Aqueous raw and ripe Pu-erh tea extracts alleviate obesity and alter cecal microbiota composition and function in diet-induced obese rats

Harnessing the Power of Fermented Tea to Improve Gut Microbiota and Combat Obesity Epidemic

The global rise in obesity rates has prompted a thorough evaluation of dietary strategies that may alleviate this metabolic issue. Fermented tea, a beverage rich in polyphenols and catechins, has emerged as a viable therapeutic option for obesity management. This review discusses the role of fermented tea in modulating the gut microbiome, a critical factor in energy regulation and obesity. We explore how the bioactive components in fermented tea influence gut health and their implications for metabolic health. Fermented tea may inhibit weight gain and fat accumulation in obese animal models, likely by promoting beneficial bacteria and suppressing harmful species. Changes in the production of short-chain fatty acids and improvements in gut barrier integrity are linked to enhanced insulin sensitivity and reduced inflammatory markers, essential for effective obesity management. However, barriers remain in applying these findings in clinical settings, such as the need for standardized fermentation techniques and accurate dosage assessments. This review underscores the therapeutic potential of fermented tea in obesity treatment and advocates for further research to enhance its integration with public health initiatives.

Effects of Differently Processed Tea on the Gut Microbiota

Tea is a highly popular beverage, primarily due to its unique flavor and aroma as well as its perceived health benefits. The impact of tea on the gut microbiome could be an important means by which tea exerts its health benefits since the link between the gut microbiome and health is strong. This review provided a discussion of the bioactive compounds in tea and the human gut microbiome and how the gut microbiome interacts with tea polyphenols. Importantly, studies were compiled on the impact of differently processed tea, which contains different polyphenol profiles, on the gut microbiota from in vivo animal feeding trials, in vitro human fecal fermentation experiments, and in vivo human feeding trials from 2004-2024. The results were discussed in terms of different tea types and how their impacts are related to or different from each other in these three study groups.

Optimizing Akkermansia muciniphila Isolation and Cultivation: Insights into Gut Microbiota Composition and Potential Growth Promoters in a Chinese Cohort

The study aims to analyze the composition of the gut microbiota in Chinese individuals using metagenomic sequencing technology, with a particular focus on the abundance of Akkermansia muciniphila (Akk). To improve the efficiency of Akk isolation and identification accuracy, modifications were made to the enrichment culture medium and 16S rRNA universal primers. Additionally, potential growth-promoting factors that stimulate Akk growth were explored through in vitro screening. The research results revealed that the abundance of Akk in Chinese fecal samples ranged from 0.004% to 0.4%. During optimization, a type of animal protein peptide significantly enhanced the enrichment efficiency of Akk, resulting in the isolation of three Akk strains from 14 fecal samples. Furthermore, 17 different growth-promoting factors were compared, and four factors, including galactose, sialic acid, lactose, and chitosan, were identified as significantly promoting Akk growth. Through orthogonal experiments, the optimal ratio of these four growth-promoting factors was determined to be 1:1:2:1. After adding 1.25% of this growth-promoting factor combination to the standard culture medium, Akk was cultivated at 37° for 36 h, achieving an OD600nm value of 1.169, thus realizing efficient proliferation and optimized cultivation of Akk. This study provides important clues for a deeper understanding of the gut microbiota composition in Chinese individuals, while also offering effective methods for the isolation and cultivation of Akk, laying the groundwork for its functional and application research in the human body.

An Update on Prebiotics and on Their Health Effects

Prebiotic compounds were originally defined as "a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health"; however, a significant modulation of the definition was carried out in the consensus panel of The International Scientific Association for Probiotics and Prebiotics (ISAPP), and the last definition states that "prebiotics are substrates that are selectively utilized by host microorganisms conferring a health benefit". Health effects of prebiotics compounds attracted the interest of researchers, food companies and Regulatory Agencies, as inferred by the number of articles on Scopus for the keywords "prebiotic" and "health effects", that is ca. 2000, for the period January 2021-January 2024. Therefore, the aim of this paper is to contribute to the debate on these topics by offering an overview of existing knowledge and advances in this field. A literature search was performed for the period 2012-2023 and after the selection of the most relevant items, the attention was focused on seven conditions for which at least 8-10 different studies were found, namely colorectal cancer, neurological or psychiatric conditions, intestinal diseases, obesity, diabetes, metabolic syndrome, and immune system disorders. In addition, the analysis of the most recent articles through the software VosViewer version 1.6.20 pointed out the existence of five clusters or macro-categories, namely: (i) pathologies; (ii) metabolic condvitions; (iii) structure and use in food; (iv) immunomodulation; (v) effect on gut microbiota.

Oolong tea of different years protects high-fat diet-fed mice against obesity by regulating lipid metabolism and modulating the gut microbiota

Long-term stored oolong tea has recently attracted considerable attention concerning its salutary effect. In this study, the anti-obesity effect of different years' oolong tea on high-fat diet-fed mice was compared. Wuyi rock tea of 2001, 2011, and 2020 were chosen to be the representative samples of oolong tea. The results showed that eight-week administration of 2001 Wuyi rock tea (WRT01), 2011 Wuyi rock tea (WRT11), and 2020 Wuyi rock tea (WRT20) extracts (400 mg per kg per d) significantly decreased the body weight and attenuated the obesity in high-fat diet-fed mice. 2001 and 2011 Wuyi rock teas reduced obesity mainly through regulating lipid metabolism and activating the AMPK/SREBP-1 pathway, downregulating the expression of SREBP-1, FAS, and ACC and upregulating CPT-1a expression; while the 2011 and 2020 Wuyi rock teas by moderating the gut microbiota dysbiosis, reshaping the gut microbiota, and promoting the growth of beneficial bacteria, especially Akkermansia. 2011 Wuyi rock tea was proven to be more effective in reducing body weight gain and liver oxidative stress than the others. Collectively, all three Wuyi rock teas of different years alleviated high-fat diet-induced obesity by regulating lipid metabolism and modulating gut microbiota, whereas the emphasis of their internal mechanism is different with different storage ages.

Proteomics reveals the enhancing mechanism for eliminating toxic hydroxylamine from water by nanocompartments containing hydroxylamine oxidase

Hydroxylamine (NH₂OH) is a potentially toxic pollutant when it is present in water, as it can damage both bacteria and the human body. It is still difficult to eliminate the toxic NH₂OH in water. Here, we showed that the model bacterium (Escherichia coli) with nanocompartments encapsulated with hydroxylamine oxidase (HAO) can remove NH₂OH from water. In addition, the removal efficiency of NH₂OH by genetically modified bacteria (with HAO-nanocompartments) was 3.87 mg N L^-1 h^-1, and that of wild-type bacteria (without HAO-nanocompartments) was only 1.86 mg N L^-1 h^-1. Label-free quantitative proteomics indicated that the nanocompartments containing HAO enhanced bacterial activity by inducing the up-regulation of proteins involved in stress and stimulus responses, and decreased their intracellular NH₂OH concentration. Moreover, the synthesis of proteins involved in energy metabolism, gene expression, and other processes in bacterial was enhanced under hydroxylamine stress, and these changes increased the resistance of bacterial to NH₂OH. This work can aid our understanding of the toxic effects of NH₂OH on bacteria as well as the development of new approaches to eliminate NH₂OH in water.

Gut Microbiota Differentially Mediated by Qingmao Tea and Qingzhuan Tea Alleviated High-Fat-Induced Obesity and Associated Metabolic Disorders: The Impact of Microbial Fermentation

Although dark tea is a unique microbial-fermented tea with a high reputation for having an antiobesity effect, little is known about the effect of microbial fermentation on tea leaves’ antiobesity properties. This study compared the antiobesity effects of microbial-fermented Qingzhuan tea (QZT) and unfermented Qingmao tea (QMT), providing insight into their underlying mechanisms associated with gut microbiota. Our results indicated that the supplementation of QMT extract (QMTe) and QZT extract (QZTe) displayed similar antiobesity effects in high-fat diet (HFD)-fed mice, but the hypolipidemic effect of QZTe was significantly stronger than that of QMTe. The microbiomic analysis indicated that QZTe was more effective than QMTe at regulating HFD-caused gut microbiota dysbiosis. Akkermansiaceae and Bifidobacteriaceae, which have negative correlations with obesity, were enhanced notably by QZTe, whereas Faecalibaculum and Erysipelotrichaceae, which are positively correlated with obesity, were decreased dramatically by QMTe and QZTe. A Tax4Fun analysis of QMTe/QZTe-mediated gut microbiota revealed that QMTe supplementation drastically reversed the HFD-induced upregulation of glycolysis and energy metabolism, whereas QZTe supplementation significantly restored the HFD-caused downregulation of pyruvate metabolism. Our findings suggested that microbial fermentation showed a limited effect on tea leaves’ antiobesity, but enhanced their hypolipidemic activity, and QZT could attenuate obesity and associated metabolic disorders by favorably modulating gut microbiota.

The effects of medicinal herbs on gut microbiota and metabolic factors in obesity models: A systematic review

BACKGROUND AND AIMS

This systematic review of animal studies aimed to identify anti-obesity medicinal herbs with prebiotic properties, and investigate their effects on gut microbiota and metabolic disorders.

METHODS

To obtain the relevant publications, four electronic databases were systematically searched up to June 2019.

RESULTS

Out of 1949 publications, 20 articles met the inclusion criteria in this study. Apart from body weight, some cases (n = 11) had reported the effects of medicinal herbs on metabolic parameters, including lipid profile (n = 7) and glycemic status (n = 4).

CONCLUSION

Although some medicinal herbs could be effective in modulating metabolic status and body weight, through making changes in the gut flora, further studies are needed to confirm the efficacy of such herbs in clinical trials.

Modulation effects of microorganisms on tea in fermentation

Tea is a popular traditional drink and has been reported to exhibit various health-promoting effects because of its abundance of polyphenols. Among all the tea products, fermented tea accounts for the majority of tea consumption worldwide. Microbiota plays an important role in the fermentation of tea, which involves a series of reactions that modify the chemical constituents and thereby affect the flavor and bioactivities of tea. In the present review, the microorganisms involved in fermented tea and tea extracts in the recent studies were summarized and the modulation effects of microorganisms on tea in fermentation, including polyphenols composition and content, biological activities and sensory characteristics, were also critically reviewed. It is expected that the data summarized could provide some references for the development of microbial fermented tea drinks with specific nutrition and health benefits.

Antihyperlipidemic effect and increased antioxidant enzyme levels of aqueous extracts from Liupao tea and green tea in vivo

Liupao tea (fermented dark tea) may improve the active function of hyperlipidemia. Utilizing a hyperlipidemia Sprague-Dawley model and UPLC-MS/MS metabolomics, we examined how the effect of Liupao and green tea extracts on hyperlipidemia and antoxidant enzyme levels and compared their constituents. The results showed that the two types of tea could reduce the levels of total cholesterol (TC), total triglyceride, and low-density lipoprotein cholesterol (LDL-C); increase the contents of bile acids and cholesterol in feces; and improve catalase and glutathione peroxidase (GSH-Px) activities. Compared with the model control group, Liupao tea effectively reduced TC and LDL-C levels by 39.53% and 58.55% and increased GSH-Px activity in the liver by 67.07%, which was better than the effect of green tea. A total of 93 compounds were identified from two samples; the amounts of alkaloids and fatty acids increased compared with green tea, and ellagic acid, hypoxanthine, and theophylline with relatively high contents in Liupao tea had a significantly positive correlation with antihyperlipidemic and antioxidant effects. Therefore, Liupao tea had better antihyperlipidemic and antioxidant activities in vivo than green tea, which might be related to the relatively high content of some active substances.

Artificial Gastrointestinal Models for Nutraceuticals Research—Achievements and Challenges: A Practical Review

Imitating the human digestive system as closely as possible is the goal of modern science. The main reason is to find an alternative to expensive, risky and time-consuming clinical trials. Of particular interest are models that simulate the gut microbiome. This paper aims to characterize the human gut microbiome, highlight the importance of its contribution to disease, and present in vitro models that allow studying the microbiome outside the human body but under near-natural conditions. A review of studies using models SHIME, SIMGI, TIM-2, ECSIM, EnteroMix, and PolyfermS will provide an overview of the options available and the choice of a model that suits the researcher’s expectations with advantages and disadvantages.

The Role of Nutritional Factors in the Modulation of the Composition of the Gut Microbiota in People with Autoimmune Diabetes

Type 1 diabetes mellitus (T1DM) is a disease marked by oxidative stress, chronic inflammation, and the presence of autoantibodies. The gut microbiota has been shown to be involved in the alleviation of oxidative stress and inflammation as well as strengthening immunity, thus its' possible involvement in the pathogenesis of T1DM has been highlighted. The goal of the present study is to analyze information on the relationship between the structure of the intestinal microbiome and the occurrence of T1DM. The modification of the intestinal microbiota can increase the proportion of SCFA-producing bacteria, which could in turn be effective in the prevention and/or treatment of T1DM. The increased daily intake of soluble and non-soluble fibers, as well as the inclusion of pro-biotics, prebiotics, herbs, spices, and teas that are sources of phytobiotics, in the diet, could be important in improving the composition and activity of the microbiota and thus in the prevention of metabolic disorders. Understanding how the microbiota interacts with immune cells to create immune tolerance could enable the development of new therapeutic strategies for T1DM and improve the quality of life of people with T1DM.

Instant Dark Tea Alleviates Hyperlipidaemia in High-Fat Diet-Fed Rat: From Molecular Evidence to Redox Balance and Beyond

Instant dark tea (IDT) is a new product gaining increasing attention because it is convenient and can endow significant health benefit to consumers, which is partially attributed to its high concentration of functional ingredients. However, the molecular mechanism underlying its regulatory effect on hyperlipidaemia is rarely studied. In this study, we performed omics and molecular verification in high-fat diet (HFD)-fed rat, aiming to reveal the mechanism and provide molecular evidence. The results showed that the major bioactive components in IDT were include 237.9 mg/g total polysaccharides, 336.6 mg/g total polyphenols, and 46.9 mg/g EGCG. Rats fed with IDT (0.27–0.54 g/kg for 12 weeks) significantly reduced the body weight and TC, TG, LDL-C, blood glucose, and MDA and induced the level of serum HDL-C and also the levels of liver SOD, CAT, GSH-Px, and Nrf2, compared to HFD group. For molecular mechanism study, HIDT feeding had significant impact on the gene expressions of biomarkers in lipogenesis (FABP, CD36, SCD1, Cyp4a1, and Kcnn2), lipid oxidation (PPARγ), and glucose glycolysis (Gck and ENO2) in liver tissue. Moreover, gut microbiome study found that rats fed with IDT dramatically modified the gut microbial species at the family level, such as suppressing the increase abundance of Proteobacteria and Firmicutes induced by HFD. HIDT significantly boosted the relative composition of beneficial bacterium Akkermansia and Rikenellaceae_RC9_gut_group and decreased the relative abundance of the harmful bacterium Ruminococcaceae_UCG-005 and Ruminiclostridium_9, compared to HFD (p < 0.01). Correlation analysis between microbiome and animal indicators found that seven genera including Akkermansia, Clostridiales, Lachnospiraceae, Lachnospiraceae_UCG-010, Ruminiclostridium_9, Ruminococaceae-UCG-005, and Ruminocuccus_1 were found as potential biomarkers that were strongly correlated with oxidative stress and metabolism genes. For instance, Ruminococcaceae_UCG-005 was significantly correlated with body weight, TG, HDL-C, Nfr2, FABP3, SCD1, Cyp4a1, and Kcnn2. Collectively, the above data obtained in this study had provided the primary molecular evidence for the molecular mechanism and brought in novel insights based on omics for the regulatory effect of IDT on hyperlipidaemia.

In vitro co-metabolism of epigallocatechin-3-gallate (EGCG) by the mucin-degrading bacterium Akkermansia muciniphila

Akkermansia muciniphila is a Gram-negative bacterium that resides within the gut mucus layer, and plays an important role in promoting gut barrier integrity, modulating the immune response and inhibiting gut inflammation. Growth stimulation of A. muciniphila by polyphenols including epigallocatechin-3-gallate (EGCG) from difference sources is well-documented. However, no published in vitro culture data on utilization of polyphenols by A. muciniphila are available, and the mechanism of growth-stimulating prebiotic effect of polyphenols on it remains unclear. Here in vitro culture studies have been carried out on the metabolism of EGCG by A. muciniphila in the presence of either mucin or glucose. We found that A. muciniphila did not metabolize EGCG alone but could co-metabolize it together with both these substrates in the presence of mineral salts and amino acids for mucin and protein sources for glucose. Our metabolomic data show that A. muciniphila converts EGCG to gallic acid, epigallocatechin, and (-)-epicatechin through ester hydrolysis. The (-)-epicatechin formed is then further converted to hydroxyhydroquinone. Co-metabolism of A. muciniphila of EGCG together with either mucin or glucose promoted substantially its growth, which serves as a further demonstration of the growth-promoting effect of polyphenols on A. muciniphila and provides an important addition to the currently available proposed mechanisms of polyphenolic prebiotic effects on A. muciniphila.

Effects and mechanisms of tea on obesity

Obesity has become a global health concern. It increases the risk of several diseases, such as type 2 diabetes mellitus, nonalcoholic fatty liver disease, and certain cancers, which threatens human health and increases social economic burden. As one of the most consumed beverages, tea contains various phytochemicals with potent bioactive properties and health-promoting effects, such as antioxidant, immune-regulation, cardiovascular protection and anticancer. Tea and its components are also considered as potential candidates for anti-obesity. Epidemiological studies indicate that regular consumption of tea is beneficial for reducing body fat. In addition, the experimental studies demonstrate that the potential anti-obesity mechanisms of tea are mainly involved in increasing energy expenditure and lipid catabolism, decreasing nutrient digestion and absorption as well as lipid synthesis, and regulating adipocytes, neuroendocrine system and gut microbiota. Moreover, most of clinical studies illustrate that the intake of green tea could reduce body weight and alleviate the obesity. In this review, we focus on the effect of tea and its components on obesity from epidemiological, experimental, and clinical studies, and discuss their potential mechanisms.

Study on the mechanism of the Pu-erh tea (Camellia sinensis var. assamica) extract inhibiting contraction of isolated mouse duodenum

The aims of this study were to investigate the effects of three different concentrations of the Pu-erh tea extract (PTE) on the contractile activity of the isolated mouse duodenum and explore their mechanism. The contraction amplitude and frequency of the isolated mouse duodenum were inhibited by all three concentrations of PTE. The high-concentration PTE significantly (P < 0.01) inhibited the promotion effects of acetylcholine chloride or BayK8644 on the amplitude and frequency of intestinal contraction, which were comparable to those of atropine sulphate and verapamil hydrochloride, respectively. The results of UV-Vis and ELISA showed that the content of methionine-enkephalin (Met-ENK) in the PTE-treated groups was decreased to varying degrees; contrarily, the activities of tyrosine hydroxylase (TH), total nitric oxide synthase, and the content of nitric oxide were increased to different degrees. The results suggest that PTE can inhibit the contraction of the isolated mouse duodenum, and the mechanism of action is that PTE can not only inhibit the signal transduction pathways of AC-cAMP-PKA and PLC-IP3-Ca2+, but also the Ca2+ signal systems mediated by G protein-coupled M receptors through the myenteric plexus. By reducing the release of Met-ENK from the motor neurons of the myenteric plexus, the GTP-cAMP-PKK signalling pathway and the Ca2+ signalling system mediated by G protein-coupled delta receptors were inhibited. By increasing the TH activity of the motor neurons in the myenteric plexus, the norepinephrine content was increased, thereby the AC-cAMP-PKA signal transduction pathway mediated by G protein-coupled β receptors was activated. This study increases knowledge regarding the medicinal value of the Pu-erh tea.

Gut microbiota as a driver of the interindividual variability of cardiometabolic effects from tea polyphenols

Tea polyphenols have been extensively studied for their preventive properties against cardiometabolic diseases. Nevertheless, the evidence of these effects from human intervention studies is not always consistent, mainly because of a large interindividual variability. The bioavailability of tea polyphenols is low, and metabolism of tea polyphenols highly depends on individual gut microbiota. The accompanying reciprocal relationship between tea polyphenols and gut microbiota may result in alterations in the cardiometabolic effects, however, the underlying mechanism of which is little explored. This review summarizes tea polyphenols-microbiota interaction and its contribution to interindividual variability in cardiometabolic effects. Currently, only a few bacteria that can biodegrade tea polyphenols have been identified and generated metabolites and their bioactivities in metabolic pathways are not fully elucidated. A deeper understanding of the role of complex interaction necessitates fully individualized data, the ntegration of multiple-omics platforms and development of polyphenol-centered databases. Knowledge of this microbial contribution will enable the functional stratification of individuals in the gut microbiota profile (metabotypes) to clarify interindividual variability in the health effects of tea polyphenols. This could be used to predict individual responses to tea polyphenols consumption, hence bringing us closer to personalized nutrition with optimal dose and additional supplementation of specific microorganisms.

Pu-erh tea extraction alleviates intestinal inflammation in mice with flora disorder by regulating gut microbiota

Pu-erh tea is very popular in Southwestern China and South Asian countries and is now becoming increasingly popular in Europe due to its well-documented beneficial effects on human health. Pu-erh tea aqueous extracts can maintain intestinal homeostasis. However, the mechanism of its beneficial effects on intestinal flora disorder is not clear. In this study, we focused on the effects of ripe Pu-erh tea aqueous extracts on the intestinal microbiota in an intestinal flora disorder mouse model. Physiological indexes and the tissue section staining results showed that feeding Pu-erh tea extract could help mice regain weight and alleviate intestinal inflammation. Further assessment of the intestinal microflora found that Pu-erh tea extract could promote the growth of intestinal probiotics and inhibit pathogenic bacteria, thereby achieving a treatment effect for enteritis. This study provides new evidence for the therapeutic effect of Pu-erh tea.

Effects of Different Treatment Methods of Dried Citrus Peel (Chenpi) on Intestinal Microflora and Short-Chain Fatty Acids in Healthy Mice

Chenpi is a kind of dried citrus peel from Citrus reticulata, and it is often used as traditional Chinese medicine to treat dyspepsia and respiratory tract inflammation. In this study, to determine which way of chenpi treatment plays a better effect on the prevention of obesity in healthy mice, we conducted 16S ribosomal RNA (rRNA) gene sequencing for intestinal microbiota and gas chromatography-mass spectrometry detector (GC/MSD) analysis for short-chain fatty acids (SCFAs) of female rats fed with either chenpi decoction or chenpi powder-based diet (n = 10 per group) for 3 weeks. Chenpi powder (CP) group significantly reduced abdominal adipose tissues, subcutaneous adipose tissue, and the serum level of total triacylglycerol (TG). At a deeper level, chenpi powder has a better tendency to increase the ratio of Bacteroidetes to Firmicutes. It alters the Muribaculaceae and Muribaculum in intestinal microbiota, though it is not significant. The concentrations of acetic acid, valeric acid, and butyric acid increased slightly but not significantly in the CP group. Chenpi decoction just reduced perirenal adipose tissues, but it shows better antioxidant activity. It has little effect on intestinal microbiota. No differences were found for SCFAs in the chenpi decoction (CD) group. The results indicated that chenpi powder has a better effect in preventing obesity in mice. It can provide a basis for the development of functional products related to chenpi powder.

Effects of Polyphenols in Tea (Camellia sinensis sp.) on the Modulation of Gut Microbiota in Human Trials and Animal Studies

A diet high in polyphenols is associated with a diversified gut microbiome. Tea is the second most consumed beverage in the world, after water. The health benefits of tea might be attributed to the presence of polyphenol compounds such as flavonoids (e.g., catechins and epicatechins), theaflavins, and tannins. Although many studies have been conducted on tea, little is known of its effects on the trillions of gut microbiota. Hence, this review aimed to systematically study the effect of tea polyphenols on the stimulation or suppression of gut microbiota in humans and animals. It was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Articles were retrieved from PubMed and Scopus databases, and data were extracted from 6 human trials and 15 animal studies. Overall, large variations were observed in terms of microbiota composition between humans and animals. A more consistent pattern of diversified microbiota was observed in animal studies. Tea alleviated the gut microbiota imbalance caused by high-fat diet-induced obesity, diabetes, and ultraviolet-induced damage. The overall changes in microbiota composition measured by beta diversity analysis showed that tea had shifted the microbiota from the pattern seen in animals that received tea-free intervention. In humans, a prebiotic-like effect was observed toward the gut microbiota, but these results appeared in lower-quality studies. The beta diversity in human microbiota remains intact despite tea intervention; supplementation with different teas affects different types of bacterial taxa in the gut. These studies suggest that tea polyphenols may have a prebiotic effect in disease-induced animals and in a limited number of human interventions. Further intervention is needed to identify the mechanisms of action underlying the effects of tea on gut microbiota.

Pu-erh tea ameliorates obesity and modulates gut microbiota in high fat diet fed mice

Obesity is regarded to be associated with fat accumulation, chronic inflammation, and gut microbiota dysbiosis. Raw and ripened pu-erh tea extract (PETe) have the effect of reducing body weight gain and fat accumulation, which are associated with gut microbiota. However, little is known about the difference of raw and ripened PETe on the regulation of gut microbiota. Here, our results suggested that supplementation of raw and ripened PETe displayed similar anti-obesogenic effect in high fat diet (HFD)-induced obesity mice, by attenuating the body weight gain, fat accumulation, oxidative injury, and low-grade inflammation, improving the glucose tolerance, alleviating the metabolic endotoxemia, and regulating the mRNA and protein expression levels of the lipid metabolism-related genes. 16S rRNA sequencing of fecal samples indicated that raw and ripened PETe intervention displayed different regulatory effect on the HFD-induced gut microbiota dysbiosis at different taxonomic levels. The microbial diversity, the relative abundance of Firmicutes and Bacteroidetes as well as F/B ratio were reversed more closer to normal by ripened PETe. Phylotypes of Bacteroidaceae, Ruminococcaceae, Lachnospiraceae, Muribaculaceae, and Rikenellaceae which are negatively correlated with obesity were enhanced notably by the intervention of ripened PETe, while Erysipelotrichaceae and Lactobacillaceae which have positive correlation with obesity were decreased dramatically. In addition, the treatment of ripened PETe had better effect on the increase of benefical Bacteroides, Alistipes, and Akkemansia and decrease of obesity associated Faecalibaculum and Erysipelatoclostridium (p < 0.05). These findings suggested that pu-erh tea especially ripened pu-erh tea could serve as a great candidate for alleviation of obesity in association with the modulation of gut microbiota.

Compositional and functional profiling of the rhizosphere microbiomes of the invasive weed Ageratina adenophora and native plants

The rhizosphere soil microbiome (RSM) plays an important role in the nutritional metabolism of the exotic weed Ageratina adenophora. However, our understanding of the composition and metabolic activity of this microbiome is limited. We used high-throughput sequencing of bacterial 16S rRNA genes and fungal internal transcribed spacer fragments in combination with transcriptome analysis to compare the composition and metabolic features of the RSMs of A. adenophora and the native plant species Artemisia indica and Imperata cylindrica. A. indica cohabitates with the weed and I. cylindrica grows in uninvaded soil areas. We found fungi belonging to the phyla Ascomycota and Basidiomycota and bacteria belonging to the phyla Proteobacteria, Acidobacteria and Bacteroidetes were highly abundant in the RSMs of A. adenophora and both native plant species. The RSM of A. adenophora differed to varying degrees in the relative abundances of bacterial and fungal phyla and genera, and in levels of expression of functional genes from those of both the native species. The RSM of A. adenophora was more metabolically active than both of these, as indicated by marked increases in the expression levels of genes associated with cell wall, membrane, and envelope biogenesis, energy production and conversion, and the transport and metabolism of carbohydrates, amino acids, coenzymes, nucleotides, and secondary metabolites. Ascomycota and Basidiomycota contributed most significantly to these differences. The composition and metabolic activities of A. adenophora RSM differed less to the RSM of A. indica than to the RSM of I. cylindrica. Fungal communities contributed most to the metabolic genes in the RSM of A. adenophora. These included the arbuscular mycorrhizal fungi Glomeromycota. The different relative abundances in the RSMs of these three plant populations may explain why A. adenophora is more successful in colonizing soils than the two native populations.

Gut Microbiome and Metabolome Response of Pu-erh Tea on Metabolism Disorder Induced by Chronic Alcohol Consumption

This study investigated the protective effects of pu-erh tea extract (PTE) on alcohol-induced microbiomic and metabolomic disorders. In chronic alcohol-exposed mice, PTE ameliorated chronic alcoholic consumption-induced oxidative stress, inflammation, lipid accumulation, and liver and colon damage through modulating microbiomic and metabolomic responses. PTE restored the alcohol-induced fecal microbiota dysbiosis by elevating the relative abundance of potentially beneficial bacteria, for example, Bifidobacterium and Allobaculum, and decreasing the relative abundance of potentially harmful bacteria, for example, Helicobacter and Bacteroides. The alcohol-induced metabolomic disorder was modulated by PTE, which was characterized by regulations of lipid metabolism (sphingolipid, glycerophospholipid, and linoleic acid metabolism), amino acid metabolism (phenylalanine and tryptophan metabolism), and purine metabolism. Besides, the bacterial metabolites of phytochemicals in PTE might contribute to the protective effects of PTE. Overall, PTE could be a functional beverage to treat chronic alcohol consumption-induced microbiomic and metabolomic disorders.

Fuzhuan Brick Tea Attenuates High-Fat Diet-Induced Obesity and Associated Metabolic Disorders by Shaping Gut Microbiota

An increasing amount of evidence suggests that the metabolic improvement of high-fat diet (HFD)-induced obese mice by Fuzhuan brick tea (FBT) is associated with gut microbiota. However, the causalities between FBT and gut microbiota have not yet been elucidated and the underlying mechanisms of action remain unclear. To impart direct evidence for the essential role of gut microbiota in the attenuation of obesity by FBT, the effects of FBT on healthy mice and microbiota-depleted mice that were treated with antibiotics were compared in an HFD-induced obesity mouse model. The results showed that FBT dramatically ameliorated obesity, serum lipid parameters, blood glucose homeostasis, hepatic steatosis, adipocyte hypertrophy, and tissue inflammation. However, the microbiota-depleted mice with single bacterium (Escherichia-Shigella) after antibiotic treatment were resistant to FBT-induced antiobesity and metabolic improvement. The beneficial effects of FBT resulted from its shift on gut microbiota composition and structure in mice. HFD-induced increase in the phyla Firmicutes/Bacteroidetes (F/B) ratio was remarkably restored by FBT. Furthermore, FBT-induced increase in abundances of beneficial bacteria Clostridiaceae, Bacteroidales, and Lachnospiraceae and decreases in harmful Ruminococcaceae, Peptococcaceae, Peptostreptococcaceae, and Erysipelotrichaceae were causal antecedents for FBT to reduce obesity and improve metabolic disorders.

Tea Compounds and the Gut Microbiome: Findings from Trials and Mechanistic Studies

In recent years, the gut microbiome has become a focal point of interest with growing recognition that a well-balanced gut microbiota composition is highly relevant to an individual’s health status and well-being. Its profile can be modulated by a number of dietary factors, although few publications have focused on the effects of what we drink. The present review performed a systematic review of trials and mechanistic studies examining the effects of tea consumption, its associated compounds and their effects on the gut microbiome. Registered articles were searched up to 10th September 2019, in the PubMed and Cochrane library databases along with references of original articles. Human trials were graded using the Jadad scale to assess quality. Altogether 24 publications were included in the main review—six were human trials and 18 mechanistic studies. Of these, the largest body of evidence related to green tea with up to 1000 mL daily (4–5 cups) reported to increase proportions of Bifidobacterium. Mechanistic studies also show promise suggesting that black, oolong, Pu-erh and Fuzhuan teas (microbially fermented ‘dark tea’) can modulate microbial diversity and the ratio of Firmicutes to Bacteroidetes. These findings appear to support the hypothesis that tea ingestion could favourably regulate the profile of the gut microbiome and help to offset dysbiosis triggered by obesity or high-fat diets. Further well-designed human trials are now required to build on provisional findings.

Dynamic Profiling of Phenolic Acids during Pu-erh Tea Fermentation Using Derivatization Liquid Chromatography-Mass Spectrometry Approach

Pu-erh tea, a famous traditional Chinese tea with multiple health benefits, is produced by microbial fermentation. It has been reported that major known bioactive compounds in green tea, e.g. epicatechin, epigallocatechin gallate, and theanine, decreased during fermentation. Then which components account for the benefits of Pu-erh tea? Phenolic acids are aromatic secondary metabolites and possess various biological properties. In this research, phenolic acids in Pu-erh tea were investigated qualitatively and quantitatively to reveal the influence of fermentation and their potential effects using 5-(diisopropylamino)amylamine (DIAAA) derivatization-ultrahigh performance liquid chromatography-quadrupole-time-of-flight/mass spectrometry (UHPLC-Q-TOF/MS) approach. A total of 33 phenolic acids were determined, and most of them were detected in Pu-erh tea for the first time. Moreover, gallic acid and theogallin were the major components in ripened and raw Pu-erh tea, respectively. Dynamic profiling revealed the increase of simple phenolic acids and the decrease of most of phenolic acid esters during Pu-erh tea fermentation. These results provided firm basis for practical fermentation and quality control of Pu-erh tea.