Abstract: Objective: To explore the effects of freeze-dried fruit powder of Rosa roxburghii Tratt (RRT), and polysaccharides (RPS) and flavonoids (RF) extracted from RRT on glucose and lipid metabolism disorders in type 2 diabetic mellitus (T2DM) mice. Methods: RPS and RF were prepared by ultrasound-assisted enzymatic extraction followed by purification with macroporous resin. A T2DM mouse model was established by feeding mice a high-fat and high-sugar diet and injecting them with streptozotocin (STZ). Six groups of mice were set up: blank control (physiological saline), model, positive control (metformin hydrochloride), RRT, RPS and RF. The intervention period lasted 28 days. During this period, body mass, food intake, water consumption, fasting blood glucose (FBG) and glucose tolerance were determined. All mice were sacrificed and anatomized to measure organ indices, fat mass, serum lipids, liver antioxidant indices, glucokinase (GK) activity, liver glycogen, and peroxisome proliferators-activated receptor-γ (PPAR-γ) levels and to examine liver pathologic changes. Results: Compared with the blank group, the body mass and brown fat content of the model group significantly decreased (P < 0.05); food intake, water intake, FBG, organ indices and white fat content significantly increased (P < 0.05); abnormal glucose tolerance appeared; serum cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) contents significantly increased (P < 0.05), high-density lipoprotein cholesterol (HDL-C) contents significantly decreased (P < 0.05); the activities of liver catalase (CAT), superoxide dismutase (SOD) and GK and liver glycogen content significantly declined (P < 0.05); the contents of malondialdehyde (MDA) and PPAR-γ significantly increased (P < 0.05); disordered liver cell arrangement, steatosis, edema, and inflammation were observed. Compared with the model group, food intake, water intake, organ indices, white fat content, and FBG of the RRT, RPS and RF groups decreased, body mass and brown fat content increased, serum TC, TG, and LDL-C levels significantly decreased, and HDL-C levels significantly increased; liver MDA and PPAR-γ levels significantly decreased, CAT, SOD and GK activity and liver glycogen content significantly increased, and liver pathological damage was significantly improved. Conclusion: RRT, RPS, and RF can improve glucose and lipid metabolism disorders in T2DM mice. The effect of RPS and RF is significantly more pronounced than that of RRT (P < 0.05), and the effect of RF is significantly more pronounced than that of RPS and the positive control metformin hydrochloride.

Key words: freeze-dried fruit powder of Rosa roxburghii Tratt; polysaccharides extraction; total flavonoids extraction; type 2 diabetes; glycolipid metabolism; oxidative stress