Protection Effects Of Pu-er Green Tea Water Extraction Again Trans Fatty Acid

The Pu-er tea, being a special type tea in Yunnan Province, China, has drawn research attention for its good effects of reducing weight and fat in the past decade. At present, many people begin to adopt western lifestyle, and the application of trans fatty acids in hydrogenated vegetable oil is becoming more and more widely, which is rich of trans fatty acids (TFA). The risk of suffering from weight and cardiovascular disease will rise, if one intakes small quantity of TFA regularly. This research aims to explore the effect of Pu-er green tea water extraction (tea extraction) preventing hyperlipemia caused by TFA, this will benefit the development and industrialization of Pu-er tea.Mice were used as animal models in this paper. Dosages used for mice are accordant to regular daily intake of an adult of 70 kg as reference quantity, that is 25g vegetable oil and tea 10 g (equivalent to tea extraction 1.5 g) respectively. Hydrogenated vegetable oil (shortening) imported from Indonesia was used as trans fatty acids source, while rapeseed oil produced in LuoPing, Yunnan, China, was used for negative control group. For evaluating the protection effects of water extraction of Pu-er tea, levels of serum total cholesterol (TC), triglyceride(TG), high density liprotein-cholesterol (HDL-C), low density liprotein-cholesterol(LDL-C) and the levels on the activity of alanine transaminase (ALT) and aspartic transaminase (AST), were assayed. Furthermore, the pathological changes in liver tissue were observed.The experimental design is as follows:Kunming mice were used as animal models, male and female in half, weight 22±2 g, were randomly divided into 17 groups:control check (CK) group, fed with normal diet; shortening (S) group, rapeseed oil (RO) group, pu-er green tea extract (TE) group, shortening+tea extract (S+TE) group were set up four dosage groups respectively, male and female in half, according to 0.1g/kg·bw,0.2g/kg·bw,0.4g/kg·bw,0.8g/kg·bw; 0.1g/kg·bw,0.2g/kg·bw,0.4 g/kg·bw,0.8g/kg·bw; 0.01 g/kg·bw,0.02g/kg·bw,0.04g/kg·bw,0.08g/kg·bw; 0.8+0.01 g/kg·bw,0.8 +0.02 g/kg·bw,0.8+0.04 g/kg·bw,0.8+0.08 g/kg·bw dosages fed mice. These groups were fed for 28 days, weighted every week. Finally the weight of 17 groups mice were all increased than the initial weight. The weight of S, RO and S+TE groups were higher than the average increase of CK group, while the average increase of weight in TE group was lower than the CK group. After the mice were killed, the blood was collected to detect the levels of serum TC, TG, HDL-C, LDL-C, as well as ALT and AST. The biopsy of mice liver tissue was also observed.Data analysis was performed by GraphPad Prism 5.0. Results showed that the levels of TC, TC, LDL-C, ALT, AST in serum of S and RO groups were relatively higher, compared with CK group, and showed dosage-related positive correlation. The level of HDL-C was significantly lower in TFA groups with negative correlation. Compared with the CK group, the levels of TC, TG, LDL-C, ALT, AST in TE group were relatively lower, and there had a obviously downward trend with the increasing dosage of tea extract, while the level of HDL-C significantly increased, positively correlated to dosage of tea extract. Despite of the levels of TC, TG, LDL-C, ALT, AST increased in S+TE group, but lower than TFA positive control group. It was concluded that shortening and rapeseed oil can elevate blood lipids in mice, while the tea extract can significantly reduce the levels of TC, TG, LDL-C, ALT, AST in serum, and increase the level of HDL-C. By observing liver tissue biopsy in each group, there was not seen any abnormality in CK group,TE group was better than S and RO group. Because of the application of tea extract, the damage of liver cells was reduced in S+TE group.There is no obvious differece of fatty degeneration in liver organazation of the testing mice. It is probably because of the short time of feeding, which is only month in this research.This research suggested that the lipid levels in mice were significantly regulated by tea extract, which were fed with high trans fatty acids diet, it contributes to the mechanism of regulation of lipid levels and the protective effect of TFA.