Structural characterization, hypoglycemic effects and mechanism of a novel polysaccharide from Tetrastigma hemsleyanum Diels et Gilg.

In the present study, a novel polysaccharide (THDP-3) purified from cane leaves of Tetrastigma hemsleyanum Diels et Gilg was obtained via anion exchange chromatography and the structural analyses of the compound indicated that THDP-3 is a homogenous polysaccharide with molecular weight of 77.98 kDa. Our results show that it consists of rhamnose, arabinose, mannose, glucose and galactose at molar ratio of 1.0: 1.3: 2.5: 2.3:3.1 with main backbones of →4)-α-D-GalAp-(1→, →4)-β-D-Galp-(1→ and →4)-α-D-Glcp-(1→, and main branches of β-D-Manp-(1→, →3,6-β-D-Manp-1→ and α-D-Araf-(1→. In the anti-diabetic assays, THDP-3 showed significant hypoglycemic activity in alloxan-induced diabetic mice. In addition, THDP-3 was found regulating the expression of glucokinase, amp-activated protein kinase, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase. These new findings indicate the high potential in therapeutic mechanisms investigation using THDP-3. Moreover, our results of hypoglycemic activity using THDP-3 demonstrated that the compound could serve as a potential anti-diabetic agent.