2010 年 19 巻 1 号 p. 39-45
Seaweeds or macroalgae are one of the important living resources since ancient times and have been explored as sources of food, feed and medicine in the orient as well as the west. They being plants of unique structure and biochemical composition, seaweeds could be exploited for their multifunctional properties. Brown seaweeds have been thoroughly researched as sources of useful bioactive components like phycocolloids, proteins, vitamins and minerals. Recently, their lipids have drawn increased interest due to several health benefits they afford. Brown seaweed carotenoid, fucoxanthin, and omega-3 highly unsaturated fatty acids (HUFA) such as eicosapentaenoic acids (EPA) and 18:4n-3 are the major functional lipid or lipid related compounds of brown seaweeds. EPA and 18:4n-3 can be converted to docosahexaenoic acid (DHA) in biological systems. Both EPA and DHA have been documented to have significant influence on biochemical and physiological changes in the body. We have found the antiobesity effect and antidiabetic effect as specific and novel bio-functions of fucoxanthin. Nutrigenomic study reveals that fucoxanthin induces uncoupling protein 1 (UCP1) expression in white adipose tissue (WAT) mitochondria to lead to oxidation of fatty acids and heat production in WAT. Fucoxanthin improves insulin resistance and decreases blood glucose level, at least in part, through the down-regulation of TNF. in WAT of animals. Moreover, omega-3 HUFA showed the synergistic effect on the anti-obesity and anti-diabetic activity of fucoxanthin. These studies strongly indicate the beneficial health effect of brown seaweed lipids by modulating one or more molecular targets in biological systems.