Green tea extract increases adiponectin and PPARα levels to improve hepatic steatosis

Coffee peel polyphenols ameliorate nonalcoholic fatty liver disease by modulating cannabinoid receptor type-1-ceramide axis

Cannabinoid receptor type-1 (CB1) signaling plays an important part in maintenance of energy homeostasis, and CB1 blockers have shown promise in the treatment of obesity-related metabolic dysfunction. Coffee peel contains abundant phytochemicals and possesses hypolipidemic and anti-inflammatory activities. The present study aimed to elucidate the preventive effect of coffee peel polyphenols (CPPs) on nonalcoholic fatty liver disease (NAFLD) from the perspective of CB1 signaling. Male C57BL/6J mice were fed a high-fat and high-cholesterol diet and CPPs (200/400 mg/kg/day) for 8 weeks. Serum biochemical indexes and liver pathological analysis were used to evaluate the effect of CPPs on NAFLD. Untargeted/targeted lipidomics analyses were used to evaluate the levels of endocannabinoid ligands and ceramides in serum and liver. The expression levels of proteins were detected by using Western blotting analysis. Administration of CPPs significantly improved hepatic steatosis, insulin resistance and biomarkers of liver function. Meanwhile, CPPs administration indicated reductions in endocannabinoid ligands, including anandamide and 2-arachidonoylglycerol levels, associated with blockade of CB1 overexpression. Blockage of CB1 signaling depleted hepatic C16:0- and C18:0-ceramide concentrations by enhancing ceramide metabolism. The reductions in hepatic ceramide concentrations contributed to down-regulating sterol regulatory element-binding protein-1c and up-regulating proliferator activated receptor alpha, leading to decrease de novo lipogenesis and increase fatty acid β-oxidation in the liver, respectively. This study demonstrated a novel mechanism that CPPs could ameliorate NAFLD through modulating CB1-ceramide axis.

Structure characterization of Grifola frondosa polysaccharide and its effect on insulin resistance in HFD-fed mice

Polysaccharide extracted from Grifola frondosa (GFP) was selected in this study. After preliminary separation, four factions were collected, named GFP-F1, GFP-F2, GFP-F3 and GFP-F4. GPF-F2 was further separated into two fractions, namely GFP-N1 and GFP-N2. The molecular weight of GFP-N1 and GFP-N2 was 3.323×103 kDa and 10.8 kDa, respectively. GFP-N1 was composed of glucose and galactose and 1 → 3, 1 → 4, and 1 → 6 glycosidic bonds. GFP-N2 was composed of glucose, galactose and mannose and 1 → 2, 1 → 3, 1 → 4, and 1 → 6 glycosidic bonds. GFP could significantly relieve the insulin resistance induced by HFD. GFP significantly alleviated gut microbiota disturbance caused by HFD and increased the production of short-chain fatty acids, and further reduced the expression of LPS/TLR4 inflammatory pathway. GFP significantly reduced the oxidative stress induced by HFD, increased the expression of the Nrf2/ARE signaling pathway. These results indicated that GFP could be developed as a potential ingredient for the management of insulin resistance.

Chemical Characterization and Differential Lipid-Modulating Effects of Selected Plant Extracts from Côa Valley (Portugal) in a Cell Model for Liver Steatosis

BACKGROUND/OBJECTIVES

Côa Valley, located in the northeast of Portugal, harbors more than 500 medicinal plant species. Among them, four species stand out due to their traditional uses: Equisetum ramosissimum Desf. (hemorrhages, urethritis, hepatitis), Rumex scutatus L. subsp. induratus (Boiss. and Reut.) Malag. (inflammation, constipation), Geranium purpureum Vill., and Geranium lucidum L. (pain relief, gastric issues). Given their rich ethnomedicinal history, we evaluated their protective effects on an in vitro model of metabolic dysfunction-associated steatotic liver disease (MASLD).

METHODS

Decoction (D) and hydroalcoholic (EtOH80%) extracts were prepared and chemically characterized. Their safety profile and effects on lipid accumulation were assessed in palmitic acid (PA)-treated HepG2 cells using resazurin, sulforhodamine B, and Nile Red assays.

RESULTS

Chemical analysis revealed diverse phenolic compounds, particularly kaempferol derivatives in E. ramosissimum. All extracts showed minimal cytotoxicity at 25-50 µg/mL. At 100 µg/mL, only E. ramosissimum extracts maintained high cell viability. In the lipotoxicity model, E. ramosissimum decoction demonstrated the most potent effect, significantly reducing PA-induced neutral lipid accumulation in a dose-dependent manner, while other extracts showed varying degrees of activity.

CONCLUSIONS

These findings highlight E. ramosissimum's decoction, rich in kaempferol derivatives, as particularly effective in reducing lipid accumulation in this MASLD cell model while also providing a comprehensive characterization of traditionally used plants from the Côa Valley region.

Valorizing Agro‐Food Waste for Nutraceutical Development: Sustainable Approaches for Managing Metabolic Dysfunction‐Associated Steatotic Liver Disease and Related Co‐Morbidities

This comprehensive investigation delves into the interconnectedness of different features of cardiometabolic syndrome, such as metabolic dysfunction‐associated steatotic liver disease (MASLD), atherosclerotic cardiovascular disease (ASCVD), and gut dysbiosis, highlighting the crucial role of nutraceuticals in their management and prevention. Given the significant overlap in the pathophysiology of these conditions, the treatment with nutraceuticals, especially those derived from agro‐food waste, offers a promising, sustainable, and innovative approach to healthcare. The 2030 Agenda for Sustainable Development and the One Health concept are key frameworks for selecting the most interesting supply chain for the production of nutraceuticals from agro‐food waste, ensuring environmental sustainability, and innovative agricultural practices. In this review, the therapeutic potential of kiwifruit and apples has been explored, detailing how their bioactive compounds, like polyphenols, fiber, pectin, kaempferol, phloretin, and phlorizin, may contribute to the management of MASLD, ASCVD, and gut dysbiosis. Various extraction methods for active ingredients, including chemical, water, and enzyme extractions, are analyzed for their respective benefits and drawbacks. By integrating scientific research, sustainable agricultural practices, and innovative extraction methods, we can develop effective strategies to combat these pervasive health issues. This holistic approach not only enhances individual health outcomes but also supports broader environmental and societal goals, promoting a healthier future for all.

Compound oolong tea ameliorates lipid accumulation through AMPK-PPAR pathway of hepatic lipid metabolism and modulates gut microbiota in HFD induced mice

Based on the modified traditional Chinese formula, Compound Oolong tea (WLT) is composed of six herbal medicines which have beneficial effects. The present study aimed to assess the effects of WLT on lipid metabolism and gut microbiota in the mouse obesity model.Totally 32 mice were randomized into 4 groups including normal control (NC), high-fat diet model (HFD), positive control (PC) receiving atorvastatin 10 mg/kg/d, and WLT group with WLT water extra 300 mg/kg/d. The HFD, PC, WLT groups were fed a High-fat Diet. The results show that body weight, Lee's index, liver index and fat index were reduced in WLT. Moreover, the accumulation of TC, TG, and LDL-C were lower, and the level of serum HDL-C in WLT was higher than HFD. The activities of ALT and AST were reduced, and the glucose tolerance was improved in WLT. Furthermore, the relative gene expression of hepatic such as Pparγ, Lxr, Srebp-1c, Srebp-2, Scd-1, Acc-1, Fas were upregulated, and Hmgcr was downregulated in WLT compared to HFD. The relative protein expression of PPARγ, SREBP-1, FAS, and SCD-1 were decreased, and p-AMPK/AMPK and p-ACC-1/ACC-1 were increased in WLT compared with HFD. In addition, the diversity of gut microbiota was increased in mice, with an increase in Bacteroidota and a decrease in Firmicutes and Desulfovibrionales were decreased in WLT, compared with HFD. Briefly, WLT improves hepatic lipid metabolism through the AMPK-PPAR pathway and regulates the gut microbiome. These findings suggest that WLT could potentially be used as a functional food ingredients for preventing obesity.

Metabolic-Associated Fatty Liver Disease: The Influence of Oxidative Stress, Inflammation, Mitochondrial Dysfunctions, and the Role of Polyphenols

Metabolic-Associated Fatty Liver Disease (MAFLD) is a clinical-pathological scenario that occurs due to the accumulation of triglycerides in hepatocytes which is considered a significant cause of liver conditions and contributes to an increased risk of death worldwide. Even though the possible causes of MAFLD can involve the interaction of genetics, hormones, and nutrition, lifestyle (diet and sedentary lifestyle) is the most influential factor in developing this condition. Polyphenols comprise many natural chemical compounds that can be helpful in managing metabolic diseases. Therefore, the aim of this review was to investigate the impact of oxidative stress, inflammation, mitochondrial dysfunction, and the role of polyphenols in managing MAFLD. Some polyphenols can reverse part of the liver damage related to inflammation, oxidative stress, or mitochondrial dysfunction, and among them are anthocyanin, baicalin, catechin, curcumin, chlorogenic acid, didymin, epigallocatechin-3-gallate, luteolin, mangiferin, puerarin, punicalagin, resveratrol, and silymarin. These compounds have actions in reducing plasma liver enzymes, body mass index, waist circumference, adipose visceral indices, lipids, glycated hemoglobin, insulin resistance, and the HOMA index. They also reduce nuclear factor-KB (NF-KB), interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), blood pressure, liver fat content, steatosis index, and fibrosis. On the other hand, they can improve HDL-c, adiponectin levels, and fibrogenesis markers. These results show that polyphenols are promising in the prevention and treatment of MAFLD.

Team players in the pathogenesis of metabolic dysfunctions-associated steatotic liver disease: The basis of development of pharmacotherapy

Nutrient metabolism is regulated by several factors. Social determinants of health with or without genetics are the primary regulator of metabolism, and an unhealthy lifestyle affects all modulators and mediators, leading to the adaptation and finally to the exhaustion of cellular functions. Hepatic steatosis is defined by presence of fat in more than 5% of hepatocytes. In hepatocytes, fat is stored as triglycerides in lipid droplet. Hepatic steatosis results from a combination of multiple intracellular processes. In a healthy individual nutrient metabolism is regulated at several steps. It ranges from the selection of nutrients in a grocery store to the last step of consumption of ATP as an energy or as a building block of a cell as structural component. Several hormones, peptides, and genes have been described that participate in nutrient metabolism. Several enzymes participate in each nutrient metabolism as described above from ingestion to generation of ATP. As of now several publications have revealed very intricate regulation of nutrient metabolism, where most of the regulatory factors are tied to each other bidirectionally, making it difficult to comprehend chronological sequence of events. Insulin hormone is the primary regulator of all nutrients' metabolism both in prandial and fasting states. Insulin exerts its effects directly and indirectly on enzymes involved in the three main cellular function processes; metabolic, inflammation and repair, and cell growth and regeneration. Final regulators that control the enzymatic functions through stimulation or suppression of a cell are nuclear receptors in especially farnesoid X receptor and peroxisome proliferator-activated receptor/RXR ligands, adiponectin, leptin, and adiponutrin. Insulin hormone has direct effect on these final modulators. Whereas blood glucose level, serum lipids, incretin hormones, bile acids in conjunction with microbiota are intermediary modulators which are controlled by lifestyle. The purpose of this review is to overview the key players in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) that help us understand the disease natural course, risk stratification, role of lifestyle and pharmacotherapy in each individual patient with MASLD to achieve personalized care and target the practice of precision medicine. PubMed and Google Scholar databases were used to identify publication related to metabolism of carbohydrate and fat in states of health and disease states; MASLD, cardiovascular disease and cancer. More than 1000 publications including original research and review papers were reviewed.

Quinoa Peptides Alleviate Obesity in Mice Induced by a High-Fat Diet via Regulating of the PPAR-α/γ Signaling Pathway and Gut Microbiota

SCOPE

The obesity epidemic continues to be a major global public health threat with limited effective treatments. Peptides are a group of promising bioactive molecules. Both in vivo and in vitro studies have demonstrated that quinoa has potential prebiotic benefits. Thus, the present study aims to investigate the influence of quinoa peptides (QP) consumption on obesity and its underlying mechanisms in high-fat diet (HFD)-induced mice.

METHODS AND RESULTS

QP (1000 mg kg-1  day-1 ) is administered to HFD mice for 8 weeks, and is found to significantly reduce the body weight, and plasma levels of triacylglycerol (TG) and total cholesterol (TC) compare to the HFD group. In addition, QP significantly decreases lipid accumulation in the liver caused by HFD. The liver transcriptome analysis shows that the alleviation of QP on obesity is related to the PPAR signaling pathway. QP upregulates the expressions of PPAR-α and its related genes and downregulates the expressions of PPAR-γ and its downstream genes. Furthermore, QP remodels the community composition of gut microbiota by lowering the ratio of Firmicutes c Bacteroidetes (F/B).

CONCLUSION

These findings suggest that QP consumption alleviates HFD-induced obesity by regulating the PPAR-α/γ signaling pathway in the liver and community structure of gut microbiota.

Dityrosine Aggravates Hepatic Insulin Resistance in Obese Mice by Altering Gut Microbiota and the LPS/TLR4/NF-κB Inflammatory Pathway

SCOPE

Dityrosine is the main product of protein oxidation, which has been proved to be a threat to human health. This study aims to investigate whether dityrosine exacerbates insulin resistance by inducing gut flora disturbance and associated inflammatory responses.

METHODS AND RESULTS

Mice fed with normal diet or high-fat diet (HFD) received daily gavage of dityrosine (320 µg kg-1 BW) or saline for consecutive 13 weeks. The effects of dityrosine on gut microbiota are verified by in vitro fermentation using fecal microbiota from db/m mice and db/db mice. As a result, dityrosine causes the insulin resistance in mice fed normal diet, and aggravates the effects of HFD on insulin sensitivity. Dityrosine increases the levels of lipopolysaccharide (LPS), lipopolysaccharide-binding protein (LBP), toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) but decreases levels of interleukin-10 (IL-10) in the plasma of CON and HFD-fed mice. The changes of gut flora composition caused by dityrosine are significantly correlated with the changes of inflammatory biomarkers.

CONCLUSION

The effects of dityrosine on insulin resistance may be attributed to the reshaping of the gut microbiota composition and promoting the activity of the LPS/TLR4/NF-κB inflammatory pathway in HFD-induced obese individuals.

Astaxanthin reduces fat storage in a fat-6/fat-7 dependent manner determined using high fat Caenorhabditis elegans

Although astaxanthin has been shown to have high potential for weight loss, the specific action site and signal pathway generally cannot be confirmed in other animal models. This prevents us from finding therapeutic targets. Hence, we further illuminated its efficacy and specific action sites by using Caenorhabditis elegans (C. elegans). In this study, 60 μM astaxanthin supplementation reduced overall fat deposition and triglyceride levels by 21.47% and 22.00% (p < 0.01). The content of large lipid droplets was reversed after astaxanthin treatment, and the ratio of oleic acid/stearic acid (C18:1Δ9/C18:0) decreased significantly, which were essential substrates for triglyceride biosynthesis. In addition, astaxanthin prevented obesity caused by excessive energy accumulation and insufficient energy consumption. Furthermore, the above effects were induced by sbp-1/mdt-15 and insulin/insulin-like growth factor pathways, and finally co-regulated the specific site-fat-6 and fat-7 down-regulation. These results provided insight into therapeutic targets for future astaxanthin as a nutritional health product to relieve obesity.

Dietary regulation of peroxisome proliferator-activated receptors in metabolic syndrome

BACKGROUND

Peroxisome proliferator-activated receptors (PPARs) are a class of ligand-activated nuclear transcription factors, members of the type nuclear receptor superfamily, with three subtypes, namely PPARα, PPARβ/δ, and PPARγ, which play a key role in the metabolic syndrome. In the past decades, a large number of studies have shown that natural products can act by regulating metabolic pathways mediated by PPARs.

PURPOSE

This work summarizes the physiological importance and clinical significance of PPARs and reviews the experimental evidence that natural products mediate metabolic syndrome via PPARs.

METHODS

This study reviews relevant literature on clinical trials, epidemiology, animals, and cell cultures published in NCBI PubMed, Scopus, Web of Science, Google Scholar, and other databases from 2001 to October 2022. Search keywords were "natural product" OR "botanical" OR "phytochemical" AND "PPAR" as well as free text words.

RESULTS

The modulatory involvement of PPARs in the metabolic syndrome has been supported by prior research. It has been observed that many natural products can treat metabolic syndrome by altering PPARs. The majority of currently described natural compounds are mild PPAR-selective agonists with therapeutic effects that are equivalent to synthetic medicines but less harmful adverse effects.

CONCLUSION

PPAR agonists can be combined with natural products to treat and prevent metabolic syndrome. Further human investigations are required because it is unknown how natural products cause harm and how they might have negative impacts.

Natural Polyphenols-Resveratrol, Quercetin, Magnolol, and β-Catechin-Block Certain Aspects of Heroin Addiction and Modulate Striatal IL-6 and TNF-α

We have examined the effects of four different polyphenols in attenuating heroin addiction using a conditioned place preference (CPP) paradigm. Adult male Sprague Dawley rats received heroin (alternating with saline) in escalating doses starting from 10 mg/kg, i.p. up to 80 mg/kg/d for 14 consecutive days. The rats were treated with distilled water (1 mL), quercetin (50 mg/kg/d), β-catechin (100 mg/kg/d), resveratrol (30 mg/kg/d), or magnolol (50 mg/kg/d) through oral gavage for 7 consecutive days, 30 min before heroin administration, starting on day 8. Heroin withdrawal manifestations were assessed 24 h post last heroin administration following the administration of naloxone (1 mg/kg i.p). Heroin CPP reinstatement was tested following a single dose of heroin (10 mg/kg i.p.) administration. Striatal interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) were quantified (ELISA) after naloxone-precipitated heroin withdrawal. Compared to the vehicle, the heroin-administered rats spent significantly more time in the heroin-paired chamber (p < 0.0001). Concomitant administration of resveratrol and quercetin prevented the acquisition of heroin CPP, while resveratrol, quercetin, and magnolol blocked heroin-triggered reinstatement. Magnolol, quercetin, and β-catechin blocked naloxone-precipitated heroin withdrawal and increased striatal IL-6 concentration (p < 0.01). Resveratrol administration was associated with significantly higher withdrawal scores compared to those of the control animals (p < 0.0001). The results of this study show that different polyphenols target specific behavioral domains of heroin addiction in a CPP model and modulate the increase in striatal inflammatory cytokines TNF-α and IL-6 observed during naloxone-precipitated heroin withdrawal. Further research is needed to study the clinical utility of polyphenols and to investigate the intriguing finding that resveratrol enhances, rather than attenuates naloxone-precipitated heroin withdrawal.

Catechins: Protective mechanism of antioxidant stress in atherosclerosis

Tea has long been valued for its health benefits, especially its potential to prevent and treat atherosclerosis (AS). Abnormal lipid metabolism and oxidative stress are major factors that contribute to the development of AS. Tea, which originated in China, is believed to help prevent AS. Research has shown that tea is rich in catechins, which is considered a potential source of natural antioxidants. Catechins are the most abundant antioxidants in green tea, and are considered to be the main compound responsible for tea's antioxidant activity. The antioxidant properties of catechins are largely dependent on the structure of molecules, and the number and location of hydroxyl groups or their substituents. As an exogenous antioxidant, catechins can effectively eliminate lipid peroxidation products. They can also play an antioxidant role indirectly by activating the endogenous antioxidant system by regulating enzyme activity and signaling pathways. In this review, we summarized the preventive effect of catechin in AS, and emphasized that improving the antioxidant effect and lipid metabolism disorders of catechins is the key to managing AS.

Obesity-related kidney disease: Beyond hypertension and insulin-resistance

Chronic kidney disease (CKD) causes considerable morbidity, mortality, and health expenditures worldwide. Obesity is a significant risk factor for CKD development, partially explained by the high prevalence of diabetes mellitus and hypertension in obese patients. However, adipocytes also possess potent endocrine functions, secreting a myriad of cytokines and adipokines that contribute to insulin resistance and induce a chronic low-grade inflammatory state thereby damaging the kidney. CKD development itself is associated with various metabolic alterations that exacerbate adipose tissue dysfunction and insulin resistance. This adipose-renal axis is a major focus of current research, given the rising incidence of CKD and obesity. Cellular senescence is a biologic hallmark of aging, and age is another significant risk factor for obesity and CKD. An elevated senescent cell burden in adipose tissue predicts renal dysfunction in animal models, and senotherapies may alleviate these phenotypes. In this review, we discuss the direct mechanisms by which adipose tissue contributes to CKD development, emphasizing the potential clinical importance of such pathways in augmenting the care of CKD.