Pu-erh tea, green tea, and black tea suppresses hyperlipidemia, hyperleptinemia and fatty acid synthase through activating AMPK in rats fed a high-fructose diet
ABSTRACT Although green tea extract has been reported to suppress hyperlipidemia, it is unclear how tea extracts prepared from green, oolong, black and pu-erh teas modulate fatty acid synthase expression in rats fed on a high-fructose diet. In this animal study, we evaluated the hypolipidemic and hypoleptinemia effect of these four different tea leaves fed to male Wistar rats for 12 weeks. The results showed that a fructose-rich diet significantly elevated serum triacylglycerols, cholesterol, insulin, and leptin concentrations, as compared with those in the control group. Interestingly, consuming tea leaves for 12 weeks almost normalized the serum triacylglycerols concentrations. Again, rats fed with fructose/green tea and fructose/pu-erh tea showed the greatest reduction in serum TG, cholesterol, insulin and leptin levels. In contrast, serum cholesterol and insulin concentrations of the fructose/oolong tea-fed rats did not normalize. The relative epididymal adipose tissue weight was lower in all rats supplemented with tea leaves than those fed with fructose alone. There was molecular evidence of improved lipid homeostasis according to fatty acid synthase (FAS) protein expression. Furthermore, supplementation of green, black, and pu-erh tea leaves significantly decreased hepatic FAS mRNA and protein levels, and increased AMPK phosphorylation, compared with those of rats fed with fructose only. These findings suggest that the intake of green, black, and pu-erh tea leaves ameliorated the fructose-induced hyperlipidemia and hyperleptinemia state in part through the suppression of FAS protein levels and increased AMPK phosphorylation.
- SourceAvailable from: Qiuping Wang
[Show abstract] [Hide abstract]
- "A unique feature of this tea is that its fragrance increases with increasing shelf time. Studies have found that pu-erh tea also has physiological functions such as lowering blood lipid levels and suppressing tumor growth   . For these reasons, pu-erh tea has been popular worldwide, especially in Asia. "
ABSTRACT: This study investigated the effects of intragastric infusion with Zijuan pu-erh tea theabrownin (ZPTB) on ZPTB metabolites in rat feces, and the relationship between fecal metabolites and lipid metabolism in rats. Fifty Sprague-Dawley rats were randomly assigned to five intervention treatments: a normal diet alone (group I), high-lipid diet alone (group II), high-lipid diet combined with low-dose ZPTB intragastric infusion (group III), high-lipid diet combined with medium-dose ZPTB infusion (group IV), and high-lipid diet combined with high-dose ZPTB infusion (group V). Fecal samples were collected 72 h after intervention and freeze-dried to constant weight. Curie-point pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS) showed that fecal samples from the different groups contained different metabolites and at varying concentrations. The normal control group, high-lipid model group, and the low-, medium-, and high-dose ZPTB infusion groups had 47 (42.0% of all MS-identified metabolites with structural match qualities greater than 80%), 49 (66.72%), 41 (68.18%), 43 (66.6%), and 29 (58.39%) common metabolites to all groups. Ten metabolites were unique to groups consuming the high-lipid diet. Nine, 13, and 13 metabolites were unique to the low-, medium-, and high-dose ZPTB infusion group, respectively. These results demonstrate that Py-GC/MS can effectively detect marker metabolites in feces. The results also suggest that ZPTB increases the cholesterol-to-bile acids conversion in hepatocytes and stimulates the fecal excretion of cholesterol and its metabolites (bile acids, lipids, acids). Therefore, ZPTB may be effective at regulating lipid metabolism in animals and lowering the serum levels of total cholesterol, low-density cholesterol, and triglycerides.Journal of Analytical and Applied Pyrolysis 11/2013; 104:226–233. DOI:10.1016/j.jaap.2013.07.011 · 3.07 Impact Factor
Article: Flavonoids and metabolic syndrome[Show abstract] [Hide abstract]
ABSTRACT: Increasing evidence indicates that several mechanisms, associated or not with antioxidant actions, are involved in the effects of flavonoids on health. Flavonoid-rich beverages, foods, and extracts, as well as pure flavonoids are studied for the prevention and/or amelioration of metabolic syndrome (MS) and MS-associated diseases. We summarize evidence linking flavonoid consumption with the risk factors defining MS: obesity, hypertriglyceridemia, hypercholesterolemia, hypertension, and insulin resistance. Nevertheless, a number of molecular mechanisms have been identified; the effects of flavonoids modifying major endpoints of MS are still inconclusive. These difficulties are explained by the complex relationships among the risk factors defining MS, the multiple biological targets controlling these risk factors, and the high number of flavonoids (including their metabolites) present in the diet and potentially responsible for the in vivo effects. Consequently, extensive basic and clinical research is warranted to assess the final relevance of flavonoids for MS.Annals of the New York Academy of Sciences 07/2012; 1259(1):87-94. DOI:10.1111/j.1749-6632.2012.06511.x · 4.31 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: The water extraction and composition of pu-erh tea, as well as the hypoglycemic effect of the water extract of pu-erh tea (WEPT) in vivo and in vitro, are reported to investigate its hypoglycemic effect on diabetes. High-performance liquid chromatography and colorimetric methods are used to analyze the tea catechins, caffeine, polyphenols, amino acids, and polysaccharides of the WEPT. The effect of the WEPT on glucose uptake by cultured HepG2 cells and the inhibition effect of rat intestinal sucrase, maltase, and porcine pancreatic amylase are determined in vitro. Then, the blood glucose and insulin levels of intragastrically administered WEPT on fasting and oral glucose tolerance test (OGTT) using type 2 diabetic db/db (BKS.Cg-m +/+ Lepr(db)/J) mice are determined in vivo. The results showed that the WEPT dose-dependently and significantly increased glucose uptake by HepG2 cells and inhibited rat intestinal sucrase, maltase, and porcine pancreatic amylase activity. The WEPT intragastrically given for 4 weeks suppressed the increase in blood insulin and glucose levels of db/db mice fasted overnight. In OGTT, the WEPT improved impaired glucose tolerance and ameliorated retarded insulin response at 60 and 120 min in db/db mice. These results suggest that the WEPT has beneficial effects on glucose homeostasis in type 2 diabetes and in amendment of insulin resistance.Journal of Agricultural and Food Chemistry 09/2012; 60(40). DOI:10.1021/jf302426w · 3.11 Impact Factor