The Pu-erh Tea Water Extractions Reduce Blood Sugar Of Type2Diabetic Mice Model

Yunnan province, in southwest of China, is rich of tea tree resources, and was thought to be the pristine area of most tea trees worldwide. Pu-erh tea shows remarkable efficacy for treating obesity, reducing high blood glucose, etc, compared with ordinary teas. Recently, it was reported that Pu-erh tea showed good efficacy for treating type2diabetes. However, the mechanisms, best dosage, type of administration, curing efficacy rate, etc. are largely unknown. Furthermore, in more recent, tea containing food is becoming popular on the basis of excellent function of Pu-erh tea, there is no data for its final function or optimal dosage yet. In this paper, type2diabetic mice were fed with instant Pu-erh tea containing diet for investigating the efficacy of Pu-erh tea treating type2diabetes.Kunming species mice were used as animal models in this research, with male and female in half in testing each group. Five different of dosages were used for mice, which were accordant to regular daily uptake of an adult of70kg as reference quantity, i.e.10g tea (equivalent to1.5g instant tea). The type2diabetic mice fed with normal diet, metformin containing diet, and tea containing diet, were set as negative (N), positive control (P), and experimental groups, relatively. Experimental groups were then set to4subgroups according to3different tea types, i.e. green tea (G), black tea (B) and ripe tea (R). The ordinary mice fed with normal diet were set as blank control group (C). In this study, levels of serum total cholesterol (TC), triglyceride (TG), high density liprotein-cholesterol (HDL-C), low density liprotein-cholesterol (LDL-C), C-Peptide and the levels on the activity of alanine transaminase (ALT), aspartic transaminase (AST) and insulin in blood serum, were assayed. Furthermore, the pathological changes in liver tissue and pancreas were examined by sections.Half number of mice in experimental group were fed with tea containing diet in the first10weeks, and then fed with normal diet in the last5weeks. While all other groups were fed with corresponding diet for14weeks, weight and blood glucose were examined every week. The data analysis was performed by GraphPad Prism5.0. Results showed that the food uptake amount of the diabetic mice is slightly higher than mice in blank control group. In the end, the weight of mice in all groups increased during the14weeks feeding period. The weights of mice in negative control group showed lowest change. During the first10weeks, the fasting-blood-glucose (FBG) in the four experimental groups (with different tea containing dosage) reduced, lower than that of N group and close to that of P group, while the FBG of some diabetic mice was relatively low and similar to mice in C group. Results showed that the levels of ALT, AST,TC, TG, LDL-C in serum of R, G, B and AAB groups were relatively lower, while the levels of HDL-C, C-Peptide, insulin were relatively higher, compared with C and N group. The Pu-erh teas made the eight serum chemistries approach to data of C group. There is a same changing trend with the increasing dosage of tea extract in some groups. It was concluded that diabetics can elevate blood lipids in diabetic mice, while the instant Pu-erh tea can significantly reduce the levels of ALT, AST, TC, TG, LDL-C in serum, and increase the level of HDL-C, C-Peptide, insulin. Pu-erh tea caused a more significant decline in the FBG of diabetic mice than AAB group, but AAB group maintain the stability of the fasting blood glucose better. Compared with C and N groups, the damage of liver and pancreas cells was reduced in R, G, B, AAB groups, there is no abnormal in C group. This is maybe because of the application of Instant Pu-erh tea, and more polyphenols and polysaccharides in Pu-erh tea reduce the tissue damage. The damage of liver and pancreas cells was worse in B group than AAB group, this is maybe because of high blood glucose to tissue damage reduce.Interestingly, fed with tea-containing diet and then followed by regular mouse diet for4weeks, the FBG and other physiological data were similar to normal mice in control group. This phenomena suggested that some type2mice might had been cured which were treated by tea-containing food for10weeks.Five dosage groups in the four groups separately consuming three kinds of Pu-erh teas are all effective, and efficient range is2/10-7/10, significant efficient range is1/10-7/10. The best doses of intaking Pu-erh ripe tea are R3(male) and R5(female); the best doses of intaking Pu-erh green tea are G3(male) and G2(female); the best doses of intaking Pu-erh black tea are B1(male) and B4(female); the best doses of intaking Pu-erh black tea and metformin are AAB1(male) and AAB5(female). In addition, stability effect of AAB group to maintain blood glucose is better than B group.This research suggested that the instant Pu-erh containing diet showed significantly corrective effect on abnormal increase of weight and the lipid levels in diabetic mice, as well as blood glucose. This contributes to the mechanism of regulation of lipid levels and the blood glucose reduce effect of Pu-erh tea.