Antioxidant, hypoglycemic and hypolipidemic activities of pectins from Citrus aurantium ‘Changshanhuyou’

To improve the utilization rate of Citrus aurantium ‘Changshanhuyou’ (Huyou) resources, the biological activities of pectins extracted from Huyou residue were studied. Huyou pectin (HYP) and its three separated components (HYP0, HYP1 and HYP3) showed considerable DPPH•, ABTS •+ and HO• scavenging abilities, bile salts-binding abilities, and marked inhibitory effect on lipase and α-glucosidase. In insulin resistance (IR)-HepG2 cells, HYPs effectively reduced ROS, triglyceride and total cholesterol levels, and increased the hepatic glycogen content and pyruvate kinase and hexokinase activities. RT-qPCR analysis showed that HYPs effectively upregulated the mRNA expression levels of PI3K, Akt, AMPK and GLUT4, and downregulated the expression of G6Pase, PEPCK, FAS, ACC and SREBP-2. Thus, HYPs modulate glycolipid metabolism possibly by activating the PI3K/Akt and AMPK signaling pathways, and regulating the gene expression of lipid metabolism-related enzymes. HYPs have potential as ingredients in functional foods due to their considerable antioxidant, hypolipidemic and hypoglycemic activities.