Fucoxanthin ameliorates hyperglycemia, hyperlipidemia and insulin resistance in diabetic mice partially through IRS-1/PI3K/Akt and AMPK pathways

Fucoxanthin has potential anti-diabetic activities, but its precise effects and underlying mechanisms remain unclear. In this study, C57BL/KsJ-db/db mice were fed diets containing fucoxanthin (0.2% and 0.4%, w/w) for 6 weeks. Results showed dietary fucoxanthin significantly improved glucose/lipid metabolism and insulin resistance, and prevented pancreatic histological changes in db/db mice. Moreover, fucoxanthin markedly lowered blood glucose by regulating glucokinase and phosphoenolpyruvate carboxykinase mRNA expressions in liver, promoted glycogen synthesis by regulating glucose transporter 4, glycogen synthase and glycogen synthase kinase-3 beta protein expressions in skeletal muscle, and lowered blood lipid levels by regulating peroxisome proliferator-activated receptor alpha, p-acetyl CoA carboxylase, carnitine palmitoyltransferase 1 and fatty acid synthetase protein expressions in liver. Mechanistic studies indicated that fucoxanthin effectively regulates the expression of IRS-1/PI3K/AKT and AMPK signaling proteins in liver and skeletal muscle. All results suggested that fucoxanthin is a potential functional food or effective drug for type 2 diabetes mellitus.