Study on the Antioxidant and Hypoglycemic Effects of Glycyrrhiza Polysaccharide

Objective: To investigate the antioxidant effect of Glycyrrhiza polysaccharide and its hypoglycemic effect on type 1 diabetes mellitus (T1DM) mice. Methods: Glycyrrhiza polysaccharides were extracted and purified, the polysaccharide content was determined by the phenol sulfuric acid method, and its antioxidant activity was determined by the clearance of DPPH· and ABTS⁺·. After 7 days of adaptive feeding, mice were intraperitoneally injected with STZ (30 mg/kg·BW) to establish a T1DM model. The experiment was divided into normal group, model group, Glycyrrhiza polysaccharide high-dose group (400 mg/kg·BW), Glycyrrhiza polysaccharide low-dose group (200 mg/kg·BW), and positive group (metformin 200 mg/kg·BW). The changes of basic indexes and indexes related to lipid metabolism and oxidative stress in mice were measured during the experiment. Results: The content of Glycyrrhiza polysaccharide was 690 mg/g, and its scavenging abilities of DPPH· and ABTS⁺· were 82.84%±0.80%, 85.52%±2.27% at 1000 μg/mL mass concentration, respectively. In the animal experiments, the body weight of mice in the high-dose group of Glycyrrhiza polysaccharide reached 20.84±0.87 g at the 8th week, which was not significantly different from the positive group (P>0.05). In the high-dose group, the fasting blood glucose (FBG) level was 15.9 mmol/L, which was not significantly different from the positive group (P>0.05), and it significantly improved the glucose tolerance (OGTT) level (P<0.05). The total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C) in the mice in the high-dose group of Glycyrrhiza polysaccharide were 2.79±0.36, 0.98±0.12, 1.28±0.23, 1.67±0.29 mmol/L, respectively, which were highly significantly different from those of the model group (P<0.05), and the levels of super oxide dismutase (SOD), catalase (CAT), and total glutathione (GSH) were increased significantly (P<0.01), and significantly reduced the content of malondialdehyde (MDA). Conclusion: Glycyrrhiza polysaccharide has good antioxidant properties and it can hypoglycemic by improving lipid metabolism and oxidative stress in T1DM mice.