Anti-Obesity Effect of Theabrownin from Dark Tea in C57BL/6J Mice Fed a High-Fat Diet by Metabolic Profiles through Gut Microbiota Using Untargeted Metabolomics

Theabrownin: The 'rich hue' of Chinese dark tea, its extraction, and role in regulating inflammation and immune response

Theabrownin (TB) is one of the most representative bioactive components in Chinese dark tea, often referred to as the "gold in dark tea." The complex macromolecular structure of TB is influenced by its source (tea materials), extraction, separation, and purification methods, which affect its final structure and bioactivity. In recent years, research on TB has surged, becoming a hotspot in the field of tea functional components and health research. Extensive studies on its health benefits indicate that TB is a crucial active ingredient in dark tea with substantial potential for application in food, health care, industry, and medical fields. This review summarizes the formation of TB during dark tea manufacturing, especially the "piling" stage, extraction methods, various purification techniques, and the physicochemical properties of TB. Additionally, it comprehensively reviews recent research on TB's role in typical inflammation and immune imbalance-induced diseases such as colitis, atherosclerosis, non-alcoholic fatty liver disease, and innate immune diseases. The review concludes with a comparative summary of the biological activities of TB from the five major types of Chinese dark tea in terms of anti-inflammatory and immune regulatory effects.

Improving dietary energy and antioxidative properties benefit early maternal BMI and further manage adverse pregnancy outcomes with better weight gain

Dietary characteristics affect maternal status in early pregnancy, which is important for later outcomes. However, Chinese dietary guidelines for pregnant women are not specific to obesity, overweight, and underweight. Moreover, since pregnancy is a prolonged process, an intermediate factor is needed to connect early maternal BMI with pregnancy outcomes. In this cohort of 1785 Chinese pregnant women from 2020 to 2022, 37.98% of participants had abnormal BMI in early pregnancy. A lower energy intake from carbohydrates (<50%) but higher intake from protein (>20%) and fat (>30%) resulted in excessive energy consumption, which was a risk factor for maternal obesity (adjusted OR (AOR): 1.49, 95%CI: 1.02-2.17) and overweight (AOR: 1.47, 95%CI: 1.00-2.18). Furthermore, the risk of maternal underweight was increased by a poor antioxidative diet (AOR: 2.80, 95%CI: 1.02-7.66) with a 20.28% lower intake of isoflavones and an imbalanced dietary structure (AOR: 3.95, 95%CI: 1.42-10.95) with less energy from fat (<20%) and unsaturated fatty acids (<3%). Following the timeline from gestation to delivery, early maternal obesity, overweight, and underweight increased the risk of abnormal body weight gain during pregnancy (AOR: 1.91-3.62, 95%CI: 1.20-6.12). Subsequently, abnormal weight gain further provoked adverse pregnancy outcomes, such as gestational diabetes mellitus, hypertensive disorders, cesarean section, and macrosomia (AOR, 1.33-2.58; 95%CI, 1.04-4.17). To minimize these threats, obese/overweight pregnant women in China might have more energy from carbohydrates (>65%) while reducing energy intake from protein (<10%) and fat (<20%). Meanwhile, underweight pregnant women are advised to increase their intake of dietary antioxidants (especially isoflavones) and consume more energy from fat (>30%) and unsaturated fatty acids (>11%). Finally, gestational body weight gain, as a potential intermediate bridge, should receive more attention.

The Preventive Effect of Theabrownin from Ya'an Tibetan Tea Against UVB-Induced Skin Photodamage in BALB/c Mice via the MAPK/NF-κB and Nrf2 Signaling Pathways

Ya'an Tibetan tea, renowned as a mysterious tea, has been used as a traditional remedy for disease prevention among ethnic minorities in the Qinghai-Tibet Plateau region, which experiences the highest levels of UVB radiation in the world, for over 1000 years. Theabrownin (TB) from Ya'an Tibetan tea exhibits various health benefits. In this study, the preventive effects of TB on UVB-induced skin damage were investigated. The results showed that TB pretreatment significantly alleviated visible skin damage, epidermal hyperplasia, and collagen destruction in BALB/c mice. The mechanism of action involved increasing the mRNA and protein levels of Nrf2 and enhancing SOD enzyme activity, thereby reducing MDA content and improving the body's antioxidant capacity. TB also inhibited the protein synthesis of inflammatory factors such as TNF-α, IL-1β, and IL-6, as well as the expression of NF-κB mRNA and protein, thereby reducing skin inflammation. Furthermore, it suppressed the overexpression of p38 MAPK, ERK, and AP-1 mRNA and protein, along with the downstream MMP-1 protein, to prevent collagen destruction in the skin. Additionally, TB pretreatment prevented cell apoptosis by reducing Caspase-3 overexpression. These results suggest that TB can prevent UVB-induced photodamage and exert its preventive effects in a dose-dependent manner by downregulating the MAPK/NF-κB signaling pathway while promoting the Nrf2 signaling pathway in the skin. Consequently, TB holds promising potential for future applications in skin photodamage prevention and skin health promotion.

Theabrownin: a dietary nutraceutical with diverse anticancer mechanisms

Cancer, a highly deadly disease, necessitates safe, cost-effective, and readily accessible treatments to mitigate its impact. Theabrownin (THBR), a polyphenolic pigment found in Pu-erh tea, has garnered attention for its potential benefits in memory, liver health, and inflammation control. By observing different biological activities of THBR, recently researchers have unveiled THBR's promising anticancer properties across various human cancer types. By examining existing studies, it is evident that THBR demonstrates substantial potential in inhibiting cell proliferation and reducing tumour size with minimal harm to normal cells. These effects are achieved through the modulation of key molecular markers such as Bcl-2, Bax, various Caspases, Poly (ADP-ribose) polymerase cleavage (Cl-PARP), and zinc finger E box binding homeobox 1 (ZEB 1). This review aims to provide in-depth insights into THBR's role in cancer research. This review also elucidates the underlying anticancer mechanisms of THBR, offering promise as a novel anticancer drug to alleviate the global cancer burden.

Global hotspots and trends in tea anti-obesity research: a bibliometric analysis from 2004 to 2024

Background

The prevalence of obesity and its related ailments is on the rise, posing a substantial challenge to public health. Tea, widely enjoyed for its flavors, has shown notable potential in mitigating obesity. Yet, there remains a lack of exhaustive bibliometric studies in this domain.

Methods

We retrieved and analyzed multidimensional data concerning tea and obesity studies from January 2004 to June 2024, using the Web of Science Core Collection database. This bibliometric investigation utilized tools such as Bibliometrix, CiteSpace, and VOSviewer to gather and analyze data concerning geographical distribution, leading institutions, prolific authors, impactful journals, citation patterns, and prevalent keywords.

Results

There has been a significant surge in publications relevant to this field within the last two decades. Notably, China, Hunan Agricultural University, and the journal Food and Function have emerged as leading contributors in terms of country, institution, and publication medium, respectively. Zhonghua Liu of Hunan Agricultural University has the distinction of most publications, whereas Joshua D. Lambert of The State University of New Jersey is the most cited author. Analyses of co-citations and frequently used keywords have identified critical focus areas within tea anti-obesity research. Current studies are primarily aimed at understanding the roles of tea components in regulating gut microbiota, boosting fat oxidation, and increasing metabolic rate. The research trajectory has progressed from preliminary mechanism studies and clinical trials to more sophisticated investigations into the mechanisms, particularly focusing on tea's regulatory effects on gut microbiota.

Conclusion

This study offers an intricate overview of the prevailing conditions, principal focus areas, and developmental trends in the research of tea's role against obesity. It delivers a comprehensive summary and discourse on the recent progress in this field, emphasizing the study's core findings and pivotal insights. Highlighting tea's efficacy in obesity prevention and treatment, this study also points out the critical need for continued research in this area.

State-of-the-art review of theabrownins: from preparation, structural characterization to health-promoting benefits

As far as health benefit is concerned, dark tea is one of the best beverages in the world. Theabrownins are the major ingredient contributing to the health benefits of dark tea and known as "the soft gold in dark tea." A growing body of evidence indicated that theabrownins are macromolecular pigments with reddish-brown color and mellow taste, and mainly derived from the oxidative polymerization of tea polyphenols. Theabrownins are the main active ingredients in dark tea which brings multiple health-promoting effects in modulating lipid metabolism, reducing body weight gain, attenuating diabetes, mitigating NAFLD, scavenging ROS, and preventing tumors. More importantly, it's their substantial generation in microbial fermentation that endows dark tea with much stronger hypolipidemic effect compared with other types of tea. This review firstly summarizes the most recent findings on the preparation, structural characteristics, and health-promoting effects of theabrownins, emphasizing the underlying molecular mechanism, especially the different mechanisms behind the effect of theabrownins-mediated gut microbiota on the host's multiple health-promoting benefits. Furthermore, this review points out the main limitations of current research and potential future research directions, hoping to provide updated scientific evidence for their better theoretical research and industrial utilization.

Formation, physicochemical properties, and biological activities of theabrownins

Theabrownins (TBs) are heterogeneous mixtures of water-soluble brown tea pigments, and important constituents to evaluate the quality of dark tea. TBs have numerous hydroxyl and carboxyl groups and are formed by the oxidative polymerization of tea polyphenols. Many biological activities attributed to TBs, including antioxidant, anti-obesity, and lipid-regulating, have been demonstrated. This review summarizes the research progress made on the formation mechanism and physicochemical properties of TBs. It also discusses their protective effects against various diseases and associated potential molecular mechanisms. Additionally, it examines the signaling pathways mediating the bioactivities of TBs and highlights the difficulties and challenges of TBs research as well as their research prospects and applications.

Cichorium glandulosum Ameliorates HFD-Induced Obesity in Mice by Modulating Gut Microbiota and Bile Acids

Obesity is an ongoing global health problem, and Cichorium glandulosum (CG, chicory) is traditionally used as a hepatoprotective and lipid-lowering drug. However, there is still a lack of research on the role of CG in the treatment of obesity. In the present study, we found that CG significantly delayed weight gain and positively affected glucolipid metabolism disorders, serum metabolism levels, and the degree of liver and kidney oxidative stress in high-fat diet (HFD) mice. Further examination of the effects of CG on intestinal microenvironmental dysregulation and its metabolites in HFD mice revealed that the CG ethanol extract high-dose group (CGH) did not have a significant regulatory effect on short-chain fatty acids. Still, CGH significantly decreased the levels of 12α-OH/non-12α-OH bile acids and also found significant upregulation of proteobacteria and downregulation of cyanobacteria at the phylum level. CG may have ameliorated obesity and metabolic abnormalities in mice by repairing gut microbiota dysbiosis and modulating bile acid biosynthesis.

Coffee, tea, and cocoa in obesity prevention: Mechanisms of action and future prospects

Obesity, a major public health problem, causes numerous complications that threaten human health and increase the socioeconomic burden. The pathophysiology of obesity is primarily attributed to lipid metabolism disorders. Conventional anti-obesity medications have a high abuse potential and frequently deliver insufficient efficacy and have negative side-effects. Hence, functional foods are regarded as effective alternatives to address obesity. Coffee, tea, and cocoa, three widely consumed beverages, have long been considered to have the potential to prevent obesity, and several studies have focused on their intrinsic molecular mechanisms in past few years. Therefore, in this review, we discuss the mechanisms by which the bioactive ingredients in these three beverages counteract obesity from the aspects of adipogenesis, lipolysis, and energy expenditure (thermogenesis). The future prospects and challenges for coffee, tea, and cocoa as functional products for the treatment of obesity are also discussed, which can be pursued for future drug development and prevention strategies against obesity.

Gut microbiota affects obesity susceptibility in mice through gut metabolites

Introduction

It is well-known that different populations and animals, even experimental animals with the same rearing conditions, differ in their susceptibility to obesity. The disparity in gut microbiota could potentially account for the variation in susceptibility to obesity. However, the precise impact of gut microbiota on gut metabolites and its subsequent influence on susceptibility to obesity remains uncertain.

Methods

In this study, we established obesity-prone (OP) and obesity-resistant (OR) mouse models by High Fat Diet (HFD). Fecal contents of cecum were examined using 16S rDNA sequencing and untargeted metabolomics. Correlation analysis and MIMOSA2 analysis were used to explore the association between gut microbiota and intestinal metabolites.

Results

After a HFD, gut microbiota and gut metabolic profiles were significantly different between OP and OR mice. Gut microbiota after a HFD may lead to changes in eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), a variety of branched fatty acid esters of hydroxy fatty acids (FAHFAs) and a variety of phospholipids to promote obesity. The bacteria g_Akkermansia (Greengene ID: 175696) may contribute to the difference in obesity susceptibility through the synthesis of glycerophosphoryl diester phosphodiesterase (glpQ) to promote choline production and the synthesis of valyl-tRNA synthetase (VARS) which promotes L-Valine degradation. In addition, gut microbiota may affect obesity and obesity susceptibility through histidine metabolism, linoleic acid metabolism and protein digestion and absorption pathways.

Theabrownin inhibits obesity and non-alcoholic fatty liver disease in mice via serotonin-related signaling pathways and gut-liver axis

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) with obesity seriously threats public health. Our previous studies showed that dark tea had more potential on regulating lipid metabolism than other teas, and theabrownin (TB) was considered to be a main contributor to the bioactivity of dark tea.

OBJECTIVES

This in vivo study aims to reveal the effects and molecular mechanisms of TB on NAFLD and obesity, and the role of the gut-liver axis is explored.

METHODS

The histopathological examinations, biochemical tests, and nuclear magnetic resonance were applied to evaluate the effects of TB on NAFLD and obesity. The untargeted metabolomics was used to find the key molecule for further exploration of molecular mechanisms. The 16S rRNA gene sequencing was used to assess the changes in gut microbiota. The antibiotic cocktail and fecal microbiota transplant were used to clarify the role of gut microbiota.

RESULTS

TB markedly reduced body weight gain (67.01%), body fat rate (62.81%), and hepatic TG level (51.35%) in the preventive experiment. Especially, TB decreased body weight (32.16%), body fat rate (42.56%), and hepatic TG level (42.86%) in the therapeutic experiment. The mechanisms of action could be the improvement of fatty acid oxidation, lipolysis, and oxidative stress via the regulation of serotonin-related signaling pathways. Also, TB increased the abundance of serotonin-related gut microbiota, such as Akkermansia, Bacteroides and Parabacteroides. Antibiotics-induced gut bacterial dysbiosis disrupted the regulation of TB on serotonin-related signaling pathways in liver, whereas the beneficial regulation of TB on target proteins was regained with the restoration of gut microbiota.

CONCLUSION

We find that TB has markedly preventive and therapeutic effects on NAFLD and obesity by regulating serotonin level and related signaling pathways through gut microbiota. Furthermore, gut microbiota and TB co-contribute to alleviating NAFLD and obesity. TB could be a promising medicine for NAFLD and obesity.

Theabrownin from Dark Tea Ameliorates Insulin Resistance via Attenuating Oxidative Stress and Modulating IRS-1/PI3K/Akt Pathway in HepG2 Cells

Dark tea has great potential in regulating glycolipid metabolism, and theabrownin (TB) is considered to be the characteristic and bioactive constituent of dark tea. This study evaluated the ability of TB1 (fermented for 7 days) and TB2 (fermented for 14 days) isolated from dark tea to reverse insulin resistance (IR) in HepG2 cells. The results indicated that TB significantly ameliorated oxidative stress by improving mitochondrial function. In addition, TB improved glycogen synthesis and glucose consumption, and inhibited gluconeogenesis and fatty acid synthesis, by regulating GSK3β (Glycogen synthase kinase 3β), G6Pase (Glucose-6-phosphatase), GCK (Glucokinase), PEPCK1 (Phosphoenolpyruvate carboxy kinase 1), SREBP-1C (sterol regulatory element-binding protein 1C), FASN (fatty acid synthase), and ACC (Acetyl-CoA carboxylase). Additionally, the results of Western blot and real-time PCR experiments demonstrated that TB modulated glucolipid metabolism through the IRS-1 (Insulin receptor substrate 1)/PI3K (phosphatidylinositol-3 kinase)/Akt (protein kinase B) signaling pathway. Treatment with the PI3K inhibitor demonstrated a favorable correlation between PI3K activation and TB action on glycolipid metabolism. Notably, we observed that TB2 had a greater effect on improving insulin resistance compared with TB1, which, due to its prolonged fermentation time, increased the degree of oxidative polymerization of TB.

Reduction of obesity and hepatic adiposity in high-fat diet-induced rats by besunyen slimming tea

Objective

Obesity is a significant risk factor for metabolic syndrome, type 2 diabetes mellitus, hypertension, nonalcoholic fatty liver disease, and cardiovascular disorders. As a well-known Chinese tea product, Besunyen Slimming Tea (BST) is believed to effectively reduce body weight (BW) and lipid profile. In this study, we aimed to elucidate the mechanisms and effects of BST on treating obesity and hepatic steatosis using a rat model fed with a high-fat diet (HFD).

Methods

Sprague-Dawley rats were subjected to random separation into three categories: Animals were fed (1) a normal diet food (ND); (2) HFD, and (3) HFD + BST (n = 12/category). After successfully establishing the obesity model at week 8, the HFD + BST received BST (0.6 g/0.6 kg) orally, and the ND and HFD received the same amount (2 ml) of distilled water orally.

Results

HFD + BST reduced waist circumference (7.84%, P = 0.015), food intake (14.66%, P = 0.011), final BW (12.73%, P = 0.010), BW gain (964.16%, P < 0.001), and body mass index (8.97%, P = 0.044) compared with the HFD. BST supplementation also decreased hyperlipidemia, inflammation, and insulin resistance in rats with HFD. Furthermore, BST suppressed hepatic lipidosis by decreasing de novo lipogenesis and increasing fatty acid oxidation.

Conclusions

The results of this study offer evidence supporting the potential health benefits of BST in the management of metabolic disorders and obesity.

Complete genome analysis of Bacillus subtilis derived from yaks and its probiotic characteristics

Probiotics have attracted attention due to their multiple health benefits to the host. Yaks inhabiting the Tibetan plateau exhibit excellent disease resistance and tolerance, which may be associated with their inner probiotics. Currently, research on probiotics mainly focuses on their positive effects on the host, but information regarding their genome remains unclear. To reveal the potential functional genes of Bacillus subtilis isolated from yaks, we sequenced its whole genome. Results indicated that the genomic length of Bacillus subtilis was 866,044,638 bp, with 4,429 coding genes. The genome of this bacteria was composed of one chromosome and one plasmid with lengths of 4,214,774 and 54,527 bp, respectively. Moreover, Bacillus subtilis contained 86 tRNAs, 27 rRNAs (9 16S_rRNA, 9 23S_rRNA, and 9 5S_rRNA), and 114 other ncRNA. KEGG annotation indicated that most genes in Bacillus subtilis were associated with biosynthesis of amino acids, carbon metabolism, purine metabolism, pyrimidine metabolism, and ABC transporters. GO annotation demonstrated that most genes in Bacillus subtilis were related to nucleic acid binding transcription factor activity, transporter activity, antioxidant activity, and biological adhesion. EggNOG uncovered that most genes in Bacillus subtilis were related to energy production and conversion, amino acid transport and metabolism, carbohydrate transport and metabolism. CAZy annotation found glycoside hydrolases (33.65%), glycosyl transferases (22.11%), polysaccharide lyases (3.84%), carbohydrate esterases (14.42%), auxiliary activities (3.36%), and carbohydrate-binding modules (22.59%). In conclusion, this study investigated the genome and genetic properties of Bacillus subtilis derived from yaks, which contributed to understanding the potential prebiotic mechanism of probiotics from the genetic perspective.