[Study on hypoglycemic effect and mechanism of total flavonoids of Propolis in STZ diabetic rats].

OBJECTIVE: To study hypoglycemic effect and mechanism of the total flavonoids of Propolis (TFP) in the STZ diabetic rats. METHODS: The model of type 2 diabetic rats was induced by high-fat diet feeding for 4 weeks combined with intraperitoneal injection of streptozotocin (STZ). Then the rats without above-mentioned treatment were selected as the normal control group,the diabetic rats were randomly divided into four groups by blood glucose, the model control group, high doses (240 mg/kg), medium doses (120 mg/kg) and low doses (60 mg/kg) TFP groups. The TFP preparation was intragastric administration given to rats in TFP groups. The model control rats were treated intragastric administration with 0.5% sodium carboxymethyl cellulose (CMC-Na) for 4 weeks. The rats were fed with high fat diet during treatment. 12 hours after the last administration, glucose (GLU), total cholesterol (TC), triglyceride (TG), high density lipoprotein( HDL-C), low density lipoprotein LDL-C), glycated hemoglobin (GHb), serum insulin INS), C-peptide (C-P), superoxide dismutase( SOD), malondialdehyde (MDA), glutathione (GSH), tumor necrosis factor-alpha (TNF-alpha), free fatty acid (FFA), nitric oxide (NO), and hepatic glycogen were determined. RESULTS: Compared with the normal group, the levels of GLU, TC, TG, HDL-C, FFA, TNF-alpha, NO, MDA and GHb in serum were increased significantly in the model control group (P < 0.05-P < 0.001), the levels of HDL-C, INS, C-P, SOD and GSH in serum and hepatic glycogen in hepatic tissue were decreased significantly (P < 0.01 or P < 0.001). The levels of all above indexes of high and medium doses groups were improved significantly compared with the model control group (P < 0.05-P < 0.01). CONCLUSION: TFP can significantly decrease the level of blood glucose,improve the glucose and lipid metabolism and inhibit insulin resistance in STZ diabetic rats.

[Effects of the polysaccharides isolated from ganoderma applanatum (PGA) on the level of PGE2 and gastric mucosal blood flow (GMBF) and gastric mucus secretion of rats with gastric mucosa injury].

OBJECTIVE: To investigate the protective effects of the polysaccharides isolated from ganoderma applanatum (PGA) on gastric mucosal injury in rats and the underlying mechanism. METHOD: Gastric ulcer was induced by either acetic acid or pylorus ligation in the rats. The level of PGE2 and GMBF, and gastric mucus secretion were examined respectively. RESULT: After oral administration of PGA (250-1000 mg x kg(-1)) repeatedly, the level of PGE2 and GMBF were obviously increased in gastric mucosa of rats as compared with the model group. The secretions of both free mucus in stomach and mucus of gastric wall were enhanced apparently by PGA in a dose-dependent manner. CONCLUSION: PGA could strengthen gastric mucosa barrier by improving the level of PGE2, GMBF and the secretion of gastric mucus, which may be one of the mechanisms underlying the protective effect of PGA on the gastric mucosa during the gastric ulcer.