Obesity, White Adipose Tissue, and Adipokines Signaling in Male Reproduction

Currently, obesity is a global pandemic characterized by systemic metabolic complications that negatively impact several organs, including white adipose tissue (WAT) and the tissues of the male reproductive system. Since the discovery of leptin in 1994, WAT has been recognized as a dynamic endocrine organ for secreting a series of molecules with hormonal functions, collectively called adipokines. The link between obesity, WAT, adipokines, and the male reproductive system is direct and little explored. With changes in nutritional status, WAT undergoes morphofunctional changes, and the secretion of adipokines is altered, negatively impacting reproductive mechanisms, including steroidogenesis and spermatogenesis. In this review, we address in an updated way the structural and functional characteristics of WAT as well as the link between obesity and changes in the signaling pathways of the adipokines leptin, adiponectin, resistin, visfatin, apelin, chemerin, omentin-1, vaspin, and asprosin in male reproduction. Understanding the relationship between obesity, these adipokines, and reproductive dysfunction can contribute to new strategies for the treatment of subfertility and male infertility.

Improvement of Theaflavins on Glucose and Lipid Metabolism in Diabetes Mellitus

In diabetes mellitus, disordered glucose and lipid metabolisms precipitate diverse complications, including nonalcoholic fatty liver disease, contributing to a rising global mortality rate. Theaflavins (TFs) can improve disorders of glycolipid metabolism in diabetic patients and reduce various types of damage, including glucotoxicity, lipotoxicity, and other associated secondary adverse effects. TFs exert effects to lower blood glucose and lipids levels, partly by regulating digestive enzyme activities, activation of OATP-MCT pathway and increasing secretion of incretins such as GIP. By the Ca2+-CaMKK ꞵ-AMPK and PI3K-AKT pathway, TFs promote glucose utilization and inhibit endogenous glucose production. Along with the regulation of energy metabolism by AMPK-SIRT1 pathway, TFs enhance fatty acids oxidation and reduce de novo lipogenesis. As such, the administration of TFs holds significant promise for both the prevention and amelioration of diabetes mellitus.

Effects of Dried Tea Residues of Different Processing Techniques on the Nutritional Parameters, Fermentation Quality, and Bacterial Structure of Silaged Alfalfa

The effects of dried tea residues on the nutritional parameters and fermentation quality, microbial community, and in vitro digestibility of alfalfa silage were investigated. In this study, dried tea residues generated from five different processing techniques (green tea, G; black tea, B; white tea, W; Pu'er raw tea, Z; Pu'er ripe tea, D) were added at two addition levels (5% and 10% fresh weight (FW)) to alfalfa and fermented for 90 days. The results showed that the tea residues increased the crude protein (CP) content (Z10: 23.85%), true protein nitrogen (TPN) content, DPPH, and ABST radical scavenging capacity, total antioxidant capacity (T-AOC), and in vitro dry matter digestibility (IVDMD) of the alfalfa silage. Moreover, the pH, ammonia-N (NH3-N) content, and acetic acid (AA) content decreased (p < 0.05). The effects of tea residues were promoted on these indicators with increasing tea residue addition. In addition, this study revealed that the influence of dried tea residues on the nutritional quality of alfalfa silage was greater than that on fermentation quality. Based on the nutrient composition, the addition of B or G to alfalfa silage can improve its silage quality, and these tea byproducts have the potential to be used as silage additives.

Phytochemical composition of Tibetan tea fermented by Eurotium cristatum and its effects on type 1 diabetes mice and gut microbiota

"Golden-flower" Tibetan tea (GTT) is an innovative dark tea fermented via fungus Eurotium cristatum. To study GTT effects on alleviating the symptoms of type 1 diabetes mellitus (T1DM), GTT's extract (GTTE) was prepared. GTTE chemical compositions were analyzed via HPLC, pyrolysis-gas chromatography-mass (Py-GC-MS) spectrometry analysis, and chemistry analyses. GTTE effects on T1DM were explored on T1DM mice model induced by streptozotocin (STZ). GTTE was composed mainly of tea pigment theabrownin (TB) (49.18%), with high percentages of polysaccharide (16.93%), protein (10.15%), polyphenols (13.90%), amino acids (5.89%), caffeine (1.83%), and flavonoids (0.67%). Py-GC-MS results exhibited that GTTE constituted of phenols, lipids, sugars, and proteins. GTTE attenuated T1DM conditions of mice, relieved their liver and pancreatic injury, restored damaged islet cells, decreased oxidative stress by increasing superoxide dismutase (SOD) and catalase (CAT) levels, modulated cytokine expression leading to the decreasing pro-inflammatory cytokines TNF-α and IL-6, increased anti-inflammatory cytokines IL-4 to improve inflammatory responses, and optimized gut microbiota composition and structure based on high-throughput 16S rDNA sequencing, suggesting multi-channel anti-diabetes mechanisms.

Possible Mechanisms of Dark Tea in Cancer Prevention and Management: A Comprehensive Review

Tea is one of the most popular drinks in the world. Dark tea is a kind of post-fermented tea with unique sensory characteristics that is produced by the special fermentation of microorganisms. It contains many bioactive substances, such as tea polyphenols, theabrownin, tea polysaccharides, etc., which have been reported to be beneficial to human health. This paper reviewed the latest research on dark tea's potential in preventing and managing cancer, and the mechanisms mainly involved anti-oxidation, anti-inflammation, inhibiting cancer cell proliferation, inducing cancer cell apoptosis, inhibiting tumor metastasis, and regulating intestinal flora. The purpose of this review is to accumulate evidence on the anti-cancer effects of dark tea, the corresponding mechanisms and limitations of dark tea for cancer prevention and management, the future prospects, and demanding questions about dark tea's possible contributions as an anti-cancer adjuvant.

Regulatory Effects and Molecular Mechanisms of Tea and Its Active Compounds on Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disease, is a multifactorial disease resulting from the interaction between environment, genetic background, and metabolic stress. Most treatments for NAFLD include dietary intervention and exercise show limited efficacy due to the complex mechanisms involved in NAFLD. Meanwhile, drug therapy is accompanied by serious side effects. The development of high-efficiency natural supplements is a sustainable strategy for the prevention and treatment of NAFLD. As the second most consumed beverage, tea has health benefits that have been widely recognized. Nevertheless, the intervention of tea active compounds in NAFLD has received limited attention. Tea contains abundant bioactive compounds with potential effects on NAFLD, such as catechins, flavonoids, theanine, tea pigments, and tea polysaccharides. We reviewed the intrinsic and environmental factors and pathogenic mechanisms that affect the occurrence and development of NAFLD, and summarized the influences of exercise, drugs, diet, and tea drinking on NAFLD. On this basis, we further analyzed the potential effects and molecular regulatory mechanisms of tea active compounds on NAFLD and proposed future development directions. This review hopes to provide novel insights into the development and application of tea active compounds in the prevention and treatment of NAFLD.

Sichuan dark tea improves lipid metabolism and prevents aortic lipid deposition in diet-induced atherosclerosis model rats

Background and aims

Sichuan dark tea (ST), Zangcha, is a traditional fermented Chinese tea found in Sichuan and Tibet and claimed for beneficial effects against lifestyle-related metabolic disorders. We examined the effects of ST on lipid metabolism and atherosclerosis.

Methods and results

Sichuan dark tea was given to fat-rich diet-induced atherosclerosis model rats in comparison with dark-fermented Chinese Pu-erh tea (PT) and Japanese green tea (GT). After 8 weeks of feeding, ST and PT induced an increase in high-density lipoprotein (HDL)-cholesterol and a decrease in glucose, and ST decreased triglyceride in plasma. ST also induced low pH in the cecum. There was no significant change in their body weight among the fat-feeding groups but a decrease was found in the visceral fat and liver weight in the ST group. Accordingly, ST reduced lipid deposition in the aorta in comparison with PT and GT. ST increased mRNA of LXRα, PPARα, PPARγ, and ABCA1 in the rat liver. The extract of ST stimulated the AMPK pathway to increase the expression of ABCA1 in J774 cells and increased expression of lipoprotein lipase and hormone-sensitive lipase in 3T3L1 cells, consistent with its anti-atherogenic effects in rats. High-performance liquid chromatography analysis showed unique spectra of original specific compounds of caffeine and catechins in each tea extract, but none of them was likely responsible for these effects.

Conclusion

Sichuan dark tea increases plasma HDL and reduces plasma triglyceride to decrease atherosclerosis through AMPK activation. Further study is required to identify specific components for the effects of this tea preparation.

Herbal Tea Essences (HTE) Ameliorate HFD-Induced Obesity

Tea is one of the most popular beverages in the world. The health-promoting effects of tea and its individual constituents, including antiobesity and antihyperlipidaemia effects, have been well accepted. In this study, we evaluated the effects of herbal tea essence (HTE), a commercial product extracted from black tea, on HFD-induced obesity in mice. HTE effectively reduces the gain in body weight and improves glucose tolerance and insulin sensitivity after HFD treatment. HTE inhibits lipid accumulation in the body and reduces serum lipid contents. Furthermore, HTE negatively regulates the expression levels of genes that control lipogenesis and gluconeogenesis and upregulates the expression of genes for lipid β oxidation. The regulatory effects of HTE on these genes may occur through activation of the AKT, IRS-1, and AMPK signalling pathways. Our observations suggest that HTE could be a promising option for nutritional intervention in the treatment of obesity.

Duyun compound green tea extracts regulate bile acid metabolism on mice induced by high-fat diet

Duyun compound green tea (DCGT) is a healthy beverage with lipid-lowering effect commonly consumed by local people, but its mechanism is not very clear. We evaluated the effect of DCGT treatment on bile acids (BA) metabolism of mice with high-fat diet (HFD) – induced hyperlipidaemia by biochemical indexes and metabolomics and preliminarily determined the potential biomarkers and metabolic pathways of hyperlipidaemia mice treated with DCGT as well as investigated its lipid-lowering mechanism. The results showed that DCGT treatment could reduce HFD – induced gain in weight and improve dyslipidaemia. In addition, a total of ten types of BA were detected, of which seven changed BA metabolites were observed in HFD group mice. After DCGT treatment, glycocholic acid, tauroursodeoxycholic acid and taurochenodeoxycholic acid were significantly down-regulated, while hyodeoxycholic acid, deoxycholic acid and chenodeoxycholic acid were markedly up-regulated. These results demonstrated that DCGT treatment was able to make the BA metabolites in the liver of hyperlipidaemia mice normal and alleviate hyperlipidaemia by regulating the metabolites such as glycocholic acid, tauroursodeoxycholic acid and taurochenodeoxycholic, as well as the BA metabolic pathway and cholesterol metabolic pathway involved.

Acute and Subacute Safety Evaluation of Black Tea Extract (Herbt Tea Essences) in Mice

Theabrownin (TB) is a heterogeneous biomacromolecule, extracted from tea, with many functional groups. Importantly, TB possesses diverse health benefits, such as antitumor activity and blood lipid-lowering effects. Presently, the content of TB in tea extract is relatively low. Here, we obtained a deep-processed black tea extract with a high content of TB (close to 80%), which was named Herbt Tea Essences (HTE). Currently, this study was designed to evaluate the biosafety of high-content TB products on mice. We implemented acute and subacute toxic experiments to assess its safety on organs, the serum biochemical and molecular levels. In the acute exposure study, we found that the median lethal dose (LD50) value of HTE was 21.68 g/kg (21.06–24.70 g/kg, greater than 5 g/kg), suggesting that HTE had a low acute toxicity. In the 28-day subacute exposure study, our results showed that no abnormal effects were observed in the 40 and 400 mg/kg/day HTE-treated groups. However, we observed slight nephrotoxicity in the 4000 mg/kg/day HTE-treated group. The HTE-induced nephrotoxic effect might involve the inflammatory response activation mediated by the nuclear transcription factor kappa-B (NF-κB) signaling pathway. This study would provide valuable data for the TB safety assessment and promote this natural biomacromolecule application in daily drinking.

Aging-related changes in metabolic indicators in female rats and their management with Tinospora cordifolia

Conflicting reports of HRT necessitates exploration of therapeutic interventions with the least side effects to preserve metabolic homeodynamics in women later in life. The current study was designed to elucidate the cumulative effects of aging and/or high fat diet (HFD) on some metabolic indicators and their management by Tinospora cordifolia stem powder (TCP) using middle-aged acyclic and young adult cyclic female rats as the model system. Animals were fed on either normal chow or HFD supplemented with or without TCP. Blood and liver tissue were collected for biochemical, and histological studies as well as for expression of proteins regulating lipid metabolism. Animals fed with TCP supplemented normal chow feed showed bodyweight management over 12-weeks despite their high feed and calories intake compared to young and age-matched controls as well as HFD-fed animals. TCP dose used was not toxic and rather prevented age-associated liver dysfunctions and ameliorated dyslipidemia and oxidative stress, normalized blood glucose, insulin, leptin, and secretary pro-inflammatory cytokines. Further, bodyweight management effect of TCP was observed to target AMPK signalling pathway as the mediator of lipogenesis, sterol biosynthesis, lipolysis, and β-oxidation of fatty acids. These findings suggest that TCP supplementation in diet may be a potential interventional strategy to ameliorate aging-associated hepatic and metabolic dysfunctions and to promote healthy aging.

Theabrownin-targeted regulation of intestinal microorganisms to improve glucose and lipid metabolism in Goto-Kakizaki rats

Diabetes is a disease that is characterized by a disturbance of glucose metabolism. Theabrownin (TB) is one of the most active and abundant pigments in Pu-erh tea, and it is a brown pigment with multiple aromatic rings and attached residues of polysaccharides and proteins. TB has been shown to be hypolipidemic and displays fasting blood glucose (FBG)-lowering properties in rats fed a high-fat diet, but the underlying mechanism has not been elucidated. This study aimed to determine the effect of TB in treating diabetes and explore the underlying mechanism of action of intestinal microbes by using Goto-Kakizaki (GK) rats. Diabetic GK rats were treated up to 8 weeks with TB (GK-TB). Following treatment, the body weight, triglyceride (TG) content, fasting blood glucose (FBG) content, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) were significantly lower in the GK-TB group than in the GK control group (P < 0.05). Meanwhile, the circulating adiponectin (ADPN), leptin, and glucokinase levels in the serum of the GK-TB group were significantly higher than those in the GK group, while there was little difference in hepatic lipase (HL) and hormone-sensitive triglyceride lipase (HSL) enzyme activities (P > 0.05). Furthermore, with the extension of treatment time, the number of unique intestinal microorganisms in GK rats greatly increased and an interaction among intestinal microorganisms was observed. The Firmicutes/Bacteroides ratio was decreased significantly, and the composition of Actinobacteria and Proteobacteria was increased. The use of multiple omics technologies showed that TB is involved in the targeted regulation of the core characteristic intestinal flora including Bacteroides thetaiotaomicron (BT), Lactobacillus murinus (LM), Parabacteroides distasonis (PD), and Bacteroides_acidifaciens (BA) which improved the glucose and lipid metabolism of GK rats via the AMP-activated protein kinase signaling pathway, insulin signaling pathway, bile secretion and glycerophospholipid metabolism. Intragastric administration of BT, LM, PD, or BA led to a significantly reduced HOMA-IR in GK rats. Furthermore, BT significantly reduced serum lipid TG and total cholesterol (TC) and BA significantly reduced the serum lipid TC and low-density lipoprotein (LDL). PD significantly reduced serum LDL, while the effect of LM was not significant. However, LM and PD significantly increased the content of ADPN in serum. Taken together, our results indicated that the effect of TB on diabetic rats mainly depends on the targeted regulation of intestinal microorganisms and that TB is a functional food component with great potential to treat or prevent diabetes.

Co-delivery of EGCG and Lycopene via a Pickering Double Emulsion induced Synergistic Hypolipidemic Effect

The concept of “synergy” and its applications has rapidly increased in the food industry as a practical strategy to preserve and improve health-promoting effects of the functional ingredients. In this...

Effects of Nigella sativa, Camellia sinensis, and Allium sativum as Food Additives on Metabolic Disorders, a Literature Review

Objective: Metabolic disorders (MD) can disturb intracellular metabolic processes. A metabolic disorder can be resulted from enzyme deficits or disturbances in function of various organs including the liver, kidneys, pancreas, cardiovascular system, and endocrine system. Some herbs were used traditionally for spices, food additives, dietary, and medicinal purposes. Medicinal plants possess biological active compounds that enhance human health. We aimed to provide evidence about therapeutic effects of some medicinal herbs on MD.

Data Sources: PubMed, Scopus, and Google Scholar were explored for publications linked to MD until February 2021. The most literature reports that were published in the last 10 years were used. All types of studies such as animal studies, clinical trials, and in vitro studies were included. The keywords included “Metabolic disorders,” “Nigella sativa L.,” “Thymoquinone,” “White tea”OR “Camellia sinensis L.” “catechin,” and “Allium sativum L.” OR “garlic” were searched.

Results: Based on the results of scientific studies, the considered medicinal plants and their active components in this review have been able to exert the beneficial therapeutic effects on obesity, diabetes mellitus and non-alcoholic fatty liver disease.

Conclusions: These effects are obvious by inhibition of lipid peroxidation, suppression of inflammatory reactions, adjustment of lipid profile, reduction of adipogenesis and regulation of blood glucose level.

Antihypertriglyceridemia activities of naturally fermented green tea, Heukcha, extract through modulation of lipid metabolism in rats fed a high-fructose diet

Hypertriglyceridemia, a symptom of elevated triglyceride level in the blood, is a potent risk factor for cardiovascular and metabolic disorders. Among the numerous treatments to regulate circulating triglyceride levels, fibrates are widely used to treat hypertriglyceridemia, although they also have side effects such as hepatotoxicity and gallstone formation. In the present study, we aimed to investigate the blood triglyceride-lowering effects of a naturally fermented green tea extract (NFGT) and the underlying mechanisms on hypertriglyceridemia in vitro and in vivo models. NFGT suppressed the expression of lipogenic genes, while augmented expression of fatty acid oxidation-related genes in cultured cells, leading to the significant decrease of intracellular triglyceride content. NFGT treated group in fructose-induced hypertriglyceridemic rat model significantly decreased plasma and hepatic triglyceride, which was accompanied by an increase in excretion of fecal fat. Taken together, we propose that NFGT could be potentially a novel functional ingredient to prevent or treat hypertriglyceridemia.

The Anti-Obesity Effect of Traditional Chinese Medicine on Lipid Metabolism

With the improvement of living conditions and the popularity of unhealthy eating and living habits, obesity is becoming a global epidemic. Obesity is now recognized as a disease that not only increases the risk of metabolic diseases such as type 2 diabetes (T2D), non-alcoholic fatty liver disease (NAFLD), cardiovascular disease (CVD), and cancer but also negatively affects longevity and the quality of life. The traditional Chinese medicines (TCMs) are highly enriched in bioactive compounds and have been used for the treatment of obesity and obesity-related metabolic diseases over a long period of time. In this review, we selected the most commonly used anti-obesity or anti-hyperlipidemia TCMs and, where known, their major bioactive compounds. We then summarized their multi-target molecular mechanisms, specifically focusing on lipid metabolism, including the modulation of lipid absorption, reduction of lipid synthesis, and increase of lipid decomposition and lipid transportation, as well as the regulation of appetite. This review produces a current and comprehensive understanding of integrative and systematic mechanisms for the use of TCMs for anti-obesity. We also advocate taking advantage of TCMs as another therapy for interventions on obesity-related diseases, as well as stressing the fact that more is needed to be done, scientifically, to determine the active compounds and modes of action of the TCMs.

Stingless Bee Honey Reduces Anxiety and Improves Memory of the Metabolic Disease-induced Rats

BACKGROUND

Scientific studies support the evidence of the involvement of Metabolic Syndrome (MetS) in the progression of neurodegenerative diseases through oxidative stress. Consumption of antioxidant compounds was found to be beneficial for brain-health as it reduced the brain oxidative stress level and improved cognitive performance in animals. Stingless bee honey or locally known as Kelulut Honey (KH) has high phenolic content and is widely used as a food supplement.

OBJECTIVES

In this study, we aimed to investigate the effects of KH on the brain of MetS-induced rats.

METHODS

Forty male Wistar rats were divided into 5 groups; 8 weeks (C8) and 16 weeks control groups (C16), groups that received High-Carbohydrate High Fructose (HCHF) diet for 8 weeks (MS8) and 16 weeks (MS16), and a group that received HCHF for 16 weeks with KH supplemented for the last 35 days (KH).

RESULTS

Serum fasting blood glucose decreased in the KH group compared to the MS16 group. HDL levels were significantly decreased in MetS groups compared to control groups. Open field experiments showed that KH group exhibits less anxious behavior compared to the MetS group. Probe trial of Morris water maze demonstrated significant memory retention of KH group compared to the MS16 group. Nissl staining showed a significant decrease in the pyramidal hippocampal cells in the MS16 compared to the KH group.

CONCLUSION

KH has the ability to normalise blood glucose and reduce serum triglyceride and LDL levels in MetS rats, while behavior studies complement its effect on anxiety and memory. This shows a promising role of KH in attenuating neurodegenerative diseases through the antioxidant activity of its polyphenolic content.

Therapeutic Effects of Morinda citrifolia Linn. (Noni) Aqueous Fruit Extract on the Glucose and Lipid Metabolism in High-Fat/High-Fructose-Fed Swiss Mice

The aim of this study was to evaluate the therapeutic effects of two different doses (250 and 500 mg/kg) of Morinda citrifolia fruit aqueous extract (AE) in high-fat/high-fructose-fed Swiss mice. The food intake, body weight, serum biochemical, oral glucose tolerance test (OGTT), and enzyme-linked immunosorbent assay (ELISA), as well as histological analyses of the liver, pancreatic, and epididymal adipose tissue, were used to determine the biochemical and histological parameters. The chemical profile of the extract was determined by ultra-fast liquid chromatography–diode array detector–tandem mass spectrometry (UFLC–DAD–MS), and quantitative real-time PCR (qRT-PCR) was used to evaluate the gene expressions involved in the lipid and glucose metabolism, such as peroxisome proliferative-activated receptors-γ (PPAR-γ), -α (PPAR-α), fatty acid synthase (FAS), glucose-6-phosphatase (G6P), sterol regulatory binding protein-1c (SREBP-1c), carbohydrate-responsive element-binding protein (ChREBP), and fetuin-A. Seventeen compounds were tentatively identified, including iridoids, noniosides, and the flavonoid rutin. The higher dose of AE (AE 500 mg/kg) was demonstrated to improve the glucose tolerance; however, both doses did not have effects on the other metabolic and histological parameters. AE at 500 mg/kg downregulated the PPAR-γ, SREBP-1c, and fetuin-A mRNA in the liver and upregulated the PPAR-α mRNA in white adipose tissue, suggesting that the hypoglycemic effects could be associated with the expression of genes involved in de novo lipogenesis.

The impact of catechins included in high fat diet on AMP-dependent protein kinase in apoE knock-out mice

Due to their health-promoting effects green tea catechins have gained a keen interest in recent years in the context of bodyweight reduction treatments and alleviation of inflammatory diseases. This study was designed to evaluate the impact of native and thermally modified catechins (TMC) on the body weight gain, fatty acid profile in subcutaneous adipose tissue and the activity of the enzymes involved in lipid metabolism regulation: AMP-dependent protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) in apoE-deficient mice maintained on a high-fat diet. We observed that TMC decreased bodyweight gain as compared to the control group. Furthermore, TMC increased AMPK activity and reduced ACC activity in the metabolically important tissues: intestine, liver and subcutaneous adipose tissue and affected adipose tissue fatty acid composition. Native catechins produced less pronounced effects. These results suggest that TMC down-regulate endogenous fatty acid synthesis, which should be taken into account in dietary applications of catechins.

Structural Characteristics and Hypolipidemic Activity of Theabrownins from Dark Tea Fermented by Single Species Eurotium cristatum PW-1

Recently, studies on theabrownins (TBs), the main bioactive polymeric pigments found in dark tea, have received increasing attention for its health effects. Thus far, information on their structural characteristics is unclear. In the present study, theabrownins were isolated from single species Eurotium cristatum PW-1-fermented loose tea and their structural and hypolipidemic characteristics were studied for the first time. The theabrownins were fractionated by their molecular weights and were then analyzed. Ultraviolet–visible spectrophotometry (UV-Vis) and Flourier transformation infrared spectroscopy (FT-IR) showed that they were polymerized phenolic substances containing abundant hydroxy and carboxyl groups. All theabrownin samples exhibited hypolipidemic activity in high-fat zebrafish; among which TBs-10-30k sample, decreased lipid level in high-fat zebrafish to 51.57% at 1000 μg/mL, was most effective. It was found that TBs-10-30k was a type of amorphous and thermostable polymer with slice shape and smooth surface under scanning electron microscope (SEM). Atomic force microscope (AFM) analysis showed that it had island-like structure because of aggregation of theabrownin molecules. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) analysis further showed that the main pyrolytic products of TBs-10-30k were hexadecanoic acid (33.72%), phenol (14.90%), and eicosane (12.95%), indicating TBs-10-30k was mainly composed of phenols, lipids, saccharides, and proteins. These results not only facilitate subsequent identification of theabrownins, but also provide insights into the applications of theabrownins in functional foods.

Anti-obesity effects of instant fermented teas in vitro and in mice with high-fat-diet-induced obesity

Obesity is a chronic metabolic disorder that is associated with higher risks of developing diabetes and cardiovascular disease. Chinese dark tea is a fermented beverage with many biological effects and could be considered for the management of obesity. This study is aimed to assess the possible anti-obesity properties of instant dark tea (IDT) and instant pu-erh tea (PET) in high fat diet (HFD)-fed mice. Male C57BL/6 mice were divided into 5 groups. They received low-fat diet (LFD), HFD, HFD supplemented with drinking IDT infusion (5 mg mL-1), PET infusion (5 mg mL-1) or water for 8 weeks. The results showed IDT exhibited better inhibitory effect than PET on body weight gain and visceral fat weights. IDT also improved the serum high-density lipoprotein cholesterol (HDL-C) level, but decreased the low-density lipoprotein cholesterol (LDL-C) and leptin levels more effectively than PET. Both IDT and PET lowered the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the plasma and significantly increased the ratio of albumin to globin (A/G) in the serum compared to the control group. IDT treatment reduced the malondialdehyde (MDA) level in the liver. Histomorphology evidenced that the liver tissue architecture was well preserved by IDT administration. Moreover, IDT regulated the expression of obesity-related genes more effectively than PET. Overall, the present findings have provided the proof of concept that dietary IDT could provide a safer and cost-effective option for people with HFD-induced obesity.

Theabrownin from Pu-erh tea attenuates hypercholesterolemia via modulation of gut microbiota and bile acid metabolism

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.

Interactions between β-cyclodextrin and tea catechins, and potential anti-osteoclastogenesis activity of the (-)-epigallocatechin-3-gallate-β-cyclodextrin complex

Galloylated catechins, the most important secondary metabolites in green tea including (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate, constitute nearly 75% of all tea catechins and have stronger health effects than non-galloylated catechins such as (-)-epigallocatechin and (-)-epicatechin. EGCG is the most abundant, active, and thoroughly investigated compound in green tea, and its bioactivity might be improved by complexing with β-cyclodextrin (β-CD). We investigated interactions between four catechins and β-CD in a PBS buffer solution of pH 6.5 at 25 °C using biolayer interferometry and isothermal titration calorimetry, and to determine whether β-CD could enhance the anti-osteoclastogenesis effect of EGCG. β-CD could directly bind galloylated catechins at a stoichiometric ratio close to 1 : 1, with high specificities and affinities, and these inclusion interactions were primarily enthalpy-driven processes. We synthesized the EGCG-β-CD complex and identified it using infrared radiation and nuclear magnetic resonance spectra. Interestingly, we revealed that the EGCG-β-CD complex could inhibit osteoclastogenesis significantly more than EGCG.

The regulation effect of EGCG3''Me phospholipid complex on gut flora of a high-fat diet-induced obesity mouse model

Despite the remarkable bioactivity, the potential of EGCG3''Me to be fully utilized has not yet been completely elucidated due to its low absorption. It has been reported that phospholipids can act as agents to improve the absorption of antioxidants. Therefore, EGCG3''Me phospholipid complex (EPC) was utilized in this study to investigate its activity on gut flora of an obesity mouse model. After the administration of the complex for 8 weeks, the relative abundance of Bacteroidetes was significantly increased (p < 0.05); meanwhile, the relative abundance of Firmicutes was decreased, suggesting the potential anti-obesity effect of the complex. Furthermore, the expression of Muc2 and Reg3g were directly upregulated by EPC intervention. PRACTICAL APPLICATIONS: Although EGCG3''Me has shown excellent biological benefits, the presence of multiple hydroxyl groups and high polar properties hindered its application. This study indicated the potential of phospholipids in promoting the bioavailability of EGCG3''Me and might contribute to the production of functional food with better tea catechins absorption.

Pu-erh Tea Regulates Fatty Acid Metabolism in Mice Under High-Fat Diet

Pu-erh tea has been extensively reported to possess lipid lowering effects but the underlying mechanisms remained unclear. Free fatty acids (FFAs) are generally correlated with the development of obesity, leading to increased risk for type 2 diabetes mellitus and cardiovascular diseases. To investigate whether Pu-erh tea treatment alters FA metabolism, we treated HFD induced obese mice with Pu-erh tea for 22 weeks and analyzed FFA profiles of experimental mice using a UPLC-QTOF-MS platform. Results showed remarkable changes in metabolic phenotypes and FFA compositions in mice treated with or without Pu-erh tea. HFD induced a marked obese phenotype in mice as revealed by significantly increased body weight, liver and adipose tissue weight, lipid levels in serum and liver, and these parameters were markedly reduced by Pu-erh tea treatment. Several FFA or FFA ratios, such as DGLA, palmitoleic acid, and OA/SA ratio, were significantly increased while the levels of SA/PA and AA/DGLA were significantly reduced in HFD-induced obese mice. Interestingly, these differential FFAs or FFA ratios were previous identified as key markers in human obese subjects, and their changes observed in the HFD group were reversed by Pu-erh tea treatment. Moreover, a panel of FFA markers including C20:3 n6/C18:3 n6 and C20:3 n6/C20:2 n6, C18:3 n6/C18:2 n6, C18:3 n3/C18:2 n6 and C24:1 n9/C22:1 n9, which were previously identified as biomarkers in predicting the remission of obesity and diabetes in human subjects who underwent metabolic surgery procedures, were reversed by Pu-erh tea intervention. Pu-erh tea significantly improved glucose homeostasis and insulin tolerance compared to the HFD group. Additionally, Pu-erh tea treatment significantly decreased FFA synthesis genes and increased the expression of genes involved in FFA uptake and β-oxidation including FATP2, FATP5, PPARα, CPT1α, and ACOX-1. These finding confirmed the beneficial effects of Pu-erh tea on regulating lipid and glucose metabolism, and further validated a panel of FFA markers with diagnostic and prognostic value for obesity and diabetes.

Ripe and Raw Pu-Erh Tea: LC-MS Profiling, Antioxidant Capacity and Enzyme Inhibition Activities of Aqueous and Hydro-Alcoholic Extracts

Herein, we reported a detailed profiling of soluble components of two fermented varieties of Chinese green tea, namely raw and ripe pu-erh. The identification and quantification of the main components was carried out by means of mass spectrometry and UV spectroscopy, after chromatographic separation. The antioxidant capacity towards different radical species, the anti-microbial and the enzyme inhibition activities of the extracts were then correlated to their main constituents. Despite a superimposable qualitative composition, a similar caffeine content, and similar enzyme inhibition and antimicrobial activities, raw pu-erh tea extract had a better antioxidant capacity owing to its higher polyphenol content. However, the activity of raw pu-erh tea seems not to justify its higher production costs and ripe variety appears to be a valid and low-cost alternative for the preparation of products with antioxidant or antimicrobial properties.

Six types of tea reduce high-fat-diet-induced fat accumulation in mice by increasing lipid metabolism and suppressing inflammation

A high-fat diet results in obesity because of white fat accumulation.

Comprehensive evaluation of the composition of Mingshan Laochuancha green tea and demonstration of hypolipidemic activity in a zebrafish obesity model

Laochuancha is an ancient tea plant originating from the Mingshan district of Ya'an city, Sichuan province, China, which is used to produce tea products with excellent quality. Mingshan Laochuancha green tea (MLGT) is a type of green tea manufactured from Laochuancha tea leaves. Currently, not much is known regarding the chemical compositions of MLGT and its bioactivity. Herein, the present study explores, for the first time, the chemical compositions and hypolipidemic activity of MLGT. It was observed that K was the most abundant element of 26.58 mg g⁻¹, and contents of toxic As, Cd, Cr and Pb elements were all below concentration limits. Alcohols (55.65%) were the main volatiles, and numerous volatiles with chestnut-like aroma were detected. Total content of 21 amino acids was 28.61 mg g⁻¹, and amino acids with velvety-like and umami taste totally accounted for 65.39%. The high content of amino acids and low ratio of polyphenols to total amino acids were attributed to strong umami and mellow taste of MLGT. Moreover, catechins and alkaloids were abundant in MLGT, where EGCG (85.82 mg g⁻¹) and caffeine (33.78 mg g⁻¹) were at highest content. Analyses of chemical compositions revealed excellent quality of MLGT. Correspondingly, MLGT showed potent hypolipidemic activity, and water extract of MLGT at 200 μg mL⁻¹ significantly reduced lipid level to 43.06% of high-fat zebrafish. Results firstly revealed the quality characteristics of MLGT and provided further insights into bioactivity of Laochuancha.

MLGT was investigated for the first time, and results revealed excellent quality and potent hypolipidemic activity of MLGT.

hiPSC-derived hepatocytes closely mimic the lipid profile of primary hepatocytes: A future personalised cell model for studying the lipid metabolism of the liver

Hepatocyte-like cells (HLCs) differentiated from human-induced pluripotent stem cells offer an alternative platform to primary human hepatocytes (PHHs) for studying the lipid metabolism of the liver. However, despite their great potential, the lipid profile of HLCs has not yet been characterized. Here, we comprehensively studied the lipid profile and fatty acid (FA) metabolism of HLCs and compared them with the current standard hepatocyte models: HepG2 cells and PHHs. We differentiated HLCs by five commonly used methods from three cell lines and thoroughly characterized them by gene and protein expression. HLCs generated by each method were assessed for their functionality and the ability to synthesize, elongate, and desaturate FAs. In addition, lipid and FA profiles of HLCs were investigated by both mass spectrometry and gas chromatography and then compared with the profiles of PHHs and HepG2 cells. HLCs resembled PHHs by expressing hepatic markers: secreting albumin, lipoprotein particles, and urea, and demonstrating similarities in their lipid and FA profile. Unlike HepG2 cells, HLCs contained low levels of lysophospholipids similar to the content of PHHs. Furthermore, HLCs were able to efficiently use the exogenous FAs available in their medium and simultaneously modify simple lipids into more complex ones to fulfill their needs. In addition, we propose that increasing the polyunsaturated FA supply of the culture medium may positively affect the lipid profile and functionality of HLCs. In conclusion, our data showed that HLCs provide a functional and relevant model to investigate human lipid homeostasis at both molecular and cellular levels.

Lipid peroxidation diminishing perspective of isolated theaflavins and thearubigins from black tea in arginine induced renal malfunctional rats

BACKGROUND

Recently oxidative stress induced maladies have amplified owing to sedentary lifestyle and monotonous diet. Introduction of plant based biomolecules may be a suitable strategy to cope with the lipid peroxidation. In this context, black tea polyphenols (theaflavin & thearubigins) are in fame among the scientific community as cost effective therapeutic agents owing to their safety, economics, structural diversity and ability to modulate various lipid peroxidation responses by halting the expression of different metabolic targets.

METHODS

The mandate of present investigation was to first time check the synergism among the isolated theaflavins & thearubigins against lipid peroxidative indicators both in vitro and in vivo. Purposely, theaflavins and thearubigins were isolated from black tea through solvent partition methods by using different solvents (Aqueous ethanol, Aqueous methanol & Water) and time intervals (30, 60 & 90 min) and subjected to in vitro characterization through different antioxidant indices to access the in vitro lipid peroxidation shooting effect of these bioactive moieties. Moreover, individual theaflavins contents also estimate through HPLC. For evaluation of in vivo antioxidant effect, renal malfunction was induced through arginine and forty rats were divided in four groups (10 each after power analysis) and 04 types of diets were given i.e. T0 (control diet without supplementation), T1 (Basic experimental Diet+ theaflavins supplementation @ 1 g), T2 (Basic experimental Diet+ Thearubigins supplementation @ 1 g) & T3 (Basic experimental Diet+ Supplementation of theaflavins+ thearubigins @ 0.5 + 0.5 g, respectively) for the period of 56 days. Alongside, a control study was also carried out for comparison by involving normal rats fed on arginine free diet. The body weight, lipid profile, glycemic responses, Renal function test, liver function test, antioxidant indices and hematological parameters were estimated at the termination of study.

RESULTS

The results indicated that theaflavins and thearubigins isolation was significantly affected by time of extraction and solvent. In this context, aqueous ethanol at 60 min extraction interval caused maximum extraction. Likewise, theaflavins isolate exhibited more antioxidant activity as compared to thearubigins. Moreover, the theaflavins and thearubigins based experimental diets imparted significant reduction in Lipid profile, glucose content, renal function tests and TBARS with enhancement in insulin, HDL and hematological parameters. In this context, theaflavin based diet caused maximum reduction in lipid profile and TBARS better as compared to thearubigins and theaflavins + thearubigins based. However, theaflavin+ thearubigins based diet caused highest glucose, urea & creatinine decline and maximum insulin increase & antioxidant indices as compared to other nutraceuticals.

CONCLUSIONS

It was deduced that theaflavins & thearubigins have strong antioxidative potential both in in vitro as well as in vivo to tackle the menace associated with lipid peroxidation.

Studies on a novel regimen for management of orofacial pain and morphine tolerance

Background/purpose

The prevalence of orofacial pain is high but the etiology of orofacial pain is not well understood. Because of clinical treatment is not so effective, it is urgent to explore novel regimens with more effective and less side effects for clinical application.

Materials and methods

Male mice (ICR strain) were injected with capsaicin (10μg/5 μl) in vibrissa pad. Spontaneous orofacial pain in 20 min was recorded after receiving capsaicin to quantify the nociceptive level. Green tea polyphenols (GTP 60 mg/kg), memantine (Mem 10 mg/kg), and GTPm (GTP 30 mg/kg plus Mem 3 mg/kg) were dissolved in 2% carboxymethyl cellulose, which was orally administered to mice twice per day and five times per week consecutively for 2 weeks. TruScan photobeam tracking was used to record changes of behavior and locomotor activities.

Results

GTPm by itself attenuated orofacial pain induced by capsaicin. Moreover, GTPm enhanced morphine analgesic effects, reduced morphine depressant side effects and delayed morphine tolerance. Along with this experiment, GTPm was tested on the hot plate (52 °C)-induced peripheral thermal pain. It was found that both memantine and GTPm reduced morphine-analgesia in hind paw thermal pain.

Conclusion

In this study, GTP (60 mg/kg/day) orally administrated produced a significant analgesic effect on capsaicin–induced orofacial pain. Memantine combined with GTP synergistically not only reduced orofacial pain but also enhanced morphine analgesic effects. Thus, a new regimen of GTPm orally administered twice per day attenuated orofacial pain after consecutive 5 days.

Green tea polyphenols alter lipid metabolism in the livers of broiler chickens through increased phosphorylation of AMP-activated protein kinase

Our previous results showed that green tea polyphenols (GTPs) significantly altered the expression of lipid-metabolizing genes in the liver of chickens. However, the underlying mechanism was not elucidated. In this study, we further characterized how GTPs influence AMP-activated protein kinase (AMPK) in the regulation of hepatic fat metabolism. Thirty-six male chickens were fed GTPs at a daily dose of 0, 80 or 160 mg/kg of body weight for 4 weeks. The results demonstrated that oral administration of GTPs significantly reduced hepatic lipid content and abdominal fat mass, enhanced the phosphorylation levels of AMPKα and ACACA, and altered the mRNA levels and enzymatic activities of lipid-metabolizing enzymes in the liver. These results suggested that the activation of AMPK is a potential mechanism by which GTPs regulate hepatic lipid metabolism in such a way that lipid synthesis is reduced and fat oxidation is stimulated.

Triglycerides Revisited to the Serial

This review discusses the role of triglycerides (TGs) in the normal cardiovascular system as well as in the development and clinical manifestation of cardiovascular diseases. Regulation of TGs at the enzymatic and genetic level, in addition to their possible relevance as preclinical and clinical biomarkers, is discussed, culminating with a description of available and emerging treatments. Due to the high complexity of the subject and the vast amount of material in the literature, the objective of this review was not to exhaust the subject, but rather to compile the information to facilitate and improve the understanding of those interested in this topic. The main publications on the topic were sought out, especially those from the last 5 years. The data in the literature still give reason to believe that there is room for doubt regarding the use of TG as disease biomarkers; however, there is increasing evidence for the role of hypertriglyceridemia on the atherosclerotic inflammatory process, cardiovascular outcomes, and mortality.

Transcriptome Profile Reveals that Pu-Erh Tea Represses the Expression of Vitellogenin Family to Reduce Fat Accumulation in Caenorhabditis elegans

Due to misbalanced energy surplus and expenditure, obesity has become a common chronic disorder that is highly associated with many metabolic diseases. Pu-erh tea, a traditional Chinese beverage, has been believed to have numerous health benefits, such as anti-obesity. However, the underlying mechanisms of its anti-obesity effect are yet to be understood. Here, we take the advantages of transcriptional profile by RNA sequencing (RNA-Seq) to view the global gene expression of Pu-erh tea. The model organism Caenorhabditis elegans was treated with different concentrations of Pu-erh tea water extract (PTE, 0 g/mL, 0.025 g/mL, and 0.05 g/mL). Compared with the control, PTE indeed decreases lipid droplets size and fat accumulation. The high-throughput RNA-Sequence technique detected 18073 and 18105 genes expressed in 0.025 g/mL and 0.05 g/mL PTE treated groups, respectively. Interestingly, the expression of the vitellogenin family (vit-1, vit-2, vit-3, vit-4 and vit-5) was significantly decreased by PTE, which was validated by qPCR analysis. Furthermore, vit-1(ok2616), vit-3(ok2348) and vit-5(ok3239) mutants are insensitive to PTE triggered fat reduction. In conclusion, our transcriptional profile by RNA-Sequence suggests that Pu-erh tea lowers the fat accumulation primarily through repression of the expression of vit(vitellogenin) family, in addition to our previously reported (sterol regulatory element binding protein) SREBP-SCD (stearoyl-CoA desaturase) axis.

Could tea polyphenols be beneficial for preventing the precocious puberty?

Precocious puberty which impacts children physically and psychologically has become one of the health problem over the world. However, the mechanism and preventive measures of precocious puberty is still not clear. Recent studies suggested that leptin may act as the 'permissive factor' to initiate the puberty by regulating gonadotrophin-releasing hormone secretion. Previous evidence from animal and human studies found that tea polyphenols can reduce serum leptin levels in vivo and inhibit the expression of leptin in adipose tissue. This article focus on whether tea polyphenols could delay the onset of puberty by reducing leptin levels. To verify the possibility of tea polyphenols on preventing precocious puberty, animal experiment can be used. Our hypothesis that tea polyphenols could prevent the precocious puberty may provide important potential way for the prevention and control of children precocious puberty.

Safety and anti-hyperglycemic efficacy of various tea types in mice

Tea, a beverage consumed worldwide, has proven anti-hyperglycemic effects in animal models. Better efficacies of tea beverages are frequently associated with high-dose levels, whose safety attracts considerable attention. Based on the inherent nature of tea catechin oxidation, fresh tea leaves are manufactured into diverse tea types by modulating the oxidation degree of catechins. The present study aimed to assess various tea types for their safety properties and anti-hyperglycemic effects. Mice were allowed free access to tea infusion (1:30, w/v) for one week, and the rare smoked tea caused salient adverse reactions, including hepatic and gastrointestinal toxicities; meanwhile, the widely-consumed green and black teas, unlike the rare yellow tea, suppressed growth in fast-growing healthy mice. When mice were fed a high-fat diet and allowed free access to tea infusion (1:30, w/v) for 25 days, only yellow tea significantly reduced blood glucose. Therefore, various teas showed different safety profiles as well as anti-hyperglycemic efficacy strengths. To achieve an effective and safe anti-hyperglycemic outcome, yellow tea, which effectively suppressed high-fat diet-induced early elevation of hepatic thioredoxin-interacting protein, is an optimal choice.

Serum metabolomics analysis of rat after intragastric infusion of Pu-erh theabrownin

BACKGROUND

The aim was to study the effects of Pu-erh theabrownin (TB) (Mw  > 50 kDa) on the metabolism of rat serum by nuclear magnetic resonance (NMR)-based metabolomics and identify candidate marker metabolites associated with Pu-erh TB, and thus provide fundamental information for a better understanding of the metabolism of Pu-erh tea in animals.

RESULTS

TB infusion induced different changes in endogenous serum metabolites depending on the type of diet. Compared with the control group, the TB infusion group showed significantly reduced serum glycine and choline levels, as well as significantly increased taurine, carnitine and high-density lipoprotein (all P < 0.05). Compared with the high-lipid group, the high-lipid TB infusion group exhibited significantly reduced low-density lipoprotein and acetate levels, as well as significantly increased inositol, carnitine and glycine levels (all P < 0.05).

CONCLUSION

Examination of the variations of these differential expressed metabolites and their individual functions revealed that the TB extract accelerated lipid catabolism in rats and might affect glucose metabolism. Of these, carnitine level significantly increased after intragastric infusion of TB regardless of the type of diet, and activities of carnitine palmitoyltransferases I and II changed significantly, suggesting carnitine may be a candidate serum marker for tracking the metabolism of TB in rats. © 2015 Society of Chemical Industry.

Pu-erh tea extract ameliorates high-fat diet-induced nonalcoholic steatohepatitis and insulin resistance by modulating hepatic IL-6/STAT3 signaling in mice

BACKGROUND

Pu-erh tea, made from the leaves of Camellia sinensis, possesses activities beneficial for human health, including anti-inflammatory, anti-oxidant, and anti-obesity properties.

OBJECTIVE

We investigated the effects of a pu-erh tea extract (PTE) on nonalcoholic steatohepatitis (NASH) and the molecular mechanisms underlying such effects.

METHODS

Eight-week-old male C57BL/6J mice were fed a normal chow diet or high-fat diet (HFD) for 17 weeks, during which PTE was simultaneously administered in drinking water. Body weight, hepatic inflammation, steatosis, insulin sensitivity, expression of lipogenesis- and gluconeogenesis-associated genes, and signal transducer and activator of transcription (STAT)-3 phosphorylation were examined. The anti-steatotic effects of PTE and/or interleukin (IL)-6 were evaluated in HepG2 cells. The lipid accumulation, STAT3 phosphorylation, and expression of lipid metabolism-related genes were analyzed.

RESULTS

PTE inhibited HFD-induced obesity and significantly attenuated HFD-induced hepatic steatosis and liver inflammation, and prevented against liver injury. PTE treatment improved glucose tolerance and insulin sensitivity in HFD-fed mice. Moreover, PTE treatment maintained the intact insulin signal and significantly decreased expression of gluconeogenesis-related genes in the livers of HFD-fed mice. PTE treatment strikingly enhanced STAT3 phosphorylation in the livers of HFD-fed mice. Consistent with this increase in STAT3 phosphorylation, pre-treatment of HepG2 cells with PTE enhanced IL-6-induced STAT3 phosphorylation and attenuated oleic acid-induced steatosis in a STAT3-dependent manner. In contrast, PTE inhibited IL-6-induced STAT3 phosphorylation in macrophages.

CONCLUSIONS

PTE ameliorates hepatic lipid metabolism, inflammation, and insulin resistance in mice with HFD-induced NASH, presumably by modulating hepatic IL-6/STAT3 signaling.

Oxidized tea polyphenols prevent lipid accumulation in liver and visceral white adipose tissue in rats

BACKGROUND

Tea polyphenols are the prominent component in tea. After the fermentation process, tea polyphenols are oxidized by polyphenol oxidase to form oxidized tea polyphenols (OTPs). OTPs contain a significant amount of hydrophobic phenyl groups that can bind with non-aqueous materials. Here, we determined whether OTPs can bind with lipids and reduce fat uptake and assessed the effect of OTPs on decreasing obesity and alleviating hyperlipidaemia and other metabolic syndromes.

METHODS

Rats were divided into three groups: control, high-fat diet (HFD) and OTP groups. The control and HFD groups were fed a chow diet and a high-fat diet, respectively, for 12 weeks; the OTP group was fed a high-fat diet for 6 weeks and then a high-fat diet containing 2 % OTP for 6 weeks. The serum and excrement triglyceride (TAG) and total cholesterol (CHOL) concentrations were determined, and liver tissue and white adipose tissue were collected to detect the expression levels of genes involved in lipid metabolism.

RESULTS

Our results revealed that OTPs failed to decrease the serum concentrations of TAG and CHOL. OTPs alleviated the accumulation of lipids in the liver tissue and changed the expression levels of the regulators of lipid metabolism, i.e., peroxisome proliferation-activated receptors (ppars), compared with the rats fed a high-fat diet alone. We also observed a significantly decreased reduction of weight in the visceral white adipose, enhanced regulation of fatty acid β-oxidation by PPARα and enhanced biosynthesis of mitochondria in the visceral white adipose of the OTP rats compared with the HFD rats. Additionally, OTPs promoted the excretion of lipids.

CONCLUSION

Our results suggest that OTPs alleviate the accumulation of lipids in liver and visceral white adipose tissue and promote lipid excretion in rats in vivo.

Safety evaluation and antihyperlipidemia effect of aqueous extracts from fermented puerh tea

Fermented puerh tea, having undergone a long period of secondary oxidization and fermentation, has become more and more popular in recent years. In the present paper, a safety evaluation of aqueous extracts from fermented puerh tea (EFPT) was performed, including an oral acute toxicity study in rats and mice, mutation tests, a mouse micronucleus test, mouse sperm abnormality test and a 30 day feeding study in rats. Meanwhile, the antihyperlipidemia effect of EFPT was investigated as well. It was found that the oral maximum tolerated dose of EFPT was more than 10.0 g per kg body weight both in rats and mice. And it had no mutagenicity as judged by negative experimental results of the mutation test. No abnormal symptoms, clinical signs or deaths have been found in rats in each group throughout the experiments. In addition, EFPT in this study showed certain effects on hyperlipidemia.

Reduction of body fat and improved lipid profile associated with daily consumption of a Puer tea extract in a hyperlipidemic population: a randomized placebo-controlled trial

OBJECTIVE

The goal for this study was to evaluate the effects of daily consumption of Puer tea extract (PTE) on body weight, body-fat composition, and lipid profile in a non-Asian population in the absence of dietary restrictions.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled study design was used. A total of 59 overweight or mildly obese subjects were enrolled upon screening to confirm fasting cholesterol level at or above 220 mg/dL (5.7 mmol/dL). After giving informed consent, subjects were randomized to consume PTE (3 g/day) or placebo for 20 weeks. At baseline and at 4-week intervals, blood lipids, C-reactive protein, and fasting blood glucose were evaluated. A dual-energy X-ray absorptiometry scan was performed at baseline and at study exit to evaluate changes to body composition. Appetite and physical and mental energy were scored at each visit using visual analog scales (0-100).

RESULTS

Consumption of PTE was associated with statistically significant weight loss when compared to placebo (P<0.05). Fat loss was seen for arms, legs, and the gynoid region (hip/belly), as well as for total fat mass. The fat reduction reached significance on within-group analysis, but did not reach between-group significance. Consumption of PTE was associated with improvements to lipid profile, including a mild reduction in cholesterol and the cholesterol:high-density lipoprotein ratio after only 4 weeks, as well as a reduction in triglycerides and very small-density lipoproteins, where average blood levels reached normal range at 8 weeks and remained within normal range for the duration of the study (P<0.08). No significant changes between the PTE group and the placebo group were seen for fasting glucose or C-reactive protein. A transient reduction in appetite was seen in the PTE group when compared to placebo (P<0.1).

CONCLUSION

The results from this clinical study showed that the daily consumption of PTE was associated with significant weight loss, reduced body mass index, and an improved lipid profile.

Hypolipidemic effects of flavonoids extracted from Lomatogonium rotatum

Contained in the Mongolian volumes of Chinese Materia Medica, Lomatogonium rotatum Fries ex Nym. may reduce blood lipid levels and prevent obesity; however, its exact mechanism of action remains unclear. The present study investigated the hypolipidemic and obesity-inhibiting effects of four similarly structured flavonoids extracted from L. rotatum. According to a well-established method, flavonoids such as decussatin were extracted from the whole herb of L. rotatum, and male Wistar rats were subsequently fed a high-fructose diet supplemented with flavonoids (20 mg/kg) for 12 weeks. The levels of total cholesterol, triglyceride (TG), low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol (HDL-C) were detected. In addition, hepatic and epididymal adipose tissues were weighed, and levels of blood glucose, alanine aminotransferase, aspartate aminotransferase, non-esterified fatty acid, insulin and leptin were determined. The mRNA expression levels of fatty acid synthase (FAS) were analyzed using a reverse transcription polymerase chain reaction; whereas FAS, adenosine monophosphate-activated protein kinase (AMPK) and threonine-172 phosphorylated AMPK protein levels were detected by western blotting. The epididymal adipose tissues of rats fed with flavonoids were lighter, as compared with those fed with fructose in the model group. Following a 12-week administration of flavonoids, the serum levels of fasting blood glucose, feeding blood glucose and leptin were decreased. Furthermore, flavonoid treatment reduced TG and cholesterol levels in the blood and increased serum HDL-C levels, as compared with the model group. High-fructose diet administration significantly increased FAS mRNA and protein expression levels, whereas the FAS protein levels of flavonoid-treated rats were markedly reduced. The flavonoid compounds also enhanced threonine-172 phosphorylation of AMPK in the liver lysate, and all flavonoids successfully downregulated leptin levels and the majority decreased the relative weights of epididymal adipose tissue. Therefore, flavonoids may function in a similar way to epigallocatechin gallate, which has previously been shown to inhibit FAS activity by stimulating AMPK in hepatocyte cells via the liver kinase B1 pathway.

Regulation of AMP-activated protein kinase by natural and synthetic activators

The AMP-activated protein kinase (AMPK) is a sensor of cellular energy status that is almost universally expressed in eukaryotic cells. While it appears to have evolved in single-celled eukaryotes to regulate energy balance in a cell-autonomous manner, during the evolution of multicellular animals its role has become adapted so that it also regulates energy balance at the whole body level, by responding to hormones that act primarily on the hypothalamus. AMPK monitors energy balance at the cellular level by sensing the ratios of AMP/ATP and ADP/ATP, and recent structural analyses of the AMPK heterotrimer that have provided insight into the complex mechanisms for these effects will be discussed. Given the central importance of energy balance in diseases that are major causes of morbidity or death in humans, such as type 2 diabetes, cancer and inflammatory disorders, there has been a major drive to develop pharmacological activators of AMPK. Many such activators have been described, and the various mechanisms by which these activate AMPK will be discussed. A particularly large class of AMPK activators are natural products of plants derived from traditional herbal medicines. While the mechanism by which most of these activate AMPK has not yet been addressed, I will argue that many of them may be defensive compounds produced by plants to deter infection by pathogens or grazing by insects or herbivores, and that many of them will turn out to be inhibitors of mitochondrial function.