Antioxidant properties of polysaccharides from platycodon grandiflorum and its hypoglycemic effect on type 2 diabetic rats

Abstract

Objective: This study aimed to investigate the antioxidant activity of polysaccharides from Platycodon grandiflorum and its hypoglycemic effect on type 2 diabetic rats. Methods: Extraction and determination of P. grandiflorum polysaccharide content and its ability to scavenge different free radicals The rats were fed with high-fat and high-sugar feed for 6 weeks. After 6 weeks, the rats were intraperitoneally injected with STZ (30 mg/kg·BW) to establish type 2 diabetes models (T2DM), which were divided into normal group, model group, and P. grandiflorum-polysaccharide high-dose group (400 mg/kg) and low-dose group (200 mg/kg), and positive group (metformin 200 mg/kg). The body weight and fasting blood glucose (FBG) were measured regularly for 8 weeks. In the last week, an oral glucose tolerance (OGTT) test was performed, and rat serum and liver were taken to determine the changes in lipid metabolism indexes and related oxidases in rats. Results: The content of platycodon grandiflorum polysaccharide was 89.65%, and the scavenging ability of DPPH·, ABTS+·, ·OH and PTIO at a concentration of 1 000 μg/mL were 91.3%, 89.7%, 83.8%, and 90.4%, respectively. Compared with the model group, P. grandiflorum polysaccharide could effectively alleviate the weight loss of T2DM rats, significantly reduced their FBG (P＜0.05), and significantly increased the level of OGTT (P＜0.05). After high-dose treatment of P. grandiflorum polysaccharide, the levels of TC, TG, LDL-C and MDA decreased significantly, and the levels of HDL-C, SOD, GSH, and CAT increased significantly (P＜0.05) with dose-dependence. Conclusion: P. grandiflorum polysaccharide has good antioxidant properties and can reduce blood sugar by improving lipid metabolism and oxidative stress levels in T2DM rats.

Keywords

• platycodon grandiflorum polysaccharide
• antioxidant
• t2dm
• hypoglycemic effect