Antiobesity Effect of Fucoxanthin from Edible Seaweeds and Its Multibiological Functions

摘要

Fucoxanthin has a unique structure including an unusual allenic bond and 5,6-monoepoxide in its molecule. It induced a remarkable reduction in the growth of leukemia and prostate cancer cells. Furthermore, we have found that fucoxanthin showed anti-obesity effect with a new molecular mechanism. Uncoupling protein (UCP) is inner-membrane mitochondrial protein that has the ability to dissipate energy through uncoupling of oxidative phosphorylation which, instead of ATP, produces heat. A great deal of interest has focused on adaptive thermogenesis by UCP families (UCP1, 2 and 3) in several tissues and organs as a physiological defense against obesity, hyperlipidemia, and diabetes. In fact, UCP1 expression in brown adipose tissue (BAT) is known as a significant component of whole body energy expenditure, at least small rodents, and its dysfunction contributes to the development of obesity. However, adult humans have very little BAT, making it unlikely to be a major contributor to human weight regulation. In humans, most of fat is stored in white adipose tissue (WAT). Considered as breakthrough discoveries for an ideal therapy of obesity, regulation of UCP expression in white adipose tissue (WAT) by food constituent should be studied. Here, we show significant reduction of WAT in wistar rats and obese KK-Ay mice by feeding fucoxanthin (0.05 or 0.2 wt%/feed).rnFucoxanthin, concentrated from edible seaweed, Undaria Pinnatifida (Japanese name is Wakame). The daily intake of fucoxanthin to KK-Ay mice also caused a significant reduction of body weight and a significant increase in BAT weight. Clear signals of UCP1 protein and mRNA were detected by Western and Northern blot analyses in WAT in mice fed fucoxanthin, although there is little expression of UCP1 in WAT in mice fed control diet. UCP1 expression in WAT by fucoxanthin intake leads to oxidation of fatty acids and heat production in WAT mitochondria. The substrate oxidation can directly reduce WAT in animals.