Antiproliferative Effect of Fucoxanthin and Its Metabolites on Human Prostate Cancer Cells

摘要

Fucoxanthin is a major nonprovitamin A carotenoid in brown algae, such as hijiki (Sargassum fusiforme), kelp (Laminaria japonica) and wakame (Undaria pinnatifida). In this study, we report potential involvement of fucoxanthin in cancer-preventing action on human prostate cancer. Fucoxanthin significantly reduced cell viability via apoptosis induction in human prostate cancer cells. The pigment was taken up by the differentiated Caco-2 human intestinal cells, a useful model for studying the absorption of dietary compounds by intestinal cells, and converted into non-conjugated fucoxanthinol. After the oral administration of fucoxanthin in mice, two metabolites, fucoxanthinol and an unknown metabolite, were found in the plasma and liver. A series of instrumental analyses identified the unknown metabolite as amarouciaxanthin A, the enzymatic dehydrogenated product of fucoxanthinol in the liver. The two metabolic products of fucoxanthin in mammals also inhibited the proliferation of human prostate cancer cells. These results suggested that ingestion of edible brown algae might have the potential to reduce the risk of prostate cancer.