Modulation of oxidative biomarkers and carbohydrate metabolic enzyme activity by Hypsizygus ulmarius polysaccharide in streptozotocin/nicotinamide-induced diabetic rats.

The objective of this study was to investigate the protective effects of Hypsizygus ulmarius polysaccharide (HUP) in streptozotocin (STZ) and nicotinamide (NA) induced diabetic rats. Experimental diabetes was induced by a single intraperitoneal injection of STZ (65 mg/kg bw), administered 15 min after intraperitoneal injection of NA (110 mg/kg bw). After 72 h post STZ induction, diabetic rats received oral administration of HUP at different dose levels (200 and 400 mg/kg bw), whereas glibenclamide was administered orally at 6 mg/kg bw for a period of 30 days to assess changes in blood glucose, glycosylated haemoglobin, haemoglobin, oxidant/antioxidant parameters, and carbohydrate metabolic enzymes. HUP reduced blood glucose levels dose-dependently, increased enzymatic (superoxide dismutase, catalase and glutathione peroxidase) and non-enzymatic antioxidants (reduced glutathione and vitamin C), and suppressed lipid peroxidation, all leading to a significant hypoglycemic impact. Moreover, HUP increased the activity of glycolytic enzymes (glucokinase and phosphoglucoisomerase), glucose-6-phosphate dehydrogenase, and decreased the activity of gluconeogenic enzymes (glucose-6-phosphatase and fructose-1,6-bisphosphatase), implying that HUP modulates carbohydrate metabolism and improves glucose homeostasis. In conclusion, our findings revealed that HUP has tremendous promise as a new dietary functional food or therapeutic agent for preventing diabetes mellitus and its consequences.