Acerola polysaccharides ameliorate high-fat diet-induced non-alcoholic fatty liver disease through reduction of lipogenesis and improvement of mitochondrial functions in mice

Targeting regulation of lipid metabolism with polysaccharide of traditional Chinese medicine for the treatment of non-alcoholic fatty liver disease: A review

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common chronic diseases in the world, and the effective treatment of NAFLD has been listed as a key problem to be solved urgently in contemporary medicine. Polysaccharides in traditional Chinese medicine (TCM) have a wide range of pharmacological activities. A large number of preclinical studies have confirmed that TCM polysaccharides can interfere with the occurrence and development of NAFLD at multiple interrelated levels, such as improving lipid metabolism and insulin resistance, regulating oxidative stress, alleviating immune inflammatory response, and regulating intestinal microbiota, thus showing great potential as a new anti-NAFLD drug. This paper summarizes the prevention and treatment effect and mechanism of TCM polysaccharides on NAFLD, which provides a basis for the application of TCM polysaccharides in plant medicine and modern medicines, and provides a reference for promoting the development and utilization of TCM polysaccharide resources and the research and development of new drugs for NAFLD.

Polysaccharides from Lanzhou Lily Attenuate Nonalcoholic Fatty Liver Disease Modifying the Gut Microbiota and Metabolite Profile

Nonalcoholic fatty liver disease (NAFLD) is closely related to gut microbiota due to the hepatic portal system, and utilizing natural polysaccharides as prebiotics has become a prospective strategy for treating NAFLD. However, the therapeutic effects and potential molecular mechanisms of Lanzhou Lily polysaccharides (LLP) on NAFLD remains unclear. Therefore, the alleviating effects of LLP on NAFLD induced by high-fat diet (HFD) were investigated. LLP treatment greatly ameliorated NAFLD by significantly reducing lipid accumulation and the levels of liver function markers in HFD-induced NAFLD mice, as evidenced by decreased serum levels of TG, TC, HDL-C and LDL-C. Furthermore, LLP administration reduced hepatic steatosis, as shown by H&E and Oil red O staining. LLP also inhibited the TNF-α and IL-1β expression, thereby reducing levels of hepatic proinflammatory cytokines. Furthermore, LLP restored gut microbiota dysbiosis (up-regulated Bacteroidota, Proteobacteria, Alistipes and Lachnospiraceae abundances, down-regulated Firmicutes, Verrucomicrobiota, Desulfobacterota and Turicibacter abundances), and regulated microbial metabolic pathways such as primary bile acid biosynthesis and amino acid metabolism. In addition, the resultes of Spearman's correlation analysis found that some key metabolites in these metabolic pathways were associated with intestinal microorganisms such as Desulfobacterota, Prevotellaceae-UCG-001, Colidextribacter and Alistipes. Therefore, our study suggests that LLP may has potential applications in the treatment of NAFLD by regulating gut microbiota and its metabolite profile.

Investigation of Active Components of Meconopsis integrifolia (Maxim.) Franch in Mitigating Non-Alcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) has rapidly emerged as the most prevalent chronic liver disease globally, representing a significant and escalating public health challenge. Meconopsis integrifolia (Maxim.) Franch, a traditional Tibetan medicinal herb used for treating hepatitis, remains largely unexplored regarding its therapeutic potential and active components in combating NAFLD. This study first evaluated the in vitro lipid accumulation inhibitory activity of different extraction fractions of M. integrifolia using a HepG2 cell steatosis model. The ethyl acetate fraction was found to significantly reduce triglyceride (TG) and low-density lipoprotein (LDL) levels, inhibit lipid droplet deposition in HepG2 cells, and promote lipid metabolism balance through modulation of the AMPK/SREPB-1c/PPAR-α signaling pathway. Further analysis utilizing chromatographic techniques and nuclear magnetic resonance spectroscopy (NMR) led to the isolation of 13 compounds from the active ethyl acetate fraction. Notably, compounds 6, 9, 10, 11, 12, and 13 were identified for the first time from this Tibetan herb. In vitro activity assays and molecular docking analyses further confirmed that the compounds Luteolin (1), Quercetin 3-O-[2‴, 6‴-O-diacetyl-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside] (6), and Quercetin 3-O-[2‴-O-acetyl-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside] (8) are potential key components responsible for the NAFLD-ameliorating effects of M. integrifolia. This study highlights the therapeutic potential of M. integrifolia in treating NAFLD and provides a foundation for its further development and application, underscoring its significance in the advanced utilization of traditional Tibetan medicine.

A Review on the Protecting Effects and Molecular Mechanisms of Berries Against a Silent Public Health Concern: Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) poses a silent threat to human health, with prevalence rising at an alarming rate. The treatment and prevention of NAFLD depend on novel approaches as no effective treatment options are currently available. Berries are unique sources of phenolic compounds that have proven roles in disease prevention and health promotion. However, a comprehensive review of the effects of different berries on NAFLD and related pathologies is lacking. Thus, the present review aims to summarize the effects of berry extracts, plant parts, and bioactive compounds from twenty-one different berries on NAFLD. The molecular mechanisms involved include the regulation of lipid homeostasis, modulation of oxidative stress and inflammation markers, and activation of different signaling pathways in different in vitro and in vivo NAFLD models. Furthermore, their modulatory effects on the gut microbiota have also been highlighted. Clinical intervention research on the benefits of berries in NAFLD is limited; nonetheless, this paper discusses clinical studies demonstrating the effects of different berries in people with NAFLD. Future research should focus on long-term clinical studies to compare the therapeutic potentials of different berries against NAFLD.

Curative role of natural PPARγ agonist in non-alcoholic fatty liver disease (NAFLD)

NAFLD is a condition that develops when the liver accumulates excess fat without alcohol consumption. This chronic liver ailment progresses along with insulin resistant and is typically not diagnosed until the patients have cirrhosis. Nuclear hormone receptor superfamily PPARs are essential for metabolism of fatty acids and glucose. In liver, lipid metabolism is regulated by nuclear receptors and PPARα, and PPARβ/δ encourages fatty acid β-oxidation. PPAR-γ, an energy-balanced receptor is a crucial regulator in NAFLD. The partial activation of PPAR-γ could lead to increased level of adiponectin and insulin sensitivity, thus improved NAFLD. Because of less side effects, natural compounds are emerged as potential therapeutic agents for NAFLD by PPARγ agonists. Although the results from preclinical studies are promising, further research is needed to determine the potential dosing and efficacy of mentioned compounds in human subjects. In this review, we summarize the effect of natural PPARγ agonist in the NAFLD.

The gut-liver axis in fatty liver disease: role played by natural products

Fatty liver disease, a condition characterized by fatty degeneration of the liver, mainly classified as non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD), has become a leading cause of cirrhosis, liver cancer and death. The gut-liver axis is the bidirectional relationship between the gut and its microbiota and its liver. The liver can communicate with the gut through the bile ducts, while the portal vein transports the products of the gut flora to the liver. The intestinal flora and its metabolites directly and indirectly regulate hepatic gene expression, leading to an imbalance in the gut-liver axis and thus contributing to the development of liver disease. Utilizing natural products for the prevention and treatment of various metabolic diseases is a prevalent practice, and it is anticipated to represent the forthcoming trend in the development of drugs for combating NAFLD/ALD. This paper discusses the mechanism of the enterohepatic axis in fatty liver, summarizes the important role of plant metabolites in natural products in fatty liver treatment by regulating the enterohepatic axis, and provides a theoretical basis for the subsequent development of new drugs and clinical research.

Acerola (Malpighia emarginata) Anti-Inflammatory Activity-A Review

The manuscript provides an overview of recent scientific reports on the properties and range of health-promoting effects of acerola (Malpighia emarginata DC) fruits and leaves. Acerola is a natural raw material that, in its unprocessed form, is known to be a rich source of vitamin C and polyphenolic compounds. For this reason, the consumption of acerola may provide a number of health-promoting benefits, particularly related to its strong anti-free radical effects. The review discusses anti-inflammatory and anticancer effects of acerola fruit and leaves as well as its therapeutic effects on selected physiological processes in the human system. Their biochemical mechanisms are also explained. Recommendations for the consumption of acerola in the prevention of inflammatory and free radical diseases are presented. The part of the article devoted to anticancer effects of acerola describes the possibilities of using the edible parts of this raw material to obtain products and preparations of potential use in cancer prevention and therapy.

Regulation of UCP2 in nonalcoholic fatty liver disease: From mechanisms to natural product

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease associated with lipid deposition in liver cells and/or subsequent inflammation, excluding other known causes. NAFLD is a subset of metabolic syndrome that ranges from simple steatohepatitis (NASH), fibrosis to cirrhosis and hepatocellular carcinoma (HCC). At present, the pathogenesis of NAFLD remains unclear. Among the many factors that shape these transitions, uncoupling protein 2 (UCP2) may be involved in every stage of the disease. UCP2 is a carrier protein that responds to fatty acids (FAs) in mitochondrial intima and has a wide tissue distribution. However, the biological function of UCP2 has not been fully elucidated, and most of our current knowledge comes from cell and animal experiments. These data suggest that UCP2 plays a role in lipid metabolism, oxidative stress, apoptosis, and even cancer. In this review, we summarize the structure, distribution, and biological function of UCP2 and its role in the progression of NAFLD, as well as natural products targeting UCP2 to improve NAFLD.

Arabinan-rich pectic polysaccharide fraction from Malpighia emarginata fruits alleviates inflammatory pain in mice

Malpighia emarginata (Malpighiaceae), popularly known as "acerola", is a tropical and subtropical fruit native to the Americas. Despite its high vitamin C content, which gives it a high antioxidant property, soluble dietary fibers, such as polysaccharides, are also abundant constituents of acerola (10% of the dried fruit). The acerola cold-water soluble (ACWS) fraction presented anti-fatigue and antioxidant effects in vivo and in vitro. To infer further systemic effects of ACWS, this study aimed to investigate the antinociceptive, anti-inflammatory, and antioxidant effects of ACWS in murine models of pain. In formalin-induced nociception, ACWS (0.1, 1, and 10 mg/kg) reduced only the inflammatory phase, and also (10 and 30 mg/kg) attenuated the acetic acid-induced writhing and leukocyte migration in the peritoneal cavity. The mechanical allodynia and paw edema induced by intraplantar injection of carrageenan were greatly reduced by ACWS (10 mg/kg). At the inflammatory pick induced by carrageenan (4 h), ACWS significantly reduced myeloperoxidase activity, TNF-α, IL-1β, and PGE2 levels, and restored IL-10 levels. ACWS also exhibited antioxidant properties by decreasing lipid hydroperoxides content, increasing GSH levels, and restoring superoxide dismutase and catalase activities in the carrageenan model and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. Collectively, these results support the antinociceptive, anti-inflammatory, and antioxidant effects of ACWS and reveal a promising candidate for the treatment of inflammatory pain conditions.

Toxicological effects of acute and repeated doses (180 days) of fruits from Malpighia emarginata (acerola) in rodents

Malpighia emarginata has a high amount of vitamin C with pharmacological or food preservation potential. However, despite its wide use and application possibilities its toxicity in repeated doses and for a long time (6 months) has not yet been studied. In this context, this study aimed to evaluate the acute toxicity and repeated doses from fruits of this plant. The extract was produced with the pulp (EMe) of the lyophilized fruit and submitted to chromatographic and spectroscopic analysis (HPLC and ESI-IT-MSn). In the acute test, the EMe was administered orally and parenterally to rodents (mice and rats) for 14 days, at a dose of 2000 mg/kg. Subsequently, the repeated dose toxicity test was administered orally for 180 days at doses of 50, 300 or 1000 mg/kg. The HPLC assay revealed a high concentration of vitamin C (16.3%), and spectroscopic analyses pointed to the presence of five other polyphenolic compounds. In the acute test, the plant extract showed no apparent toxicity or lethality in rodents. The LD50 was estimated to be greater than 2000 mg/kg and falls into category 5 (low toxicity). In the repeated dose assay, there was no evidence of toxicity, and no differences were observed in water intake, food, weight development, or behavior of the animals in relation to the vehicle group (water). However, hematological and biochemical evaluations pointed out some nonconformities in the levels of cholesterol, leukocytes, and neutrophils of the male rats, but overall, these results did not reveal significant toxicity. Therefore, the Level of Unobserved Adverse Effects (NOAEL) was 1000 mg/kg. Together, the results suggest that the extract obtained from the fruits of M. emarginata does not present representative toxicity in rodents.

Mechanism of Action and Related Natural Regulators of Nrf2 in Nonalcoholic Fatty Liver Disease

With the acceleration of people's pace of life, non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in the world, which greatly threatens people's health and safety. Therefore, there is still an urgent need for higher-quality research and treatment in this area. Nuclear factor Red-2-related factor 2 (Nrf2), as a key transcription factor in the regulation of oxidative stress, plays an important role in inducing the body's antioxidant response. Although there are no approved drugs targeting Nrf2 to treat NAFLD so far, it is still of great significance to target Nrf2 to alleviate NAFLD. In recent years, studies have reported that many natural products treat NAFLD by acting on Nrf2 or Nrf2 pathways. This article reviews the role of Nrf2 in the pathogenesis of NAFLD and summarizes the currently reported natural products targeting Nrf2 or Nrf2 pathway for the treatment of NAFLD, which provides new ideas for the development of new NAFLD-related drugs.

Antioxidant potential of acerola by-product along the enterohepatic axis of rats fed a high-fat diet

Acerola (Malpighia emarginata DC) by-product (ABP) has bioactive compounds that can provide antioxidant and hypolipidemic effects in vivo. In this study we aimed to evaluate the antioxidant potential of ABP on oxidative damage along the enterohepatic axis of rats fed a high-fat diet for 7 weeks. In addition, we analysed the phenolic compound profile in the enterohepatic axis, and the lipid accumulation in the liver, colon and liver tissue structure of high-fat diet-fed rats treated with fenofibrate drug (100 mg/kg) or ABP (400 mg/kg) via orogastric administration in the 4th to 7th weeks of the experiment. ABP had increased antioxidant potential in vitro and presented ascorbic acid (2022.06 μg/g), carotenoid (2.63 μg/g), and total phenolic compound (5366.44 μg/g) contents. The high-fat diet-fed rats that received ABP (compared to fenofibrate treatment) presented a non-significant reduction of 9.87% in guanine oxidation product, lower relative liver weight, degree of hepatic steatosis, and aspartate aminotransferase level in their blood. ABP also provided high-fat diet-fed rats: an increased amount of total phenolic compounds in caecal digesta (946.42 µg/g), faeces (3299.07 µg/g), colon (256.15 µg/g) and hepatic tissues (454.80 µg/g); higher total antioxidant capacity in plasma and colon; and lower lipid peroxidation in plasma, colonic and hepatic tissues. The results point to the potential antioxidant activity of ABP against oxidative damage along the enterohepatic axis caused by high-fat diet intake. The ABP had a greater protective effect on the healthy liver compared to fenofibrate treatment due to its bioactive compound content.

Mei-Gin Formula Ameliorates Obesity through Lipolysis, Fatty Oxidation, and Thermogenesis in High-Fat Diet-Induced Obese Rats

Obesity is a metabolic dysfunction characterized by excessive body fat deposition as a consequence of an energy imbalance. Novel therapeutic strategies have emerged that are safe and have comparatively low side effects for obesity treatment. Functional foods and nutraceuticals have recently received a great deal of attention because of their components with the properties of antimetabolic syndrome. Based on our previous in vitro and in vivo investigations on anti-adipogenesis activity and improved body fat accumulation in serials, the combination of three ingredients (including bainiku-ekisu, black garlic, and Mesona procumbens Hemsl), comprising the Mei-Gin formula (MGF), was eventually selected as a novel inhibitor that exhibited preventive effects against obesity. Herein, we verify the anti-obesity effects of MGF in obese rats induced by a high-fat diet and discuss the potential molecular mechanisms underlying obesity development. Oral administration of MGF significantly suppressed the final body weight, weight change, energy and water intake, subcutaneous and visceral fat mass, liver weight, hepatic total lipids and triglycerides (TG), and serum levels of TG, triglycerides (TC), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (AST), uric acid, and ketone bodies and augmented fecal total lipids, TG, and cholesterol excretion in the high-dose MGF-supplemented groups. Furthermore, the corresponding lipid metabolic pathways revealed that MGF supplementation effectively increased lipolysis and fatty acid oxidation gene expression and attenuated fatty acid synthesis gene expression in the white adipose tissue (WAT) and liver and it also increased mitochondrial activation and thermogenic gene expression in the brown adipose tissue (BAT) of rats with obesity induced by a high-fat diet (HFD). These results demonstrate that the intake of MGF can be beneficial for the suppression of HFD-induced obesity in rats through the lipolysis, fatty oxidation, and thermogenesis pathway. In conclusion, these results demonstrate the anti-obesity efficacy of MGF in vivo and suggest that MGF may act as a potential therapeutic agent against obesity.

Preventive and therapeutic effects of natural products and herbal extracts on nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a common condition that is prevalent in patients who consume little or no alcohol, and is characterized by excessive fat accumulation in the liver. The disease is becoming increasingly common with the rapid economic development of countries. Long-term accumulation of excess fat can lead to NAFLD, which represents a global health problem with no effective therapeutic approach. NAFLD is a complex, multifaceted pathological process that has been the subject of extensive research over the past few decades. Herbal medicines have gained attention as potential therapeutic agents to prevent and treat NAFLD due to their high efficacy and low risk of side effects. Our overview is based on a PubMed and Web of Science database search as of Dec 22 with the keywords: NAFLD/NASH Natural products and NAFLD/NASH Herbal extract. In this review, we evaluate the use of herbal medicines in the treatment of NAFLD. These natural resources have the potential to inform innovative drug research and the development of treatments for NAFLD in the future.

Tartary buckwheat root polysaccharides ameliorate non-alcoholic fatty liver disease via the IL6-SOCS3-SREBP1c pathway

Our previous study demonstrated that Tartary buckwheat root polysaccharides (TBRP) could reduce insulin resistance in diabetes mellitus by inhibiting SOCS3-stimulated IRS1 protein degradation. However, whether TBRP has the efficiency to treat non-alcoholic fatty liver disease (NAFLD) is still undetermined. This investigation aimed to examine the effects of TBRP on a high-fat diet (HFD)-triggered NAFLD, and elucidate the underlying molecular mechanisms. Briefly, TBRP toxicity in hepatoma (BEL7404) and pancreatic cancer (BxPC3) cells and zebrafish embryos developmental models, were evaluated in-vitro and in-vivo, respectively. TBRP inhibited cellular lipid accumulation by suppressing fat synthesis, furthermore, it improved body weight gain, liver weight, liver-to-body weight ratio, serum lipids triglyceride, total cholesterol, ALT, LDL-C, HDL-C, and AST levels in the NAFLD mice model. Additionally, TBRP treatment also lowered the nitric oxide content. The qPCR assay revealed that mRNA expression of TNF, IL1β, and IL6 was also markedly reduced in TBRP-treated NAFLD mice. The expression of SOCS3, SREBP1c, and STAT3 was elucidated by western blot analysis, which indicated that TBRP markedly decreased the gene expression for de novo fat synthesis by the SOCS3-SREBP1c pathway. These findings reveal that TBRP ameliorates NAFLD via the IL6-SOCS3-SREBP1c signaling pathway and therefore, may represent a promising approach for NAFLD treatment.

CRISPR/Cas9-Based Screening of FDA-Approved Drugs for NRF2 Activation: A Novel Approach to Discover Therapeutics for Non-Alcoholic Fatty Liver Disease

With the rising prevalence of obesity, non-alcoholic fatty liver disease (NAFLD) now affects 20-25% of the global population. NAFLD, a progressive condition associated with oxidative stress, can result in cirrhosis and liver cancer in 10% and 3% of patients suffering NAFLD, respectively. Therapeutic options are currently limited, emphasizing the need for novel treatments. In this study, we examined the potential of activating the transcription factor NRF2, a crucial player in combating oxidative stress, as an innovative approach to treating NAFLD. Utilizing a CRISPR/Cas9-engineered human HEK293T cell line, we were able to monitor the expression of heme oxygenase-1 (HMOX1), an NRF2 target, using a Nanoluc luciferase tag. Our model was validated using a known NRF2 activator, after which we screened 1200 FDA-approved drugs, unearthing six compounds (Disulfiram, Thiostrepton, Auranofin, Thimerosal, Halofantrine, and Vorinostat) that enhanced NRF2 activity and antioxidant response. These compounds demonstrated protective effects against oxidative stress induced by hydrogen peroxide and lipid droplets accumulation in vitro with hepatoma HUH-7 cells. Our study underscores the utility of CRISPR/Cas9 tagging with Nanoluc luciferase in identifying potential NRF2 activators, paving the way for potential NAFLD therapeutics.

Uncarboxylated Osteocalcin Decreases SCD1 by Activating AMPK to Alleviate Hepatocyte Lipid Accumulation

Uncarboxylated osteocalcin (GluOC), a small-molecule protein specifically synthesized and secreted by osteoblasts, is important in the regulation of energy metabolism. In our previous study, GluOC was shown to be effective in ameliorating dyslipidemia and hepatic steatosis in KKAy mice. However, the underlying mechanism of GluOC action on hepatocytes has not been well validated. In this study, oleic acid/palmitic acid (OA/PA)-induced HepG2 and NCTC 1469 cells were used as non-alcoholic fatty liver disease (NAFLD) cell models, and triacylglycerol (TG) levels were measured by oil red O staining, Nile Red staining, and ELISA. The fatty acid synthesis-related protein expression was detected by real-time quantitative polymerase chain reaction, Western blotting, and immunofluorescence. The results show that GluOC reduced triglyceride levels, and decreased the expression of sterol regulatory element-binding protein-1c (SREBP-1c) and stearyl-coenzyme A desaturase 1 (SCD1). si-SCD1 mimicked the lipid accumulation-reducing effect of GluOC, while overexpression of SCD1 attenuated the effect of GluOC. In addition, GluOC activated AMP-activated protein kinase (AMPK) phosphorylation to affect lipid metabolism in hepatocytes. Overall, the results of this study suggest that GluOC decreases SCD1 by activating AMPK to alleviate hepatocyte lipid accumulation, which provides a new target for improving NAFLD in further research.

Managing metabolic diseases: The roles and therapeutic prospects of herb-derived polysaccharides

Metabolic diseases have become a public health problem worldwide. Effective, novel and natural therapies are urgently needed to treat metabolic diseases. As natural bioactive compounds, polysaccharides have many physiological and medicinal properties. Recently, herb-derived polysaccharides have shown beneficial effects in the treatment of metabolic diseases, but the underlying mechanisms remain unclear. This review comprehensively summarizes the pharmacological progress and clinical evidence of herb-derived polysaccharides in the treatment of three metabolic diseases, namely type 2 diabetes mellitus, nonalcoholic fatty liver disease and obesity, and more importantly, discusses the molecular mechanism involved. Existing evidence has proved that herb-derived polysaccharides can maintain glucose homeostasis, promote insulin secretion, improve insulin resistance, reduce weight gain and hepatic steatosis, inhibit lipogenesis, alleviate oxidative stress and inflammation, and improve gut microbiota disorders in rodents with metabolic diseases. Notably, so far, human clinical trials of herb-derived polysaccharides for these three metabolic diseases remain rare. All in all, herb-derived polysaccharides may have good potential as drug candidates for the prevention and management of metabolic diseases. More high-quality clinical trials are needed to further validate its effectiveness and safety in human subjects.

Research progress on the therapeutic effects of polysaccharides on non-alcoholic fatty liver diseases

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease and is a leading cause of cirrhosis and hepatocellular carcinoma. Due to its complex pathophysiology, there is currently no approved therapy. Polysaccharide, a kind of natural product, possesses a wide range of pharmacological activities. Numerous preclinical studies have confirmed that polysaccharides could interfere with the occurrence and development of NAFLD at multiple interrelated levels, such as improvement of glucose and lipid metabolism, antioxidation, anti-inflammation, and regulation of gut-liver axis, thus showing great potential as novel anti-NAFLD drugs. In this paper, we reviewed the polysaccharides with anti-NAFLD effect in recent years, and also systematically analyzed their possible pharmacological mechanisms.

Advances in health-promoting effects of natural polysaccharides: Regulation on Nrf2 antioxidant pathway

Natural polysaccharides (NPs) possess numerous health-promoting effects, such as liver protection, kidney protection, lung protection, neuroprotection, cardioprotection, gastrointestinal protection, anti-oxidation, anti-diabetic, and anti-aging. Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway is an important endogenous antioxidant pathway, which plays crucial roles in maintaining human health as its protection against oxidative stress. Accumulating evidence suggested that Nrf2 antioxidant pathway might be one of key regulatory targets for the health-promoting effects of NPs. However, the information concerning regulation of NPs on Nrf2 antioxidant pathway is scattered, and NPs show different regulatory behaviors in their different health-promoting processes. Therefore, in this article, structural features of NPs having regulation on Nrf2 antioxidant pathway are overviewed. Moreover, regulatory effects of NPs on this pathway for health-promoting effects are summarized. Furthermore, structure-activity relationship of NPs for health-promoting effects by regulating the pathway is preliminarily discussed. Otherwise, the prospects on future work for regulation of NPs on this pathway are proposed. This review is beneficial to well-understanding of underlying mechanisms for health-promoting effects of NPs from the view angle of Nrf2 antioxidant pathway, and provides a theoretical basis for the development and utilization of NPs in promoting human health.

Salvia plebeia R. Br. Water Extract Ameliorates Hepatic Steatosis in a Non-Alcoholic Fatty Liver Disease Model by Regulating the AMPK Pathway

Salvia plebeia R. Br. (SP), grown from autumn to spring, is used as a medicinal herb from roots to leaves. This herb exhibits antioxidant activities and various physiological effect, including anti-asthma, immune-promoting, anti-obesity, and anti-cholesterol effects. However, the effectiveness of SP against non-alcoholic fatty liver disease (NAFLD) and the associated mechanism have not been elucidated. In this study, alleviation of NAFLD by SP was confirmed in a mouse model of hepatic steatosis induced by a high-fat diet and in HepG2 cells administered free fatty acids (FFA). In the experimental model, intrahepatic lipid accumulation was investigated using the AdipoRed^TM assay, Oil Red O staining, biomarker analysis, and hematoxylin and eosin staining. Furthermore, glucose tolerance was examined based on the fasting glucose levels and oral glucose tolerance. The molecular mechanisms related to hepatic steatosis were determined based on marker mRNA levels. Blood FFAs were found to flow into the liver via the action of fatty acid translocase, cluster of differentiation 36, and fatty acid transporter proteins 2 and 5. Salvia plebeia R. Br. water extract (SPW) suppressed the FFAs inflow by regulating the expression of the above-mentioned proteins. Notably, modulating the expression of AMP-activated protein kinase (AMPK) and liver X receptor, which are involved in the regulation of lipid metabolism, stimulated peroxisome proliferator activated receptor α in the nucleus to induce the expression genes involved in β-oxidation and increase β-oxidation in the mitochondria. AMPK modulation also increased the expression of sterol regulatory element binding protein-1c, which activated lipid synthesis enzymes. As a consequence of these events, triglyceride synthesis was reduced and lipid accumulation in hepatocytes was alleviated. Overall, our findings suggested that SPW could ameliorate NAFLD by inhibiting hepatic steatosis through AMPK modulation.

Nutritional Characterization, Antioxidant, and Lipid-Lowering Effects of Yellow Mombin (Spondias mombin) Supplemented to Rats Fed a High-Fat Diet

The aim of this study was to evaluate the effects of supplementing yellow mombin (YM) on the oxidative, somatic, and lipid parameters in rats fed a high-fat diet. A total of 24 adult Wistar rats were randomized into three groups: normal-fat diet (NF), high-fat diet (HF), and high-fat diet with YM supplementation (HFYM). Diets were administered for four weeks, and YM (400 mg/kg) was supplemented via gavage in the last two weeks of the experiment. After the four-week period, the somatic, serum biochemical, and liver oxidative parameters were evaluated. YM has a high antioxidant activity and significant amounts of phenolic compounds, carotenoids, vitamin C, dietary fibre, and minerals. The HFYM group had the lowest body weight (18.75%), body mass index (17.74%), and adiposity (31.63%) compared with the HF group. YM supplementation reduced low-density lipoprotein by 43.05% and increased high-density lipoprotein by 25.73%, but did not improve the triglyceride levels in the serum. YM treatment improved glucose tolerance and lipid peroxidation, and also enhanced the antioxidant capacity, superoxide dismutase, and glutathione peroxidase activities in the liver. These results indicate the lipid-lowering property and potential antioxidant activity of YM against liver oxidative damage caused by a high-fat diet intake, which may be associated with the bioactive compounds present in this fruit.

Progress in Nonalcoholic Fatty Liver Disease: SIRT Family Regulates Mitochondrial Biogenesis

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, insulin resistance, mitochondrial dysfunction, inflammation, and oxidative stress. As a group of NAD+-dependent III deacetylases, the sirtuin (SIRT1-7) family plays a very important role in regulating mitochondrial biogenesis and participates in the progress of NAFLD. SIRT family members are distributed in the nucleus, cytoplasm, and mitochondria; regulate hepatic fatty acid oxidation metabolism through different metabolic pathways and mechanisms; and participate in the regulation of mitochondrial energy metabolism. SIRT1 may improve NAFLD by regulating ROS, PGC-1α, SREBP-1c, FoxO1/3, STAT3, and AMPK to restore mitochondrial function and reduce steatosis of the liver. Other SIRT family members also play a role in regulating mitochondrial biogenesis, fatty acid oxidative metabolism, inflammation, and insulin resistance. Therefore, this paper comprehensively introduces the role of SIRT family in regulating mitochondrial biogenesis in the liver in NAFLD, aiming to further explain the importance of SIRT family in regulating mitochondrial function in the occurrence and development of NAFLD, and to provide ideas for the research and development of targeted drugs. Relatively speaking, the role of some SIRT family members in NAFLD is still insufficiently clear, and further research is needed.

Corn peptides improved obesity-induced non-alcoholic fatty liver disease through relieving lipid metabolism, insulin resistance and oxidative stress

Non-alcoholic fatty liver disease (NAFLD) is increasingly threatening human health. The remarkable effects of corn peptides (CPs) as bioactive peptides on liver protection have attracted much attention. Nevertheless, the specific effect of CPs on NAFLD remains unclear. The present study was designed to investigate the efficacy of CPs in the prevention and auxiliary treatment of high-fat diet (HFD)-induced NAFLD in SD rats, and puerarin was used as the positive control. SD rats were fed a high-fat diet to establish the NAFLD rat model, and LO2 cells were treated with a high concentration of fructose to simulate the NAFLD cell model. NAFLD was comprehensively examined in terms of body weight, liver function markers, serum biochemistry and liver histology. Protein expression was determined using western blot analysis. The results of animal experiments showed that CPs could effectively inhibit the rate of weight gain, reduce the blood lipid level and liver index, and enhance glucose tolerance. The results of cell experiments showed that CPs could effectively reduce the accumulation of lipids in LO2 cells and inhibit the accumulation of reactive oxygen species (ROS). In addition, CPs could markedly reduce liver lipid accumulation in the liver cell and liver tissue, as further evidenced by the reduced expression of SREBP-1c in human non-tumour hepatic (LO2) cells. Meanwhile, the increased expression of SIRT1/PPAR-α and Nrf2/HO-1 pathways under the pretreatment of CPs in LO2 cells indicated that CPs could markedly relieve high fat-induced fatty liver injury, regulate insulin sensitivity, and reduce production of ROS. The results of in vivo and in vitro experiments demonstrated that CPs provided potential prevention and auxiliary treatment for NAFLD through reducing lipid accumulation, alleviating insulin resistance, and inhibiting oxidative stress. This study investigated the biological activity of CPs and laid the theoretical basis for the development of CP-based functional foods and dietary supplements.

Clitorin ameliorates western diet-induced hepatic steatosis by regulating lipogenesis and fatty acid oxidation in vivo and in vitro

Nonalcoholic fatty liver disease (NAFLD) is usually correlated with metabolic diseases, such as obesity, insulin resistance, and hyperglycemia. Herein, we investigated the inhibitory effects and underlying governing mechanism of clitorin in a western diet (WD)-induced hepatic steatosis mouse model, and in oleic acid-stimulated HepG2 cells. Male C57BL/6 mice were fed a normal diet, WD, WD + 10 or 20 mg/kg orlistat, and WD + 10 or 20 mg/kg clitorin. HepG2 cells were treated with 1 mM oleic acid to induce lipid accumulation with or without clitorin. Clitorin significantly alleviated body weight gain and hepatic steatosis features (NAFLD activity score, micro-, and macro-vesicular steatosis) in WD-induced hepatic steatosis mice. Additionally, clitorin significantly decreased protein expressions of sterol regulatory element-binding protein 1 (SREBP1), peroxisome proliferator-activated receptor γ (PPARγ), and CCAAT/enhancer binding protein α (C/EBPα) in WD-induced hepatic steatosis mice. Moreover, clitorin significantly diminished the mRNA levels of SREBP1, acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and enhanced the mRNA levels of peroxisome proliferator-activated receptor α (PPARα) and carnitine palmitoyltranserase-1 (CTP-1), as well as adenosine monophosphate-activated protein kinase (AMPK) in the liver of WD-induced hepatic steatosis mice and oleic acid-stimulated HepG2 cells. Overall, our findings demonstrated that clitorin can be a potentially efficacious candidate for NAFLD management.

Erythritol Improves Nonalcoholic Fatty Liver Disease by Activating Nrf2 Antioxidant Capacity

Nonalcoholic fatty liver disease (NAFLD) is a kind of serious fat disorder that has become a critical problem to human society. Therefore, finding drugs that are safe and effective has become more and more important. Erythritol (Ery) is a polyol sweetener with a variety of biological functions. However, whether Ery has a relieving effect on NAFLD has not been reported yet. Therefore, we induced HepG2 cells with oleic acid and palmitic acid as our in vitro model. Moreover, we choose wild-type mice with tyloxapol and high-fat diet and nuclear factor E2-related factor 2 (Nrf2) knockout mice with high-fat diet as our in vivo model. We found that Ery could reverse the lipid accumulation, oxidative stress, and endoplasmic reticulum stress caused by the NAFLD model. The mechanism studies showed that Ery promoted the translocation of Nrf2 from cytoplasm to nucleus, and the molecular simulation docking results of Ery and Nrf2 showed that there was a hydrogen bond between them. Moreover, Ery could promote the production of HO-1 and NQO1 antioxidant proteins and inhibit the expression of endoplasmic reticulum stress proteins GPR78, p-PERK, and CHOP. On the contrast, when Nrf2 was knocked out in mice, Ery lost its protective effect on NAFLD. In conclusion, we found that the potential mechanism of Ery's protective effect is that it plays an antioxidant role by activating the Nrf2 signaling pathway, thereby inhibiting endoplasmic reticulum stress and lipid accumulation in NAFLD.

Combination of Anoectochilus roxburghii Polysaccharide and Exercise Ameliorates Diet-Induced Metabolic Disorders in Obese Mice

Metabolic syndrome is a cluster of metabolic disorders that threatens public health. Nevertheless, its exact mechanism and relative intervention remain largely obscure. Accumulating evidence indicate that tither Anoectochilus roxburghii polysaccharide (ARP) or exercise (EX) exhibited the beneficial effects on metabolic health. However, the synergetic beneficial effects of ARP and EX as a combined intervention on obesity-induced metabolic disorders remain largely obscure. Male C57BL/6 mice were fed a high-fat diet (HFD) and intervened with ARP and EX for 12 continuous weeks. The results indicated that the ARP, EX, and ARP combined with EX treatment group regulated lipogenesis by suppressing the fatty acid pathway, dampening the system oxidative stress by stimulating Nrf2-mediated phase II enzyme system, and promoting the mitochondrial function by activating the mitochondrial complexes and PGC-1α in HFD mice. More importantly, the combination of ARP and EX showed an even greater beneficial effects relative to either ARP or EX alone, especially in decreasing reactive oxygen species (ROS) level and increasing adenosine triphosphate (ATP) content. Taken together, these findings further confirmed that ARP and EX could be effective interventions on obesity-induced metabolic abnormalities, and that the combination of ARP and EX exhibited the beneficial synergetic effects.

Rotundic acid ameliorates non-alcoholic steatohepatitis via SREBP-1c/ SCD1 signaling pathway and modulating gut microbiota

Non-alcoholic steatohepatitis (NASH) is a devastating form of non-alcoholic fatty liver disease (NAFLD) with distinguished hallmarks of steatosis and inflammation. Rotundic acid (RA) is a natural pentacyclic triterpene compound extracted from the bank of Ilex rotunda Thunb with a wide range of biological activities. The aim of the study is to evaluate the pharmacological effect and action mechanism of RA on NASH in vitro and in vivo. RA has weak lipid lowering ability in rat primary hepatocytes, significantly decreases serum LDL level, hepatic TG and TC levels and lipid droplets, reduces NAS compared with the NASH group, and alleviates hepatic inflammation. RA also enhances the recovery of intestinal bacterial community and intestinal-derived short-chain fatty acid caused by high food diet (HFD). Further investigation shows that RA protects against HFD-induced NASH via downregulating the expression of SREBP-1c/SCD1 signaling pathway and improving gut microbiota. These findings imply that RA might be helpful for the alleviation of NASH.

A double-edged sword: The Kelch-like ECH-associated protein 1-nuclear factor erythroid-derived 2-related factor 2-antioxidant response element pathway targeted pharmacological modulation in nonalcoholic fatty liver disease

Nutraceuticals activating the Kelch-like epichlorohydrin (ECH)-associated protein 1 (Keap1)-nuclear factor erythroid-derived 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway are widely used for nonalcoholic fatty liver disease (NAFLD) because no specific drugs are approved yet. The pathology of NAFLD is summarized as the 'two-hit' hypothesis. The 'first hit' includes insulin resistance and lipid accumulation. Oxidative stress, lipid peroxidation, and inflammation are regarded as the 'second hit'. Now there is controversial evidence about the roles of the Keap1-Nrf2-ARE pathway and its activators in NAFLD. When the 'first hit' occurs, the hepatocyte-specific Nrf2 deficiency reduces insulin resistance and significantly attenuates lipid accumulation. However, when the 'second hit' occurs, Nrf2 activation reduces oxidative stress and combats inflammation. We reviewed the roles of the Keap1-Nrf2-ARE pathway as a double-edged sword in the development of NAFLD, its inhibitors as a novel therapeutic approach for early NAFLD, and the nutraceutical character of its activators.

Dimethyl fumarate reduces oxidative stress, inflammation and fat deposition by modulation of Nrf2, SREBP-1c and NF-κB signaling in HFD fed mice

Nonalcoholic fatty liver disease (NAFLD) occurs due to lipid metabolic disorders, which is associated with hepatic oxidative stress and inflammation. There is no definitive drug treatment for this disease. Accordingly, the present study aimed to evaluate the effects of dimethyl fumarate (DMF) as one of the superior effective drugs that induces a transcription factor of nuclear factor erythroid 2-related factor 2 (Nrf2) on development of NAFLD in mice. The metabolic disturbance in High-fat diet (HFD)-treated animals was associated with hyperlipidemia, increased activity levels of hepatic enzymes in serum, hyperglycemia, hyperinsulinemia, oxidative stress and inflammation. DMF supplementation had anti-inflammatory, antioxidant, anti-lipogenic and molecular compatibility effects induced by HFD in mice. In comparison to the HFD group, the DMF therapy could significantly suppress the sterol regulatory element binding protein-1 c (SREBP-1c) gene and protein levels, as well as upregulate the Nrf2 gene and protein levels. Additionally, the anti-inflammatory activity was observed for the DMF by inhibiting the nuclear factor kappa B (NF-κB) level. DMF reduces the development of NAFLD induced by HFD in mice through the modulation of transcription factors Nrf2, SREBP-1c and NF-κB. Thus, DMF can be considered as an effective candidate in the treatment of human NAFLD.

DHA-enriched phosphatidylserine ameliorates non-alcoholic fatty liver disease and intestinal dysbacteriosis in mice induced by a high-fat diet

Docosahexaenoic acid-enriched phosphatidylserine (DHA-PS) has attracted increasing attention because of its unique health benefits. In this study, DHA-PS was biosynthesized from DHA-enriched phosphatidylcholine (DHA-PC), which was extracted from herring roe, Clupea harengus. The ameliorating effect of DHA-PS on high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) was investigated using a mouse model. The DHA-PS treatment ameliorated NAFLD and effectively decreased the serum total cholesterol, triglyceride, non-esterified fatty acid, and low-density lipoprotein cholesterol levels and considerably increased the serum high-density lipoprotein cholesterol levels. Moreover, the DHA-PS treatment reduced the levels of liver-function enzymes and pro-inflammatory cytokines and also the oxidative stress indices. Furthermore, DHA-PS increased the diversity and richness of the beneficial intestinal microorganisms, suggesting its potential as a dietary supplement and functional food to combat HFD-induced NAFLD.

Saskatoon berry powder reduces hepatic steatosis and insulin resistance in high fat-high sucrose diet-induced obese mice

Non-alcoholic fatty liver disease is a common metabolic disorder associated with insulin resistance and lacks a specific treatment. Our previous studies demonstrated that freeze-dried Saskatoon berry powder (SBp) reduced high fat-high sucrose (HFHS) diet-induced hyperglycemia and insulin resistance in mice. The present study examined the effect of SBp and one of its active components, cyanidin-3-glucoside (C3G), on hepatic steatosis in mice fed with HFHS diet for 10 weeks. HFHS diet significantly increased fasting plasma glucose, cholesterol, triglycerides, insulin resistance, inflammatory markers (tumor necrosis factor-α, monocyte chemotactic protein-1, plasminogen activator inbitor-1), alanine aminotransferase activity, and monocyte adhesion compared to control diet. In the liver, HFHS diet increased steatosis, lipid accumulation, collagen deposition, and the abundance of patatin-like phospholipase domain-containing 3, CCAAT-enhancer-binding protein homologous protein, toll-like receptor-4, and macrophage marker. Supplementation with SBp (5%) or C3G in an amount corresponding to that in 5% SBp to HFHS diet had similar effects to reduced fasting plasma glucose, liver steatosis, enzyme activity, lipid, collagen and macrophage deposition, hyperglycemia, hyperlipidemia, insulin resistance, monocyte adhesion, markers related to liver steatosis, inflammation, oxidative or endoplasmic reticulum stress in the peripheral circulation and/or liver compared to mice fed with HFHS diet alone. No significant difference in the studied variables was detected between mice treated with HFHS+SBp and C3G diet. The results suggest that SBp or C3G administration attenuates HFHS diet-induced liver steatosis in addition to insulin resistance and chronic inflammation in mice. C3G may contribute to the beneficial effects of SBp.

Systematic investigation of the relationships of trimethylamine N-oxide and L-carnitine with obesity in both humans and rodents

Previous studies suggested the potential associations of trimethylamine N-oxide (TMAO) and its metabolic precursor l-carnitine with obesity. However, existing evidence is limited and inconsistent. In the present study, we perform a cross-sectional analysis of the associations of serum levels of TMAO and l-carnitine with obesity measures, including BMI, body fat distribution and body composition in 1081 participants from the general Newfoundland population. The dietary effects of TMAO and l-carnitine in preventing high fat diet-induced obesity in both male and female mice were also evaluated. We found significant associations between higher serum l-carnitine levels and obesity (higher BMI, body fat mass and VT%) in women, but not in men after controlling multiple confounding factors. Serum TMAO levels were positively associated with age, but not obesity in both men and women. Dietary TMAO had no influence on fat accumulation in high fat diet-fed mice. However, l-carnitine supplementation prevented high fat diet-fed induced obesity in both male and female mice by up-regulating lipolysis and down-regulating lipogenesis in white adipose tissues. The present study provides further evidence for the relationships between TMAO, l-carnitine and obesity.

Elucidation of SIRT-1/PGC-1α-associated mitochondrial dysfunction and autophagy in nonalcoholic fatty liver disease

Background

Nonalcoholic fatty liver disease (NAFLD) can lead to chronic liver diseases associated with mitochondrial damages. However, the exact mechanisms involved in the etiology of the disease are not clear.

Methods

To gain new insights, the changes affecting sirtuin 1 (SIRT-1) during liver fat accumulation was investigated in a NAFLD mouse model. In addition, the in vitro research investigated the regulation operated by SIRT-1 on mitochondrial structures, biogenesis, functions, and autophagy.

Results

In mice NAFLD, high-fat-diet (HFD) increased body weight gain, upregulated serum total cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, blood glucose, insulin levels, and liver malondialdehyde, and decreased liver superoxide dismutase activity. In liver, the levels of SIRT-1 and peroxisome proliferator-activated receptor-gamma coactivator -1α (PGC-1α) decreased. The expression of peroxisome proliferator-activated receptor-α and Beclin-1 proteins was also reduced, while p62/SQSTM1 expression increased. These results demonstrated SIRT-1 impairment in mouse NAFLD. In a well-established NAFLD cell model, exposure of the HepG2 hepatocyte cell line to oleic acid (OA) for 48 h caused viability reduction, apoptosis, lipid accumulation, and reactive oxygen species production. Disturbance of SIRT-1 expression affected mitochondria. Pre-treatment with Tenovin-6, a SIRT-1 inhibitor, aggravated the effect of OA on hepG2, while this effect was reversed by CAY10602, a SIRT-1 activator. Further investigation demonstrated that SIRT-1 activity was involved in mitochondrial biogenesis through PGC-1α and participated to the balance of autophagy regulatory proteins.

Conclusion

In conclusion, in high-fat conditions, SIRT-1 regulates multiple cellular properties by influencing on mitochondrial physiology and lipid autophagy via the PGC-1α pathway. The SIRT-1/PGC-1α pathway could be targeted to develop new NAFLD therapeutic strategies.

Plant-Based Foods and Their Bioactive Compounds on Fatty Liver Disease: Effects, Mechanisms, and Clinical Application

Fatty liver disease (FLD), including nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD), is a serious chronic metabolic disease that affects a wide range of people. Lipid accumulation accompanied by oxidative stress and inflammation in the liver is the most important pathogenesis of FLD. The plant-based, high-fiber, and low-fat diet has been recommended to manage FLD for a long time. This review discusses the current state of the art into the effects, mechanisms, and clinical application of plant-based foods in NAFLD and AFLD, with highlighting related molecular mechanisms. Epidemiological evidence revealed that the consumption of several plant-based foods was beneficial to alleviating FLD. Further experimental studies found out that fruits, spices, teas, coffee, and other plants, as well as their bioactive compounds, such as resveratrol, anthocyanin, curcumin, and tea polyphenols, could alleviate FLD by ameliorating hepatic steatosis, oxidative stress, inflammation, gut dysbiosis, and apoptosis, as well as regulating autophagy and ethanol metabolism. More importantly, clinical trials confirmed the beneficial effects of plant-based foods on patients with fatty liver. However, several issues need to be further studied especially the safety and effective doses of plant-based foods and their bioactive compounds. Overall, certain plant-based foods are promising natural sources of bioactive compounds to prevent and alleviate fatty liver disease.

Effect of Quercetin on Lipids Metabolism Through Modulating the Gut Microbial and AMPK/PPAR Signaling Pathway in Broilers

The present study was conducted to investigate effects and mechanism of quercetin on lipids metabolism in broilers. 480 AA broilers were randomly allotted to four treatments (0, 0.2, 0.4, and 0.6 g/kg quercetin) for 42 days. Compared with the control, 0.6 g/kg quercetin significantly decreased percentage of abdominal fat (P < 0.05); 0.2, 0.4, and 0.6 g/kg quercetin significantly decreased relative abundance of Lachnospiraceae and Desulfovibrionaceae (P < 0.05, P < 0.05, P < 0.01; P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased mRNA expression of PI3K, AMPKα1, AMPKα2, AMPKβ2, LKB1 (P < 0.01, P < 0.01, P < 0.05, P < 0.01, P < 0.05), and significantly reduced mRNA expression of SREBP1 and PPARγ (P < 0.01, P < 0.05); 0.4 g/kg quercetin significantly increased mRNA expression of LKB1 and PKB (P < 0.05, P < 0.01) and significantly reduced mRNA expression of ACC, HMGR, PPARγ, and SREBP1 (P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.6 g/kg quercetin significantly increased mRNA expression of AMPKγ, LKB1, CPT1, PPARα, PKB (P < 0.01, P < 0.01, P < 0.01, P < 0.05, P < 0.05), and significantly reduced the mRNA expression of PI3K, ACC, HMGR, PPARγ, SREBP1 (P < 0.05, P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased protein expression of AMPK (P < 0.01); 0.6 g/kg quercetin significantly increased protein expression of LKB1 (P < 0.01), 0.2 and 0.6 g/kg quercetin significantly increased protein expression of PI3K, PKB, CPT1 (P < 0.05, P < 0.01, P < 0.05, P < 0.01, P < 0.01, P < 0.01), and significantly reduced protein expression of ACC and SREBP1 (P < 0.01, P < 0.01, P < 0.01, P < 0.01). In conclusion, quercetin improved lipid metabolism by modulating gut microbial and AMPK/PPAR signaling pathway in broilers.

Chemical Activators of the Nrf2 Signaling Pathway in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is paralleling the insulin resistance and obesity epidemic and is regarded as liver metabolic syndrome, and its prevalence rate is increasing rapidly. The best explanation for the occurrence and development of NAFLD is the “multiple hit” hypothesis instead of the “two-hit” hypothesis. At present, NAFLD therapies are limited. The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway is a key pathway in oxidative stress. Its downstream proteins/enzymes are regulated. Metabolic enzymes and antioxidant proteins/enzymes play a vital role in cell defense protection and have attracted attention in the field of antioxidant research in recent years. This paper summarizes the regulatory mechanism of the Nrf2 signaling pathway and the research progress of Nrf2 activators in NAFLD to provide guidance for NAFLD therapy in the future.

The Interplay between Oxidative Stress and miRNAs in Obesity-Associated Hepatic and Vascular Complications

Nowadays, the obesity pandemic is one of the most relevant health issues worldwide. This condition is tightly related to comorbidities such as non-alcoholic fatty liver disease (NAFLD) and cardiovascular diseases (CVDs), namely atherosclerosis. Dysregulated lipid metabolism and inflammation link these three diseases, leading to a subsequent increase of oxidative stress (OS) causing severe cellular damage. On the other hand, microRNAs (miRNAs) are short, single-stranded, non-coding RNAs that act as post-transcriptional negative regulators of gene expression, thus being involved in the molecular mechanisms that promote the development of many pathologies including obesity and its comorbidities. The involvement of miRNAs in promoting or opposing OS in disease progression is becoming more evident. Some miRNAs, such as miR-200a and miR.421, seem to play important roles in OS control in NAFLD. On the other hand, miR-92a and miR-133, among others, are important in the development of atherosclerosis. Moreover, since both diseases are linked to obesity, they share common altered miRNAs, being miR-34a and miR-21 related to OS. This review summarizes the latest advances in the knowledge about the mechanisms of oxidative stress (OS) generation in obesity-associated NAFLD and atherosclerosis, as well as the role played by miRNAs in the regulation of such mechanisms.