Green Tea Polyphenol Epigallocatechin Gallate Inhibits Adipogenesis and Induces Apoptosis in 3T3-L1 Adipocytes

Resveratrol and (-)-Epigallocatechin-3-gallate Regulate Lipid Metabolism by Activating the AMPK Pathway in Hepatocytes

The purpose of this study was to explore the effects of Res and EGCG on cell growth, cellular antioxidant levels, and cellular lipid metabolism in hepatocytes. In this experiment, leghorn male hepatoma (LMH) cells were used as hepatocytes. The results showed that 6.25-25 μM Res and EGCG had no adverse effects on cell viability and growth. Meanwhile, with the increasing dosage of Res and EGCG, the contents of total cholesterol (TC), total glyceride (TG), and malondialdehyde (MDA) in hepatocytes decreased significantly (p < 0.05), while the contents of glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD), and catalase (CAT) increased significantly (p < 0.05). In addition, western blot results showed that Res and EGCG could significantly increase the expression of p-AMPK protein and reduce the expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) protein in hepatocytes (p < 0.05). Moreover, q-PCR results showed that with the increase in Res and EGCG, the expression of cholesterol- and fatty acid synthesis-related genes decreased significantly (p < 0.05). In conclusion, Res and EGCG can increase the antioxidant capacity of hepatocytes and reduce the synthesis of TC and TG in hepatocytes by activating AMPK, thereby regulating lipid metabolism in hepatocytes.

Docosahexaenoic acid (DHA) inhibits abdominal fat accumulation by promoting adipocyte apoptosis through PPARγ-LC3-BNIP3 pathway-mediated mitophagy

Obesity has always been an overwhelming health concern worldwide. Docosahexaenoic acid (DHA) reduces abdominal fat accumulation by inducing adipocyte apoptosis, but the underlying mechanism remains unclear. Mitophagy, the process of maintaining mitochondrial homeostasis, has a double-edged sword effect that positively or negatively regulates apoptosis. In this study, grass carp (Ctenopharyngodon idellus) was used as an animal model to investigate the role of mitophagy in regulating apoptosis and the potential molecular mechanisms for DHA-induced mitophagy in vivo and in vitro. Firstly, we found that DHA induced the intrinsic apoptosis in grass carp adipocytes, accompanying by activating BNIP3/NIX-mediated mitophagy. Then, suppression of mitophagy alleviated apoptosis and eliminated the inhibition of lipid accumulation induced by DHA in vivo and in vitro. Mechanistically, the DHA-induced mitophagy was caused by activating PPARγ and its DNA binding capacity to the LC3 promoter, which promoted the interaction of BNIP3 (rather than NIX) with LC3. However, the inhibition of PPARγ in vitro significantly decreased the expression of autophagy-related genes (P < 0.05), reducing the colocalization of mitochondria and lysosomes while preventing BNIP3/NIX-mediated mitophagy-mediated apoptosis and subsequently alleviating the inhibition of lipid accumulation in adipocytes induced by DHA. For the first time, we demonstrated that DHA activates mitophagy by regulating the PPARγ-LC3-BNIP3 pathway, consequently inducing apoptosis, which decreases adipocytes, inhibiting lipid accumulation in grass carp. These findings provide new insight into the mechanism of DHA-induced apoptosis mediated by mitophagy as the potential therapeutic target of inhibiting abdominal fat accumulation in vertebrates.

The inhibitory effect of Gremlin-2 on adipogenesis suppresses breast cancer cell growth and metastasis

BACKGROUND

Gremlin-1 (GREM1) and Gremlin-2 (GREM2) are bone morphogenetic protein antagonists that play important roles in organogenesis, tissue differentiation, and tissue homeostasis. Although GREM1 has been reported to be involved in promoting various cancers, little has been reported about effects of GREM2 on cancer. Recently, it has been reported that GREM2 can inhibit adipogenesis in adipose-derived stromal/stem cells. However, as an inhibitor of adipogenesis, the role of GREM2 in cancer progression is not well understood yet.

METHODS

Pre-adipocyte 3T3-L1 cells overexpressing mock or Grem2 were established using a lentiviral transduction system and differentiated into adipocytes-mock and adipocytes-Grem2, respectively. To investigate the effect of adipocyte-Grem2 on breast cancer cells, we analyzed the proliferative and invasion abilities of spheroids using a 3D co-culture system of breast cancer cells and adipocytes or conditioned medium (CM) of adipocytes. An orthotopic breast cancer mouse model was used to examine the role of adipocytes-Grem2 in breast cancer progression.

RESULTS

Grem2 overexpression suppressed adipogenesis of 3T3-L1 cells. Proliferative and invasion abilities of spheroids formed by co-culturing MTV/TM-011 breast cancer cells and adipocytes-Grem2 were significantly reduced compared to those of spheroids formed by co-culturing MTV/TM-011 cells and adipocytes-mock. Compared to adipocytes-mock, adipocytes-Grem2 showed decreased mRNA expression of several adipokines, notably IL-6. The concentration of IL-6 in the CM of these cells was also decreased. Proliferative and invasive abilities of breast cancer cells reduced by adipocytes-Grem2 were restored by IL-6 treatment. Expression levels of vimentin, slug, and twist1 in breast cancer cells were decreased by treatment with CM of adipocytes-Grem2 but increased by IL-6 treatment. In orthotopic breast cancer mouse model, mice injected with both MTV/TM-011 cells and adipocytes-Grem2 showed smaller primary tumors and lower lung metastasis than controls. However, IL-6 administration increased both the size of primary tumor and the number of metastatic lung lesions, which were reduced by adipocytes-Grem2.

CONCLUSIONS

Our study suggests that GREM2 overexpression in adipocytes can inhibit adipogenesis, reduce the expression and secretion of several adipokines, including IL-6, and ultimately inhibit breast cancer progression.

Management of Obesity-Related Inflammatory and Cardiovascular Diseases by Medicinal Plants: From Traditional Uses to Therapeutic Targets

Inflammation is a crucial factor in the development and progression of cardiovascular diseases (CVD). Cardiac remodeling in the presence of persistent inflammation leads to myocardial fibrosis and extracellular matrix changes, which reduce cardiac function, induce arrhythmias, and finally, cause heart failure. The majority of current CVD treatment plans concentrate on reducing risk factors such as hyperlipidemia, type 2 diabetes, and hypertension. One such strategy could be inflammation reduction. Numerous in vitro, animal, and clinical studies indicate that obesity is associated with low-grade inflammation. Recent studies have demonstrated the potential of medicinal plants and phytochemicals to cure and prevent obesity and inflammation. In comparison to conventional therapies, the synergistic effects of several phytochemicals boost their bioavailability and impact numerous cellular and molecular targets. Focusing on appetite, pancreatic lipase activity, thermogenesis, lipid metabolism, lipolysis and adipogenesis, apoptosis in adipocytes, and adipocyte life cycle by medicinal plants and phytochemicals represent an important goal in the development of new anti-obesity drugs. We conducted an extensive review of the literature and electronic databases, including Google Scholar, PubMed, Science Direct, and MedlinePlus, for collecting data on the therapeutic effects of medicinal plants/phytochemicals in curing obesity and its related inflammation and CVD diseases, including cellular and molecular mechanisms, cytokines, signal transduction cascades, and clinical trials.

Natural products as novel anti-obesity agents: insights into mechanisms of action and potential for therapeutic management

Obesity affects more than 10% of the adult population globally. Despite the introduction of diverse medications aimed at combating fat accumulation and obesity, a significant number of these pharmaceutical interventions are linked to substantial occurrences of severe adverse events, occasionally leading to their withdrawal from the market. Natural products serve as attractive sources for anti-obesity agents as many of them can alter the host metabolic processes and maintain glucose homeostasis via metabolic and thermogenic stimulation, appetite regulation, pancreatic lipase and amylase inhibition, insulin sensitivity enhancing, adipogenesis inhibition and adipocyte apoptosis induction. In this review, we shed light on the biological processes that control energy balance and thermogenesis as well as metabolic pathways in white adipose tissue browning, we also highlight the anti-obesity potential of natural products with their mechanism of action. Based on previous findings, the crucial proteins and molecular pathways involved in adipose tissue browning and lipolysis induction are uncoupling protein-1, PR domain containing 16, and peroxisome proliferator-activated receptor-γ in addition to Sirtuin-1 and AMP-activated protein kinase pathway. Given that some phytochemicals can also lower proinflammatory substances like TNF-α, IL-6, and IL-1 secreted from adipose tissue and change the production of adipokines like leptin and adiponectin, which are important regulators of body weight, natural products represent a treasure trove for anti-obesity agents. In conclusion, conducting comprehensive research on natural products holds the potential to accelerate the development of an improved obesity management strategy characterized by heightened efficacy and reduced incidence of side effects.

The Preventive Mechanisms of Bioactive Food Compounds against Obesity-Induced Inflammation

Dietary patterns are promising strategies for preventing and treating obesity and its coexisting inflammatory processes. Bioactive food compounds have received considerable attention due to their actions against obesity-induced inflammation, with limited harmful side effects. They are perceived as food ingredients or dietary supplements other than those necessary to meet basic human nutritional needs and are responsible for positive changes in the state of health. These include polyphenols, unsaturated fatty acids, and probiotics. Although the exact mechanisms of bioactive food compounds' action are still poorly understood, studies have indicated that they involve the modulation of the secretion of proinflammatory cytokines, adipokines, and hormones; regulate gene expression in adipose tissue; and modify the signaling pathways responsible for the inflammatory response. Targeting the consumption and/or supplementation of foods with anti-inflammatory potential may represent a new approach to obesity-induced inflammation treatment. Nevertheless, more studies are needed to evaluate strategies for bioactive food compound intake, especially times and doses. Moreover, worldwide education about the advantages of bioactive food compound consumption is warranted to limit the consequences of unhealthy dietary patterns. This work presents a review and synthesis of recent data on the preventive mechanisms of bioactive food compounds in the context of obesity-induced inflammation.

New Synthesized Activating Transcription Factor 3 Inducer SW20.1 Suppresses Resistin-Induced Metabolic Syndrome

Obesity is an emerging concern globally with increasing prevalence. Obesity is associated with many diseases, such as cardiovascular disease, dyslipidemia, and cancer. Thus, effective new antiobesity drugs should be urgently developed. We synthesized SW20.1, a compound that induces activating transcription factor 3 (ATF3) expression. The results of Oil Red O staining and quantitative real-time polymerase chain reaction revealed that SW20.1 was more effective in reducing lipid accumulation in 3T3-L1 preadipocytes than the previously synthesized ST32db, and that it inhibited the expression of the genes involved in adipogenesis and lipogenesis. A chromatin immunoprecipitation assay indicated that SW20.1 inhibited adipogenesis and lipogenesis by binding to the upstream promoter region of resistin at two sites (-2861/-2854 and -241/-234). In mice, the intraperitoneal administration of SW20.1 reduced body weight, white adipocyte weight in different regions, serum cholesterol levels, adipogenesis-related gene expression, hepatic steatosis, and serum resistin levels. Overall, SW20.1 exerts antiobesity effects by inhibiting resistin through the ATF3 pathway. Our study results indicate that SW20.1 is a promising therapeutic drug for diet-induced obesity.

Methionine sulfoxide suppresses adipogenic differentiation by regulating the mitogen-activated protein kinase signaling pathway

In this study, methionine sulfoxide (MetO) was identified as an active metabolite that suppresses adipogenesis after screening obese individuals versus the normal population. MetO suppressed the gene and protein expression of CCAAT/enhancer binding protein (C/EBP) α, adipocyte fatty acid binding protein 4 (FABP4), and the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) during human preadipocyte (HPA) differentiation. Adipogenesis decreased following MetO treatment; however, the preadipocyte number, proliferation, and apoptosis were unaffected. The activity of phosphorylated extracellular signal-related kinase (P-ERK) of the mitogen-activated protein kinase (MAPK) pathway was significantly inhibited in HPA after MetO treatment. Furthermore, treatment of preadipocytes with the selective P-ERK1/2 agonist Ro 67-7476 abolished the effect of MetO against adipogenesis suggesting that MetO function is dependent on the MAPK pathway. The mechanistic insights of adipogenesis suppression by MetO presented in this study shows its potential as an antiobesity drug.

Functional Complementation of Anti-Adipogenic Phytonutrients for Obesity Prevention and Management

Obesity is an established risk factor for metabolic disease. This study explores the functional complementation of anti-adipogenic phytonutrients for obesity prevention and management. Nine phytonutrients were selected based on their ability to affect the expression of one or more selected adipogenic biomarker proteins. The phytonutrients include berberine, luteolin, resveratrol, fisetin, quercetin, fucoidan, epigallocatechin gallate, hesperidin, and curcumin. The selected adipogenic biomarker proteins include PPARɣ, SREBP1c, FASN, PLIN1, FABP4, and β-catenin. Individually, phytonutrients had variable effects on the expression level of selected adipogenic biomarker proteins. Collectively, the functional complementation of nine phytonutrients suppressed de novo fatty acid biosynthesis via the negative regulation of PPARɣ, FASN, PLIN1, and FABP4 expression; activated glycolysis via the positive regulation of SREBP1c expression; and preserved cell–cell adhesion via the inhibition of β-catenin degradation. In primary human subcutaneous preadipocytes, the composition of nine phytonutrients had more potent and longer lasting anti-adipogenic effects compared to individual phytonutrients. In a diet-induced obesity murine model, the composition of nine phytonutrients improved glucose tolerance and reduced weight gain, liver steatosis, visceral adiposity, circulating triglycerides, low-density lipoprotein cholesterol, and inflammatory cytokines and chemokines. The functional complementation of anti-adipogenic phytonutrients provides an effective approach toward engineering novel therapeutics for the prevention and management of obesity and metabolic syndrome.

Effects of Camellia tea and herbal tea on cardiometabolic risk in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

Evidence for the anti-diabetic actions of camellia and herbal tea in diabetic patients has not been summarized. Several data sources were searched for randomized trials assessing the effect of different teas on cardiometabolic risk factors in T2D subjects. Two independent reviewers extracted relevant data and assessed the risk of bias. Results were summarized using mean differences (MDs) based on a random model. Sixteen studies (19 trials, N = 832) fulfilled the eligibility criteria. Mean differences were measured for body weight, body mass index, fasting blood glucose, glycosylated hemoglobin, a homeostatic model for insulin resistance, high and low-density lipoproteins, triglycerides, and systolic and diastolic blood pressure. No effects on total cholesterol and waist circumference were observed when either camellia or herbal tea was consumed. Tea produced moderate regulatory effects on adipose, glycemic control, lipid profiles, and blood pressure. In terms of efficacy, camellia and herbal teas yield different benefits in regulating metabolism. This discovery has some implications for clinical research and drug development. However, more high-quality trials are needed to improve the certainty of our estimates.

Green tea epigallocatechin gallate suppresses 3T3-L1 cell growth via microRNA-143/MAPK7 pathways

Green tea epigallocatechin gallate (EGCG) and microRNA (miRNA) molecules modulate obesity. Nevertheless, it is still unknown whether EGCG modulates fat cell growth via miRNA-related signaling. In this study, white preadipocytes were used to examine whether the antimitogenic effect of EGCG on fat cells is regulated by the miR-143/MAPK7 pathway. We showed that EGCG upregulated the levels of miR-143, but not miR-155, in 3T3-L1 preadipocytes. Moreover, EGCG downregulated MAPK7 mRNA and protein levels time- and dose-dependently. MAPK7 expression increased during 3T3-L1 cell proliferation. miR-143 overexpression in the absence of EGCG mimicked the effects of EGCG to suppress preadipocyte growth and MAPK7 expression, whereas knockdown of miR-143 antagonized the EGCG-altered levels of miR-143, MAPK7, and pERK1/2 and reversed the EGCG-inhibited cell growth. These findings suggest that EGCG inhibits 3T3-L1 cell growth via miR-143/MAPK7 pathway.

α-Glucosidase Inhibitory Activity and Anti-Adipogenic Effect of Compounds from Dendrobium delacourii

Chemical investigation of Dendrobium delacourii revealed 11 phenolic compounds, and the structures of these compounds were determined by analysis of their NMR and HR-ESI-MS data. All compounds were investigated for their α-glucosidase inhibitory activity and anti-adipogenic properties. Phoyunnanin E (10) and phoyunnanin C (11) showed the most potent α-glucosidase inhibition by comparing with acarbose, which was used as a positive control. Kinetic study revealed the non-competitive inhibitors against the enzyme. For anti-adipogenic activity, densifloral B (3) showed the strongest inhibition when compared with oxyresveratrol (positive control). In addition, densifloral B might be responsible for the inhibition of adipocyte differentiation via downregulating the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer-binding protein alpha (C/EBPα), which are major transcription factors in adipogenesis.

Growth Performance, Meat Quality and Antioxidant Status of Sheep Supplemented with Tannins: A Meta-Analysis

The objective of this study was to evaluate the effects of dietary supplementation with tannins (TANs) on productive performance, carcass characteristics, meat quality, oxidative stability, and blood serum antioxidant capacity of sheep through a meta-analysis. Using Scopus, Web of Science, ScienceDirect, and PubMed databases, a systematic search was performed for studies published in scientific journals that investigated the effects of TANs supplementation on the variables of interest. Only studies with weaned or older sheep were included. The data analyzed were extracted from 53 peer-reviewed publications. The sheep included in the present study were between 2 and 6 months old, and between 12 and 31 kg of body weight. The effects of TANs were analyzed using random-effects statistical models to examine the standardized mean difference (SMD) between treatments with TANs and control (no TANs). Heterogeneity was explored by meta-regression and a subgroup analysis was performed for covariates that were significant. Supplementation with TANs did not affect dry matter intake, pH, color (L* and b*), Warner-Bratzler shear force, cooking loss and meat chemical composition (p > 0.05). Supplementation with TANs increased daily weight gain (SMD = 0.274, p < 0.05), total antioxidant capacity (SMD = 1.120, p < 0.001), glutathione peroxidase enzyme activity (SMD = 0.801, p < 0.001) and catalase (SMD = 0.848, p < 0.001), and decreased malondialdehyde (MDA) concentration in blood serum (SMD = -0.535, p < 0.05). Supplementation with TANs decreased feed conversion rate (SMD = -0.246, p < 0.05), and the concentration of MDA (SMD = -2.020, p < 0.001) and metmyoglobin (SMD = -0.482, p < 0.05) in meat. However, meat redness (SMD = 0.365), hot carcass yield (SMD = 0.234), cold carcass yield (SMD = 0.510), backfat thickness (SMD = 0.565) and the Longissimus dorsi muscle area (SMD = 0.413) increased in response to TANs supplementation (p < 0.05). In conclusion, the addition of tannins in sheep diets improves productive performance, antioxidant status in blood serum, oxidative stability of meat and some other characteristics related to meat and carcass quality.

Untargeted fecal metabolome analysis in obese dogs after weight loss achieved by feeding a high-fiber-high-protein diet

INTRODUCTION

In humans and companion animals, obesity is accompanied by metabolic derangements. Studies have revealed differences in the composition of the fecal microbiome between obese dogs and those with an ideal body weight.

OBJECTIVES

We have previously reported that the fecal microbiome in obese dogs changes after controlled weight reduction, induced by feeding a diet high in fiber and protein. Despite these findings, it is unclear if taxonomic differences infer differences at the functional level between obese dogs and those with an ideal body weight.

METHODOLOGY

Untargeted fecal metabolome analysis was performed on dogs with obesity before and after weight loss achieved by feeding a high-fiber-high-protein diet.

RESULTS

Fecal metabolome analysis revealed a total of 13 compounds that changed in concentration in obese dogs after weight loss. Of these compounds, metabolites associated with bacterial metabolism decreased after weight loss including purine, L-(-)-methionine, coumestrol, and the alkaloids 1-methylxanthine and trigonelline. Conversely, the polyphenols (-)-epicatechin and matairesinol and the quinoline derivatives 1,5-isoquinolinediol and 2-hydroxiquinoline increased after weight loss.

CONCLUSION

These results suggest differences in intestinal microbiome at the functional level after weight loss, but further studies are needed to determine the role of these compounds in the etiology of obesity and weight loss.

Metabolic and Epigenetics Action Mechanisms of Antiobesity Medicinal Plants and Phytochemicals

Ever-growing research efforts are demonstrating the potential of medicinal plants and their phytochemicals to prevent and manage obesity, either individually or synergistically. Multiple combinations of phytochemicals can result in a synergistic activity that increases their beneficial effects at molecular, cellular, metabolic, and temporal levels, offering advantages over chemically synthesized drug-based treatments. Herbs and their derived compounds have the potential for controlling appetite, inhibiting pancreatic lipase activity, stimulating thermogenesis and lipid metabolism, increasing satiety, promoting lipolysis, regulating adipogenesis, and inducing apoptosis in adipocytes. Furthermore, targeting adipocyte life cycle using various dietary bioactives that affect different stages of adipocyte life cycle represents also an important target in the development of new antiobesity drugs. In this regard, different stages of adipocyte development that are targeted by antiobesity drugs can include preadipocytes, maturing preadipocytes, and mature adipocytes. Various herbal-derived active compounds, such as capsaicin, genistein, apigenin, luteolin, kaempferol, myricetin, quercetin, docosahexaenoic acid, quercetin, resveratrol, and ajoene, affect adipocytes during specific stages of development, resulting in either inhibition of adipogenesis or induction of apoptosis. Although numerous molecular targets that can be used for both treatment and prevention of obesity have been identified, targeted single cellular receptor or pathway has resulted in limited success. In this review, we discuss the state-of-the-art knowledge about antiobesity medicinal plants and their active compounds and their effects on several cellular, molecular, and metabolic pathways simultaneously with multiple phytochemicals through synergistic functioning which might be an appropriate approach to better management of obesity. In addition, epigenetic mechanisms (acetylation, methylation, miRNAs, ubiquitylation, phosphorylation, and chromatin packaging) of phytochemicals and their preventive and therapeutic perspective are explored in this review.

Obesity and aging: Molecular mechanisms and therapeutic approaches

The epidemic of obesity is a major challenge for health policymakers due to its far-reaching effects on population health and potentially overwhelming financial burden on healthcare systems. Obesity is associated with an increased risk of developing acute and chronic diseases, including hypertension, stroke, myocardial infarction, cardiovascular disease, diabetes, and cancer. Interestingly, the metabolic dysregulation associated with obesity is similar to that observed in normal aging, and substantial evidence suggests the potential of obesity to accelerate aging. Therefore, understanding the mechanism of fat tissue dysfunction in obesity could provide insights into the processes that contribute to the metabolic dysfunction associated with the aging process. Here, we review the molecular and cellular mechanisms underlying both obesity and aging, and how obesity and aging can predispose individuals to chronic health complications. The potential of lifestyle and pharmacological interventions to counter obesity and obesity-related pathologies, as well as aging, is also addressed.

EGCG Inhibits Adipose-Derived Mesenchymal Stem Cells Differentiation into Adipocytes and Prevents a STAT3-Mediated Paracrine Oncogenic Control of Triple-Negative Breast Cancer Cell Invasive Phenotype

Obese subjects have an increased risk of developing triple-negative breast cancer (TNBC), in part associated with the chronic low-grade inflammation state. On the other hand, epidemiological data indicates that increased consumption of polyphenol-rich fruits and vegetables plays a key role in reducing incidence of some cancer types. Here, we tested whether green tea-derived epigallocatechin-3-gallate (EGCG) could alter adipose-derived mesenchymal stem cell differentiation into adipocytes, and how this impacts the secretome profile and paracrine regulation of the TNBC invasive phenotype. Here, cell differentiation was performed and conditioned media (CM) from preadipocytes and mature adipocytes harvested. Human TNBC-derived MDA-MB-231 real-time cell migration was performed using the exCELLigence system. Differential gene arrays and RT-qPCR were used to assess gene expression levels. Western blotting was used to assess protein expression and phosphorylation status levels. In vitro vasculogenic mimicry (VM) was assessed with Matrigel. EGCG was found to inhibit the induction of key adipogenic biomarkers, including lipoprotein lipase, adiponectin, leptin, fatty acid synthase, and fatty acid binding protein 4. Increased TNBC-derived MDA-MB-231 cell chemotaxis and vasculogenic mimicry were observed in response to mature adipocytes secretome, and this was correlated with increased STAT3 phosphorylation status. This invasive phenotype was prevented by EGCG, the JAK/STAT inhibitors Tofacitinib and AG490, as well as upon STAT3 gene silencing. In conclusion, dietary catechin-mediated interventions could, in part through the inhibition of adipogenesis and modulation of adipocytes secretome profile, prevent the onset of an obesogenic environment that favors TNBC development.

Role of Flavonoids in The Interactions among Obesity, Inflammation, and Autophagy

Nowadays, obesity is considered as one of the main concerns for public health worldwide, since it encompasses up to 39% of overweight and 13% obese (WHO) adults. It develops because of the imbalance in the energy intake/expenditure ratio, which leads to excess nutrients and results in dysfunction of adipose tissue. The hypertrophy of adipocytes and the nutrients excess trigger the induction of inflammatory signaling through various pathways, among others, an increase in the expression of pro-inflammatory adipocytokines, and stress of the endoplasmic reticulum (ER). A better understanding of obesity and preventing its complications are beneficial for obese patients on two facets: treating obesity, and treating and preventing the pathologies associated with it. Hitherto, therapeutic itineraries in most cases are based on lifestyle modifications, bariatric surgery, and pharmacotherapy despite none of them have achieved optimal results. Therefore, diet can play an important role in the prevention of adiposity, as well as the associated disorders. Recent results have shown that flavonoids intake have an essential role in protecting against oxidative damage phenomena, and presents biochemical and pharmacological functions beneficial to human health. This review summarizes the current knowledge of the anti-inflammatory actions and autophagic flux of natural flavonoids, and their molecular mechanisms for preventing and/or treating obesity.

Phytochemical Targeting of STAT3 Orchestrated Lipid Metabolism in Therapy-Resistant Cancers

Lipids are critical for maintaining homeostasis and cellular metabolism. However, the dysregulation of lipid metabolism contributes to the pathogenesis of chronic inflammatory diseases and is a hallmark of several cancer types. Tumours exist in a microenvironment of poor vascularization-depleted oxygen and restricted nutrients. Under these conditions, tumours have been shown to increasingly depend on the metabolism of fatty acids for sustained proliferation and survival. Signal transducer and activator of transcription 3 (STAT3) plays a key role in cellular processes such as cell growth, apoptosis and lipid metabolism. Aberrant STAT3 activity, as seen in several cancer types, is associated with tumour progression and malignancy, in addition to propagating crosstalk between tumour cells and the microenvironment. Furthermore, STAT3-regulated lipid metabolism is critical for cancer stem cell self-renewal and therapy resistance. Plant-derived compounds known as phytochemicals are a potential source for novel cancer therapeutic drugs. Dietary phytochemicals are known to modulate key cellular signalling pathways involved in lipid homeostasis and metabolism, including the STAT3 signalling pathways. Targeting STAT3 orchestrated lipid metabolism has shown therapeutic promise in human cancer models. In this review, we summarize the antitumour activity of phytochemicals with an emphasis placed on their effect on STAT3-regulated lipid metabolism and their role in abrogating therapy resistance.

Anacardic acid mitigates liver fat accumulation and impaired glucose tolerance in mice fed a high-fat and high-sucrose diet

In this study, we evaluated the effects of anacardic acid (AA), a phenolic lipid found in cashew nuts (Anacardium occidentale), on metabolic disorders related to obesity, fatty liver disease, and diabetes using both in vitro and in vivo models. The application of AA led to a reduction in lipid accumulation in 3T3-L1 cells without observable cytotoxicity. Results from Western blot analysis revealed that AA treatment also led to decreased expression of fatty acid synthase and peroxisome proliferator-activated receptor gamma. In vivo studies were performed to evaluate the effects of AA treatment on fatty liver disease and diabetes. Mice fed a high-fat and high-sucrose diet had significantly higher body and liver weights, and higher levels of liver fat, cholesterol, fasting glucose, and homeostasis model assessment of insulin resistance (HOMA-IR). However, 12 weeks of oral treatment with 500 μg/kg BW AA slowed down lipid accumulation rates in the liver and mitigated insulin resistance in these mice. Thus, AA may reduce lipid levels and have an antidiabetic effect.

Antioxidant and Anti-Obesity Activities of Polygonum cuspidatum Extract through Alleviation of Lipid Accumulation on 3T3-L1 Adipocytes

Natural products are widely used due to their various biological activities which include antiinflammatory, antioxidant, and anti-obesity effects. In this study, we determined the antioxidative and anti-obesity effects of Polygonum cuspidatum 50% ethanol extract (PEE). The antioxidative effect of PEE was evaluated using its radical scavenging activity, total phenolic content, and reducing power. The anti-obesity effect of PEE was investigated using 3T3-L1 adipocytes. The antioxidative activity of PEE was progressively increased in various concentrations, mainly due to the presence of phenolic compounds. PEE also alleviated lipid accumulation on 3T3-L1 adipocytes and downregulated the mRNA and protein production of adipogenesis-related (SREBP-1c, PPARγ, C/EBPα) and lipogenesis-related (aP2, FAS, ACC) markers. Furthermore, we found that the inhibitory effect on lipid accumulation via PEE was caused by the alleviation of NF-κB, p38 MAPK, ERK1/2, and JNK at the protein level. Taken together, our results imply that PEE is a potential antioxidant that can prevent obesityassociated disorders.

Green tea polyphenols decrease weight gain, ameliorate alteration of gut microbiota, and mitigate intestinal inflammation in canines with high-fat-diet-induced obesity

Green tea polyphenols (GTPs) exhibit beneficial effects towards obesity and intestinal inflammation; however, the mechanisms and association with gut microbiota are unclear. We examined the role of the gut microbiota of GTPs treatment for obesity and inflammation. Canines were fed either a normal diet or high-fat diet with low (0.48% g/kg), medium (0.96% g/kg), or high (1.92% g/kg), doses of GTPs for 18 weeks. GTPs decreased the relative abundance of Bacteroidetes and Fusobacteria and increased the relative abundance of Firmicutes as revealed by 16S rRNA gene sequencing analysis. The relative proportion of Acidaminococcus, Anaerobiospirillum, Anaerovibrio, Bacteroides, Blautia, Catenibactetium, Citrobacter, Clostridium, Collinsella, and Escherichia were significantly associated with GTPs-induced weight loss. GTPs significantly (P<.01) decreased expression levels of inflammatory cytokines, including TNF-α, IL-6, and IL-1β, and inhibited induction of the TLR4 signaling pathway compared with high-fat diet. We show that the therapeutic effects of GTPs correspond with changes in gut microbiota and intestinal inflammation, which may be related to the anti-inflammatory and anti-obesity mechanisms of GTPs.

Epigallocatechin Exerts Anti-Obesity Effect in Brown Adipose Tissue

Catechins in green tea are well-known to be effective in reducing the risk of obesity. The purpose of this study was to elucidate the effects of catechins present in green tea on adipocyte differentiation and mature adipocyte metabolism. Treatment of 3T3-L1 mouse adipocyte during differentiation adipocytes with (-)-epigallocatechin (EGC) and gallic acid (GA) resulted in dose-dependent inhibition of adipogenesis. Specifically, EGC increased adiponectin and uncoupling protein 1 (UCP1) transcription in mature adipocytes. Transcription levels of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) were not significantly impacted by either of the compounds. These results suggest that the EGC is the most effective catechin having anti-obesity activity. Finally, EGC is an attractive candidate component for remodeling obesity.

The modulatory effect and the mechanism of flavonoids on obesity

With the improvement of living standards, obesity has become a serious health problem all over the word. Currently, the methods and drugs for obesity treatment have some limitations and side effects. Flavonoids are active constituents with various biological activities, widely found in plants, and numerous studies have shown that flavonoids can inhibit obesity and related metabolism disorders effectively. This perspective reviews the recent progress in understanding the anti-obesity effects of flavonoids through modulating food intake, enzyme activities, nutrition absorption, adipogenesis and adipocyte lifecycle, thermogenesis, energy consumption, and intestinal microbiota. PRACTICAL APPLICATIONS: Natural bioactive substance flavonoids have anti-obesity property, which may play a role in anti-obesity drugs or functional food without any side effects. Flavonoids can inhibit weight gain directly or through their biologically active metabolites by various potential pathways. A better understanding of the modulatory effect and the mechanism of flavonoids on obesity will allow us to better utilize flavonoids in plants to treat obesity and related metabolic syndrome.

Does tea extract supplementation benefit metabolic syndrome and obesity? A systematic review and meta-analysis

BACKGROUND

Given the global epidemic of obesity, numerous strategies have been employed in the management of metabolic syndrome (MS) in this population. A meta-analysis was designed in the present investigation to evaluate the benefits of tea extract (TE) supplementation in MS in obesity.

METHODS

We conducted searches of published literature in MEDLINE, PsycINFO, Scopus, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception in 1985 to May 2017. Randomized controlled trials (RCTs) which studied TE consumption in obesity with MS were analyzed. Results were summarized using weighted mean differences (WMDs), standardized mean differences (SMDs) or odds ratio (OR) by suitable effect model.

RESULTS

Sixteen eligible randomized controlled trials, including 1090 subjects were identified. Benefits were demonstrated on reduction of Body Mass Index (BMI) (SMD, -0.27; 95% CI, -0.40 to -0.15, P < 0.0001) and blood glucose (SMD, -0.22; 95% CI, -0.34 to -0.10, P = 0.0003), and increasing high-density lipoprotein (HDL) (SMD, 0.18; 95% CI, 0.01 to 0.35, P = 0.03). Limited benefits without significance were observed on blood pressure and other anthropometric, cholesterol, and biochemistry outcomes. All-cause adverse events were minimal (0.99; 95% CI: 0.55, 1.77, P = 0.97).

CONCLUSIONS

This meta-analysis suggests that consumption of TE supplementation in the obese with MS has beneficial effects on improvement of lipid and glucose metabolism, as well as in the facilitation of weight loss.

Placental extract suppresses differentiation of 3T3-L1 preadipocytes to mature adipocytes via accelerated activation of p38 MAPK during the early phase of adipogenesis

Background

Adipogenesis, the process of preadipocyte differentiation to mature adipocytes accompanied by accumulation of intracytoplasmic lipid droplets, is regulated by various genetic and environmental factors, and closely associated with the development of obesity. Numerous recent studies suggest that some bioactive peptides and proteins derived from animals, and chemical compounds isolated from plants may be useful for prevention and treatment of obesity and obesity-related chronic diseases. In the present study, we examined the broad spectrum of effects of placental extract, with a focus on the influence of placental extract on adipogenesis.

Method

We cultured 3T3-L1 cells, which are widely used as a model of white preadipocytes, under differentiation conditions in the presence of porcine placental extract (PPE) for 8 days, and then stained the lipid droplets accumulated in the cytoplasm with Oil Red O. We also analyzed the effects of PPE on the mitogen-activated protein kinases (MAPKs) signaling, mitotic clonal expansion (MCE) and gene expressions associated with 3T3-L1 differentiation.

Results

When we cultured 3T3-L1 cells with PPE under differentiation conditions, the accumulation of lipid droplets and expression of adipocyte differentiation marker genes (Cebpa, Pparg, Slc2a4, Fasn and Adipoq) were dramatically attenuated. The suppressive activity of PPE against adipogenesis was heat-stable and recovered in a low-molecular-weight fraction after ultrafiltration (< 3 kDa) and gel-filtration chromatography (fraction No. 9). We also found that the suppressive activity of PPE affected the early phase of adipocyte differentiation (Days 0–2) without influencing the expression levels of C/EBPβ and C/EBPδ. The PPE and fraction No. 9 obtained from gel-filtration chromatography both promoted mitotic clonal expansion of 3T3-L1 while accelerating p38 MAPK phosphorylation. In addition, SB203580, a p38 MAPK inhibitor, partially restored the accumulation of lipid droplets and the expression of adipocyte differentiation marker genes that were suppressed by fraction No. 9.

Conclusion

These results indicate that PPE suppresses the differentiation of preadipocytes via accelerated activation of p38 MAPK during the early phase of adipogenesis, suggesting PPE or its functional component could be a potential therapy for treating obesity.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0361-8) contains supplementary material, which is available to authorized users.

Erigeron annuus (L.) Pers. Extract Inhibits Reactive Oxygen Species (ROS) Production and Fat Accumulation in 3T3-L1 Cells by Activating an AMP-Dependent Kinase Signaling Pathway

Obesity is one of the major public health problems in the world because it is implicated in metabolic syndromes, such as type 2 diabetes, hypertension, and cardiovascular diseases. The objective of this study was to investigate whether Erigeron annuus (L.) Pers. (EAP) extract suppresses reactive oxygen species (ROS) production and fat accumulation in 3T3-L1 cells by activating an AMP-dependent kinase (AMPK) signaling pathway. Our results showed that EAP water extract significantly inhibits ROS production, adipogenesis, and lipogenesis during differentiation of 3T3-L1 preadipocytes. In addition, EAP decreased mRNA and protein levels of proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα). Moreover, EAP suppressed mRNA expressions of fatty acid synthase (FAS), lipoprotein lipase (LPL), adipocyte protein 2 (aP2) in a dose-dependent manner. Whereas, EAP upregulated adiponectin expression, phosphorylation levels of AMPK and carnitine palmitoyltransferase 1 (CPT-1) protein level during differentiation of 3T3-L1 preadipocytes. These results suggest that EAP water extract can exert ROS-linked anti-obesity effect through the mechanism that might involve inhibition of ROS production, adipogenesis and lipogenesis via an activating AMPK signaling pathway.

Quercetin and Epigallocatechin Gallate in the Prevention and Treatment of Obesity: From Molecular to Clinical Studies

Obesity is a worldwide epidemic, which is characterized by the excess accumulation of adipose tissue and to an extent that impairs both the physical and psychosocial health and well-being. There are several weight-loss strategies available, including dietary modification, pharmacotherapy, and bariatric surgery, but many are ineffective or not a long-term solution. Bioactive compounds present in medicinal plants and plant extracts, like polyphenols, constitute the oldest and most extensive form of alternative treatments for the prevention and management of obesity. Their consumption is currently increasing in the population due to the high cost, potential adverse effects, and limited benefits of the currently available pharmaceutical drugs. A great number of studies has explored how dietary polyphenols can interfere with the different mechanisms associated with obesity development. They suggest that these compounds can decrease energy and food intake, lipogenesis, and preadipocyte differentiation and proliferation, while increasing energy expenditure, lipolysis, and fat oxidation. Both quercetin, one of the most common dietary flavonols in the western diet, and epigallocatechin gallate (EGCG), the most abundant polyphenol in green tea, exhibit antiobesity effects in adipocyte cultures and animal models. However, the extrapolation of these potential benefits to obese humans remains unclear. Although quercetin supplementation does not seem to exert any beneficial effects on body weight, this polyphenol could prevent the obesity-associated mortality by reducing cardiovascular disease risk. An important consideration for the design of further trials is the occurrence of gene polymorphisms in key enzymes involved in flavanol metabolism, which determines a subject's sensitivity to catechins and seems, therefore, crucial for the success of the antiobesity intervention. Although the evidence supporting antiobesity effects is more consistent in EGCG than with quercetin studies, they could still be beneficial by reducing the cardiovascular risk of obese subjects, rather than inducing body weight loss.

Epigallocatechin-3-gallate enhances the osteoblastogenic differentiation of human adipose-derived stem cells

Purpose

The aim of this study is to investigate the effects of epigallocatechin-3-gallate (EGCG), a major polyphenol extracted from green tea, on the osteoblastogenic differentiation of human adipose-derived stem cells (hASCs).

Patients and methods

hASCs were acquired from human adipose tissue. With informed consent, subcutaneous adipose tissue samples were harvested from periorbital fat pad resections from ten healthy female adults who underwent double eyelid surgery. hASCs were cultured in osteogenic medium with or without EGCG (1 μM, 5 μM, or 10 μM) for 14 days. We evaluated the effects of EGCG by quantifying cell growth, ALP activity (an early osteoblastogenic differentiation marker), BSP, OCN (a late osteoblastogenic differentiation marker), and extracellular matrix mineralization. We also performed Western blots to measure osteoblastogenesis-related proteins such as Runx2 and adipoblastogenesis-related transcription factors, such as STAT3, C/EBP-α, and PPAR-γ.

Results

EGCG at 5 μM resulted in significantly higher cell proliferation and ALP activity than did the control on days 3, 7, and 14. On day 7, 5 μM EGCG significantly enhanced BSP expression. On day 14, EGCG at all concentrations promoted OCN expression. In addition, EGCG at 5 μM resulted in the highest level of extracellular matrix mineralization. On day 3, the expression levels of Runx2 were significantly higher in the 5 μM EGCG group than in the other groups, whereas later, on days 7 and 14, Runx2 expression levels in the EGCG group were significantly lower than those of the control group. EGCG at all three concentrations was associated with significantly lower levels of phosphorylated STAT3, C/EBP-α, and PPAR-γ.

Conclusion

EGCG at 5 μM significantly enhanced the osteoblastogenic differentiation of hASCs.

Enhancing the Yield of Bioactive Compounds from Sclerocarya birrea Bark by Green Extraction Approaches

Sclerocarya birrea is a tree indigenous to Southern Africa with significant importance in rural livelihoods for food, medicine, and carving. The bark, which contains 10⁻20% tannin, provides several pharmacological benefits as an antidiabetic, anti-inflammatory, antimicrobial, anti-atherogenic, and antioxidant medication, among others. This study compared different extraction techniques used to recover bioactive compounds from marula bark. For this purpose, solid⁻liquid extraction, supercritical fluid extraction (SFE), and pressurized liquid extraction (PLE) were performed under selected conditions, using only "food-grade" solvents. The potential use of the proposed extraction methodologies was evaluated in term of yield, and the individual phenolic composition determined by HPLC⁻ESI⁻TOF⁻MS. PLE provided a high extraction yield in all experimental conditions. With regard to bioactive compounds composition, a total of 71 compounds, a significant percentage of which in a galloyl form, were distributed in five major categories. The largest number of compounds, mostly flavonoid aglycones, were extracted by PLE, generally when the extraction was developed at low temperatures. SFE did prove effective as a way of extracting antidiabetic proanthocyanidins. Advanced extraction techniques represent a powerful tool to obtain bioactive compounds from S. birrea bark, which can be used as supplements or food ingredients, promoting the valorization of this crop.

The effects of green tea on lipid metabolism and its potential applications for obesity and related metabolic disorders - An existing update

Obesity is one of the top global issues, which induces several serious health consequences both physically and mentally, such as type 2 diabetes, cardiovascular diseases, dyslipidemia, eating disorders, depression and stress. However, the effective therapy to prevent and treat obesity and overweight, up to now, cannot be found nowadays. Several methods/medicines namely diet control, energy balance, environmental changes, genetic and stem cell therapies, new drugs/chemicals have been extensively studied to enhance the ability to control bodyweight and prevent obesity. Of all the aforementioned methods, green tea, used as a daily beverage, has shown beneficial impacts for the health, especially its anti-obesity effects. Available evidence shows that green tea can interrupt lipid emulsification, reduce adipocyte differentiation, increase thermogenesis, and reduce food intake, thus green tea improves the systemic metabolism and decreases fat mass. Here, we highlight and sum up the update investigations of anti-obesity effect of green tea as well as discuss the potential application of them for preventing obesity and its related metabolic disorders.

Epigallocatechin gallate targets FTO and inhibits adipogenesis in an mRNA m6A-YTHDF2-dependent manner

BACKGROUND/OBJECTIVE

N⁶-methyladenosine (m⁶A) modification of mRNA plays a role in regulating adipogenesis. However, its underlying mechanism remains largely unknown. Epigallocatechin gallate (EGCG), the most abundant catechin in green tea, plays a critical role in anti-obesity and anti-adipogenesis.

METHODS

High-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HPLC-QqQ-MS/MS) was performed to determine the m⁶A levels in 3T3-L1 preadipocytes. The effects of EGCG on the m⁶A levels in specific genes were determined by methylated RNA immunoprecipitation coupled with quantitative real-time PCR (meRIP-qPCR). Several adipogenesis makers and cell cycle genes were analyzed by quantitative real-time PCR (qPCR) and western blotting. Lipid accumulation was evaluated by oil red O staining. All measurements were performed at least for three times.

RESULTS

Here we showed that EGCG inhibited adipogenesis by blocking the mitotic clonal expansion (MCE) at the early stage of adipocyte differentiation. Exposing 3T3-L1 cells to EGCG reduced the expression of fat mass and obesity-associated (FTO) protein, an m⁶A demethylase, which led to increased overall levels of RNA m⁶A methylation. Cyclin A2 (CCNA2) and cyclin dependent kinase 2 (CDK2) play vital roles in MCE. The m⁶A levels of CCNA2 and CDK2 mRNA were dramatically enhanced by EGCG. Interestingly, EGCG increased the expression of YTH N⁶-methyladenosine RNA binding protein 2 (YTHDF2), which recognized and decayed methylated mRNAs, resulting in decreased protein levels of CCNA2 and CDK2. As a result, MCE was blocked and adipogenesis was inhibited. FTO overexpression and YTHDF2 knockdown in 3T3-L1 cells significantly increased CCNA2 and CDK2 protein levels and ameliorated the EGCG-induced adipogenesis inhibition. Thus, m⁶A-dependent CCNA2 and CDK2 expressions mediated by FTO and YTHDF2 contributed to EGCG-induced adipogenesis inhibition.

CONCLUSION

Our findings provide mechanistic insights into how m⁶A is involved in the EGCG regulation of adipogenesis and shed light on its anti-obesity effect.

Glehnia littoralis Root Extract Inhibits Fat Accumulation in 3T3-L1 Cells and High-Fat Diet-Induced Obese Mice by Downregulating Adipogenic Gene Expression

Glehnia littoralis has been reported to have several pharmacological properties but no reports describing the antiadipogenic effect of this plant have been published. This study was conducted to investigate the effects of Glehnia littoralis root hot water extract (GLE) and its underlying mechanism on 3T3-L1 cell adipogenesis and in high-fat diet- (HFD-) induced obese mice. We measured intracellular lipid accumulation using oil red O staining in vitro. For in vivo study, twenty-eight C57BL/6J male mice were randomly divided into four groups, Control, HFD, HFD + 1% GLE, and HFD + 5% GLE, which was performed for eight weeks. We determined the expression levels of the adipogenesis-related proteins by RT-PCR and western blotting in HFD-induced obese mice. The GLE dose-dependently inhibited 3T3-L1 adipocyte differentiation and intracellular lipid accumulation in differentiated adipocytes. Further, body weight gain and fat accumulation were significantly lower in the GLE-treated HFD mice than in the untreated HFD mice. GLE treatment suppressed the expression of adipogenic genes such as peroxisome proliferator-activated receptor (PPAR) γ, CCAAT/enhancer-binding protein (C/EBP) α, fatty acid synthase (aP2), and fatty acid synthase (FAS). These results suggest that the GLE inhibits adipocyte differentiation and intracellular lipid accumulation by downregulating the adipogenic gene expression both in vitro and in vivo.

Differential effects of dietary flavonoids on adipogenesis

Propose

Obesity is a fast growing epidemic worldwide. During obesity, the increase in adipose tissue mass arise from two different mechanisms, namely, hyperplasia and hypertrophy. Hyperplasia which is the increase in adipocyte number is characteristic of severe obese patients. Recently, there has been much interest in targeting adipogenesis as therapeutic strategy against obesity. Flavonoids have been shown to regulate several pathways and affect a number of molecular targets during specific stages of adipocyte development.

Methods

Presently, we provide a review of key studies evaluating the effects of dietary flavonoids in different stages of adipocyte development with a particular emphasis on the investigations that explore the underlying mechanisms of action of these compounds in human or animal cell lines as well as animal models.

Results

Flavonoids have been shown to regulate several pathways and affect a number of molecular targets during specific stages of adipocyte development. Although most of the studies reveal anti-adipogenic effect of flavonoids, some flavonoids demonstrated proadipogenic effect in mesenchymal stem cells or preadipocytes.

Conclusion

The anti-adipogenic effect of flavonoids is mainly via their effect on regulation of several pathways such as induction of apoptosis, suppression of key adipogenic transcription factors, activation of AMPK and Wnt pathways, inhibition of clonal expansion, and cell-cycle arrest.

Molecular mechanisms of the anti-obesity effect of bioactive compounds in tea and coffee

Obesity is a serious health problem in adults and children worldwide. However, the basic strategies for the management of obesity (diet, exercise, drugs and surgery) have limitations and side effects. Therefore, many researchers have sought to identify bioactive components in food. Tea and coffee are the most frequently consumed beverages in the whole world. Their health benefits have been studied for decades, especially those of green tea. The anti-obesity effect of tea and coffee has been studied for at least ten years. The results have shown decreased lipid accumulation in cells via the regulation of the cell cycle during adipogenesis, changes in transcription factors and lipogenesis-related proteins in the adipose tissue of animal models, and decreased body weight and visceral fat in humans. Tea and coffee also influence the gut microbiota in obese animals and humans. Although the anti-obesity mechanism of tea and coffee still needs further clarification, they may have potential as a new strategy to prevent or treat obesity.

Effects of Epigallocatechin-3-Gallate on Autophagic Lipolysis in Adipocytes

Previous studies demonstrated effects of green tea on weight loss; however, green tea-induced modulation of adipocyte function is not fully understood. Here, we investigated effects of the major green tea phytochemical, epigallocatechin-3-gallate (EGCG) on triglyceride contents, lipolysis, mitochondrial function, and autophagy, in adipocytes differentiated from C₃H₁₀T1/2 cells and immortalized pre-adipocytes in vitro. EGCG reduced the triglycerol content significantly in adipocytes by 25%, comparable to the nutrient starvation state. EGCG did not affect protein kinase A signaling or brown adipocyte marker expression in adipocytes; however, EGCG increased autophagy, as measured by autophagy flux analysis and immunoblot analysis of LC3B, ATG7, and Beclin1. EGCG treatment reduced mitochondrial membrane potential by 56.8% and intracellular ATP levels by 49.1% compared to controls. Although mammalian target of rapamycin signaling was not upregulated by EGCG treatment, EGCG treatment induced AMP-activated protein kinase phosphorylation, indicating an energy-depleted state. In addition, EGCG increased the association between RAB7 and lipid droplets, suggesting that lipophagy was activated. Finally, knockdown of Rab7 attenuated the EGCG-dependent reduction in lipid contents. Collectively, these results indicated that EGCG upregulated autophagic lipolysis in adipocytes, supporting the therapeutic potential of EGCG as a caloric restriction mimetic to prevent obesity and obesity-related metabolic diseases.

Almond Skin Polyphenol Extract Inhibits Inflammation and Promotes Lipolysis in Differentiated 3T3-L1 Adipocytes

Studies have shown that polyphenols reduce the risk of inflammation-related diseases and upregulates energy expenditure in adipose tissue. Here, we investigated the mechanism of the anti-inflammatory and antiobesity effects of almond skin polyphenol extract (ASP) in differentiated 3T3-L1 adipocytes. The antioxidant effects of ASP were measured based on DPPH radical scavenging activity, Trolox equivalent antioxidant capacity, and total phenolic content. Differentiated 3T3-L1 cells were treated with ASP. Subsequently, lipolysis proteins and transcription factors of adipogenesis were measured. The proinflammatory mediators monocyte chemotactic protein-1 (MCP-1) and chemokine ligand 5 (CCL-5) were determined by enzyme-linked immunosorbent assay. We found that ASP significantly promoted phosphorylation of AMP-activated protein kinase (AMPK), increased activity of adipose triglyceride lipase and hormone-sensitive lipase, and inhibited adipogenesis-related transcription factors. In addition, ASP inhibited the tumor necrosis factor-α (TNF-α)-induced cell inflammatory response via downregulation of MCP-1 and CCL-5 secretion. This study suggests that ASP regulates lipolysis through activation of AMPK, reduced adipogenesis, and suppresses proinflammatory cytokines in adipocytes.

Anti-obesogenic and antidiabetic effects of plants and mushrooms

Obesity is reaching global epidemic proportions as a result of factors such as high-calorie diets and lack of physical exercise. Obesity is now considered to be a medical condition, which not only contributes to the risk of developing type 2 diabetes mellitus, cardiovascular disease and cancer, but also negatively affects longevity and quality of life. To combat this epidemic, anti-obesogenic approaches are required that are safe, widely available and inexpensive. Several plants and mushrooms that are consumed in traditional Chinese medicine or as nutraceuticals contain antioxidants, fibre and other phytochemicals, and have anti-obesogenic and antidiabetic effects through the modulation of diverse cellular and physiological pathways. These effects include appetite reduction, modulation of lipid absorption and metabolism, enhancement of insulin sensitivity, thermogenesis and changes in the gut microbiota. In this Review, we describe the molecular mechanisms that underlie the anti-obesogenic and antidiabetic effects of these plants and mushrooms, and propose that combining these food items with existing anti-obesogenic approaches might help to reduce obesity and its complications.

Effect of (-)-epigallocatechin-3-gallate on anti-inflammatory response via heme oxygenase-1 induction during adipocyte-macrophage interactions

In this study, we examined the effects of (-)-epigallocatechin-3-gallate (EGCG) on anti-inflammatory responses through the induction of heme oxygenase-1 (HO-1) in cocultured macrophages and adipocytes. EGCG significantly decreased the secretion of nitric oxide (NO) and monocyte chemoattractant protein-1 in the coculture of RAW 264.7 macrophages and differentiated 3T3-L1 adipocytes. In addition, EGCG inhibited the expression of inducible nitric oxide synthase in cocultured macrophages and peroxisome proliferator-activated receptor-gamma in cocultured adipocytes. Furthermore, the HO-1 expression showed an approximately 4-fold increase in cocultured adipocytes and an approximately 6-fold increase in cocultured macrophages. Lastly, HO-1 silencing induced NO generation in cocultured cells regardless of EGCG treatment. These results indicate that EGCG inhibited inflammatory responses by suppressing the production of proinflammatory cytokines through HO-1 induction during adipocyte-macrophage interaction.

Potential of Natural Products in the Inhibition of Adipogenesis through Regulation of PPARγ Expression and/or Its Transcriptional Activity

Obesity is a global health problem characterized as an increase in the mass of adipose tissue. Adipogenesis is one of the key pathways that increases the mass of adipose tissue, by which preadipocytes mature into adipocytes through cell differentiation. Peroxisome proliferator-activated receptor γ (PPARγ), the chief regulator of adipogenesis, has been acutely investigated as a molecular target for natural products in the development of anti-obesity treatments. In this review, the regulation of PPARγ expression by natural products through inhibition of CCAAT/enhancer-binding protein β (C/EBPβ) and the farnesoid X receptor (FXR), increased expression of GATA-2 and GATA-3 and activation of the Wnt/β-catenin pathway were analyzed. Furthermore, the regulation of PPARγ transcriptional activity associated with natural products through the antagonism of PPARγ and activation of Sirtuin 1 (Sirt1) and AMP-activated protein kinase (AMPK) were discussed. Lastly, regulation of mitogen-activated protein kinase (MAPK) by natural products, which might regulate both PPARγ expression and PPARγ transcriptional activity, was summarized. Understanding the role natural products play, as well as the mechanisms behind their regulation of PPARγ activity is critical for future research into their therapeutic potential for fighting obesity.

Immobilized tannase treatment alters polyphenolic composition in teas and their potential anti-obesity and hypoglycemic activities in vitro

The aim of this work was to assess the effect of immobilized-tannase treatment on black, green, white and mate tea components and on their bioactivities relevant to obesity. Tannase treatment caused predictable changes in polyphenol composition with substantial reduction in galloylated catechins in green, white and black tea. Mate tea, which is rich in chlorogenic acids, was much less affected by tannase treatment although some degradation of caffeoyl quinic acid derivatives was noted. The original tea samples were effective in inhibiting digestive enzymes in vitro. They inhibited amylase activity, some with IC50 values ∼70 μg mL(-1), but were much less effective against α-glucosidase. They also inhibited lipase activity in vitro and caused dose-dependent reductions in lipid accumulation in cultured adipocytes. The bio-transformed tea samples generally matched the effectiveness of the original samples but in some cases they were markedly improved. In particular, tannase treatment reduced the IC50 value for amylase inhibition for green tea and white tea by 15- and 6-fold respectively. In addition, the bio-transformed samples were more effective than the original samples in preventing lipid accumulation in adipocytes. These in vitro studies indicate that bio-transformed tea polyphenols could assist in the management of obesity through improvement in energy uptake and lipid metabolism and also indicate that biotechnological modification of natural food molecules can improve the benefits of a common beverage such as tea.

Pulicaria jaubertii E. Gamal-Eldin reduces triacylglyceride content and modifies cellular antioxidant pathways in 3T3-L1 adipocytes

Levels of obesity in Middle Eastern countries are increasing. Phytochemicals have anti-obesogenic properties as evidenced by prevention of adipocyte differentiation and blocking triacylglyceride (TG) accumulation. In Yemen, Pulicaria jaubertii E. Gamal-Eldin (PJ) is a food additive and a traditional medicine. We tested the hypothesis that phytochemicals present in PJ inhibit adipocytic responses during differentiation of 3T3-L1 preadipocytes to adipocytes. Methanolic extracts of PJ did not block expression of fatty acid binding protein 4 (FABP4) a marker of differentiation but did inhibit TG accumulation. Treatment of 3T3-L1 preadipocytes increased NADPH:quinone oxidoreductase 1 (NQO1), a suppressor of TG accumulation. Further fractionation of the methanolic PJ extract with hexane and dichloromethane (DCM) demonstrated that bioactivity towards TG reduction and elevated expression of NQO1 and other antioxidant genes (glutamate cysteine ligase catalytic unit, glutathione disulfide reductase, glutathione peroxidase (GPx) 4 resided in the DCM fraction. Activity towards depleting GSH and elevating the expression of catalase and GPx3 were found in the DCM and hexane fractions. Analysis by gas chromatography and liquid chromatography coupled with mass spectrometry demonstrated the presence of catechin-like moieties in the DCM and methanolic fractions and suggest that these components were partially responsible for the bioactivity of these fractions. In summary, our data indicate that fractions derived PJ exhibit anti-adipogenic properties in part through the presence of catechin-like compounds.

Molecular Regulation of Adipogenesis and Potential Anti-Adipogenic Bioactive Molecules

Adipogenesis is the process by which precursor stem cells differentiate into lipid laden adipocytes. Adipogenesis is regulated by a complex and highly orchestrated gene expression program. In mammalian cells, the peroxisome proliferator-activated receptor γ (PPARγ), and the CCAAT/enhancer binding proteins (C/EBPs) such as C/EBPα, β and δ are considered the key early regulators of adipogenesis, while fatty acid binding protein 4 (FABP4), adiponectin, and fatty acid synthase (FAS) are responsible for the formation of mature adipocytes. Excess accumulation of lipids in the adipose tissue leads to obesity, which is associated with cardiovascular diseases, type II diabetes and other pathologies. Thus, investigating adipose tissue development and the underlying molecular mechanisms is vital to develop therapeutic agents capable of curbing the increasing incidence of obesity and related pathologies. In this review, we address the process of adipogenic differentiation, key transcription factors and proteins involved, adipogenic regulators and potential anti-adipogenic bioactive molecules.