The potential of flavonoids in the treatment of non-alcoholic fatty liver disease

Nano-drug delivery systems (NDDS) in metabolic dysfunction-associated steatotic liver disease (MASLD): current status, prospects and challenges

About one-third of the global population suffers from metabolic dysfunction-associated steatotic liver disease (MASLD), but specific treatments for MASLD have long been lacking, primarily due to the unclear etiology of the disease. In addition to lifestyle modifications and weight loss surgery, pharmacotherapy is the most common treatment among MASLD patients, and these drugs typically target the pathogenic factors of MASLD. However, bioavailability, efficacy, and side effects all limit the maximum therapeutic potential of the drugs. With the development of nanomedicine, recent years have seen attempts to combine MASLD pharmacotherapy with nanomaterials, such as liposomes, polymer nanoparticles, micelles, and cocrystals, which effectively improves the water solubility and targeting of the drugs, thereby enhancing therapeutic efficacy and reducing toxic side effects, offering new perspectives and futures for the treatment of MASLD.

Cyanidin-3-O-glucoside alleviates ethanol-induced liver injury by promoting mitophagy in a Gao-binge mouse model of alcohol-associated liver disease

BACKGROUND

Alcohol-associated liver disease (ALD) is a leading cause of liver disease-related deaths worldwide. Unfortunately, approved medications for the treatment of this condition are quite limited. One promising candidate is the anthocyanin, Cyanidin-3-O-glucoside (C3G), which has been reported to protect mice against hepatic lipid accumulation, as well as fibrosis in different animal models. However, the specific effects and mechanisms of C3G on ALD remain to be investigated.

EXPERIMENTAL APPROACH

In this report, a Gao-binge mouse model of ALD was used to investigate the effects of C3G on ethanol-induced liver injury. The mechanisms of these C3G effects were assessed using AML12 hepatocytes.

RESULTS

C3G administration ameliorated ethanol-induced liver injury by suppressing hepatic oxidative stress, as well as through reducing hepatic lipid accumulation and inflammation. Mechanistically, C3G activated the AMPK pathway and enhanced mitophagy to eliminate damaged mitochondria, thus reducing mitochondria-derived reactive oxidative species in ethanol-challenged hepatocytes.

CONCLUSIONS

The results of this study indicate that mitophagy plays a potentially important role underlying the hepatoprotective action of C3G, as demonstrated in a Gao-binge mouse model of ALD. Accordingly, C3G may serve as a promising, new therapeutic drug candidate for use in ALD.

Discovery of Cell-Permeable Allosteric Inhibitors of Liver Pyruvate Kinase: Design and Synthesis of Sulfone-Based Urolithins

Metabolic dysfunction-associated fatty liver disease (MAFLD) presents a significant global health challenge, characterized by the accumulation of liver fat and impacting a considerable portion of the worldwide population. Despite its widespread occurrence, effective treatments for MAFLD are limited. The liver-specific isoform of pyruvate kinase (PKL) has been identified as a promising target for developing MAFLD therapies. Urolithin C, an allosteric inhibitor of PKL, has shown potential in preliminary studies. Expanding upon this groundwork, our study delved into delineating the structure-activity relationship of urolithin C via the synthesis of sulfone-based urolithin analogs. Our results highlight that incorporating a sulfone moiety leads to substantial PKL inhibition, with additional catechol moieties further enhancing this effect. Despite modest improvements in liver cell lines, there was a significant increase in inhibition observed in HepG2 cell lysates. Specifically, compounds 15d, 9d, 15e, 18a, 12d, and 15a displayed promising IC50 values ranging from 4.3 µM to 18.7 µM. Notably, compound 15e not only demonstrated a decrease in PKL activity and triacylglycerol (TAG) content but also showed efficient cellular uptake. These findings position compound 15e as a promising candidate for pharmacological MAFLD treatment, warranting further research and studies.

Revealing Comprehensive Food Functionalities and Mechanisms of Action through Machine Learning

Foods possess a range of unexplored functionalities; however, fully identifying these functions through empirical means presents significant challenges. In this study, we have proposed an in silico approach to comprehensively predict the functionalities of foods, encompassing even processed foods. This prediction is accomplished through the utilization of machine learning on biomedical big data. Our focus revolves around disease-related protein pathways, wherein we statistically evaluate how the constituent compounds collaboratively regulate these pathways. The proposed method has been employed across 876 foods and 83 diseases, leading to an extensive revelation of both food functionalities and their underlying operational mechanisms. Additionally, this approach identifies food combinations that potentially affect molecular pathways based on interrelationships between food functions within disease-related pathways. Our proposed method holds potential for advancing preventive healthcare.

7-Hydroxyflavone improves nonalcoholic fatty liver disease by acting on STK24

The escalating incidence of nonalcoholic fatty liver disease (NAFLD) is closely associated with a high-fat diet, leading to a decline in quality of life and significant health impairment. 7-Hydroxyflavone (7-HY) is a flavonoid known for its anti-inflammatory, anticarcinogenic, and antioxidant effects. This study aims to assess the ameliorative effects of 7-HY on NAFLD induced by a high-fat diet and elucidate underlying mechanisms. Oleic acid/palmitic acid-induced HepG2 cells and C57BL/6 mice on a high-fat diet were utilized as in vitro and in vivo models. In animal experiments, 7-HY was utilized as a dietary supplement. The 15-week in vivo experiment monitored body weight, body fat percentage, glucose tolerance, insulin tolerance, and metabolic indexes. Commercial kits assessed triglyceride (TG) and total cholesterol levels in cells, liver tissue, and blood. Discovery Studio identified potential targets of 7-HY, compared with NAFLD-associated targets in the GeneCards database. Results indicated 7-HY mitigated fat accumulation, hepatic steatosis, and oxidative stress induced by a high-fat diet. Furthermore, 7-HY showed potential efficacy in ameliorating abnormal glucose metabolism and promoting energy metabolism. Reverse target finding and molecular docking demonstrated a robust interaction between 7-HY and serine/threonine kinase 24 (STK24). Subsequent experimental results confirmed 7-HY's ability to inhibit TG deposition in HepG2 cells through interaction with STK24. In conclusion, 7-HY demonstrated the capacity to alleviate high-fat diet-induced NAFLD, presenting a novel strategy for the prevention and treatment of NAFLD.

Salidroside inhibits insulin resistance and hepatic steatosis by downregulating miR-21 and subsequent activation of AMPK and upregulation of PPARα in the liver and muscles of high fat diet-fed rats

This study evaluated if salidroside (SAL) alleviates high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) by downregulating miR-21. Rats (n = 8/group) were treated for 12 weeks as normal diet (control/ND), ND + agmoir negative control (NC) (150 µg/kg), ND + SAL (300 mg/kg), HFD, HFD + SAL, HFD + compound C (an AMPK inhibitor) (200 ng/kg), HFD + SAL + NXT629 (a PPAR-α antagonist) (30 mg/kg), and HFD + SAL + miR-21 agomir (150 µg/kg). SAL improved glucose and insulin tolerance and preserved livers in HFD-fed rats. In ND and HFD-fed rats, SAL reduced levels of serum and hepatic lipids and the hepatic expression of SREBP1, SREBP2, fatty acid (FA) synthase, and HMGCOAR. It also activated hepatic Nrf2 and increased hepatic/muscular activity of AMPK and levels of PPARα. All effects afforded by SAL were prevented by CC, NXT629, and miR-21 agmoir. In conclusion, activation of AMPK and upregulation of PPARα mediate the anti-steatotic effect of SAL.

Resveratrol attenuates against high-fat-diet-promoted non-alcoholic fatty liver disease in rats mainly by targeting the miR-34a/SIRT1 axis

This study evaluated if miR-34a/SIRT1 signalling mediates the anti-hepatosteatotic effect of resveratrol (RSV) in high-fat-diet (HFD)-fed rats. Rats were divided into seven groups (n = 6/each) as control, control + miR-34a agomir negative control, HFD, HFD + miR-34a, HFD + RSV, HFD + RSV + Ex-527 (a SIRT1 inhibitor), and HFD + RSV + miR-34a agomir. After 8 weeks, RSV suppressed dyslipidemia, lowered fasting glucose and insulin levels, improved insulin sensitivity, and prevented hepatic lipid accumulation. These effects were associated with hepatic downregulation of SREBP1 and SREBP2, upregulation of PPARα, and acetylation of Nrf2 (activation) and NF-κβ p65 (inhibition). Also, RSV reduced the transcription of miR-34a and increased the nuclear localisation of SIRT1 in the livers, muscles, and adipose tissues of HFD-fed rats. All these effects were prevented by EX-527 and miR-34a agmir. In conclusion, RSV prevents HFD-induced insulin resistance and hepatic steatosis by suppressing miR-34a-induced activation of SIRT1.

The impact of replacing corn with elephant grass (Pennisetum purpureum) on growth performance, serum parameters, carcass traits, and nutrient digestibility in geese

This study investigated the effects of partially replacing corn with elephant grass dry matter (air drass) on growth performance, serum parameters, carcass traits, and nutrient digestibility in geese. A total of 360 one-day-old Hortobágyi geese were randomly divided into three groups: control (basic diet), 12 % elephant grass, and 24 % elephant grass. The geese were raised for 70 days. The results showed that compared to the control, 12 % elephant grass had no adverse effects on final body weight, feed/gain ratio, mortality, serum liver and kidney function markers. However, 24 % elephant grass significantly reduced the final body weight (P < 0.001) and feed/gain ratio (P = 0.026) compared to the control group. Both experiment groups had decreased serum aspartate aminotransferase (P < 0.001), alanine aminotransferase (P < 0.001), alkaline phosphatase (P < 0.001), triglycerides (P < 0.001), and total cholesterol (P < 0.001). The addition of 12 % and 24 % elephant grass reduced abdominal fat (P = 0.002), but it had no significant effect on slaughter rate, half-bore rate, full-bore rate, breast muscle rate and leg muscle rate. For nutrient digestibility, 12 % elephant grass improved neutral detergent fiber digestibility compared to the control group (P = 0.026). The 24 % grass group had reduced Ca absorption (P = 0.020). Overall, the findings suggest that partially replacing corn with 12 % elephant grass in goose diet can maintain growth performance and carcass traits.It also has no negative effect on nutrient digestibility while improving serum parameters.

Antidiabetic and hepatoprotection effect of butterfly pea flower (Clitoria ternatea L.) through antioxidant, anti-inflammatory, lower LDH, ACP, AST, and ALT on diabetes mellitus and dyslipidemia rat

This study explores the antidiabetic and hepatoprotective potential of Butterfly pea flower extract (Clitoria ternatea L.) (CTE) in diabetic and dyslipidemia rat models. Diabetes Mellitus (DM) is a chronic metabolic disorder marked by high levels of blood glucose, which can cause dyslipidemia and liver damage as a result of oxidative stress. CTE, a natural substance, is recognized for its positive attributes, such as anti-inflammatory, antioxidant, anti-diabetic, anti-dyslipidemia, antibiotic, and liver tissue protection capabilities. Dyslipidemia was induced in rats using a high-fat diet (HFD) and propylthiouracil (PTU) for 28 days. DM was induced using streptozotocin (STZ) and nicotinamide (NA). Rats were treated with varying doses of CTE for 28 days, along with glibenclamide and simvastatin. The research showed that CTE raised the levels of SOD, CAT, and liver proteins while lowering the levels of MDA, LDH, ACP, AST, ALT, IL-1β, and CRP in rats with DM and dyslipidemia. This suggests that CTE might be useful for treating DM.

Natural compounds proposed for the management of non-alcoholic fatty liver disease

Although non-alcoholic fatty liver disease (NAFLD) presents as an intricate condition characterized by a growing prevalence, the often-recommended lifestyle interventions mostly lack high-level evidence of efficacy and there are currently no effective drugs proposed for this indication. The present review delves into NAFLD pathology, its diverse underlying physiopathological mechanisms and the available in vitro, in vivo, and clinical evidence regarding the use of natural compounds for its management, through three pivotal targets (oxidative stress, cellular inflammation, and insulin resistance). The promising perspectives that natural compounds offer for NAFLD management underscore the need for additional clinical and lifestyle intervention trials. Encouraging further research will contribute to establishing more robust evidence and practical recommendations tailored to patients with varying NAFLD grades.

Polyphenols synergistic drugs to ameliorate non-alcoholic fatty liver disease via signal pathway and gut microbiota: A review

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease with an increasing incidence worldwide. Single drug therapy may have toxic side effects and disrupt gut microbiota balance. Polyphenols are widely used in disease intervention due to their distinctive nutritional properties and medicinal value, which a potential gut microbiota modulator. However, there is a lack of comprehensive review to explore the efficacy and mechanism of combined therapy with drugs and polyphenols for NAFLD.

AIM OF REVIEW

Based on this, this review firstly discusses the link between NAFLD and gut microbiota, and outlines the effects of polyphenols and drugs on gut microbiota. Secondly, it examined recent advances in the treatment and intervention of NAFLD with drugs and polyphenols and the therapeutic effect of the combination of the two. Finally, we highlight the underlying mechanisms of polyphenol combined drug therapy in NAFLD. This is mainly in terms of signaling pathways (NF-κB, AMPK, Nrf2, JAK/STAT, PPAR, SREBP-1c, PI3K/Akt and TLR) and gut microbiota. Furthermore, some emerging mechanisms such as microRNA potential biomarker therapies may provide therapeutic avenues for NAFLD.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Drawing inspiration from combination drug strategies, the use of active substances in combination with drugs for NAFLD intervention holds transformative and prospective potential, both improve NAFLD and restore gut microbiota balance while reducing the required drug dosage. This review systematically discusses the bidirectional interactions between gut microbiota and NAFLD, and summarizes the potential mechanisms of polyphenol synergistic drugs in the treatment of NAFLD by modulating signaling pathways and gut microbiota. Future researches should develop multi-omics technology to identify patients who benefit from polyphenols combination drugs and devising individualized treatment plans to enhance its therapeutic effect.

Pharmacology of bioactive compounds from plant extracts for improving non-alcoholic fatty liver disease through endoplasmic reticulum stress modulation: A comprehensive review

Background

Non-alcoholic fatty liver disease (NAFLD) is a prevalent chronic liver condition with significant clinical implications. Emerging research indicates endoplasmic reticulum (ER) stress as a critical pathogenic factor governing inflammatory responses, lipid metabolism and insulin signal transduction in patients with NAFLD. ER stress-associated activation of multiple signal transduction pathways, including the unfolded protein response, disrupts lipid homeostasis and substantially contributes to NAFLD development and progression. Targeting ER stress for liver function enhancement presents an innovative therapeutic strategy. Notably, the natural bioactive compounds of plant extracts have shown potential for treating NAFLD by reducing the level of ER stress marker proteins and mitigating inflammation, stress responses, and de novo lipogenesis. However, owing to limited comprehensive reviews, the effectiveness and pharmacology of these bioactive compounds remain uncertain.

Objectives

To address the abovementioned challenges, the current review categorizes the bioactive compounds of plant extracts by chemical structures and properties into flavonoids, phenols, terpenoids, glycosides, lipids and quinones and examines their ameliorative potential for NAFLD under ER stress.

Methods

This review systematically analyses the literature on the interactions of bioactive compounds from plant extracts with molecular targets under ER stress, providing a holistic view of NAFLD therapy.

Results

Bioactive compounds from plant extracts may improve NAFLD by alleviating ER stress; reducing lipid synthesis, inflammation, oxidative stress and apoptosis and enhancing fatty acid metabolism. This provides a multifaceted approach for treating NAFLD.

Conclusion

This review underscores the role of ER stress in NAFLD and the potential of plant bioactive compounds in treating this condition. The molecular mechanisms by which plant bioactive compounds interact with their ER stress targets provide a basis for further exploration in NAFLD management.

Interaction between dietary flavonoid intake and trouble sleeping on non-alcoholic fatty liver disease risk: a cross-sectional study

OBJECTIVE

The possible interaction of dietary flavonoid intake and sleep on non-alcoholic fatty liver disease (NAFLD) has not been well studied. This study investigated the interaction between dietary flavonoid intake and trouble sleeping on the risk of NAFLD.

METHODS

Three discrete National Health and Nutrition Examination Survey data cycles from 2007 to 2010 and 2017 to 2018 were used. NAFLD was diagnosed by a US Fatty Liver Index ≥30. A sleep questionnaire diagnosed trouble sleeping. Univariate and multivariate logistic regression, restricted cubic spline (RCS) and subgroup analyses were used to evaluate the association between dietary flavonoids, trouble sleeping and NAFLD. We employed the relative excess risk due to interaction, attributable proportion of interaction and synergy index to evaluate additive interactions.

RESULTS

Ultimately, 5056 participants were enrolled, and higher anthocyanidins and flavanones intake was negatively correlated with NAFLD. Conversely, trouble sleeping was positively associated with NAFLD. These correlations remained stable after adjusting for confounders, and there was a sex difference in this relationship. In the RCS model, anthocyanins were negatively non-linearly related to NAFLD, while flavanones showed a negative linear relationship. Moreover, there was a synergistic interplay between low dietary anthocyanin intake and trouble sleeping on the risk of NAFLD. A similar relationship existed for flavanone intake.

CONCLUSION

Anthocyanin and flavanone intake were negatively associated, whereas trouble sleeping was positively associated with NAFLD risk. There was a synergistic effect of low anthocyanin intake and trouble sleeping. The same relationship existed for low flavanone intake.

Delivering Relaxin Plasmid by Polymeric Metformin Lipid Nanoparticles for Liver Fibrosis Treatment

BACKGROUND

Liver fibrosis usually progresses to liver cirrhosis and even results in hepatocellular carcinoma, which accounts for one million deaths annually worldwide. To date, anti-liver fibrosis drugs for clinical treatment have not yet been approved. Nowadays, as a natural regulator, Relaxin (RLX) has received increased attention because the expression of RLX could deactivate the activation of hepatic stellate cells (aHSCs) and resolve liver fibrosis. However, its application in treatment is limited due to the short half-life in circulation and low accumulation within the target organ.

METHODS

To address these problems, a kind of polymeric metformin (PolyMet)-loaded relaxin plasmid (pRLX) core-membrane lipid nanoparticle (PolyMet-pRLX-LNPs, PRLNP) was prepared. Here, PolyMet was used as a carrier to replace the traditional polymer polyethylene diene (PEI), which is of higher toxicity, to prolong the circulation time of pRLX in vivo. Then, the antifibrotic ability of PRLNP to overcome liver fibrosis was carried out in C57BL/6 mice. It is worth mentioning that this is the first time to investigate the potential of PRLNP in carbon tetrachloride-induced liver fibrosis.

RESULTS

The results showed that PRLNP effectively downregulated fibrosis-related biomarkers such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Meanwhile, histopathological examinations also showed low collagen accumulation, revealing that PRLNP could histologically and functionally alleviate liver fibrosis. In addition, no significant difference in serum biochemical value between the PRLNP and the normal group, suggesting the safety profile of PRLNP.

CONCLUSION

This research proposed a novel non-toxic treatment method for liver fibrosis with a nanosystem to effectively treat liver fibrosis.

Does Flavonoid Supplementation Alleviate Non-Alcoholic Fatty Liver Disease? A Systematic Review and Meta-Analysis of Randomized Controlled Trials

SCOPE

Higher flavonoid intake is associated with reduced risk of non-alcoholic fatty liver disease (NAFLD). However, there is a large discrepancy in the effects of flavonoid supplementation on NAFLD. To fill such knowledge gap, we systematically reviewed randomized clinical trials (RCTs) to critically assess flavonoid supplementation effect on liver function, lipid profile, inflammation, and insulin resistance in adults with NAFLD.

METHODS AND RESULTS

A systematic search was conducted from 4 databases from inception until May 2023. Twelve RCTs were included in the final analysis demonstrating beneficial effects of flavonoids on ALT (SMD = -3.59, p = 0.034), AST (SMD = -4.47, p = 0.001), GGT (SMD = -8.70, p = 0.000), CK-18M30 (SMD = -0.35, p = 0.042), TG (SMD = -0.37, p = 0.001), LDL-C (SMD = -0.38, p = 0.039), TC (MD = -0.25 mmol/l, p = 0.017), steatosis score (MD = -18.97, p = 0.30), TNF-α (MD = -0.88, p = 0.000), and NF-κB (MD = -1.62, p = 0.001).

CONCLUSION

This meta-analysis suggests that flavonoid alleviates NAFLD through exerting favourable effects on liver function, lipid profile, and inflammation, indicating flavonoid supplementation presents a promising drug regimen for the management of NAFLD and its associated complications.

Plant-based diets, genetic predisposition and risk of non-alcoholic fatty liver disease

BACKGROUND

Diets rich in plant-based foods are associated with lower risks of non-alcoholic fatty liver disease (NAFLD), while the prospective evidence is limited. We aimed to examine longitudinal associations of plant-based diets and genetic susceptibility with NAFLD risk.

METHODS

This longitudinal cohort study included 159,222 participants (58.0 ± 8.0 years old, 55.7% female) free of NAFLD in the UK Biobank. We calculated the overall plant-based diet index (PDI), the healthful plant-based diet index (hPDI), and the unhealthful plant-based diet index (uPDI). New-onset NAFLD was the primary outcome. The weighted polygenic risk score was calculated based on risk variants associated with NAFLD. Hazard ratios (HR) and 95% confidential intervals (CI) were estimated by Cox proportional hazards model. Magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) measured liver fat content in a subsample of 20,692 participants (57.5 ± 7.4 years old, 52.6% female) was the secondary outcome. The associations between plant-based diet indices and MRI-PDFF were evaluated using generalized linear models.

RESULTS

During a median follow-up of 9.5 years, 1541 new-onset NAFLD cases were documented. Compared to the lowest quintile, multivariable-adjusted hazard ratios (HRs) of NAFLD in the highest quintile were 0.78 (95% confidential intervals [CI], 0.66-0.93, p-trend =0.02), 0.74 (95% CI, 0.62-0.87, p-trend <0.0001), and 1.24 (95% CI, 1.05-1.46, p-trend = 0.02) for overall PDI, hPDI, and uPDI, respectively. For liver fat content, higher overall PDI and hPDI were associated with lower MRI-PDFF, while higher uPDI was associated with higher liver fat content. We observed a significant interaction between hPDI and PRS (p-interaction =0.03), and the NAFLD risk was lowest among participants with the highest hPDI and low genetic risk.

CONCLUSIONS

Higher intake of plant-based diets especially healthful plant-based diets was associated with lower NAFLD risk and liver fat content regardless of genetic susceptibility, whereas an unhealthful plant-based diet was associated with higher NAFLD risk and intrahepatic steatosis. These results suggest that the quality of plant-based foods should be highlighted when adopting a plant-based diet.

Modulation of NRF2/KEAP1-Mediated Oxidative Stress for Cancer Treatment by Natural Products Using Pharmacophore-Based Screening, Molecular Docking, and Molecular Dynamics Studies

Oxidative stress plays a significant role in the development of cancer. Inhibiting the protein-protein interaction (PPI) between Keap1 and Nrf2 offers a promising strategy to activate the Nrf2 antioxidant pathway, which is normally suppressed by the binding of Keap1 to Nrf2. This study aimed to identify natural compounds capable of targeting the kelch domain of KEAP1 using structure-based drug design methods. A pharmacophore model was constructed based on the KEAP1-inhibitor complex, leading to the selection of 6178 compounds that matched the model. Subsequently, docking and MM/GBSA analyses were conducted, resulting in the identification of 10 compounds with superior binding energies compared to the reference compound. From these, three compounds (ZINC000002123788, ZINC000002111341, and ZINC000002125904) were chosen for further investigation. Ligand-residue interaction analysis revealed specific interactions between these compounds and key residues, indicating their stability within the binding site. ADMET analysis confirmed that the selected compounds possessed desirable drug-like properties. Furthermore, molecular dynamics simulations were performed, demonstrating the stability of the ligand-protein complexes over a 100 ns duration. These findings underscore the potential of the selected natural compounds as agents targeting KEAP1 and provide valuable insights for future experimental studies.

Icariin Supplementation Suppresses the Markers of Ferroptosis and Attenuates the Progression of Nonalcoholic Steatohepatitis in Mice Fed a Methionine Choline-Deficient Diet

Icariin, a flavonoid abundant in the herb Epimedium, exhibits anti-ferroptotic activity. However, its impact on nonalcoholic steatohepatitis (NASH) development remains unclear. This study aimed to investigate the potential role of icariin in mitigating methionine choline-deficient (MCD) diet-induced NASH in C57BL/6J mice. The results showed that icariin treatment significantly reduced serum alanine aminotrasferase and aspartate aminotransferase activities while improving steatosis, inflammation, ballooning, and fibrosis in the liver tissues of mice fed the MCD diet. These improvements were accompanied by a substantial reduction in the hepatic iron contents and levels of malondialdehyde and 4-hydroxynonenal, as well as an increase in the activities of catalase and superoxide dismutase. Notably, icariin treatment suppressed the hepatic protein levels of ferroptosis markers such as acyl-CoA synthetase long-chain family member 4 and arachidonate 12-lipoxygenase, which were induced by the MCD diet. Furthermore, transmission electron microscopy confirmed the restoration of morphological changes in the mitochondria, a hallmark characteristic of ferroptosis, by icariin. Additionally, icariin treatment significantly increased the protein levels of Nrf2, a cystine/glutamate transporter (xCT), and glutathione peroxidase 4 (GPX4). In conclusion, our study suggests that icariin has the potential to attenuate NASH, possibly by suppressing ferroptosis via the Nrf2-xCT/GPX4 pathway.

Recent Advances in Potential Health Benefits of Quercetin

Quercetin, a flavonoid found in fruits and vegetables, has been a part of human diets for centuries. Its numerous health benefits, including antioxidant, antimicrobial, anti-inflammatory, antiviral, and anticancer properties, have been extensively studied. Its strong antioxidant properties enable it to scavenge free radicals, reduce oxidative stress, and protect against cellular damage. Quercetin's anti-inflammatory properties involve inhibiting the production of inflammatory cytokines and enzymes, making it a potential therapeutic agent for various inflammatory conditions. It also exhibits anticancer effects by inhibiting cancer cell proliferation and inducing apoptosis. Finally, quercetin has cardiovascular benefits such as lowering blood pressure, reducing cholesterol levels, and improving endothelial function, making it a promising candidate for preventing and treating cardiovascular diseases. This review provides an overview of the chemical structure, biological activities, and bioavailability of quercetin, as well as the different delivery systems available for quercetin. Incorporating quercetin-rich foods into the diet or taking quercetin supplements may be beneficial for maintaining good health and preventing chronic diseases. As research progresses, the future perspectives of quercetin appear promising, with potential applications in nutraceuticals, pharmaceuticals, and functional foods to promote overall well-being and disease prevention. However, further studies are needed to elucidate its mechanisms of action, optimize its bioavailability, and assess its long-term safety for widespread utilization.

Adherence to Mediterranean Diet: Any Association with NAFLD?

Oxidative stress is considered one of the main determinants in the pathophysiology of non-alcoholic fatty liver disease (NAFLD) and obesity. The alterations of oxidant/antioxidant balance are related to chronic impairment of metabolism leading to mitochondrial dysfunction. Increased oxidative stress also triggers hepatocytes stress pathways, leading to inflammation and contributing to the progression of non-alcoholic steatohepatitis (NASH). Currently, the first-line therapeutic treatment of NAFLD is based on lifestyle interventions, suggesting the Mediterranean Diet (MD) as a preferable nutritional approach due to its antioxidant properties. However, it is still debated if adherence to MD could have a role in determining the risk of developing NAFLD directly or indirectly through its effect on weight. We enrolled 336 subjects (aged 35.87 ± 10.37 years; BMI 31.18 ± 9.66 kg/m²) assessing anthropometric parameters, lifestyle habits, metabolic parameters (fasting plasma glucose, fasting plasma insulin, triglycerides (TG), total cholesterol, low-density (LDL) and high-density lipoprotein (HDL) cholesterol, alanine transaminase (ALT), aspartate aminotransferase (AST), and γ-glutamyltransferase (γGT), cardio-metabolic indices [Homeostatic Model Assessment Insulin Resistance (HoMA-IR), visceral adipose index (VAI) and fatty liver index (FLI)] and adherence to MD [with the PREvención con DIetaMEDiterránea (PREDIMED) questionnaire]. Subjects with NAFLD had significantly higher anthropometric parameters, cardio-metabolic indices and lower adherence to MD than subjects without NAFLD. In a multiple regression analysis, PREDIMED score was the main predictor of FLI (p < 0.001) and came in first, followed by HoMA-IR, while VAI was not a predictor. A PREDIMED score value of <6 could serve as a threshold to identify patients who are more likely to have NAFLD (p < 0.001). In conclusion, high adherence to MD resulted in a lower risk of having NAFLD. Adherence to MD could have a direct role on the risk of developing NAFLD, regardless of visceral adipose tissue.

The great potential of flavonoids as candidate drugs for NAFLD

Non-alcoholic fatty liver disease (NAFLD) has a global prevalence of approximately 25 % and is associated with high morbidity and high mortality. NAFLD is a leading cause of cirrhosis and hepatocellular carcinoma. Its pathophysiology is complex and still poorly understood, and there are no drugs used in the clinic to specifically treat NAFLD. Its pathogenesis involves the accumulation of excess lipids in the liver, leading to lipid metabolism disorders and inflammation. Phytochemicals with the potential to prevent or treat excess lipid accumulation have recently received increasing attention, as they are potentially more suitable for long-term use than are traditional therapeutic compounds. In this review, we summarize the classification, biochemical properties, and biological functions of flavonoids and how they are used in the treatment of NAFLD. Highlighting the roles and pharmacological uses of these compounds will be of importance for enhancing the prevention and treatment of NAFLD.

An Ethyl Acetate Extract of Eryngium carlinae Inflorescences Attenuates Oxidative Stress and Inflammation in the Liver of Streptozotocin-Induced Diabetic Rats

Secondary metabolites such as flavonoids are promising in the treatment of non-alcoholic fatty liver disease (NAFLD), which is one of the complications of diabetes due to oxidative stress and inflammation. Some plants, such as Eryngium carlinae, have been investigated regarding their medicinal properties in in vitro and in vivo assays, showing favorable results for the treatment of various diseases such as diabetes and obesity. The present study examined the antioxidant and anti-inflammatory effects of the phenolic compounds present in an ethyl acetate extract of the inflorescences of Eryngium carlinae on liver homogenates and mitochondria from streptozotocin (STZ)-induced diabetic rats. Phenolic compounds were identified and quantified by UHPLC-MS. In vitro assays were carried out to discover the antioxidant potential of the extract. Male Wistar rats were administered with a single intraperitoneal injection of STZ (45 mg/kg) and were given the ethyl acetate extract at a level of 30 mg/kg for 60 days. Phytochemical assays showed that the major constituents of the extract were flavonoids; in addition, the in vitro antioxidant activity was dose dependent with IC50 = 57.97 mg/mL and IC50 = 30.90 mg/mL in the DPPH and FRAP assays, respectively. Moreover, the oral administration of the ethyl acetate extract improved the effects of NAFLD, decreasing serum and liver triacylglycerides (TG) levels and oxidative stress markers and increasing the activity of the antioxidant enzymes. Likewise, it attenuated liver damage by decreasing the expression of NF-κB and iNOS, which lead to inflammation and liver damage. We hypothesize that solvent polarity and consequently chemical composition of the ethyl acetate extract of E. carlinae, exert the beneficial effects due to phenolic compounds. These results suggest that the phenolic compounds of the ethyl acetate extract of E. carlinae have antioxidant, anti-inflammatory, hypolipidemic, and hepatoprotective activity.

Evaluation of the Effects of Chia (Salvia hispanica L.) Leaves Ethanolic Extracts Supplementation on Biochemical and Hepatic Markers on Diet-Induced Obese Mice

Obesity is a significant health concern affecting 13% of the world's population. It is often associated with insulin resistance and metabolic-associated fatty liver disease (MAFLD), which can cause chronic inflammation in the liver and adipose tissue. Obese hepatocytes show increased lipid droplets and lipid peroxidation, which can lead to the progression of liver damage. Polyphenols have been shown to have the ability to reduce lipid peroxidation, thereby promoting hepatocyte health. Chia leaves, a by-product of chia seed production, are a natural source of bioactive antioxidant compounds, such as cinnamic acids and flavonoids, which have antioxidant and anti-inflammatory properties. In this study, chia leaves' ethanolic extracts of two seed phenotypes were tested on diet-induced obese mice to evaluate their therapeutic potential. Results show that the chia leaf extract positively affected insulin resistance and lipid peroxidation in the liver. In addition, the extract improved the HOMA-IR index compared to the obese control group, reducing the number and size of lipid droplets and lipid peroxidation. These results suggest that chia leaf extract may help treat insulin resistance and liver damage associated with MAFLD.

Does the Mediterranean Diet Have Any Effect on Lipid Profile, Central Obesity and Liver Enzymes in Non-Alcoholic Fatty Liver Disease (NAFLD) Subjects? A Systematic Review and Meta-Analysis of Randomized Control Trials

The effectiveness of the Mediterranean diet (MD) in non-alcoholic fatty liver disease (NAFLD) subjects has been evaluated in several randomized controlled trials (RCTs). This systematic review and meta-analysis aimed to evaluate the overall effects of MD intervention in a cohort of NAFLD patients targeting specific markers such as central obesity, lipid profile, liver enzymes and fibrosis, and intrahepatic fat (IHF). Google Scholar, PubMed, and Scopus were explored to collect relevant studies from the last 10 years. RCTs with NAFLD subjects were included in this systematic review with a mean intervention duration from 6 weeks to 1 year, and different intervention strategies, mainly including energy restriction MD (normal or low glycaemic index), low-fat MD with increased monounsaturated and polyunsaturated fatty acids, and increased exercise expenditure. The outcomes measured in this meta-analysis were gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), total cholesterol (TC), waist circumference (WC), and liver fibrosis. Ten randomized controlled trials, which involved a total of 737 adults with NAFLD, were included. According to the results, the MD seems to decrease the liver stiffness (kPa) by -0.42 (CI95% -0.92, 0.09) (p = 0.10) and significantly reduce the TC by -0.46 mg/dl (CI95% -0.55, -0.38) (p = 0.001), while no significant findings were documented for liver enzymes and WC among patients with NAFLD. In conclusion, the MD might reduce indirect and direct outcomes linked with NAFLD severity, such as TC, liver fibrosis, and WC, although it is important to consider the variations across trials. Further RCTs are necessary to corroborate the findings obtained and provide further evidence on the role of the MD in the modulation of other disorders related to NAFLD.

The Preventive and Therapeutic Potential of the Flavonoids in Liver Cirrhosis: Current and Future Perspectives

Non-alcoholic fatty liver disease (NAFLD) may vary from moderately mild non-alcohol fatty liver (NAFL) towards the malignant variant known as non-alcoholic steatohepatitis (NASH), which is marked by fatty liver inflammation and may progress to liver cirrhosis (LC), liver cancer, fibrosis, or liver failure. Flavonoids can protect the liver from toxins through their anti-inflammatory, antioxidant, anti-cancer, and antifibrogenic pharmacological activities. Furthermore, flavonoids protect against LC by regulation of hepatic stellate cells (HSCs) trans-differentiation, inhibiting growth factors like TGF-β and platelets-derived growth factor (PDGF), vascular epithelial growth factor (VEGF), viral infections like hepatitis-B, C and D viruses (HBV, HCV & HDV), autoimmune-induced, alcohol-induced, metabolic disorder-induced, causing by apoptosis, and regulating MAPK pathways. These flavonoids may be explored in the future as a therapeutic solution for hepatic diseases.

Ellagic Acid and Its Metabolites as Potent and Selective Allosteric Inhibitors of Liver Pyruvate Kinase

Liver pyruvate kinase (PKL) has recently emerged as a new target for non-alcoholic fatty liver disease (NAFLD), and inhibitors of this enzyme could represent a new therapeutic option. However, this breakthrough is complicated by selectivity issues since pyruvate kinase exists in four different isoforms. In this work, we report that ellagic acid (EA) and its derivatives, present in numerous fruits and vegetables, can inhibit PKL potently and selectively. Several polyphenolic analogues of EA were synthesized and tested to identify the chemical features responsible for the desired activity. Molecular modelling studies suggested that this inhibition is related to the stabilization of the PKL inactive state. This unique inhibition mechanism could potentially herald the development of new therapeutics for NAFLD.

Pluchea indica Leaf Extract Alleviates Dyslipidemia and Hepatic Steatosis by Modifying the Expression of Lipid Metabolism-Related Genes in Rats Fed a High Fat-High Fructose Diet

This study evaluated the effect of Pluchea indica leaf extract (PIE) on dyslipidemia and lipid accumulation in the liver, emphasizing its molecular mechanisms in regulating lipid metabolism in rats fed a high fat-high fructose diet (HFFD). Male rats were fed HFFD (40% lard and 20% fructose) for ten weeks. They were then divided into four groups receiving distilled water, PIE (100 or 300 mg/kg/d), and pioglitazone (10 mg/kg/d) for a further six weeks, during which the HFFD was continued. After the experiment, fasting blood glucose (FBG), oral glucose tolerance (OGT), serum insulin and leptin levels, lipid profiles, and hepatic triglyceride content were measured. Histological examination and expression levels of lipid metabolism-related genes in the liver were measured. HFFD-fed rats indicated a significantly increased FBG, serum leptin, and homeostasis model assessment of insulin resistance (HOMA-IR) scores with impaired OGT and dyslipidemia compared to rats fed a normal diet. PIE significantly reduced FBG, serum leptin, and HOMA-IR scores and improved OGT. Additionally, PIE significantly improved dyslipidemia and decreased serum-free fatty acids and liver triglyceride content. Hepatic histological examination showed a marked reduction lipid accumulation in relation to HFFD controls. Interestingly, PIE significantly downregulated the expression of lipid synthesis-related genes and upregulated the expression of fatty-acid oxidation-related genes. In conclusion, PIE alleviates dyslipidemia and hepatic steatosis in HFFD rats plausibly by increasing insulin resistance and modifying the gene expression associated with lipid metabolism. PIE may be used as preventive nutrition for dyslipidemia and hepatic steatosis.

The Synergistic Protective Effect of γ-Oryzanol (OZ) and N-Acetylcysteine (NAC) against Experimentally Induced NAFLD in Rats Entails Hypoglycemic, Antioxidant, and PPARα Stimulatory Effects

This study estimated that the combined effect of γ-Oryzanol and N-acetylcysteine (NAC) against high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in rats also estimated some of their mechanisms of action. Adult male rats were divided into seven groups (n = 8 each) as control, control + NAC, control + γ-Oryzanol, HFD, HFD + NAC, HFD + γ-Oryzanol, and HFD + NAC + γ-Oryzanol. NAC was administered orally at a final concentration of 200 mg/kg, whereas γ-Oryzanol was added to diets at a concentration of 0.16. All treatments were conducted for 17 weeks and daily. Both NAC and γ-Oryzanol were able to reduce final body weights, fat weights, fasting glucose, fasting insulin, serum, and serum levels of liver function enzymes as well as the inflammatory markers such as tumor necrosis factor-α (TNF-α), interleukine-6 (IL-6), and leptin in HFD-fed rats. They also improved hepatic structure and glucose tolerance, increased adiponectin levels, and reduced serum and hepatic levels of triglycerides (TGs) and cholesterol (CHOL) in these rats. These effects were concomitant with a reduction in the hepatic levels of lipid peroxides (MDA) and serum levels of LDL-C, but also with an increment in the hepatic levels of superoxide dismutase (SOD) and glutathione (GSH). Interestingly, only treatment with γ-Oryzanol stimulated the mRNA levels of proliferator-activated receptor alpha (PPARα) and carnitine palmitoyltransferase 1 (CPT1) in the liver and white adipose tissue (WAT) of rats. Of note, the combination therapy of both drugs resulted in maximum effects and restored almost normal liver structure and basal levels of all the above-mentioned metabolic parameters. In conclusion, a combination therapy of γ-Oryzanol and NAC is an effective therapy to treat NAFLD, which can act via several mechanisms on the liver and adipose tissue.

Dietary phytochemical index and the risk of non-alcoholic fatty liver disease: A case-control study among Iranian adults

BACKGROUNDS

Dietary phytochemical index (DPI) is an inexpensive method for estimating the amounts of phytochemicals in foods. No study has investigated the association between DPI and non-alcoholic fatty liver disease (NAFLD). Our study aimed to compare DPI in patients with NAFLD and the control group.

METHODS

This is a case-control study of 250 subjects with NAFLD and 450 healthy subjects attending the Metabolic Liver Disease Research Center as a referral center affiliated to Isfahan University of Medical Sciences. DPI was calculated based on data collected from a 168-item validated food frequency questionnaire. Sociodemographic data, physical activity, and anthropometric measures such as body weight, height, and waist circumference were determined.

RESULTS

In the final adjusted model, the odds ratio (OR) of NAFLD across the DPI tertiles decreased significantly (OR = 0.55, 95 %CI = 0.31-0.95) (P-trend = 0.03). The highest vs. lowest tertiles of vegetable and olives PI were significantly associated with a lower risk of NAFLD (OR and 95 % CI = 0.26 (0.14-0.47); OR and 95 % CI = 0.51 (0.29-0.90), p for trend < 0.001, respectively), however, there was no significant relation between other PI components and NAFLD.

CONCLUSION

This case-control study suggested that a higher PI score is associated with a reduced chance of NAFLD after adjusting for confounding variables. In addition, the highest tertile of vegetable and olives PI was significantly associated with a lower risk of NAFLD.

Black ginseng protects against Western diet-induced nonalcoholic steatohepatitis by modulating the TLR4/NF-κB signaling pathway in mice

Black ginseng (BG) shows beneficial effects on liver injury, but the related mechanism has not been fully revealed. This study attempted to investigate the protective effects and associated mechanisms of BG against nonalcoholic steatohepatitis (NASH). Twelve ginsenosides in BG were annotated by ultrahigh performance liquid chromatography combined with high resolution mass spectrometry (UHPLC-HRMS). The Western diet (WD) together with the low-dose CCl₄ was given to mice to create the NASH model. Histopathological examination and liver/serum biochemical analysis revealed that the NASH mice displayed severe steatosis and liver damage compared with control mice. After BG administration, the serum and liver triglycerides (TG) concentrations and the serum level of low-density lipoprotein (LDL) were dramatically reduced. Besides, the BG treatment greatly decreased the serum values of interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α), and the hepatic expression of fibrotic-related genes, such as alpha-smooth muscle actin (α-SMA) and collagen type I alpha 1 (Col1α1). We further discovered that BG administration could block the protein expression of toll-like receptor 4 (TLR4) and the phosphorylation of nuclear factor-kappa B p65 (NF-κB p65), indicating that BG exerted a liver protective effect via regulating the TLR4/NF-κB pathway. This study demonstrated the therapeutic efficacy and the associated mechanism of BG in the treatment of NASH, giving evidence for BG as a potential functional food to prevent NASH. PRACTICAL APPLICATIONS: BG is a type of processed ginseng product that has been used as diet supplementation and has shown favorable effects on liver injury. However, the pharmacological impact of BG on NASH has not been studied in depth. The present study showed that BG could effectively reduce WD-induced liver fibrosis and inflammation through the TLR4/NF-κB axis, which indicated that BG has the potential to be utilized as a functional herb to attenuate liver injury.

Structural Insights into Amelioration Effects of Quercetin and Its Glycoside Derivatives on NAFLD in Mice by Modulating the Gut Microbiota and Host Metabolism

The sugar moieties of natural flavonoids determine their absorption, bioavailability, and bioactivity in humans. To explore structure-dependent bioactivities of quercetin, isoquercetin, and rutin, which have the same basic skeleton linking different sugar moieties, we systemically investigated the ameliorative effects of dietary these flavonoids on high-fat diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) of mice. Our results revealed that isoquercetin exhibits the strongest capability in improving NAFLD phenotypes of mice, including body and liver weight gain, glucose intolerance, and systemic inflammation in comparison with quercetin and rutin. At the molecular level, dietary isoquercetin markedly ameliorated liver dysfunction and host metabolic disorders in mice with NAFLD. At the microbial level, the three flavonoids compounds, especially isoquercetin, can effectively regulate the gut microbiota composition, such as genera Akkermansia, Bifidobacterium, and Lactobacillus, which were significantly disrupted in NAFLD mice. These comparative findings offer new insights into the structure-dependent activities of natural flavonoids for NAFLD treatment.

Fagopyrum dibotrys extract alleviates hepatic steatosis and insulin resistance, and alters autophagy and gut microbiota diversity in mouse models of high-fat diet-induced non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a major global health concern with increasing prevalence, with a lack of currently available effective treatment options; thus, the investigation of novel therapeutic approaches is necessary. The study aimed to investigate the outcomes and mechanisms of action of Fagopyrum dibotrys extract (FDE) in a high-fat diet (HFD)-induced mouse model of obesity. The findings showed that FDE supplementation attenuated glucose tolerance, insulin resistance (IR), hepatic steatosis, and abnormal lipid metabolism. In addition, FDE also promoted autophagic activity and inhibited the phosphorylation of transcription factor EB in HFD-fed mice. Furthermore, gut microbiota characterization via 16S rRNA sequencing revealed that the supplementation of FDE increased Bacteroidetes and Verrucomicrobia populations while decreased Firmicutes, thus modifying the gut microbiome. FDE also increased the relative abundance of Akkermansia. Our findings suggest that FDE may protect against HFD-induced NAFLD by activating autophagy and alleviating dysbiosis in the gut microbiome. FDE may be beneficial as a nutraceutical treatment for NAFLD.

Is it possible to treat nonalcoholic liver disease using a flavanol-based nutraceutical approach? Basic and clinical data

Nonalcoholic fatty liver disease (NAFLD) is characterized by a spectrum of diseases, ranging from simple steatosis to hepatocellular carcinoma. The main factors for NAFLD are closely related to obesity, insulin resistance, intestinal microbiota alterations, hyperinsulinism, low-grade systemic inflammation, nitroxidative stress, lipid peroxidation, and mitochondrial dysfunction. Currently, the treatment of NAFLD is based on diet and exercise because, to date, there is no specific pharmacological agent, already approved, that raises the need for new therapeutic strategies. Nutraceuticals, such as polyphenols, have potential beneficial effects for health. In this article, the beneficial effects of epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC) are discussed. EGCG is the main catechin in green tea, which has shown in various studies its potential effect preventing and treating NAFLD since it has shown antihyperlipidemic, anti-inflammatory, antifibrotic, antioxidant, and improvement of liver lipid metabolism. However, it has been found that excessive consumption may cause hepatotoxicity. EC is widely distributed in nature (fruits and vegetables). This flavanol has shown many beneficial effects, including antihypertensive, anti-inflammatory, anti-hyperglycemic, antithrombotic, and antifibrotic properties. It increases mitochondrial biogenesis, and it also has effects on the regulation of synthesis and metabolism of lipids. This flavanol is a nontoxic substance; it has been classified by the United States Food and Drug Administration as harmless. The EC-induced effects can be useful for the prevention and/or treatment of NAFLD.

The effect of a fruit-rich diet on liver biomarkers, insulin resistance, and lipid profile in patients with non-alcoholic fatty liver disease: a randomized clinical trial

BACKGROUND

Despite confirmed dietary approaches to improve the Non-Alcoholic Fatty Liver Disease (NAFLD), the effect of fruits on NAFLD is not clear. The present study aimed to investigate the effect of a fruit rich diet (FRD) on liver steatosis, liver enzymes, Insulin resistance, and lipid profile in patients with NAFLD.

METHODS

Eighty adults with NAFLD participated in this randomized controlled trial. The participants were randomly assigned to the FRD group with consumption of at least 4 servings of fruits daily or the control group with fruits consumption of less than 2 servings/day. The grade of steatosis, serum levels of liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), glucose, and homeostatic model assessment for insulin resistance (HOMA-IR) were measured at the baseline and at the end of the study.

RESULTS

After 6 months of intervention, the FRD group had significantly higher BMI (31.40 ± 2.61 vs. 25.68 ± 2.54, p < .001), WC (113.5 ± 10.7 vs. 100.5 ± 7.5, p < .001), the grade of steatosis, ALT (89.1 ± 92.9 vs. 32.0 ± 19.2, p < .001), AST (74.5 ± 107.8 vs. 24.0 ± 8.5, p < .001), ALP (273.4 ± 128.5 vs. 155.0 ± 43.9, p < .001), GGT (92.7 ± 16.2 vs. 21.2 ± 7.7, p < .001), TC (206.1 ± 40.5 vs. 172.7 ± 42.4, p < .01), LDL (126.9 ± 32.3 vs. 99.8 ± 29.8, p < .001), glucose (115.5 ± 30.0 vs. 97.7 ± 19.0, p < .01), and insulin resistance (7.36 ± 4.37 vs. 2.66 ± 1.27, p < .001), and lower HDL (41.4 ± 8.9 vs. 53.8 ± 15.1, p < .001) compared to the control group. Adjusting for BMI and calorie intake did not change the results.

CONCLUSION

The results of the present study indicated that consumption of fruits more than 4 servings/day exacerbates steatosis, dyslipidemia, and glycemic control in NAFLD patients. Further studies are needed to identify the underlying mechanisms of the effects of fruits on NAFLD.

CLINICAL TRIAL REGISTRATION

This trial was registered at Iranian randomized clinical trial website with IRCT registration no. IRCT20201010048982N1on October 15, 2020.

Natural flavonoids: Potential therapeutic strategies for non-alcoholic fatty liver disease

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing rapidly worldwide; however, there are currently limited treatments for NAFLD. The disease spectrum includes simple fatty liver, non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and progression to hepatocellular carcinoma (NASH-HCC). The therapeutic effects of NAFLD remain controversial. Although researchers have conducted studies on the pathogenesis of NAFLD, its pathogenesis and anti-NAFLD mechanisms have not been fully elucidated. Previous studies have found that flavonoids, as natural substances with extensive pharmacological activity and good therapeutic effects, have excellent antioxidant, anti-inflammatory, metabolic disease improvement, anti-tumor, and other properties and can significantly alleviate NAFLD. Flavonoids could be further developed as therapeutic drugs for NAFLD. In this paper, the pathogenesis of NAFLD and the mechanisms of flavonoids against NAFLD are summarized to provide a theoretical basis for screening flavonoids against non-alcoholic liver injury.

Wax apple (Syzygium samarangense) fruit extract ameliorates endothelial dysfunction and liver damage in high cholesterol diet-fed rats

Background and aim

Wax apple fruit (Syzygium samarangense) is one of the most popular tropical fruit in Asia, and contains several essential nutrients. Therefore, this study explored the effects of the wax apple fruit extract on a high-cholesterol diet-induced vascular endothelial dysfunction and fatty liver in rats.

Experimental procedure

Male Sprague Dawley rats were fed a diet with 1.5% cholesterol (HCD) for 8 weeks, and were given wax apple fruit extract (50 and 100 mg/kg/day) orally for the last 4 weeks. After 8 weeks, blood sample, thoracic aorta, and liver were collected and processed for biochemical and histological analysis. Additionally, vascular endothelial function and the protein expression of oxidative stress markers in aortae were evaluated.

Results and conclusion

Wax apple reduced serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), but increased high-density lipoprotein cholesterol (HDL-C) levels. Furthermore, the liver levels of TG and TC were reduced in wax apple-treated hypercholesterolemic rats. Histological studies revealed that wax apple ameliorated HCD-induced morphologic changes of aortic and liver tissues of rats. In aortic tissues, the impaired endothelium-dependent responses to acetylcholine, the reduced nitric oxide (NO) contents, the elevated endothelin (ET)-1 contents, and the increased expression of NADPH oxidase subunit p47^phox and 4-hydroxynonenal in HCD-fed rats were reversed by wax apple treatment. These results suggest that oral administration of wax apple improves vascular dysfunction and damage in hypercholesterolemic rats possibly through increasing NO bioavailability, decreasing ET-1 levels and reducing oxidative stress. Furthermore, wax apple ameliorates the HCD-induced fatty liver in rats.

Phytochemicals targeting NAFLD through modulating the dual function of forkhead box O1 (FOXO1) transcription factor signaling pathways

Literature evidence reveals that natural compounds are potential candidates for ameliorating obesity-associated non-alcoholic fatty liver disease (NAFLD) by targeting forkhead box O1 (FOXO1) transcription factor. FOXO1 has a dual and complex role in regulating both increase and decrease in lipid accumulation in hepatocytes and adipose tissues (AT) at different stages of NAFLD. In insulin resistance (IR), it is constitutively expressed, resulting in increased hepatic glucose output and lipid metabolism irregularity. The studies on different phytochemicals indicate that dysregulation of FOXO1 causes disturbance in cellular nutrients homeostasis, and the natural entities have an enduring impact on the mitigation of these abnormalities. The current review communicates and evaluates certain phytochemicals through different search engines, targeting FOXO1 and its downstream cellular pathways to find lead compounds as potential therapeutic agents for treating NAFLD and related metabolic disorders. The findings of this review confirm that polyphenols, flavonoids, alkaloids, terpenoids, and anthocyanins are capable of modulating FOXO1 and associated signaling pathways, and they are potential therapeutic agents for NAFLD and related complications. HIGHLIGHTS: • FOXO1 has the potential to be targeted by novel drugs from natural sources for the treatment of NAFLD and obesity. • FOXO1 regulates cellular autophagy, inflammation, oxidative stress, and lipogenesis through alternative mechanisms. • Phytochemicals treat NAFLD by acting on FOXO1 or SREBP1c and PPARγ transcription factor signaling pathways.

Hepatoprotective mechanism of Silybum marianum on nonalcoholic fatty liver disease based on network pharmacology and experimental verification

The study aimed to identify the key active components in Silybum marianum (S. marianum) and determine how they protect against nonalcoholic fatty liver disease (NAFLD). TCMSP, DisGeNET, UniProt databases, and Venny 2.1 software were used to identify 11 primary active components, 92 candidate gene targets, and 30 core hepatoprotective gene targets in this investigation, respectively. The PPI network was built using a string database and Cytoscape 3.7.2. The KEGG pathway and GO biological process enrichment, biological annotation, as well as the identified hepatoprotective core gene targets were analyzed using the Metascape database. The effect of silymarin on NAFLD was determined using H&E on pathological alterations in liver tissues. The levels of liver function were assessed using biochemical tests. Western blot experiments were used to observe the proteins that were expressed in the associated signaling pathways on the hepatoprotective effect, which the previous network pharmacology predicted. According to the KEGG enrichment study, there are 35 hepatoprotective signaling pathways. GO enrichment analysis revealed that 61 biological processes related to the hepatoprotective effect of S. marianum were identified, which mainly involved in response to regulation of biological process and immune system process. Silymarin was the major ingredient derived from S. marianum, which exhibited the hepatoprotective effect by reducing the levels of ALT, AST, TC, TG, HDL-C, LDL-C, decreasing protein expressions of IL-6, MAPK1, Caspase 3, p53, VEGFA, increasing protein expression of AKT1. The present study provided new sights and a possible explanation for the molecular mechanisms of S. marianum against NAFLD.

Abelmoschus esculentus (L.) Moench improved blood glucose, lipid, and down-regulated PPAR-α, PTP1B genes expression in diabetic rats

Okra (Abelmoschus esculentus (L.) Moench) is one of the most important medicinal plants for the treatment of diabetes. Flavonoids are one of the most significant components of okra and are responsible for their antioxidant, anti-inflammatory, and anti-diabetic effects. The aim of this research was to investigate the effect of okra extract on biochemical parameters and expression of protein tyrosine phosphatase 1B (PTP1B) and Peroxisome proliferator-activated receptors (PPARs) genes in a model of streptozotocin-induced diabetic male Wistar rat. Rats were given oral dosages of okra extract, (75% ethanolic extract) (200-400 mg/kg) for eight weeks. Our findings indicate that okra extract and quercetin therapy may lower blood glucose (BS), insulin, Triglyceride (TG), Cholesterol (Cho), and glucose transporter protein type-4 (GLUT4) levels. PTP1B and Peroxisome proliferator-activated receptor alpha (PPAR-α), which are important regulators of glucose and lipid homeostasis, are similarly inhibited by okra extract. According to the findings, okra extract also has antioxidant properties. Our results support the anti-hyperglycemic and hypolipidemic properties of okra extract. As a result, it appears to play a crucial role in controlling diabetes. PRACTICAL APPLICATIONS: In this paper, we show that flavonoids in okra may help diabetes by inhibiting the PTP1B and PPAR-pathways. This is significant because little research has been done on the impact of flavonoid chemicals in A. esculentus on the expression of PTP1B and PPAR using traditional methods of diabetes treatment. Many of today's essential drugs (e.g., atropine, ephedrine, tubocurarine, digoxin, and reserpine) have been developed by studding traditional treatments. Plant-derived medications are still used as a prototype by chemists in an effort to develop more effective and less risky treatments (e.g., morphine, taxol, physostigmine, quinidine, and emetine.

Peach Kernel Extracts Inhibit Lipopolysaccharide-Induced Activation of HSC-T6 Hepatic Stellate Cells

There is an important role for hepatic stellate cells (HSCs) in liver fibrosis. As it stands, many traditional Chinese medicine formulations can effectively improve liver fibrosis, whether it is clinically used or in animal studies; however, the efficacy and mechanism of the main formulations remain unclear, including the peach kernel, which contains numerous phytochemicals with a wide range of biological activities. The purpose of this study was to investigate peach kernel's anti-liver fibrosis effects. In this study, peach kernel extracts inhibited lipopolysaccharide (LPS) activation in HSC-T6 cells and the expression of α-smooth muscle actin and connective tissue growth factor induced by LPS in HSC-T6 cells. Furthermore, peach kernel extracts inhibited signal transducers involving protein kinase B and mitogen-activated protein kinase, which regulate downstream genes associated with inflammation. As a result, peach kernel extracts inhibited inflammatory responses and subsequently inhibited LPS-induced transformation of activated HSC-T6 cells.

Flavonoids Seen through the Energy Perspective

In all life forms, opposing forces provide the energy that flows through networks in an organism, which fuels life. In this concept, health is the ability of an organism to maintain the balance between these opposing forces, which creates resilience, and a deranged flow of energy is the basis for diseases. Treatment should focus on adjusting the deranged flow of energy, e.g., by the redox modulating activity of antioxidants. A major group of antioxidants is formed by flavonoids, a group of polyphenolic compounds abundantly present in our diet. The objective here is to review how the redox modulation by flavonoids fits in the various concepts on the mode of action of bioactive compounds, so we can 'see' where there is overlap and where the missing links are. Based on this fundament, we should choose our research path aiming to 'understand' the redox modulating profile of specific flavonoids, so we can ultimately rationally apply the redox modulating power of flavonoids to improve our health.

The Hepatic Sinusoid in Chronic Liver Disease: The Optimal Milieu for Cancer

Simple Summary

During the development of chronic liver disease, the hepatic sinusoid undergoes major changes that further compromise the hepatic function, inducing persistent inflammation and the formation of scar tissue, together with alterations in liver hemodynamics. This diseased background may induce the formation and development of hepatocellular carcinoma (HCC), which is the most common form of primary liver cancer and a major cause of mortality. In this review, we describe the ways in which the dysregulation of hepatic sinusoidal cells—including liver sinusoidal cells, Kupffer cells, and hepatic stellate cells—may have an important role in the development of HCC. Our review summarizes all of the known sinusoidal processes in both health and disease, and possible treatments focusing on the dysregulation of the sinusoid; finally, we discuss how some of these alterations occurring during chronic injury are shared with the pathology of HCC and may contribute to its development.

Abstract

The liver sinusoids are a unique type of microvascular beds. The specialized phenotype of sinusoidal cells is essential for their communication, and for the function of all hepatic cell types, including hepatocytes. Liver sinusoidal endothelial cells (LSECs) conform the inner layer of the sinusoids, which is permeable due to the fenestrae across the cytoplasm; hepatic stellate cells (HSCs) surround LSECs, regulate the vascular tone, and synthetize the extracellular matrix, and Kupffer cells (KCs) are the liver-resident macrophages. Upon injury, the harmonic equilibrium in sinusoidal communication is disrupted, leading to phenotypic alterations that may affect the function of the whole liver if the damage persists. Understanding how the specialized sinusoidal cells work in coordination with each other in healthy livers and chronic liver disease is of the utmost importance for the discovery of new therapeutic targets and the design of novel pharmacological strategies. In this manuscript, we summarize the current knowledge on the role of sinusoidal cells and their communication both in health and chronic liver diseases, and their potential pharmacologic modulation. Finally, we discuss how alterations occurring during chronic injury may contribute to the development of hepatocellular carcinoma, which is usually developed in the background of chronic liver disease.

Hepatic Krüppel-like factor 16 (KLF16) targets PPARα to improve steatohepatitis and insulin resistance

OBJECTIVE

Impaired hepatic fatty acids oxidation results in lipid accumulation and redox imbalance, promoting the development of fatty liver diseases and insulin resistance. However, the underlying pathogenic mechanism is poorly understood. Krüppel-like factor 16 (KLF16) is a transcription factor that abounds in liver. We explored whether and by what mechanisms KLF16 affects hepatic lipid catabolism to improve hepatosteatosis and insulin resistance.

DESIGN

KLF16 expression was determined in patients with non-alcoholic fatty liver disease (NAFLD) and mice models. The role of KLF16 in the regulation of lipid metabolism was investigated using hepatocyte-specific KLF16-deficient mice fed a high-fat diet (HFD) or using an adenovirus/adeno-associated virus to alter KLF16 expression in mouse primary hepatocytes (MPHs) and in vivo livers. RNA-seq, luciferase reporter gene assay and ChIP analysis served to explore the molecular mechanisms involved.

RESULTS

KLF16 expression was decreased in patients with NAFLD, mice models and oleic acid and palmitic acid (OA and PA) cochallenged hepatocytes. Hepatic KLF16 knockout impaired fatty acid oxidation, aggravated mitochondrial stress, ROS burden, advancing hepatic steatosis and insulin resistance. Conversely, KLF16 overexpression reduced lipid deposition and improved insulin resistance via directly binding the promoter of peroxisome proliferator-activated receptor α (PPARα) to accelerate fatty acids oxidation and attenuate mitochondrial stress, oxidative stress in db/db and HFD mice. PPARα deficiency diminished the KLF16-evoked protective effects against lipid deposition in MPHs. Hepatic-specific PPARα overexpression effectively rescued KLF16 deficiency-induced hepatic steatosis, altered redox balance and insulin resistance.

CONCLUSIONS

These findings prove that a direct KLF16-PPARα pathway closely links hepatic lipid homeostasis and redox balance, whose dysfunction promotes insulin resistance and hepatic steatosis.

Nonalcoholic fatty liver disease: The role of quercetin and its therapeutic implications

Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease, affecting almost one-third of the general population and 75% of obese patients with type 2 diabetes. The aim of this article is to review the current evidence concerning the role of quercetin, a natural compound and flavonoid, and its possible therapeutic effects on this modern-day disease. Despite the fact that the exact pathophysiological mechanisms through which quercetin has a hepatoprotective effect on NAFLD are still not fully elucidated, this review clearly demonstrates that this flavonoid has potent antioxidative stress action and inhibitory effects on hepatocyte apoptosis, inflammation, and generation of reactive oxygen species, factors which are linked to the development of the disease. NAFLD is closely associated with increased dietary fat consumption, especially in Western countries. The hepatoprotective effect of quercetin against NAFLD merits serious consideration and further validation by future studies.

Nanoencapsulation of Polyphenols as Drugs and Supplements for Enhancing Therapeutic Profile - A Review

Polyphenolic phytoconstituents have been widely in use worldwide since ages and are categorised as secondary metabolites of plants. The application of polyphenols such as quercetin, resveratrol. curcumin as nutritional supplement has been researched widely. The use of polyphenols, and specifically quercetin for improving the memory and mental endurance have shown significant effects among rats. Even though similar results has not been resonated among human but encouraging preclinical results have encouraged researchers to explore other polyphenols to study the effects as supplements among athletes. The phytopharmacological research has elucidated the use of natural polyphenols to prevent and treat various physiological and metabolic disorders owing to its free radical scavenging properties, anti-inflammatory, anti-cancer and immunomodulatory effects. In spite of the tremendous pharmacological profile, one of the most dominant problem regarding the use of polyphenolic compounds is their low bioavailability. Nanonization is considered as one of the most prominent approaches among many. This article aims to review and discuss the molecular mechanisms of recently developed nanocarrier-based drug delivery systems for polyphenols and its application as drugs and supplements. Nanoformulations of natural polyphenols are bioactive agents, such as quercetin, kaempferol, fisetin, rutin, hesperetin, and naringenin epigalloccatechin-3-gallate, genistein, ellagic acid, gallic acid, chlorogenic acid, ferulic acid, curcuminoids and stilbenes is expected to have better efficacy. These delivery systems are expected to provide higher penetrability of polyphenols at cellular levels and exhibit a controlled release of the drugs. It is widely accepted that natural polyphenols do demonstrate significant therapeutic effect. However, the hindrances in their absorption, specificity and bioavailability can be overcome using nanotechnology.

Placental extract ameliorates liver fibrosis in a methionine- and choline-deficient diet-induced mouse model of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is a severe form of fatty liver disease that is defined by the presence of inflammation and fibrosis, which ultimately leads to cirrhosis and hepatocellular carcinoma. We previously showed that human placental extract (hPE) was intramuscularly injected to ameliorates liver injury in a methionine- and choline-deficient (MCD) diet-induced NASH model. In the present study, we investigated the effects of hPE using dB/dB mice which exhibit obesity and insulin resistance and are thought to reproduce the pathological background of NASH. The MCD-diet induced liver atrophy accompanied by fibrosis around the liver sinusoids. hPE dose-dependently reduced the perivascular fibrosis. Moreover, αSMA-positive activated hepatic stellate cells increased in number in mice on the MCD diet, with this effect reversed by hPE treatment. hPE significantly decreased expression of Acta2, Col1a1, and Tgfb1 genes in hepatic stellate cells, and inhibited Smad phosphorylation. Moreover, hPE treatment increased the expression of the anti-oxidative genes Hmox1, Nqo1, Cat, and Sod1, and significantly enhanced nuclear factor erythroid 2-related factor 2 activity. Furthermore, hPE decreased the expression of Nox4 and attenuated the levels of intracellular reactive oxygen species. These results, along with our previous study, suggest that hPE effectively ameliorates liver fibrosis in NASH. This beneficial effect may, in part, be due to suppression of hepatic stellate cell activation.

The effect of (Cornus mas L.) fruit extract on liver function among patients with nonalcoholic fatty liver: A double-blind randomized clinical trial

This double-blind randomized clinical trial aimed to investigate impact of Cornus mas L. fruit extract (CMFE) on liver function in nonalcoholic fatty liver disease (NAFLD). Fifty patients were randomly assigned into the CMFE and placebo groups to receive 20 ml of the extract or placebo for 12 weeks, respectively. Serum alanine aminotransferase, aspartate aminotransferase, cytokeratin 18 (CK-18) levels, and steatosis and fibrosis scores were examined before and after the intervention. Although, a significant decrease was observed in CK-18 levels among the CMFE group (288.80 ± 85.40 vs. 235.66 ± 60.38; p = .001) after 12 weeks, no significant difference was found between the two groups. Moreover, a significant increase in fibrosis score in the placebo group (8.20 (6.35-9.40) vs. 8.40 (7.70-13.00); p = .03) as well as a significant difference in this marker (CMEF: 7.64 (6.30-8.25); placebo: 8.40 (7.70-13.00); p = .02) and its changes (CMEF: 0.60 (-1.00-1.07); placebo: 0.80 (-0.25-3.95); p = .02) were found between the groups after 12 weeks. No significant effect was noted on other variables. Therefore, consuming CMFE might have some beneficial effects on liver function markers in NAFLD. However, more studies are required in this area.

Parthenolide plays a protective role in the liver of mice with metabolic dysfunction‑associated fatty liver disease through the activation of the HIPPO pathway

Metabolic dysfunction‑associated fatty liver disease (MAFLD) is a serious threat to human health. Parthenolide (PAR) displays several important pharmacological activities, including the promotion of liver function recovery during hepatitis. The aim of the present study was to assess the effect of PAR on MAFLD in a mouse model. Body weight, liver to body weight ratios, histological score, alanine transaminase, aspartate transaminase, total cholesterol and triglyceride levels were determined to evaluate liver injury. Liver hydroxyproline concentrations were also assessed. The expression levels of lipid metabolism‑related genes (sterol regulatory element binding protein‑1c, fatty acid synthase, acetyl CoA carboxylase 1, stearoyl CoA desaturase 1 and carbohydrate response element‑binding protein, peroxisome proliferator‑activated receptor α, carnitine palmitoyl transferase 1α and acyl‑CoA dehydrogenase short chain), liver fibrosis‑associated genes (α‑smooth muscle actin, tissue inhibitor of metalloproteinase 1 and TGF‑β1), pro‑inflammatory cytokines (TNF‑α, IL‑1β and IL‑6) and oxidative stress‑associated enzymes (malondialdehyde, superoxide dismutase and glutathione peroxidase) were measured in mice with MAFLD. The expression levels of genes associated with the HIPPO pathway were also measured. In vivo experiments using a specific inhibitor of HIPPO signalling were performed to verify the role of this pathway in the effects of PAR. PAR exerted beneficial effects on liver injury, lipid metabolism, fibrosis, inflammation and oxidative stress in mice with MAFLD, which was mediated by activation of the HIPPO pathway.

Grape-Seed Proanthocyanidin Extract Reverts Obesity-Related Metabolic Derangements in Aged Female Rats

Obesity and ageing are current issues of global concern. Adaptive homeostasis is compromised in the elderly, who are more likely to suffer age-related health issues, such as obesity, metabolic syndrome, and cardiovascular disease. The current worldwide prevalence of obesity and higher life expectancy call for new strategies for treating metabolic disorders. Grape-seed proanthocyanidin extract (GSPE) is reported to be effective in ameliorating these pathologies, especially in young animal models. In this study, we aimed to test the effectiveness of GSPE in modulating obesity-related pathologies in aged rats fed an obesogenic diet. To do so, 21-month-old rats were fed a high-fat/high-sucrose diet (cafeteria diet) for 11 weeks. Two time points for GSPE administration (500 mg/kg body weight), i.e., a 10-day preventive GSPE treatment prior to cafeteria diet intervention and a simultaneous GSPE treatment with the cafeteria diet, were assayed. Body weight, metabolic parameters, liver steatosis, and systemic inflammation were analysed. GSPE administered simultaneously with the cafeteria diet was effective in reducing body weight, total adiposity, and liver steatosis. However, the preventive treatment was effective in reducing only mesenteric adiposity in these obese, aged rats. Our results confirm that the simultaneous administration of GSPE improves metabolic disruptions caused by the cafeteria diet also in aged rats.

Soyasaponin A2 Alleviates Steatohepatitis Possibly through Regulating Bile Acids and Gut Microbiota in the Methionine and Choline-Deficient (MCD) Diet-induced Nonalcoholic Steatohepatitis (NASH) Mice

SCOPE

Nonalcoholic steatohepatitis (NASH) is a chronic progressive disease with complex pathogenesis of which the bile acids (BAs) and gut microbiota are involved. Soyasaponins (SS) exhibits many health-promoting effects including hepatoprotection, but its prevention against NASH is unclear. This study aims to investigate the preventive bioactivities of SS monomer (SS-A₂ ) against NASH and further clarify its mechanism by targeting the BAs and gut microbiota.

METHODS AND RESULTS

The methionine and choline deficient (MCD) diet-fed male C57BL/6 mice were intervened with obeticholic acid or SS-A₂ for 16 weeks. Hepatic pathology is assessed by hematoxylin-eosin and Masson's trichrome staining. BAs in serum, liver, and colon are measured by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-TQMS). Gut microbiota in caecum are determined by 16S rDNA amplicon sequencing. In the MCD diet-induced NASH mice, SS-A₂ significantly reduces hepatic steatosis, lobular inflammation, ballooning, nonalcoholic fatty liver disease activity score (NAS) scores, and fibrosis, decreases Erysipelotrichaceae (Faecalibaculum) and Lactobacillaceae (Lactobacillus) and increases Desulfovibrionaceae (Desulfovibrio). Moreover, SS-A₂ reduces serum BAs accumulation and promotes fecal BAs excretion. SS-A₂ changes the BAs profiles in both liver and serum and specifically increases the taurohyodeoxycholic acid (THDCA) level. Faecalibaculum is negatively correlated with serum THDCA.

CONCLUSION

SS-A₂ alleviates steatohepatitis possibly through regulating BAs and gut microbiota in the MCD diet-induced NASH mice.