Pumpkin Polysaccharide Extracted by Subcritical Water: Physicochemical Characterization and Anti‐Diabetic Effects in T2DM Rats

This study aims to optimize the extraction of pumpkin polysaccharide by subcritical water, investigates the physicochemical properties and biological activities of pumpkin polysaccharide.Subcritical water is used to extract pumpkin polysaccharide. The structure and composition of pumpkin polysaccharide are analyzed by infrared spectroscopy, gel filtration chromatography, and high-performance liquid chromatography. The hypoglycemic and hypolipidemic potential of pumpkin polysaccharide aere determined by the physicochemical indexes, pathological, and immunohistochemical analysis in T2DM rats induced by STZ + high-fat diet. The optimal conditions for subcritical water are 1:15, 150°C, and 10 min. Pumpkin polysaccharide has α-configurations and are mainly composed of seven different monosaccharides, and it exhibits good free-radical scavenging ability and inhibition of α-amylase, α-glucosidase, and pancreatic lipase activities. Pumpkin polysaccharide treatment in T2DM rats significantly decreases the concentrations of blood glucose, insulin, TC, TG, LDL-C, and MDA; increases the levels of HDL-C; and enhances the antioxidant enzymes activities (SOD and CAT). Histopathology and immunohistochemical analyses reveal that pumpkin polysaccharide has protective effects on kidney and pancreatic organs in T2DM rats.Pumpkin polysaccharide extracted by SWE shows great potential as functional food ingredients and candidates for T2DM treatment.