Structural Characterization and Hypoglycemic Effects of a Purified Polysaccharide From Cinnamomum cassia

A purified polysaccharide, designated CCP1A, was extracted and isolated from Cinnamomum cassia bark using ultrasonic‐assisted composite enzymatic extraction followed by DEAE‐52 and Sephadex G‐100 column chromatography. CCP1A had a molecular weight of 8.161 kDa and was primarily composed of glucose and galacturonic acid, with minor amounts of rhamnose, arabinose, galactose, xylose, and mannose. Spectroscopic analyses (FT‐IR and 1 H NMR) confirmed the coexistence of α‐ and β‐glycosidic linkages and a pyranose ring structure. The Congo red assay indicated a stable helical conformation, and transmission electron microscopy revealed dendritic, coiled aggregates. In a mouse model of type 2 diabetes induced by a high‐fat diet combined with low‐dose streptozotocin, oral administration of CCP1A (100, 200, and 300 mg/kg/day for 4 weeks) dose‐dependently reduced fasting blood glucose, improved glucose tolerance and lipid profiles (TG, TC, LDL‐C, and HDL‐C), and alleviated polydipsia, polyphagia, weight loss, as well as pancreatic pathological damage. Mechanistically, CCP1A suppressed intestinal α‐amylase and α‐glucosidase activities, promoted hepatic and muscle glycogen synthesis, upregulated the hepatic mRNA expression of GCK, GLUT2, PI3K, AKT, and Nrf2, downregulated PEPCK mRNA expression, increased serum levels of T‐SOD, GSH‐Px, CAT, and T‐AOC, and decreased MDA and GSP levels. These findings suggest that CCP1A exerts multi‐target hypoglycemic effects potentially involving inhibition of intestinal glucose absorption, modulation of insulin signaling‐related genes, promotion of glycogen synthesis, suppression of gluconeogenesis, and upregulation of Nrf2 mRNA. Hence, CCP1A represents a promising natural candidate for functional food development against type 2 diabetes.