Gallocatechin Gallate-Containing Fermented Green Tea Extract Ameliorates Obesity and Hypertriglyceridemia Through the Modulation of Lipid Metabolism in Adipocytes and Myocytes

In-silico annotation of the chemical composition of Tibetan tea and its mechanism on antioxidant and lipid-lowering in mice

BACKGROUND/OBJECTIVES

Tibetan tea is a kind of dark tea, due to the inherent complexity of natural products, the chemical composition and beneficial effects of Tibetan tea are not fully understood. The objective of this study was to unravel the composition of Tibetan tea using knowledge-guided multilayer network (KGMN) techniques and explore its potential antioxidant and hypolipidemic mechanisms in mice.

MATERIALS/METHODS

The C57BL/6J mice were continuously gavaged with Tibetan tea extract (T group), green tea extract (G group) and ddH₂O (H group) for 15 days. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in mice was detected. Transcriptome sequencing technology was used to investigate the molecular mechanisms underlying the antioxidant and lipid-lowering effects of Tibetan tea in mice. Furthermore, the expression levels of liver antioxidant and lipid metabolism related genes in various groups were detected by the real-time quantitative polymerase chain reaction (qPCR) method.

RESULTS

The results showed that a total of 42 flavonoids are provisionally annotated in Tibetan tea using KGMN strategies. Tibetan tea significantly reduced body weight gain and increased T-AOC and SOD activities in mice compared with the H group. Based on the results of transcriptome and qPCR, it was confirmed that Tibetan tea could play a key role in antioxidant and lipid lowering by regulating oxidative stress and lipid metabolism related pathways such as insulin resistance, P53 signaling pathway, insulin signaling pathway, fatty acid elongation and fatty acid metabolism.

CONCLUSIONS

This study was the first to use computational tools to deeply explore the composition of Tibetan tea and revealed its potential antioxidant and hypolipidemic mechanisms, and it provides new insights into the composition and bioactivity of Tibetan tea.

Research progress on the lipid-lowering and weight loss effects of tea and the mechanism of its functional components

Obesity caused by poor eating habits has become a great challenge faced by public health organizations worldwide. Optimizing dietary intake and ingesting special foods containing biologically active substances (such as polyphenols, alkaloids, and terpenes) is a safe and effective dietary intervention to prevent the occurrence and development of obesity. Tea contains several active dietary factors, and daily tea consumption has been shown to have various health benefits, especially in regulating human metabolic diseases. Here, we reviewed recent advances in research on tea and its functional components in improving obesity-related metabolic dysfunction, and gut microbiota homeostasis and related clinical research. Furthermore, the potential mechanisms by which the functional components of tea could promote lipid-lowering and weight-loss effects by regulating fat synthesis/metabolism, glucose metabolism, gut microbial homeostasis, and liver function were summarized. The research results showing a "positive effect" or "no effect" objectively evaluates the lipid-lowering and weight-loss effects of the functional components of tea. This review provides a new scientific basis for further research on the functional ingredients of tea for lipid lowering and weight loss and the development of lipid-lowering and weight-loss functional foods and beverages derived from tea.

Fermented Foods in the Management of Obesity: Mechanisms of Action and Future Challenges

Fermented foods are part of the staple diet in many different countries and populations and contain various probiotic microorganisms and non-digestible prebiotics. Fermentation is the process of breaking down sugars by bacteria and yeast species; it not only enhances food preservation but can also increase the number of beneficial gut bacteria. Regular consumption of fermented foods has been associated with a variety of health benefits (although some health risks also exist), including improved digestion, enhanced immunity, and greater weight loss, suggesting that fermented foods have the potential to help in the design of effective nutritional therapeutic approaches for obesity. In this article, we provide a comprehensive overview of the health effects of fermented foods and the corresponding mechanisms of action in obesity and obesity-related metabolic abnormalities.

Anti-obesity effect of Angelica keiskei Jiaosu prepared by yeast fermentation on high-fat diet-fed mice

In this study, an Angelica keiskei (A. keiskei) Jiaosu (FAK) was prepared by yeast fermentation to investigate its anti-obesity effect on high-fat diet (HFD)-fed mice. 70 SPF grade male C57BL/6J mice were randomly divided into 7 groups (n = 10): blank control group (N), high-fat model group (M), positive control group (Orl), unfermented control group (NF), high-dose intervention group (FH), medium-dose intervention group (FM), and low-dose intervention group (FL). The results showed that FAK intervention significantly reduced the body weight, Lee's index and liver index of HFD-fed mice (P < 0.05). Compared with M group, the serum levels of triglyceride (TG), total cholesterol (TC), leptin and glucose (GLU) in FH group were remarkably decreased and that of interleukin-27 (IL-27) were increased (P < 0.05). The levels of TG, and TC in the liver of mice were also markedly decreased in the FH group (P < 0.05). HE staining results showed that the liver cells in the three intervention groups had less degeneration and fatty vacuoles in the cytoplasm, and the liver cords were orderly arranged compared with that of M group. Furthermore, FAK significantly inhibited epididymal adipose tissue cell expansion induced by HFD. FAK up-regulated the protein expression levels of p-AMPK and PPARα to promote lipolysis and down-regulated the expression of PPARγ to reduce lipid synthesis (P < 0.05). Additionally, the results of gut microbiota showed that after the intervention, a decrease trend of F/B value and Deferribacterota was noticed in the FH group compared with M group. At the genus level, FAK intervention significantly increased that of Ileiobacterium compared to the M group (p < 0.05). A rising trend of norank_f_Muribaculaceae, Lactobacillus, and Bifidobacterium were also observed in the HF group. Conclusively, these findings demonstrated that FAK intervention can effectively improve obesity in mice caused by HFD and the potential mechanisms was related to the regulation of serum levels of leptin and IL-27, lipogenesis and lipolysis in adipose tissue and gut microbiota composition.

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.

Molecular mechanisms underlying health benefits of tea compounds

Tea is one of the three most widely consumed beverages in the world, not only because of its unique flavor but also due to its various health benefits. The bioactive components in tea, such as polyphenols, polysaccharides, polypeptides, pigments, and alkaloids, are the main contributors to its health functions. Based on epidemiological surveys, the consumption of tea and its compounds in daily life has positive effects on cardiovascular diseases, cancers, hepatopathy, obesity, and diabetes mellitus. In experimental studies, the antioxidant, anti-inflammatory, anti-cancer, anti-obesity, cardiovascular protective, liver protective, and hypoglycemic activities of tea and the related mechanisms of action have been widely investigated. The regulation of several classical signaling pathways, such as nuclear factor-κB (NF-κB), AMP activated protein kinase (AMPK), and wingless/integrated (Wnt) signaling, is involved. Clinical trials have also demonstrated the potential of tea products to be applied as dietary supplements and natural medicines. In this paper, we reviewed and discussed the recent literature on the health benefits of tea and its compounds, and specifically explored the molecular mechanisms involved.

Adipogenesis and therapeutic potentials of antiobesogenic phytochemicals: Insights from preclinical studies

Obesity is one of the most serious public health problems in both developed and developing countries in recent years. While lifestyle and diet modifications are the most important management strategies of obesity, these may be insufficient to ensure long-term weight reduction in certain individuals and alternative strategies including pharmacotherapy need to be considered. However, drugs option remains limited due to low efficacy and adverse effects associated with their use. Hence, identification of safe and effective alternative therapeutic agents remains warranted to combat obesity. In recent years, bioactive phytochemicals are considered as valuable sources for the discovery of new pharmacological agents for the treatment of obesity. Adipocyte hypertrophy and hyperplasia increases with obesity and undergo molecular and cellular alterations that can affect systemic metabolism giving rise to metabolic syndrome and comorbidities such as type 2 diabetes and cardiovascular diseases. Many phytochemicals have been reported to target adipocytes by inhibiting adipogenesis, inducing lipolysis, suppressing the differentiation of preadipocytes to mature adipocytes, reducing energy intake, and boosting energy expenditure mainly in vitro and in animal studies. Nevertheless, further high-quality studies are needed to firmly establish the clinical efficacy of these phytochemicals. This review outlines common pathways involved in adipogenesis and phytochemicals targeting effector molecules of these pathways, the challenges faced and the way forward for the development of phytochemicals as antiobesity agents.

Investigating the Opposing Effect of Two Different Green Tea Supplements on Oxidative Stress, Mitochondrial Function and Cell Viability in HepG2 Cells

Green tea extract (GTE) improves exercise outcomes and reduces obesity. However, case studies indicate contradictory physiology regarding liver function and toxicity. We studied the effect of two different decaffeinated GTE (dGTE) products, from a non-commercial (dGTE1) and commercial (dGTE2) supplier, on hepatocyte function using the human cell model, HepG2. dGTE1 was protective against hydrogen peroxide (H₂O₂)-induced apoptosis and cell death by attenuating oxidative stress pathways. Conversely, dGTE2 increased cellular and mitochondrial oxidative stress and apoptosis. A bioavailability study with dGTE showed the major catechin in GTE, EGCG, reached 0.263 µg·ml^-1. In vitro, at this concentration, EGCG mimicked the protective effect of dGTE1. GC/MS analysis identified steric acid and higher levels of palmitic acid in dGTE2 versus dGTE1 supplements. We demonstrate the significant biological differences between two GTE supplements which may have potential implications for manufacturers and consumers to be aware of the biological effects of supplementation.

Exploring Phytotherapeutic Alternatives for Obesity, Insulin Resistance and Diabetes Mellitus

At present, the pathologic spectrum of obesity-insulin resistance (IR)-diabetes mellitus (DM) represents not only a pressing matter in public health but also a paramount object of study in biomedical research, as they constitute major risk factors for cardiovascular disease (CVD), and other chronic non-communicable diseases (NCD). Phytotherapy, the use of medicinal herbs (MH) with treatment purposes, offers a wide array of opportunities for innovation in the management of these disorders; mainly as pharmacological research on small molecules accumulates. Several MH has displayed varied mechanisms of action relevant to the pathogenesis of obesity, IR and DM, including immunological and endocrine modulation, reduction of inflammation and oxidative stress (OS), regulation of appetite, thermogenesis and energy homeostasis, sensitisation to insulin function and potentiation of insulin release, among many others. However, the clinical correlates of these molecular phenomena remain relatively uncertain, with only a handful of MH boasting convincing clinical evidence in this regard. This review comprises an exploration of currently available preclinical and clinical research on the role of MH in the management of obesity, IR, and DM.

Herbal therapy as a promising approach for regulation on lipid profiles: A review of molecular aspects

Impaired lipid profile is defined as abnormal plasma levels of low-density lipoprotein, triglycerides, and total cholesterol. This disease state is associated with the development and progression of various disorders, such as diabetes mellitus, cardiovascular diseases, and acute myocardial infarction. Globally, all of these disorders are related to a significant rate of death. Therefore, finding a suitable approach for the prevention and treatment of lipid profile-related disorders is in the spotlight. Recently, herbal therapy has been considered a promising therapeutic approach for the treatment of hyperlipidemia or its related disorders due to its safety and efficacy. Hereby, we address the potential benefits of some of these herbal compounds on different aspects of lipid profile and its abnormalities with a special focus on their underlying mechanisms. Using herbal products, such as teas and mushrooms, or their derivatives, Rosmarinus officinalis Linn, Curcuma longa, Green tea, Lippia triphylla, Lippia citriodora, Plantago asiatica L, Vine tea, and Grifola frondosa have been proved to exert several therapeutic impacts on lipid profile and its related disorders, and we would provide a brief review on them in this literature.