesis. Fucoxanthin is a natural carotenoid prepared from brown algae which is an ingredient used daily in Japanese food. In this study, all mice were given 0.01% N-ethyl-N'-nitro-N-nitrosoguanidine in their drinking water for 4 weeks. This was followed by 0.005% fucoxanthin in dimethylsulfoxide or the vehicle alone in the drinking water. In the 16-week fucoxanthin-treated group both the percentage of tumor-bearing mice and the average number of tumors per mouse were significantly lower than those of the control group. The results indicate that fucoxanthin inhibited duodenal carcinogenesis induced by N-ethyl-N'-nitro-N-nitrosoguanidine in mice.