Swertiamarin, an active iridoid glycoside from Swertia pseudochinensis H. Hara, protects against alpha-naphthylisothiocyanate-induced cholestasis by activating the farnesoid X receptor and bile acid excretion pathway

Farnesoid X receptor: From Structure to Function and Its Pharmacology in Liver Fibrosis

The farnesoid X receptor (FXR), a ligand-activated transcription factor, plays a crucial role in regulating bile acid metabolism within the enterohepatic circulation. Beyond its involvement in metabolic disorders and immune imbalances affecting various tissues, FXR is implicated in microbiota modulation, gut-to-brain communication, and liver disease. The liver, as a pivotal metabolic and detoxification organ, is susceptible to damage from factors such as alcohol, viruses, drugs, and high-fat diets. Chronic or recurrent liver injury can culminate in liver fibrosis, which, if left untreated, may progress to cirrhosis and even liver cancer, posing significant health risks. However, therapeutic options for liver fibrosis remain limited in terms of FDA-approved drugs. Recent insights into the structure of FXR, coupled with animal and clinical investigations, have shed light on its potential pharmacological role in hepatic fibrosis. Progress has been achieved in both fundamental research and clinical applications. This review critically examines recent advancements in FXR research, highlighting challenges and potential mechanisms underlying its role in liver fibrosis treatment.

Emodin alleviates cholestatic liver injury by modulating Sirt1/Fxr signaling pathways

Emodin (EMO) has the effect of anti-cholestasis induced by alpha-naphthylisothiocyanate (ANIT). But its mechanism is still unclear. The farnesoid X receptor (Fxr) is the master bile acid nuclear receptor. Recent studies have reported that Sirtuin 1 (Sirt1) can regulate the activities of Fxr. The purpose of the current study was to investigate the mechanism of EMO against ANIT-induced liver injury based on Sirt1/Fxr signaling pathway. The ANIT-induced cholestatic rats were used with or without EMO treatment. Serum biochemical indicators, as well as liver histopathological changes were examined. The genes expressions of Sirt1, Fxr, Shp, Bsep and Mrp2 were detected. The expressions of Sirt1, Fxr and their downstream related genes were investigated in vitro. The results showed that EMO significantly alleviated ANIT-induced liver injury in rats, and increased Sirt1, Fxr, Shp, Bsep and Mrp2 gene expression in liver, while decreased the expression of Cyp7a1. EMO significantly activated Fxr, while Sirt1 inhibitor and Sirt1 gene silencing significantly reduced Fxr activity in vitro. Collectively, EMO in the right dose has a protective effect on liver injury induced by ANIT, and the mechanism may be through activation of Fxr by Sirt1, thus regulating bile acid metabolism, and reducing bile acid load in hepatocytes.

Exploring the Potential Mechanisms of Action of Gentiana Veitchiorum Hemsl. Extract in the Treatment of Cholestasis using UPLC-MS/MS, Systematic Network Pharmacology, and Molecular Docking

INTRODUCTION

Gentiana veitchiorum Hemsl. (GV) has a long history in Tibetan medicine for treating hepatobiliary disease cholestasis. However, the mechanisms mediating its efficacy in treating cholestasis have yet to be determined.

AIM

To elucidate the mechanisms of action of GV in the treatment of cholestasis, an integrated approach combining ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis with network pharmacology was established.

MATERIALS AND METHODS

A comprehensive analysis of the chemical composition of GV was achieved by UPLC-MS/MS. Subsequently, a network pharmacology method that integrated target prediction, a protein-protein interaction (PPI) network, gene set enrichment analysis, and a component- target-pathway network was established, and finally, molecular docking and experiments in vitro were conducted to verify the predicted results.

RESULTS

Twenty compounds that were extracted from GV were identified by UPLC-MS/MS analysis. Core proteins such as AKT1, TNF, and IL6 were obtained through screening in the Network pharmacology PPI network. The Kyoto Encyclopedia of the Genome (KEGG) pathway predicted that GV could treat cholestasis by acting on signaling pathways such as TNF/IL-17 / PI3K-Akt. Network pharmacology suggested that GV might exert a therapeutic effect on cholestasis by regulating the expression levels of inflammatory mediators, and the results were further confirmed by the subsequent construction of an LPS-induced RAW 264.7 cell model.

CONCLUSIONS

In this study, UPLC-MS/MS analysis, network pharmacology, and experiment validation were used to explore potential mechanisms of action of GV in the treatment of cholestasis.

Farnesoid X receptor activation is required for the anti-inflammatory and anti-oxidative stress effects of Alisol B 23-acetate in carbon tetrachloride-induced liver fibrosis in mice

Previous studies have shown that Alisol B 23-acetate (23ABA) had potent liver-protection effects, however, its roles and potential mechanisms in carbon tetrachloride (CCl4)-induced liver fibrosis remain to be determined. The present study aimed to investigate the effects of 23ABA on CCl4-induced liver fibrosis and tried to elucidate the underlying mechanisms by focusing on regulating of farnesoid X receptor (FXR). In vivo study found that 23ABA alleviated the CCl4-induced liver injury, and showed no obvious systemic toxicity on mice. 23ABA inhibited the collagen production, decreased sera levels of hyaluronic acid (HA) and procollagen type III (PC-III), lowered mRNA expression of α-smooth muscle actin (α-SMA), fibronectin, collagen I and collagen III in livers of mice. 23ABA inhibited the mRNA expressions and the sera levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α), as well as decreased the expression of cyclooxygenase 2 (COX-2) in fibrotic livers of mice. Besides, 23ABA decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA), increased glutathione (GSH) level, enhanced activities of superoxide dismutase (SOD) and glutathione reductase (GR) as well as increased mRNA expression of nuclear factor-E2-related factor 2 (Nrf2), glutamate-cysteine ligase, catalytic subunit (GCLC) and glutamate-cysteine ligase, modifier subunit (GCLM). Further study showed that the anti-liver injury and anti-fibrotic effects of 23ABA were abrogated by FXR antagonist guggulsterone (GS) in vivo. In addition, the inhibition effects of 23ABA on liver inflammation and oxidative stress were also weakened by treatment with GS in CCl4-induced fibrotic mice livers. In conclusion, the protective effects of 23ABA against CCl4-induced liver injury and fibrosis, due to FXR-mediated regulation of liver inflammation and oxidative stress.

Structural characterization and anti-oxidation activity of pectic polysaccharides from Swertia mileensis

In this study, we isolated the pectic polysaccharide WSMP-A2b (37 kDa) from the stems and leaves of Swertia mileensis, and we investigated its compositional/structural features and antioxidant activity. FT-IR, NMR, monosaccharide composition, enzymatic hydrolysis and methylation analyses indicated that WSMP-A2b is composed of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HG) domains with mass ratios of 2.1:1.0:2.2. The RG-I domain is primarily substituted with α-L-1,5-arabinan and type II arabinogalactan (AG-II) side chains, as well as minor contributions of β-D-1,4-galactan and/or type I arabinogalactan (AG-I) side chains. The HG domain was released in the form of un-esterified and partly methyl-esterified and/or acetyl-esterified oligogalacturonides with a 1 to 7 degree of polymerization after endo-polygalacturonase degradation. WSMP-A2b showed stronger antioxidant activity in vitro, in part this might due to the presence of galacturonic acid (GalA). In addition, WSMP-A2b exerted a protective effect on tert-butyl hydroperoxide (tBHP)-induced oxidative stress in INS-1 cells by reducing reactive oxygen species (ROS) production and increasing the glutathione/oxidized glutathione (GSH/GSSG) ratio. Our results provide crucial structural information on this pectic polysaccharide from Swertia mileensis, thus prompting further investigation into its structure-activity relationship.

Specnuezhenide Ameliorates Age-Related Hepatic Lipid Accumulation via Modulating Bile Acid Homeostasis and Gut Microbiota in D-Galactose-Induced Mice

Age-related hepatic lipid accumulation has become a major health problem in the elderly population. Specnuezhenide (SPN) is a major active iridoid glycoside from an edible herb Fructus Ligustri Lucidi, which is commonly used for preventing age-related diseases. However, the beneficial effects of SPN on age-related liver injury remain unknown. This study aimed to reveal the effect of SPN on age-related hepatic lipid accumulation and the underlying mechanism. D-galactose (D-gal)-induced aging mice were treated with vehicle or SPN for 12 weeks. Treatment of SPN decreased lipid accumulation and inflammation in the liver of D-gal-induced mice. Untargeted and targeted metabolomics showed that the SPN could regulate the bile acid (BA) synthesis pathway and restore the BA compositions in serum, livers, and feces of the D-gal-induced mice. Furthermore, SPN enhanced the protein and mRNA levels of hepatic BAs synthesis enzymes cytochrome P45027A1, cytochrome P4507A1, cytochrome P4507B1, and cytochrome P4508B1. Meanwhile, SPN alleviated D-gal-induced gut dysbiosis and reversed the proportions of microbes associated with bile salt hydrolase activity, including Lactobacillus, Ruminiclostridium, and Butyrivibrio. Our study revealed that SPN attenuated age-related hepatic lipid accumulation by improving BA profiles via modulating hepatic BA synthesis enzymes and gut microbiota.

Secoiridoids from the traditional Chinese medicine Swertia pseudochinensis

Detailed phytochemical investigation on the traditional Chinese medicine Swertia pseudochinensis Hara led to the isolation of ten undescribed secoiridoids and fifteen known analogs. Their structures were elucidated by extensive spectroscopic analysis (including 1D and 2D NMR, and HRESIMS). Selected isolates were assayed for their anti-inflammatory and antibacterial activities, and moderate anti-inflammatory activity via inhibiting the secretion of cytokines IL-6 and TNF-α in macrophages RAW264.7 induced by LPS were observed. Antibacterial activity against Staphylococcus aureus was not found at 100 μM.

Xanthones and Phenylpropanoids from the Whole Herb of Swertia pseudochinensis and Their Anti-Inflammatory Activity

An undescribed xanthone dimer, 1,3,5,8-tetrahydroxy-7-(1',5',8'-trihydroxy-3'-methoxy-2'-xanthonyl)xanthone (1) was separated together with eleven known compounds (2-12) from the dried whole herb of Swertia pseudochinensis. It was the first time that the compounds 8-12 were isolated from the Swertia genus. The structure of compound 1 was illuminated based on chemical evidence and spectral data analysis (UV, 1D and 2D-NMR, HR-ESI-MS). Moreover, the inhibitory effects of all compounds on NO production in LPS-induced RAW 264.7 cells were tested, compounds 8, 9, 10, 11 and 12 showing significant inhibition. The IC₅₀ value of compound 12 was 3.05±1.10 μM. Using target screening and molecular docking, we hypothesized that compound 12 may bind neutrophil elastase to exert its anti-inflammatory effects.