Hypoglycemic effect of the polyphenols rich extract from Rose rugosa Thunb on high fat diet and STZ induced diabetic rats.
J Ethnopharmacol. 2017 Feb 14. Epub 2017 Feb 14. PMID: 28213107
ETHNOPHARMACOLOGICAL RELEVANCE: Rosa rugosa Thunb is traditional Uygur medicine, it is widely used for regulating blood condition, nourishing liver and gallbladder in Uygur ancient prescription. But the mechanism of Rosa rugosa Thunb on diabetes is still unclear. In here, we studied the hypoglycemic effect and explained one probable pathway of polyphenols rich extract from Rosa rugosa Thunb (RPE) on diabetic rats.
MATERIALS AND METHODS: In vitro, the effect of RPE onα-glucosidase inhibition was finished, and the antioxidant activity of RPE was evaluated by ABTS and DPPH assay. Then, hypoglycemic effect was evaluated on a diabetic rat model which was induced by 8 weeks of high fat diet and low dose of STZ (30mg/kg), 37.5, 75 and 150mg/kg doses of RPE were administered on diabetic rats for four weeks. Blood glucose, body weight were measured weekly. At the end of the experiment, oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were conducted, blood and tissue were taken to measure physiological, biochemical parameters and protein expression of insulin signal pathway.
RESULTS: In vitro RPE showed a good effect on antioxidant and inhibition ofα-glucosidase. In vivo after oral administration for four weeks, compared with the model group, RPE significantly decreased blood glucose levels, serum insulin levels, insulin resistance index, serum lipids and organ coefficient of liver, improved glucose tolerance and insulin sensitivity which were impaired by HFD and STZ. It also increased glycogen synthesis and the activity of antioxidant enzymes T-SOD, CAT, GSH-PX in liver. Western blot analysis suggested that the protein expression of p-IRS, p-IR, p-AKT, p-GSK-3β were increased.
CONCLUSIONS: Our study results show that RPE has good hypoglycemic effect on diabetic rats, and the effect is probably achieved by PI3K/AKT pathway and antioxidation.