18β-Glycyrrhetinic Acid Protects against Cholestatic Liver Injury in Bile Duct-Ligated Rats

Involvement of SIRT1-mediated aging in liver diseases

Liver disease is a significant global health issue, responsible for millions of deaths annually. Aging, characterized by the gradual decline in cellular and physiological functions, impairs tissue regeneration, increases susceptibility to liver diseases, and leads to a decline in liver health. Silent information regulator 1 (SIRT1), a NAD⁺-dependent deacetylase, has emerged as a pivotal factor in modulating age-related changes in the liver. SIRT1 preserves liver function by regulating essential aging-related pathways, including telomere maintenance, epigenetic modifications, cellular senescence, intercellular communication, inflammation, and mitochondrial function. Notably, SIRT1 levels naturally decline with age, contributing to liver disease progression and increased vulnerability to injury. This review summarizes the regulatory role of SIRT1 in aging and its impact on liver diseases such as liver fibrosis, alcoholic associated liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and metabolic dysfunction-associated steatohepatitis (MASH), hepatocellular carcinoma (HCC). We also discuss emerging therapeutic approaches, including SIRT1 activators, gene therapy, and nutritional interventions, which are evaluated for their potential to restore SIRT1 function and mitigate liver disease progression. Finally, we highlight future research directions to optimize SIRT1-targeted therapies for clinical applications in age-related liver conditions.

Glycyrrhiza uralensis Fisch. Attenuates Dioscorea bulbifera L.-induced liver injury by regulating the FXR/Nrf2-BAs-related proteins and intestinal microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

Dioscorea bulbifera L. (DBL) was a traditional Chinese medicine commonly used to treat goitre and cancer. Nevertheless, its clinical application may lead to liver injury. Glycyrrhiza uralensis Fisch. (GRR) was primarily utilized in traditional Chinese medicine for its ability to harmonize various medicines and mitigate the toxic effects of poisonous herbs. However, the role of GRR in mitigating the liver toxicity of DBL has not been established after combination.

AIM OF THE STUDY

This study aimed to clarify the protective effect of GRR against DBL-induced liver injury in mice and investigate its mechanisms of action.

MATERIALS AND METHODS

75% ethanol was employed to extract DBL and GRR. The extracted components were characterized using LC-MS. Mice were orally gavaged with extracts from each group for 30 days. After the experiment, the pathological changes in the liver of mice were evaluated. Additionally, biochemical markers associated with liver injury were assessed. The primary mechanisms through which GRR mitigates DBL-induced liver injury and the modulation of the liver-intestinal axis by GRR were explored utilizing untargeted metabolomics, targeted BAs metabolomics and 16S rDNA analyses. Furthermore, Western blot and qPCR assessed the protein and mRNA transcription of the farnesoid X receptor (FXR) and nuclear factor-erythroid 2-related factor 2 (Nrf2) as well as BA-related transporters.

RESULTS

GRR dose-dependently attenuated DBL-induced liver injury in mice. It mitigated hepatic pathological changes and alleviated hepatic inflammation and oxidative stress. GRR improved metabolic disorders induced by DBL in mice at the metabolite level, focusing on the ABC transporter. Moreover, GRR may be attributed to its activation of FXR/Nrf2 expression, reduction of cholesterol 7-alpha hydroxylase (CYP7A1) expression, promotion of bile salt export pump (BSEP), multi-drug resistance protein 2 (MRP2), P-glycoprotein (P-gp) and sodium taurocholate cotransport polypeptide (NTCP) expression, reduction of bile acid (BA) synthesis, promotion of BA efflux and reabsorption, and improvement of BA metabolic disorders. In addition, GRR ameliorated DBL-induced intestinal barrier injury and improved the structural organization of the intestinal flora, restoring the overall composition of the intestinal microbiota.

CONCLUSION

GRR exhibited significant alleviation of DBL-induced liver injury, potentially by modulating FXR/Nrf2-BA-related proteins, reducing hepatic BA accumulation, mitigating liver inflammation and oxidative stress, and regulating intestinal flora.

18β-glycyrrhetinic acid Mitigates bisphenol A-induced liver and renal damage: Inhibition of TNF-α/NF-κB/p38-MAPK, JAK1/STAT1 pathways, oxidative stress and apoptosis

Bisphenol A (BPA) has been commonly used in various consumer products, including water bottles, food containers, and canned food linings. However, there are concerns about its potential toxicity to human health, particularly its impact on the liver and kidneys. The objective of this research was to investigate the potential ameliorative effects of 18β-glycyrrhetinic acid (GA) against BPA-induced hepatotoxicity and nephrotoxicity in rats. The animals were supplemented with BPA (250 mg/kg b.w.) alone or with GA (50 and 100 mg/kg b.w.) for 14 days. GA treatment alleviated the BPA-induced hepato-renal tissue injuries through reducing the serum ALT, AST and ALP levels, and urea and creatinine levels. GA co-treatment also increased activities of SOD, CAT and GPx enzymes and levels of GSH, and suppressed MDA levels in BPA induced tissues. BPA also induced inflammation by increasing the levels of TNF-α, NF-κB, JAK1, STAT1, P38 MAPK and JNK in liver and kidney tissues and GA treatment ameliorated these effects. BPA triggered apoptosis by increasing caspase-3, Bax, and cytochrome c at protein levels and also by decreasing the antiapoptotic Bcl-2 level. However, treatment with GA (50 and 100 mg/kg) decreased apoptosis. Overall, our results have revealed the potential ameliorative mechanisms of GA, as a possible agent for BPA-induced hepatotoxicity and nephrotoxicity.

18beta-glycyrrhetinic acid alleviates deoxynivalenol-induced hepatotoxicity by inhibiting GPX4-dependent ferroptosis

Deoxynivalenol (DON), a mycotoxin that severely contaminates agri-food products can cause hepatotoxicity. Ferroptosis is an iron-dependent form of cell death, and the liver is an important organ for iron accumulation. 18beta-glycyrrhetinic acid (GA) has anti-ferroptosis and hepatoprotective effects. This study aimed to investigate the role of ferroptosis in the protective effects of GA against DON-induced hepatotoxicity in HepG2 cells and mice. The in vitro results revealed that DON (0.4 μM) decreased GPX4, SLC7A11, GCLC, NQO1, and Nrf2 expression; promoted TFR-1 expression and MDA, 4-HNE, and total ROS production; accelerated GSH depletion; and enhanced lipid ROS accumulation and Fe(II) overload, leading to ferroptosis. Pre-treatment with GA (0.4 and 6 μM) reversed these changes and alleviated DON-induced ferroptosis, thereby increasing cell viability and proliferation. In vivo results also showed that GA (10 mg/kg bw) pre-administration attenuated DON (2 mg/kg bw)-induced mouse liver injury, in part by inhibiting ferroptosis through reducing mitochondrial damage and lipid peroxidation. In addition, GA prevented erastin- and RSL3-induced ferroptosis by promoting GPX4 and SLC7A11 expression. Altogether, GA attenuated DON-induced hepatotoxicity by preventing ferroptosis via activation of GPX4-dependent pathway. The findings of this study provide a theoretical basis for the prevention of food mycotoxin toxicity.

Enhancing Cardioprotection Through Neutrophil-Mediated Delivery of 18β-Glycyrrhetinic Acid in Myocardial Ischemia/Reperfusion Injury

Myocardial ischemia/reperfusion injury (MI/RI) generates reactive oxygen species (ROS) and initiates inflammatory responses. Traditional therapies targeting specific cytokines or ROS often prove inadequate. An innovative drug delivery system (DDS) is developed using neutrophil decoys (NDs) that encapsulate 18β-glycyrrhetinic acid (GA) within a hydrolyzable oxalate polymer (HOP) and neutrophil membrane vesicles (NMVs). These NDs are responsive to hydrogen peroxide (H2O2), enabling controlled GA release. Additionally, NDs adsorb inflammatory factors, thereby reducing inflammation. They exhibit enhanced adhesion to inflamed endothelial cells (ECs) and improved penetration. Once internalized by cardiomyocytes through clathrin-mediated endocytosis, NDs protect against ROS-induced damage and inhibit HMGB1 translocation. In vivo studies show that NDs preferentially accumulate in injured myocardium, reducing infarct size, mitigating adverse remodeling, and enhancing cardiac function, all while maintaining favorable biosafety profiles. This neutrophil-based system offers a promising targeted therapy for MI/RI by addressing both inflammation and ROS, holding potential for future clinical applications.

One-Step Organic Synthesis of 18β-Glycyrrhetinic Acid-Anthraquinone Ester Products: Exploration of Antibacterial Activity and Structure-Activity Relationship, Toxicity Evaluation in Zebrafish

To combine the activity characteristics of 18β-glycyrrhetinic acid (18β-GA) and anthraquinone compounds (rhein and emodin), reduce toxicity, and explore the structure-activity relationship (SAR) of anthraquinones, 18β-GA-anthraquinone ester compounds were synthesized by one-step organic synthesis. The products were separated and purified by HPLC and characterized by NMR and EI-MS. It was finally determined as di-18β-GA-3-rhein ester (1, New), GA dimer (2, known), 18β-GA-3-emodin ester (3, known), and di-18β-GA-1-emodin ester (4, new). The MIC of three reactants and four products against Escherichia coli and Staphylococcus aureus were detected in vitro. Its developmental toxicity and cardiotoxicity were assessed using zebrafish embryos. The experimental results showed that rhein had the best antibacterial activity against Staphylococcus aureus with MIC50 of 2.4 mM, and it was speculated that -COOH, -OH, and intramolecular hydrogen bonds in anthraquinone compounds would enhance the antibacterial effect, while the presence of-CH3 might weaken the antibacterial activity. Product 1 increased the hatching rate and survival rate of zebrafish embryos and reduced the malformation rate and cardiomyocyte apoptosis. This experiment lays the foundation for further studying the SAR of anthraquinones and providing new drug candidates.

Cross-Omics Analyses Reveal the Effects of Ambient PM2.5 Exposure on Hepatic Metabolism in Female Mice

Ambient particulate matter (PM2.5) is a potential risk factor for metabolic damage to the liver. Epidemiological studies suggest that elevated PM2.5 concentrations cause changes in hepatic metabolism, but there is a lack of laboratory evidence. Here, we aimed to evaluate the effects of PM2.5 exposure on liver metabolism in C57BL/6j female mice (10 months old) and to explore the mechanisms underlying metabolic alterations and differential gene expressions by combining metabolomics and transcriptomics analyses. The metabolomics results showed that PM2.5 exposure notably affected the metabolism of amino acids and organic acids and caused hepatic lipid and bile acid accumulation. The transcriptomic analyses revealed that PM2.5 exposure led to a series of metabolic pathway abnormalities, including steroid biosynthesis, steroid hormone biosynthesis, primary bile acid biosynthesis, etc. Among them, the changes in the bile acid pathway might be one of the causes of liver damage in mice. In conclusion, this study clarified the changes in liver metabolism in mice caused by PM2.5 exposure through combined transcriptomic and metabolomic analyses, revealed that abnormal bile acid metabolism is the key regulatory mechanism leading to metabolic-associated fatty liver disease (MAFLD) in mice, and provided laboratory evidence for further clarifying the effects of PM2.5 on body metabolism.

18β-Glycyrrhetinic acid protects against deoxynivalenol-induced liver injury via modulating ferritinophagy and mitochondrial quality control

Deoxynivalenol (DON), a widespread mycotoxin, represents a substantial public health hazard due to its propensity to contaminate agricultural produce, leading to both acute and chronic health issues in humans and animals upon consumption. The role of ferroptosis in DON-induced hepatic damage remains largely unexplored. This study investigates the impact of 18β-glycyrrhetinic acid (GA), a prominent constituent of glycyrrhiza, on DON hepatotoxicity and elucidates the underlying mechanisms. Our results indicate that GA effectively attenuates liver injury inflicted by DON. This was achieved by inhibiting nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy and ferroptosis, as well as by adjusting mitochondrial quality control (MQC). Specifically, GA curtails ferritinophagy by diminishing NCOA4 expression without affecting the autophagic flux. At a molecular level, GA binds to and stabilizes programmed cell death protein 4 (PDCD4), thereby inhibiting its ubiquitination and subsequent degradation. This stabilization of PDCD4 leads to the downregulation of NCOA4 via the JNK-Jun-NCOA4 axis. Knockdown of PDCD4 weakened GA's protective action against DON exposure. Furthermore, GA improved mitochondrial function and limited excessive mitophagy and mitochondrial division induced by DON. Disrupting GA's modulation of MQC nullified its anti-ferroptosis effects. Overall, GA offers protection against DON-induced ferroptosis by blocking ferritinophagy and managing MQC. ENVIRONMENTAL IMPLICATION: Food contamination from mycotoxins, is a problem for agricultural and food industries worldwide. Deoxynivalenol (DON), the most common mycotoxins in cereal commodities. A survey in 2023 showed that the positivity rate for DON contamination in food reached more than 70% globally. DON can damage the health of humans whether exposed to high doses for short periods of time or low doses for long periods of time. We have discovered 18β-Glycyrrhetinic acid (GA), a prominent constituent of glycyrrhiza. Liver damage caused by low-dose DON can be successfully treated with GA. This study will support the means of DON control, including antidotes.

Quantitative proteomics reveals the protective effects of Yinchenzhufu decoction against cholestatic liver fibrosis in mice by inhibiting the PDGFRβ/PI3K/AKT pathway

Introduction: Yinchenzhufu decoction (YCZFD) is a traditional Chinese medicine formula with hepatoprotective effects. In this study, the protective effects of YCZFD against cholestatic liver fibrosis (CLF) and its underlying mechanisms were evaluated. Methods: A 3, 5-diethoxycarbonyl-1, 4-dihydro-collidine (DDC)-induced cholestatic mouse model was used to investigate the amelioration of YCZFD on CLF. Data-independent acquisition-based mass spectrometry was performed to investigate proteomic changes in the livers of mice in three groups: control, model, and model treated with high-dose YCZFD. The effects of YCZFD on the expression of key proteins were confirmed in mice and cell models. Results: YCZFD significantly decreased the levels of serum biochemical, liver injury, and fibrosis indicators of cholestatic mice. The proteomics indicated that 460 differentially expressed proteins (DEPs) were identified among control, model, and model treated with high-dose YCZFD groups. Enrichment analyses of these DEPs revealed that YCZFD influenced multiple pathways, including PI3K-Akt, focal adhesion, ECM-receptor interaction, glutathione metabolism, and steroid biosynthesis pathways. The expression of platelet derived growth factor receptor beta (PDGFRβ), a receptor associated with the PI3K/AKT and focal adhesion pathways, was upregulated in the livers of cholestatic mice but downregulated by YCZFD. The effects of YCZFD on the expression of key proteins in the PDGFRβ/PI3K/AKT pathway were further confirmed in mice and transforming growth factor-β-induced hepatic stellate cells. We uncovered seven plant metabolites (chlorogenic acid, scoparone, isoliquiritigenin, glycyrrhetinic acid, formononetin, atractylenolide I, and benzoylaconitine) of YCZFD that may regulate PDGFRβ expression. Conclusion: YCZFD substantially protects against DDC-induced CLF mainly through regulating the PDGFRβ/PI3K/AKT signaling pathway.

Gallic acid improves liver cirrhosis by reducing oxidative stress and fibrogenesis in the liver of rats induced by bile duct ligation

Disturbance in the production and excretion of bile acid causes cholestatic liver disease. Liver cirrhosis is a disease that occurs if cholestasis continues. This study evaluated the protective effect of gallic acid (GA) on liver damage caused by biliary cirrhosis. Rats were randomly divided into 4 groups, each with 8 subjects: 1) control, 2) BDL, 3) BDL + GA 20, and 4) BDL + GA 30. The rats were anesthetized 28 days after the BDL, followed by collecting their blood and excising their liver. Their serum was used to measure liver enzymes, and the liver was used for biochemical analysis, gene expression, and histopathological analysis. Serum levels of liver enzymes, total bilirubin, liver Malondialdehyde level (MDA), expression of inflammatory cytokines and caspase-3, necrosis of hepatocytes, bile duct proliferation, lymphocytic infiltration, and liver fibrosis showed an increase in the BDL group compared to the control group (p < 0.05). In addition, BDL decreased the activity of liver antioxidant enzymes and glutathione (GSH) levels compared to the control group (p < 0.05). The groups receiving GA indicated a decrease in liver enzymes, total bilirubin, MDA, the expression of inflammatory cytokines and caspase-3, and a reduction in liver tissue damage compared to the BDL group (p < 0.05). The level of GSH in the BDL + GA 20 group showed a significant increase compared to the BDL group (p < 0.05). Moreover, it was found that GA, with its anti-fibrotic and anti-inflammatory properties, reduces liver damage caused by biliary cirrhosis.

Comparison of pharmacokinetic profiles of seven major bioactive components in normal and non-alcoholic fatty liver disease (NAFLD) rats after oral administration of Ling-Gui-Zhu-Gan decoction by UPLC-MS/MS

A sensitive and rapid ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was hereby developed for the determination of seven components, namely, glycyrrhizic acid, glycyrrhetinic acid, dehydrotumulosic acid, isoliquiritin, liquiritin, atractylenolide III, and cinnamic acid, in the plasma of rats after the oral administration of Ling-Gui-Zhu-Gan decoction (LGZGD). Besides, this very method was methodologically validated for specificity, linearity, inter-day and intra-day precision, accuracy, matrix effect, extraction recovery, and stability. It was also successfully used for the first time to compare the pharmacokinetic characteristics of the seven components after oral administration of LGZGD to normal rats and non-alcoholic fatty liver disease (NAFLD) rats. The results indicated significant differences between the pharmacokinetic characteristics of normal and NAFLD rats. To further reveal the different pharmacokinetic behaviors, the expressions of enzymes and transporters in the liver of normal and NAFLD rats were detected using UPLC-MS/MS. In the NAFLD rats, UDP-glucuronosyltransferase 1-1 (UGT1A1) and nine transporters were significantly inhibited and a positive correlation was observed between them and the AUC of the major components. The present results indicate that the pharmacokinetic differences between the normal and NAFLD rats might be attributed to the significant lower expression levels of both the metabolic enzyme UGT1A1 and nine transporter proteins in the NAFLD rats than in the normal rats. Meanwhile, UGT1A1 and the nine transporter proteins might be used as potential biomarkers to assess the ameliorative effect of LGZGD on NAFLD, which could provide useful information to guide the clinical application of LGZGD.

Pharmacological Features of 18β-Glycyrrhetinic Acid: A Pentacyclic Triterpenoid of Therapeutic Potential

Glycyrrhiza glabra L. (belonging to the family Leguminosae), commonly known as Licorice, is a popular medicinal plant that has been used in traditional medicine worldwide for its ethnopharmacological efficacy in treating several ailments. Natural herbal substances with strong biological activity have recently received much attention. The main metabolite of glycyrrhizic acid is 18β-glycyrrhetinic acid (18βGA), a pentacyclic triterpene. A major active plant component derived from licorice root, 18βGA has sparked a lot of attention due to its pharmacological properties. The current review thoroughly examines the literature on 18βGA, a major active plant component obtained from Glycyrrhiza glabra L. The current work provides insight into the pharmacological activities of 18βGA and the potential mechanisms of action involved. The plant contains a variety of phytoconstituents such as 18βGA, which has a variety of biological effects including antiasthmatic, hepatoprotective, anticancer, nephroprotective, antidiabetic, antileishmanial, antiviral, antibacterial, antipsoriasis, antiosteoporosis, antiepileptic, antiarrhythmic, and anti-inflammatory, and is also useful in the management of pulmonary arterial hypertension, antipsychotic-induced hyperprolactinemia, and cerebral ischemia. This review examines research on the pharmacological characteristics of 18βGA throughout recent decades to demonstrate its therapeutic potential and any gaps that may exist, presenting possibilities for future drug research and development.