Degradation of Fucoxanthin to Elucidate the Relationship between the Fucoxanthin Molecular Structure and Its Antiproliferative Effect on Caco-2 Cells

Fucoxanthin has an antiproliferative effect on cancer cells, but its detailed structure–activity correlation has not yet been elucidated. To elucidate this correlation, fucoxanthin was degraded by ozonolysis. The degraded compounds of fucoxanthin obtained by ozonolysis were purified by HPLC and analyzed by NMR. The polyene chain of fucoxanthin was cleaved by ozonolysis, and the fucoxanthin was divided into two types of cyclohexyl derivatives, one with a β,γ-epoxy ketone group and the other with an allenic bond. In order to elucidate the structure–activity correlation, Caco-2 cells (human colorectal carcinoma) were treated with fucoxanthin degradation compounds. It was found that the entire structure of fucoxanthin is not essential for its antiproliferative effect and that even a partial structure exerts this effect.

Health impact of marine carotenoids

Marine organisms produce a variety of carotenoids with unique functional groups such as allene, acetylene, acetyl, and hydroxymethyl. Astaxanthin and fucoxanthin are representative marine carotenoids on which numerous studies have been performed. Due to the characteristic conjugated polyene chain and terminal ring structures, both carotenoids can act as strong antioxidants. Major nutritional effects of astaxanthin, such as cardio-, skin-, and ocular-protective effects, are based on its in vivo antioxidant activity. However, the antioxidant activity of fucoxanthin is not largely involved in its characteristic nutritional activity and anti-obesity and anti-diabetic effects. The major molecular mechanisms of both effects involve modulating the expression of related genes and proteins by fucoxanthin metabolites.