Project description:Pu-erh tea has attracted increasing attention worldwide because of its special flavor and health effects, but its impact on composition and function of the gut microbiota remains unclear. The aim of this study was to investigate effects of aqueous extracts of fermented (ripe) and non-fermented (raw) Pu-erh teas on the composition and function of intestinal microbiota of rats with diet-induced obesity. We conducted a comparative metagenomic and metaproteomic investigation of the microbial communities in cecal samples taken from obese rats administrated with or without extracts of raw and ripe Pu-erh tea. By analyzing the composition and diversity of 16S rRNA amplicons and expression profiles of 814 distinct proteins, we found that, despite differences in the chemical compositions of the raw and ripe Pu-erh tea, administration of either at two different doses (0.15 and 0.40 g/Kg body weight), significantly (P<0.05) increased community diversity, and changed the composition of the cecal microbiota by increasing the relative abundances of Firmicutes and decreasing those of Bacteroidetes. Community metabolic processes including sucrose metabolism, glycolysis, syntheses of proteins, rRNA and antibiotics were significantly (P<0.05), or had a tendency (0.10<P<0.05) to be, promoted by enriching relevant enzymes. Furthermore, evidences from population, molecular and metabolic levels have shown that polyphenols of raw Pu-erh tea and their metabolites can promote potentially the growth of Akkermansia municiphila by stimulating the type II and III secretion system protein, elongation factor Tu, and glyceraldehyde-3-phosphate dehydrogenase. This study has provided new evidences for the prebiotic effects of Pu-erh tea.
Project description:Metabolic syndrome (MS) is a common metabolic disorder characterized by obesity, insulin resistance, cardiovascular disease and gut microbiota dysbiosis. Pu-erh tea and its ingredient theabrownin have known functions on the reduction of body weight gain and fat accumulation. However, few studies systematicly analyze the different contributions and mechanisms of their anti-metabolic syndrome functions through multi-omics combination analysis. Here, we used metagenomics, transcriptomics and metabolomics technology to investigate the anti-metabolic syndrome mechanism of Pu-erh tea and theabrownin in MS mice. Our results suggested that Pu-erh tea and theabrownin interventions could improve the physiological functions of liver, jejunum and adipose tissues in MS mice. Hepatic transcriptome revealed that both interventions could regulate the circadian rhythm pathway. Glycerophospholipid and linoleic acid metabolism were also modulated by both interventions through serum and brain metabolome analysis. Faecal metagenome demonstrated that both interventions could increase the relative abundance of Clostridiales bacterium 42_27, Blautia coccoides and Firmicutes bacterium ASF500, but decrease the relative abundance of Brevundimonas vesicularis. Otherwise, compared with Pu-erh tea, theabrownin markedly upregulated the levels of hepatic antioxidants (i.e., SOD, GSH), prominently downregulated hepatic inflammatory factors (i.e., IL-1, IL-6, TNF-α) and malondialdehyde oxidant, but modestly reduced obesity-associated short-chain fatty acids in faeces in MS mice. Taken together, our data provided insights into the homogeneous and heterogeneous natural biological functions of theabrownin and Pu-erh tea in the treatment of metabolic syndrome.
Project description:Pu-erh tea displays cholesterol-lowering properties, but the underlying mechanism has not been elucidated. Theabrownin is one of the most active and abundant pigments in Pu-erh tea. Here, we show that theabrownin alters the gut microbiota in mice and humans, predominantly suppressing microbes associated with bile-salt hydrolase (BSH) activity. Theabrownin increases the levels of ileal conjugated bile acids (BAs) which, in turn, inhibit the intestinal FXR-FGF15 signaling pathway, resulting in increased hepatic production and fecal excretion of BAs, reduced hepatic cholesterol, and decreased lipogenesis. The inhibition of intestinal FXR-FGF15 signaling is accompanied by increased gene expression of enzymes in the alternative BA synthetic pathway, production of hepatic chenodeoxycholic acid, activation of hepatic FXR, and hepatic lipolysis. Our results shed light into the mechanisms behind the cholesterol- and lipid-lowering effects of Pu-erh tea, and suggest that decreased intestinal BSH microbes and/or decreased FXR-FGF15 signaling may be potential anti-hypercholesterolemia and anti-hyperlipidemia therapies.