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

The therapeutic mechanisms of quercetin on inflammatory diseases: an update

Bioactive compounds derived from medicinal plants have become a significant source of drugs for inflammatory diseases treatment, particularly those caused by immune system abnormalities. Quercetin, a flavonol found in a wide variety of herbs, fruits, and vegetables, has garnered attention for its diverse biological properties, including anti-inflammatory, anticancer, and antiviral activities. Numerous in vivo and ex vivo studies have validated quercetin's role in treating inflammatory diseases through multiple pathways, mainly involving anti-oxidative stress, modulation of metabolism, intestinal flora, apoptosis, endoplasmic reticulum stress, and macrophage polarization, indicating it a promising pharmaceutical candidate for managing inflammatory and autoimmune conditions. We aimed to systematically review quercetin's anti-inflammatory activity and the mechanisms of action across various inflammatory diseases in the digestive, respiratory, endocrine, neurological, and osteoarticular systems. By summarizing the therapeutic potential of quercetin in these multifaceted conditions, this review seeks to provide a solid foundation for future clinical research and application strategies involving quercetin.

Beacon of Hope for Age-Related Retinopathy: Antioxidative Mechanisms and Pre-Clinical Trials of Quercetin Therapy

Age-related retinopathy is one of the leading causes of visual impairment and irreversible blindness, characterized by progressive neuronal and myelin loss. The damages caused by oxidation contributes to the hallmarks of aging and represents fundamental components in pathological pathways that are thought to drive multiple age-related retinopathies. Quercetin (Que), a natural polyphenol abundant in vegetables, herbs, and fruits, has been extensively studied for its long-term antioxidative effects mediated through diverse mechanisms. Additionally, Que and its derivatives exhibit a broad spectrum of pharmacological characteristics in the cellular responses of age-related retinopathy induced by oxidative stress, including anti-inflammatory, anti-neovascularization, regulatory, and neuroprotective effects in autophagy and apoptosis processes. This review mainly focuses on the antioxidative mechanisms and curative effects of Que treatment for various age-related retinopathies, such as retinitis pigmentosa, diabetic retinopathy, age-related macular degeneration, and glaucoma. Furthermore, we discuss emerging technologies and methods involving Que and its derivatives in the therapeutic strategies for age-related retinopathies, highlighting their promise for clinical translation.

Integrated network pharmacology, metabolomics and molecular docking analysis to reveal the mechanisms of quercetin in the treatment of hyperlipidemia

Hyperlipidemia (HLP) is a significant contributor to cardiovascular diseases. Quercetin (QUE), a naturally occurring flavonoid with diverse bioactivities, has garnered attention due to its potential therapeutic effects. However, the precise mechanisms underlying the effects of QUE on HLP remain unclear. In this study, an ultra-high-performance liquid chromatography-quadrupole/electrostatic field Orbitrap high-resolution mass spectrometry (UPLC-Q-Exactive-MS) metabolomics strategy was employed to obtain metabolite profiles, and potential biomarkers were identified following data analysis. Network pharmacology and Drug Affinity Responsive Target Stability (DARTS) assays were utilized to explore the potential targets of QUE for HLP treatment. The results of metabolomics and network pharmacology were then integrated to identify the key targets and metabolic pathways involved in the therapeutic action of the QUE against HLP. Molecular docking and experimental validation were performed to confirm these key targets. A comprehensive database search identified 138 QUE-HLP-related targets. A protein-protein interaction (PPI) network was constructed using STRING, and the shared targets were filtered with Cytoscape. Among these, AKT1, TNF, VEGFA, mTOR, SREBP1, and SCD emerged as potential therapeutic targets. These findings were validated using in vitro cell experiments. Additionally, the mechanism of action of QUE against HLP was evaluated by integrating network pharmacology with metabolomics, identifying two metabolomic pathways crucial to HLP treatment. DARTS experiments confirmed the stable binding of QUE to FASN, p-mTOR, SREBP1, and p-AKT. In HepG2 cells treated with palmitic acid (PA), QUE significantly reduced the mRNA expression of ACLY, ACACA, FASN, and SCD (p < 0.05). Western blot analysis revealed that PA significantly increased protein expression of p-mTOR, SREBP1, FASN, and p-AKT (p < 0.05). In summary, our study provides novel insights into the protective mechanisms of QUE against HLP and offers valuable information regarding its potential benefits in clinical treatment.

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

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

Effects of Metabolites Derived from Guava (Psidium guajava L.) Leaf Extract Fermented by Limosilactobacillus fermentum on Hepatic Energy Metabolism via SIRT1-PGC1α Signaling in Diabetic Mice

BACKGROUND/OBJECTIVES

Type 2 diabetes mellitus (T2DM) is considered a serious risk to public health since its prevalence is rapidly increasing worldwide despite numerous therapeutics. Insulin resistance in T2DM contributes to chronic inflammation and other metabolic abnormalities that generate fat accumulation in the liver, eventually leading to the progression of metabolic dysfunction-associated fatty liver disease (MAFLD). Recently, the possibility that microbial-derived metabolites may alleviate MAFLD through enterohepatic circulation has emerged, but the underlying mechanism remains unclear. In this research, we utilized metabolites obtained from the fermentation of guava leaf extract, which is well-known for its antidiabetic activity, to investigate their effects and mechanisms on MAFLD.

METHODS

Diabetes was induced by a high-fat diet and streptozotocin injection (80 mg/kg body weight) twice in mice. Subsequently, mice whose fasting blood glucose levels were measured higher than 300 mg/dL were administered with metabolites of Limosilactobacillus fermentum (LF) (50 mg/kg/day) or guava leaf extract fermented by L. fermentum (GFL) (50 mg/kg/day) by gavage for 15 weeks.

RESULTS

GFL supplementation mitigated hyperglycemia and hepatic insulin resistance. Moreover, GFL regulated abnormal hepatic histological changes and lipid profiles in diabetic mice. Furthermore, GFL enhanced energy metabolism by activating the sirtuin1 (SIRT1)/proliferator-activated receptor γ coactivator 1α (PGC1α)/peroxisome proliferator-activated receptor (PPAR)-α pathway in diabetic mice. Meanwhile, GFL supplementation suppressed hepatic inflammation in diabetic mice.

CONCLUSIONS

Taken together, the current study elucidated that GFL could be a potential therapeutic to ameliorate hyperglycemia and hepatic steatosis by improving SIRT1/PGC-1α/ PPAR-α-related energy metabolism in T2DM.

Treatment of Metabolic (Dysfunction)-Associated Fatty Liver Disease: Evidence from Randomized Controlled Trials-A Short Review

Metabolic-associated fatty liver disease (MALFD) is a highly prevalent and progressive disease, strongly related to obesity, metabolic syndrome, and cardiovascular disease. It comprises a spectrum of liver pathology from steatosis (fat accumulation in the hepatocytes) to steatosis with inflammation (metabolic-associated steatohepatitis, MASH), fibrosis, cirrhosis, and hepatocellular carcinoma. There is currently only one medication, resmetirom, US Food and Drug Administration approved for the treatment of MALFD. Evidence from randomized trials supports the efficacy of hypocaloric diets and exercise in MASH resolution. Moreover, substantial weight loss after bariatric surgery can lead to significant and longitudinally sustained MASH resolution, improvement in liver fibrosis, and decrease in the risk of major cardiovascular adverse events. Pioglitazone, an insulin sensitizer, initiated at the early stages, before the progression to fibrosis, may be effective in resolution of MASH in patients with or without type 2 diabetes. Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs), semaglutide and liraglutide, may also be effective in resolution of MASH but not of fibrosis. Preliminary data from interventions with tirzepatide, a dual GLP-1 and glucose-dependent insulinotropic polypeptide RA, and sodium-glucose cotransporter 2 inhibitors are encouraging, but more data based on liver biopsy are needed.

Quercetin: A Promising Candidate for the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a chronic liver disease. The development of MASLD is influenced by a multitude of diseases associated with modern lifestyles, including but not limited to diabetes mellitus, hypertension, hyperlipidaemia and obesity. These conditions are often consequences of the adoption of unhealthy habits, namely a sedentary lifestyle, a lack of physical activity, poor dietary choices and excessive alcohol consumption. The treatment of MASLD is primarily based on modifying the patient's lifestyle and pharmacological intervention. Despite the absence of FDA-approved pharmacological agents for the treatment of MASLD, several potential therapeutic modalities have demonstrated efficacy in reversing the histopathological features of the disease. Among the botanical ingredients belonging to the flavonoid group is quercetin (QE). QE has been demonstrated to possess a number of beneficial physiological effects, including anti-inflammatory, anticancer and antifungal properties. Additionally, it functions as a natural antioxidant. Preclinical evidence indicates that QE may play a beneficial role in reducing liver damage and improving metabolic health. Early human studies also suggest that QE may be an effective treatment for MASLD due to its antioxidant, anti-inflammatory, and lipid-regulating properties. This review aims to summarize the available information on the therapeutic effects of QE in MASLD.

Quercetin's Potential in MASLD: Investigating the Role of Autophagy and Key Molecular Pathways in Liver Steatosis and Inflammation

Metabolic dysfunction-associated fatty liver disease (MASLD) is a widespread liver disorder characterized by excessive fat accumulation in the liver, commonly associated with metabolic syndrome components such as obesity, diabetes, and dyslipidemia. With a global prevalence of up to 30%, MASLD is projected to affect over 100 million people in the U.S. and 20 million in Europe by 2030. The disease ranges from Steatotic Lived Disease (SLD) to more severe forms like metabolic dysfunction-associated steatohepatitis (MASH), which can progress to cirrhosis and hepatocellular carcinoma. Autophagy, a cellular process crucial for lipid metabolism and homeostasis, is often impaired in MASLD, leading to increased hepatic lipid accumulation and inflammation. Key autophagy-related proteins, such as Beclin1, LC3A, SQSTM1 (p62), CD36, and Perilipin 3, play significant roles in regulating this process. Disruption in these proteins contributes to the pathogenesis of MASLD. Quercetin, a natural polyphenolic flavonoid with antioxidant and anti-inflammatory properties, has promising results in mitigating MASLD. It may reduce hepatic lipid accumulation, improve mitochondrial function, and enhance autophagy. However, further research is needed to elucidate its mechanisms and validate its therapeutic potential in clinical settings. This underscores the need for continued investigation into autophagy and novel treatments for MASLD.

Understanding Macrophage Complexity in Metabolic Dysfunction-Associated Steatotic Liver Disease: Transitioning from the M1/M2 Paradigm to Spatial Dynamics

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses metabolic dysfunction-associated fatty liver (MASL) and metabolic dysfunction-associated steatohepatitis (MASH), with MASH posing a risk of progression to cirrhosis and hepatocellular carcinoma (HCC). The global prevalence of MASLD is estimated at approximately a quarter of the population, with significant healthcare costs and implications for liver transplantation. The pathogenesis of MASLD involves intrahepatic liver cells, extrahepatic components, and immunological aspects, particularly the involvement of macrophages. Hepatic macrophages are a crucial cellular component of the liver and play important roles in liver function, contributing significantly to tissue homeostasis and swift responses during pathophysiological conditions. Recent advancements in technology have revealed the remarkable heterogeneity and plasticity of hepatic macrophage populations and their activation states in MASLD, challenging traditional classification methods like the M1/M2 paradigm and highlighting the coexistence of harmful and beneficial macrophage phenotypes that are dynamically regulated during MASLD progression. This complexity underscores the importance of considering macrophage heterogeneity in therapeutic targeting strategies, including their distinct ontogeny and functional phenotypes. This review provides an overview of macrophage involvement in MASLD progression, combining traditional paradigms with recent insights from single-cell analysis and spatial dynamics. It also addresses unresolved questions and challenges in this area.

Pharmacological benefits of durva swaras (Cynodon dactylon L. Pers.) administration in APAP-induced liver injury model of mice - Assessment by metabolic and inflammatory markers

OBJECTIVE

Liver derangement underlies the development of metabolic syndrome in perimenopause. Previously, we have observed that durva swaras (DS) improved metabolic-associated fatty liver disease (MAFLD) and abnormal liver enzymes (aspartate aminotransferase and alanine aminotransferase) along with other complications of menopause in ovariectomized rats. We aimed to decipher the hepatoprotective mechanisms of DS in acetaminophen (APAP)-induced liver injury model, which is analogous to the pathophysiology of MAFLD.

MATERIALS AND METHODS

Male Swiss albino mice were distributed into three groups at random. Group I (Control) was administered with vehicle (distilled water) for 7 days. Group II (APAP) received vehicle for the first 6 days and APAP (350 mg/kg - single dose) on the 7th day. Group III (APAP + D) received test compound DS (quality complied) at a dose of 133 mg/kg for 6 days and APAP (350 mg/kg - single dose) on the 7th day. Subsequently, blood and liver tissues were subjected to biochemical, ultrastructural, and gene expression analysis.

RESULTS

DS pretreatment protected the liver from APAP-induced disruption of sinusoids and necrosis. DS prevented the elevation of liver enzymes - AST and ALT induced by APAP. Importantly, DS inhibited the APAP-elicited increase in messenger ribonucleic acid levels of hepatic nuclear factor-kappa beta (NF-κB) and pro-inflammatory cytokines, namely interleukin-1 beta, interleukin 6, and tumor necrosis factor-alpha. Moreover, DS activated gene expression of nuclear factor erythroid 2-related factor 2 and liver-X-receptor-alpha (LXR-α) to combat the liver damage.

CONCLUSION

DS hinders APAP-induced liver damage by activating LXR-α and inhibiting the NF-κB-associated pro-inflammatory cytokine gene expression. These observations confirm the protective role of DS in metabolic dysfunction-associated liver conditions.

Quercetin isolated from Hedysarum neglectum Ledeb. as a preventer of metabolic diseases

Diseases associated with metabolic disorders seem to affect more and more people worldwide. Biologically active supplements may prevent or relieve metabolic disorders. Quercetin is known for its potential to inhibit metabolic syndrome. This paper introduces an in vivo experiment on rodents. It featured hypoglycemic, hypocholesterolemic, and hepatotoxic properties of quercetin. Quercetin was obtained from the hairy root extract of Hedysarum neglectum Ledeb. Two doses (50 and 100 mg/kg) were used to evaluate its hypoglycemic potential. Rats with induced diabetes were tested for body weight, glucose, and cholesterol while mice with induced hypercholesterolemia were checked for blood cholesterol changes. Potential biochemical and pathological changes in the liver were also studied on rats. Quercetin treatment caused neither significant health problems nor death in the model animals. It had no effect on body weight, even in the animals with induced diabetes. In addition, quercetin did not increase glucose and cholesterol in the blood and triggered no pathological changes in the liver. Quercetin isolated from H. neglectum hairy root extract demonstrated no hepatotoxicity. Unfortunately, it showed no beneficial effect on cholesterol and glucose levels and had no efficacy against metabolic syndrome. Further research is needed to assess the effect of quercetin on other metabolic markers, e.g., genes associated with the metabolism of lipids, carbohydrates, etc.

Human diet-derived polyphenolic compounds and hepatic diseases: From therapeutic mechanisms to clinical utilization

This review focuses on the potential ameliorative effects of polyphenolic compounds derived from human diet on hepatic diseases. It discusses the molecular mechanisms and recent advancements in clinical applications. Edible polyphenols have been found to play a therapeutic role, particularly in liver injury, liver fibrosis, NAFLD/NASH, and HCC. In the regulation of liver injury, polyphenols exhibit anti-inflammatory and antioxidant effects, primarily targeting the TGF-β, NF-κB/TLR4, PI3K/AKT, and Nrf2/HO-1 signaling pathways. In the regulation of liver fibrosis, polyphenolic compounds effectively reverse the fibrotic process by inhibiting the activation of hepatic stellate cells (HSC). Furthermore, polyphenolic compounds show efficacy against NAFLD/NASH by inhibiting lipid oxidation and accumulation, mediated through the AMPK, SIRT, and PPARγ pathways. Moreover, several polyphenolic compounds exhibit anti-HCC activity by suppressing tumor cell proliferation and metastasis. This inhibition primarily involves blocking Akt and Wnt signaling, as well as inhibiting the epithelial-mesenchymal transition (EMT). Additionally, clinical trials and nutritional evidence support the notion that certain polyphenols can improve liver disease and associated metabolic disorders. However, further fundamental research and clinical trials are warranted to validate the efficacy of dietary polyphenols.

Non-alcoholic fatty liver disease: Dietary and nutraceutical approaches

Non-alcoholic fatty liver disease (NAFLD), defined as the presence of fat accumulation in imaging or histology in more than 5% of hepatocytes and exclusion of other causes for secondary hepatic fat accumulation, is one of the major causes of chronic liver disease worldwide. Metabolic syndrome is associated with an increased risk of progression from NAFLD to non-alcoholic steatohepatitis (NASH), fibrosis, and forthcoming liver failure. Also, genetic predisposition contributes to the risk of NAFLD development. This review explores the role of diets and nutraceuticals in delaying the development and the evolution of NAFLD to chronic liver disease. The Mediterranean diet, high-protein diet, low-carbohydrate/high-fat diet, high-carbohydrate/low-fat diet, and intermittent fasting are the dietary approaches investigated given the presence of relevant literature data. Moreover, this review focused on nutraceuticals with proven efficacy in ameliorating NAFLD and grouped them into four different categories: plant-based nutraceuticals (Ascophyllum nodosum and Fucus vesiculosus, Silymarin, Berberine, Curcumin, Resveratrol, Nigella sativa, Quercetin), vitamin-like substances (vitamin E, vitamin D, vitamin C, coenzyme Q10, inositol), fatty acids (omega-3), and microbiota-management tools (probiotics).

Molecular Mechanism Pathways of Natural Compounds for the Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world, and its incidence continues to increase each year. Yet, there is still no definitive drug that can stop its development. This review focuses mainly on lipotoxicity, oxidative stress, inflammation, and intestinal flora dysbiosis to understand NAFLD's pathogenesis. In this review, we used NCBI's PubMed database for retrieval, integrating in vivo and in vitro experiments to reveal the therapeutic effects of natural compounds on NAFLD. We also reviewed the mechanisms by which the results of these experiments suggest that these compounds can protect the liver from damage by modulating inflammation, reducing oxidative stress, decreasing insulin resistance and lipid accumulation in the liver, and interacting with the intestinal microflora. The natural compounds discussed in these papers target a variety of pathways, such as the AMPK pathway and the TGF-β pathway, and have significant therapeutic effects. This review aims to provide new possible therapeutic lead compounds and references for the development of novel medications and the clinical treatment of NAFLD. It offers fresh perspectives on the development of natural compounds in preventing and treating NAFLD.

Effect of Isoquercitrin on Free Fatty Acid-Induced Lipid Accumulation in HepG2 Cells

Liver metabolic disorders and oxidative stress are crucial factors in the development of nonalcoholic fatty liver disease (NAFLD); however, treatment strategies to combat NAFLD remain poorly established, presenting an important challenge that needs to be addressed. Herein, we aimed to examine the effect of isoquercitrin on lipid accumulation induced by exogenous free fatty acids (FFA) using HepG2 cells and elucidate the underlying molecular mechanism. The cells were exposed to 0.5 mM FFA to induce intracellular lipid accumulation, followed by co-treatment with isoquercitrin to confirm the potential inhibitory effect on FFA-induced lipid production. HepG2 cells exposed to FFA alone exhibited intracellular lipid accumulation, compromised endoplasmic reticulum (ER) stress, and enhanced expression of proteins and genes involved in lipid synthesis; however, co-treatment with isoquercitrin decreased the expression of these molecules in a dose-dependent manner. Furthermore, isoquercitrin could activate AMP-activated protein kinase (AMPK), a key regulatory protein of hepatic fatty acid oxidation, suppressing new lipid production by phosphorylating acetyl-CoA carboxylase (ACC) and inhibiting sterol regulatory element-binding transcription factor 1 (SREBP-1)/fatty acid synthase (FAS) signals. Overall, these findings suggest that isoquercitrin can be employed as a therapeutic agent to improve NAFLD via the regulation of lipid metabolism by targeting the AMPK/ACC and SREBP1/FAS pathways.

A review of edible plant-derived natural compounds for the therapy of liver fibrosis

Liver fibrosis has a high incidence worldwide and is the common pathological basis of many chronic liver diseases. Liver fibrosis is caused by the excessive deposition of extracellular matrix and concomitant collagen accumulation in livers and can lead to the development of liver cirrhosis and even liver cancer. A large number of studies have provided evidence that liver fibrosis can be blocked or even reversed by appropriate medical interventions. However, the antifibrosis drugs with ideal clinical efficacy are still insufficient. The edible plant-derived natural compounds have been reported to exert effective antifibrotic effects with few side-effects, representing a kind of promising source for the treatment of liver fibrosis. In this article, we reviewed the current progress of the natural compounds derived from dietary plants in the treatment of liver fibrosis, including phenolic compounds (capsaicin, chlorogenic acid, curcumin, ellagic acid, epigallocatechin-3-gallate, resveratrol, sinapic acid, syringic acid, vanillic acid and vitamin E), flavonoid compounds (genistein, hesperidin, hesperetin, naringenin, naringin and quercetin), sulfur-containing compounds (S-allylcysteine, ergothioneine, lipoic acid and sulforaphane) and other compounds (betaine, caffeine, cucurbitacin B, lycopene, α-mangostin, γ-mangostin, ursolic acid, vitamin C and yangonin). The pharmacological effects and related mechanisms of these compounds in in-vivo and in-vitro models of liver fibrosis are focused.

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.

Total Flavonoids from Chimonanthus nitens Oliv. Leaves Ameliorate HFD-Induced NAFLD by Regulating the Gut–Liver Axis in Mice

Non-alcoholic fatty liver disease (NAFLD) is one of the chronic liver diseases with high incidence in the world. This study aimed to investigate whether total flavonoids from Chimonanthus nitens Oliv. leaves (TFC) can ameliorate NAFLD. Herein, a high-fat diet (HFD)-induced NAFLD mice model was established, and TFC was administered orally. The results showed that TFC reduced the body weight and liver index and decreased the serum and hepatic levels of triglyceride (TG) and total cholesterol (TC). TFC significantly reduced the activity of liver functional transaminase. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) decreased by 34.61% and 39.57% in serum and 22.46% and 40.86% in the liver, respectively. TFC regulated the activities of oxidative-stress-related enzymes and upregulated the protein expression of nuclear factor E2-related factor (Nrf2)/heme oxygenase (HO-1) pathway in NAFLD mice, and the activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) in serum were increased by 89.76% and 141.77%, respectively. In addition, TFC reduced the levels of free fatty acids (FFA), endotoxin (ET), and related inflammatory factors in mouse liver tissue and downregulated the expression of proteins associated with inflammatory pathways. After TFC treatment, the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β in the liver tissues of NAFLD mice were downregulated by 67.10%, 66.56%, and 61.45%, respectively. Finally, TFC reduced liver fat deposition, oxidative stress, and inflammatory response to repair liver damage and alleviate NAFLD. Further studies showed that TFC regulated the expression of intestinal-barrier-related genes and improved the composition of gut microbiota. Therefore, TFC reduced liver inflammation and restored intestinal homeostasis by regulating the gut–liver axis. Overall, our findings revealed a novel function of TFC as a promising prophylactic for the treatment of NAFLD.

Mechanochemical-Assisted Extraction and Hepatoprotective Activity Research of Flavonoids from Sea Buckthorn (Hippophaë rhamnoides L.) Pomaces

Pomaces of sea buckthorn berry were usually side-products during the processing of juice. Due to a lack of an economical and effective extraction method, it was typically recognized as waste. For the purpose of resource utilization, the mechanochemical-assisted extraction (MCAE) method was applied to develop an ecofriendly extraction method and product with better pharmacology activity. The parameters were investigated through response surface methodology (RSM) design experiments. The processing conditions were optimized as follows: amount of Na₂CO₃ 40%, ball-to-material rate 29:1 g/g, milling speed 410 rpm, milling time 24 min, extraction temperature 25 °C, extraction time 20 min and the solid-to-solution ratio 1:10 g/mL. Under these conditions, the yields of flavonoids from sea buckthorn pomaces were 26.82 ± 0.53 mg/g, which corresponds to an increase of 2 times in comparison with that extracted by the heat reflux extraction method. Meanwhile, the hepatoprotective activity of sea buckthorn pomaces extracts was studied by the liver injury induced by ip injection of tetracycline. Biochemical and histopathological studies showed that biomarkers in serum and liver of nonalcoholic fatty liver disease (NAFLD) mice were significantly ameliorated when sea buckthorn flavonoids extracted by MCAE were used. Altogether, these results demonstrate that, as a green and efficient extraction, MCAE treatment could increase the extraction yield of sea buckthorn flavonoids, meanwhile it could exhibit significant activity of improving liver function. This research provided a new way to use pomaces of sea buckthorn as a functional food. It also has great value on the comprehensive utilization of nature’s resources.