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Objective: To compare tea polysaccharides(TPS) characteristics and their role in scavenging free radicals and reducing blood glucose(BG) in diabetic mice(DM). Methods: TPS was extracted from green,Oolong and black tea which were made from the same fresh leaves from Hubei,Fujian and Yunnan. Then the recovery rate of TPS, contents of neutral sugar, uronic acid and protein were analysed, and scavenging rate of -2Oand 稯H in vitro and hypoglycemic effect were also determined. Results: 1. The yield and contents of neutral sugar, uronic acid and protein of green tea TPS were the highest, and those of black tea TPS were the lowest. Oolong tea TPS acted the best in scavenging-2O and 稯H . 2. The hypoglycemic effect of TPS from Hubei tea was the best . The effect of TPS extracted from semi-fermented Oolong tea and fermented black tea was better than that of non-fermented green tea. 3. There were obvious differences in yield, free radical scavenging rate and effect of reducing BG among TPS extracted from tea in different regions. TPS extracted from Fujian tea had the best effect in reducing BG,but that from Yunnan tea had not. Conclusion: There was remarkable effect of region and process on physico-chemical characteristics,effect of scavenging radical and reducing blood sugar TSP.
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Objective To study tea polysaccharides(TP) on glucose metabolism,histopathology,and pancreatic islet ?-cell ultrastructure in diabetic mice.Method The alloxan diabetic mice were randomly divided into 4 groups,and orally given distilled water,TP 0.25,0.50,1.00 g/(kg bw?d).for 5 w,and weighed once every week.In experiment 2 and 4 w,the fasting blood glucose was tested once.The glucose tolerance test was conducted at the end of experiments.Blood serum insulin and liver glycogen were measured.The protein content,hexokinase(HK) and pyruvate kinase(PK) activity of 10% liver homogenate were measured.The histopathology of liver,pancreas,kidney and spleen tissue and the ultra structure of pancreas were observed.Results TP could significantly alleviate the symptoms of diabetic mice.The fasting blood glucose values in three TP groups were significantly decreased(P
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Objective To investigate the effects of tea polysaccharides (TPS) on blood lipids and liver trace elements in hyperlipidemic rats. Method The hyperlipidemic rats were treated by gavage with tea polysaccharides of three purities, named TPS I, TPS II, and TPS III at 27.43%,57.82%,and 89.50% purity, respectively for 4 w. Then the rats were killed and the influence of TPS on concentrations of total cholesterol (TC)、triglyceride (TG)、low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), malondialdehyde (MDA) in blood serum, and Ca,Fe,Zn,Cu and Mg ion in liver were determined. Results The TC and MDA concentrations in blood serum of the experimental rats decreased significantly(P
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Objective: To investigate the effects of green tea polysaccharides (TPs) on glucose metabolism and the activity of peroxisome proliferator-activated receptor gamma (PPAR-?) in KKAy type 2 diabetic mice. Methods: Glucose tolerance test, fasting and postprandial glucose, gluconeogenesis, and insulin sensitivity were investigated in type 2 diabetic mice with orally administered TPs at the dose of 500mg/kg for 4-10 w. Effect of TPs on activity of PPAR-? was tested in vitro. Results: TPs could not only improve glucose tolerance, but also reduce fasting and postprandial blood glucose. In addition, TPs could inhibit gluconeogenesis and enhance insulin sensitivity in KKAy diabetic mice. TPs had also an effect of activating of PPAR-? with dose-response. Conclusion: TPs have beneficial effect of lowering blood glucose in KKAy type 2 diabetic mice, which may be induced by enhancing insulin sensitivity by activating of PPAR-?.