4-Methylcoumarin-[5,6-g]-hesperetin attenuates inflammatory responses in alcoholic hepatitis through PPAR-γ activation

Acer tegmeutosum Maxim extract alleviates acute alcohol-induced liver disease and regulates gut microbiota dysbiosis in mice

Acer tegmentosum Maxim (AT) has a variety of pharmacological activities, however, the effects of AT on liver injury and gut microbiota in alcoholic liver disease (ALD) mice is still unclear. This study aimed to evaluate the preventive effect of AT extract on acute alcoholic liver disease. Six-week-old male C57BL/6J mice were randomly divided into 6 groups. Each group was intragastrically treated saline or different concentration of AT extract solution for 5 weeks continuously. After the last gavage, except for the NC group, all the other groups were gavaged twice with 56 % alcohol to establish the acute ALD model and biochemical indexes, histopathological, and gut microbiota were analyzed. Established an acute ALD mouse model and detected serum, liver oxidation levels, and alcohol metabolism-related gene expressions. Through 16S rRNA sequencing, analyzed gut microbiota, explored the relationship between gut microbiota and liver indicators. AT extract significantly decreased lipid levels, promoted ADH, ALDH, and increased the antioxidant activities. Meanwhile, AT extract significantly downregulated the expression of lipid oxidation and inflammatory factors, upregulated alcohol metabolism genes. In addition, 16S rRNA sequencing and analysis showed that AT extract effectively regulated the gut microbiota diversity of ALD mice, significantly improved the structural disturbance of intestinal microflora. AT extract regulated gut microbiota and had a strong correlation with serum, liver-related indexes, and gene expression levels. All these results showed that AT can alleviate alcohol induced liver injury by regulating oxidative stress, inflammatory response, alcohol metabolism, and gut microbiota disorder.

Advances in Flavonoid Research: Sources, Biological Activities, and Developmental Prospectives

At present, the occurrence of a large number of infectious and non-communicable diseases poses a serious threat to human health as well as to drug development for the treatment of these diseases. One of the most significant challenges is finding new drug candidates that are therapeutically effective and have few or no side effects. In this respect, the active compounds in medicinal plants, especially flavonoids, are potentially useful compounds with a wide range of pharmacological activities. They are naturally present in nature and valuable in the treatment of many infectious and non-communicable diseases. Flavonoids are divided into fourteen categories and are mainly derived from plant extraction, chemical synthesis and structural modification, and biosynthesis. The structural modification of flavonoids is an important way to discover new drugs, but biosynthesis is currently considered the most promising research direction with the potential to revolutionize the new production pipeline in the synthesis of flavonoids. However, relevant problems such as metabolic pathway analyses and cell synthesis protocols for flavonoids need to be addressed on an urgent basis. In the present review, new research techniques for assessing the biological activities of flavonoids and the mechanisms of their biological activities are elucidated and their modes of interaction with other drugs are described. Moreover, novel drug delivery systems, such as nanoparticles, bioparticles, colloidals, etc., are gradually becoming new means of addressing the issues of poor hydrophilicity, lipophilicity, poor chemical stability, and low bioavailability of flavonoids. The present review summarizes the latest research progress on flavonoids, existing problems with their therapeutic efficacy, and how these issues can be solved with the research on flavonoids.

Si-Ni-San Reduces Hepatic Lipid Deposition in Rats with Metabolic Associated Fatty Liver Disease by AMPK/SIRT1 Pathway

Background

Metabolic associated fatty liver disease (MAFLD) is a chronic disease characterized by excessive lipid deposition in the liver without alcohol or other clear liver-damaging factors. AMP-activated protein kinase (AMPK)/silencing information regulator (SIRT)1 signaling pathway plays an important role in MAFLD development. Si-Ni-San (SNS), a traditional Chinese medicine, has shown reducing hepatic lipid deposition in MAFLD rats, however, the underlying mechanisms of SNS are barely understood.

Purpose

The aim of this research was to investigate the mechanisms of SNS in reducing hepatic lipid deposition in MAFLD rats by regulating AMPK/SIRT1 signaling pathways.

Methods

The components of SNS were determined by high performance liquid chromatography with mass spectrometry (HPLC-MS) analysis. MAFLD rats were induced by high-fat and high-cholesterol diet (HFHCD), and treated by SNS. SNS-containing serum and Compound C (AMPK inhibitor) were used to treat palmitic acid (PA)-induced HepG2 cells. To elucidate the potential mechanism, lipid synthesis-related proteins (SREBP-1c and FAS), fatty acid oxidation (PPARα and CPT-1), and AMPK/SIRT1 signaling pathway (p-AMPK and SIRT1) were assessed by Western blot.

Results

SNS improved serum lipid levels, liver function and reduced hepatic lipid deposition in MAFLD rats. SNS-containing serum reduced lipid deposition in PA-induced HepG2 cells. SNS could up-regulate protein expressions of PPARα, CPT-1, p-AMPK and SIRT1, and down-regulate protein expressions of SREBP-1c and FAS. Similar effects of SNS-containing serum were observed in PA-induced HepG2 cells. Meanwhile, Compound C weakened the therapeutic effects of SNS-containing serum on lipid deposition.

Conclusion

SNS could reduce hepatic lipid deposition by inhibiting lipid synthesis and promoting fatty acid oxidation, which might be related with activating the AMPK/SIRT1 signaling pathway. This study could provide a theoretical basis for the clinical use of SNS to treat MAFLD.

Puerarin inhibits inflammation and lipid accumulation in alcoholic liver disease through regulating MMP8

Alcoholic liver disease (ALD) is a growing global health concern, and its early pathogenesis includes steatosis and steatohepatitis. Inhibiting lipid accumulation and inflammation is a crucial step in relieving ALD. Evidence shows that puerarin (Pue), an isoflavone isolated from Pueraria lobata, exerts cardio-protective, neuroprotective, anti-inflammatory, antioxidant activities. However, the therapeutic potential of Pue on ALD remains unknown. In the study, both the NIAAA model and ethanol (EtOH)-induced AML-12 cell were used to explore the protective effect of Pue on alcoholic liver injury in vivo and in vitro and related mechanism. The results showed that Pue (100 mg·kg-1) attenuated EtOH-induced liver injury and inhibited the levels of SREBP-1c, TNF-α, IL-6 and IL-1β, compared with silymarin (Sil, 100 mg·kg-1). In vitro results were consistent within vivo results. Mechanistically, Pue might suppress liver lipid accumulation and inflammation by regulating MMP8. In conclusion, Pue might be a promising clinical candidate for ALD treatment.

Verbenalin attenuates hepatic damage and mitochondrial dysfunction in alcohol-associated steatohepatitis by regulating MDMX/PPARα-mediated ferroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Verbenalin is a major compound in Verbena officinalis L. Verbena officinalis L was first recorded in the 'Supplementary Records of Famous Physicians.' Verbenalin (VE) is its active constituent and has been found to have many biological effects, including anti-obesity, anti-inflammatory, and antioxidant activities, removing jaundice, and treating malaria. It could treat lump accumulation, dysmenorrhea, throat obstruction, edema, jaundice, and malaria. Palmitic acid (PA), oleic acid (OA), ethanol, and acetaminophen liver injuries have been proven to benefit from verbenalin.

AIM OF THE STUDY

To study the effects of verbenalin on the prevention of alcoholic steatohepatitis (ASH) through the regulation of oxidative stress and mitochondrial dysfunction by regulating MDMX (Murine double minute X)/PPARα (Peroxisome proliferator-activated receptor alpha)-mediated ferroptosis.

MATERIAL AND METHODS

C57BL/6 mice treated with alcohol followed by the Gao-Binge protocol were administered verbenalin by gavage simultaneously. The mitochondrial mass and morphology were visualized using TEM. AML-12 cells were stimulated with ethanol to mimic ASH in vitro. Western blotting, co-immunoprecipitation, and kit determination were simultaneously performed. The target protein of verbenalin was identified by molecular docking, and cellular thermal shift assay (CETSA) further confirmed its interactions.

RESULTS

Verbenalin alleviates oxidative stress and ferroptosis in alcohol-associated steatohepatitis. To elucidate the molecular mechanism by which verbenalin inhibits abnormal mitochondrial dysfunction, molecular docking was performed, and MDMX was identified as the target protein of verbenalin. CETSA assays revealed a specific interaction between MDMX and verbenalin. Co-immunoprecipitation demonstrated that PPARα played a critical role in promoting the ability of MDMX to affect ferroptosis. Verbenalin regulates MDMX/PPARα-mediated ferroptosis in AML-12 cells.

CONCLUSION

Verbenalin regulates ferroptosis and highlights the therapeutic potential of verbenalin and ferroptosis inhibition in reducing alcoholic steatohepatitis.

LncRNA 1700020I14Rik promotes AKR1B10 expression and activates Erk pathway to induce hepatocyte damage in alcoholic hepatitis

Alcoholic hepatitis (AH), a kind of alcoholic liver disease, shows poor prognosis. Long noncoding RNAs (lncRNAs) exert critical role in liver diseases. Here, we intended to investigate the possible molecular mechanism that 1700020I14Rik-based regulation of microRNA (miR)-137/Aldo-keto reductase family 1 member B10 (AKR1B10) affecting the inflammatory response and hepatocyte damage in AH. AH-related genes and the down-stream regulatory pathway were screnned by bioinformatics. Mouse normal hepatocyte cell line AML12 was selected to construct an ethanol-induced hepatocyte injury model for in vitro mechanistic validation, while we also established an AH mouse model using the ethanol with gradually increased concentration of 2–4% (v/v) for in vivo study. Specific role of 1700020I14Rik/miR-137/AKR1B10 in AML12 cell viability, proliferation and apoptotic capacity as well as inflammation and liver damage in mice were analyzed following ectopic and depletion approaches. We found elevated AKR1B10 and 1700020I14Rik but reduced miR-137 in AH. 1700020I14Rik was able to elevated miR-137-mediated AKR1B10. In vitro cell experiments and in vivo animal experiments validated that 1700020I14Rik reduced ethanol-induced hepatocyte damage and inflammation in AH mice through regulation of miR-137–mediated AKR1B10/Erk axis. The current study underlied that 1700020I14Rik could activate AKR1B10/Erk signaling through inhibition of miR-137, thereby promoting the hepatocyte damage in AH mice.

Progress in the treatment of drug-induced liver injury with natural products

There are numerous prescription drugs and non-prescription drugs that cause drug-induced liver injury (DILI), which is the main cause of liver disease in humans around the globe. Its mechanism becomes clearer as the disease is studied further. For an instance, when acetaminophen (APAP) is taken in excess, it produces N-acetyl-p-benzoquinone imine (NAPQI) that binds to biomacromolecules in the liver causing liver injury. Treatment of DILI with traditional Chinese medicine (TCM) has shown to be effective. For example, activation of the Nrf2 signaling pathway as well as regulation of glutathione (GSH) synthesis, coupling, and excretion are the mechanisms by which ginsenoside Rg1 (Rg1) treats APAP-induced acute liver injury. Nevertheless, reducing the toxicity of TCM in treating DILI is still a problem to be overcome at present and in the future. Accumulated evidences show that hydrogel-based nanocomposite may be an excellent carrier for TCM. Therefore, we reviewed TCM with potential anti-DILI, focusing on the signaling pathway of these drugs' anti-DILI effect, as well as the possibility and prospect of treating DILI by TCM based on hydrogel materials in the future. In conclusion, this review provides new insights to further explore TCM in the treatment of DILI.

O-alkyl and o-benzyl hesperetin derivative-1L attenuates inflammation and protects against alcoholic liver injury via inhibition of BRD2-NF-κB signaling pathway

Alcoholic liver injury (ALI) is a major risk factor for alcoholic liver disease, characterized by excessive inflammatory response and abnormal liver dysfunction. Previous studies have indicated that O-alkyl and o-benzyl hesperetin derivative-1 L (HD-1 L) has anti-inflammatory and hepato-protective effects in CCl₄-induced liver injury. However, its effect on ALI and underlying mechanism has not been elucidated. This study was designed to evaluate the protective effects of HD-1 L on alcoholic liver injury and reveal the underlying mechanisms. ALI model was established in male C57BL/6 J mice (aged 6-8 weeks) by Gao-Binge protocol. The mice were received different doses of HD-1 L (25 mg/kg, 50 mg/kg, 100 mg/kg) by daily intragastric administration, respectively. Liver function and inflammation were measured. Mechanism underlying the anti-inflammatory and hepato-protective effect of HD-1 L were studied in RAW264.7 cells. In alcoholic liver injury mice, HD-1 L effectively improved the liver pathology, and remarkably reduced the levels of alanine transaminase (ALT), aspartate transaminase (AST), triglyceride (TG) and total cholesterol (T-CHO) in serum. Moreover, HD-1 L markedly suppressed inflammation in vivo and inhibited the secretion of inflammatory factors in vitro. Our results showed that HD-1 L decreased the activity of Bromodomain-containing Protein 2 (BRD2) and inhibited expression of BRD2 in vivo and in vitro. Furthermore, HD-1 L further alleviated alcohol-induced inflammation after blocking BRD2 with inhibitor (JQ1) or BRD2 small interfering (si)-RNA in RAW264.7 cells. Besides, HD-1 L failed to effectively exert its anti-inflammatory effects after over expression of BRD2. In addition, HD-1 L significantly inhibited the phosphorylation and activation of NF-κB-P65 mediated by BRD2. In conclusion, HD-1 L alleviated liver injury and inflammation mainly by inhibiting BRD2-NF-κB signaling pathway, and HD-1 L may be a potential anti-inflammatory compound in treatment of alcoholic liver disease.

Interleukin-9 attenuates inflammatory response and hepatocyte apoptosis in alcoholic liver injury

Alcoholic liver injury is a liver cell dysfunction disease caused by long-term or excessive alcohol consumption. Inhibiting the production of inflammatory factors is an important way to alleviate liver injury. Interleukin-9 (IL-9) is one of the members of IL-2Rγc family. It has multiple biological functions. Previous studies have shown that IL-9 is a cytokine that is closely related to inflammatory disease, allergic diseases, autoimmune diseases, and parasitic infections. However, no systematic studies have been performed to address the role of IL-9 in ALI. This project aims to investigate the effects of IL-9 on macrophage-related inflammatory response and hepatocyte apoptosis in alcohol-induced liver injury by injecting adeno-associated virus (AAV9) into tail vein. In the ALI model group, western blot and ELISA assays demonstrated that the expression of IL-9 was reduced. Overexpression of IL-9 relieved the injury and reduced the serum levels of IL-6, TNF-α in EtOH-induced ALI mouse model. Moreover, by using western blot, it was indicated that IL-9 can inhibit the expression of pro-apoptotic protein, such as cleaved caspase 3 and Bax. In vitro, mouse recombinant protein IL-9 inhibited the expression of IL-6, TNF-α in EtOH-induced RAW264.7 cells. Moreover, flow cytometry and western blot results displayed that macrophage-derived IL-9 inhibited hepatocyte apoptosis. After silencing STAT3 in AML-12 cells, the anti-apoptotic effect of macrophage-derived IL-9 was further enhanced. These results indicate that IL-9 reduces the production of pro-inflammatory factors in ALI. Furthermore, macrophage-derived IL-9 can reduce hepatocyte apoptosis by inhibiting the activation of the STAT3 pathway.

The upshot of Polyphenolic compounds on immunity amid COVID-19 pandemic and other emerging communicable diseases: An appraisal

Polyphenols are a large family of more than 10,000 naturally occurring compounds, which exert countless pharmacological, biological and physiological benefits for human health including several chronic diseases such as cancer, diabetes, cardiovascular, and neurological diseases. Their role in traditional medicine, such as the use of a wide range of remedial herbs (thyme, oregano, rosemary, sage, mint, basil), has been well and long known for treating common respiratory problems and cold infections. This review reports on the most highlighted polyphenolic compounds present in up to date literature and their specific antiviral perceptive properties that might enhance the body immunity facing COVID-19, and other viral infectious diseases. In fact, several studies and clinical trials increasingly proved the role of polyphenols in controlling numerous human pathogens including SARS and MERS, which are quite similar to COVID-19 through the enhancement of host immune response against viral infections by different biological mechanisms. Thus, polyphenols ought to be considered as a potential and valuable source for designing new drugs that could be used effectively in the combat against COVID-19 and other rigorous diseases.

Flavonoids from Aurantii Fructus Immaturus and Aurantii Fructus: promising phytomedicines for the treatment of liver diseases

Background

Liver diseases and related complications are major sources of morbidity and mortality, which places a huge financial burden on patients and lead to nonnegligible social problems. Therefore, the discovery of novel therapeutic drugs for the treatment of liver diseases is urgently required. Aurantii Fructus Immaturus (AFI) and Aurantii Fructus (AF) are frequently used herbal medicines in traditional Chinese medicine (TCM) formulas for the treatment of diverse ailments. A variety of bioactive ingredients have been isolated and identified from AFI and AF, including alkaloids, flavonoids, coumarins and volatile oils.

Main body

Emerging evidence suggests that flavonoids, especially hesperidin (HD), naringenin (NIN), nobiletin (NOB), naringin (NRG), tangeretin (TN), hesperetin (HT) and eriodictyol (ED) are major representative bioactive ingredients that alleviate diseases through multi-targeting mechanisms, including anti-oxidative stress, anti-cytotoxicity, anti-inflammation, anti-fibrosis and anti-tumor mechanisms. In the current review, we summarize the recent progress in the research of hepatoprotective effects of HD, NIN, NOB, NRG, TN, HT and ED and highlight the potential underlying molecular mechanisms. We also point out the limitations of the current studies and shed light on further in-depth pharmacological and pharmacokinetic studies of these bioactive flavonoids.

Conclusion

This review outlines the recent advances in the literature and highlights the potential of these flavonoids isolated from AFI and AF as therapeutic agents for the treatment of liver diseases. Further pharmacological studies will accelerate the development of natural products in AFI and AF and their derivatives as medicines with tantalizing prospects in the clinical application.

Nano-Zn Increased Zn Accumulation and Triglyceride Content by Up-Regulating Lipogenesis in Freshwater Teleost, Yellow Catfish Pelteobagrus fulvidraco

The present study was conducted to explore the mechanism of nano-Zn absorption and its influence on lipid metabolism in the intestine of yellow catfish Pelteobagrus fulvidraco. Compared to ZnSO₄, dietary nano-Zn addition increased the triglyceride (TG) content, enzymatic activities of malic enzyme (ME) and fatty acid synthase (FAS), and up-regulated mRNA levels of 6pgd, fas, acca, dgat1, pparγ, and fatp4. Using primary intestinal epithelial cells of yellow catfish, compared to the ZnSO₄ group, nano-Zn incubation increased the contents of TG and free fatty acids (FFA), the activities of glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6GPD), ME, and FAS, up-regulated mRNA levels of lipogenic genes (6pgd, g6pd, fas, dgat1, and pparγ), genes of lipid transport (fatp4 and ifabp), and Zn transport genes (znt5, znt7, mt, and mtf1), and increased the protein expression of fatty acid transport protein 4 (FATP4) and peroxisome proliferator activated receptor gamma (PPARγ). Further studies found that nano-Zn absorption was via the clathrin-dependent endocytic mechanism. PPARγ mediated the nano-Zn-induced increase in TG, and nano-Zn increased Zn accumulation and induced TG accumulation by activating the PPARγ pathway and up-regulating lipogenesis.

Therapeutic potential of PPARγ natural agonists in liver diseases

Peroxisome proliferator‐activated receptor gamma (PPARγ) is a vital subtype of the PPAR family. The biological functions are complex and diverse. PPARγ plays a significant role in protecting the liver from inflammation, oxidation, fibrosis, fatty liver and tumours. Natural products are a promising pool for drug discovery, and enormous research effort has been invested in exploring the PPARγ‐activating potential of natural products. In this manuscript, we will review the research progress of PPARγ agonists from natural products in recent years and probe into the application potential and prospects of PPARγ natural agonists in the therapy of various liver diseases, including inflammation, hepatic fibrosis, non‐alcoholic fatty liver and liver cancer.

Design, Synthesis and Investigation of the Potential Anti-Inflammatory Activity of 7-O-Amide Hesperetin Derivatives

To develop new anti-inflammatory agents, a series of 7-O-amide hesperetin derivatives was designed, synthesized and evaluated for anti-inflammatory activity using RAW264.7 cells. All compounds showed inhibitory effect on LPS-induced NO production. Among them, 7-O-(2-(Propylamino)-2-oxoethyl)hesperetin (4d) and 7-O-(2-(Cyclopentylamino)-2-oxoethyl)hesperetin (4k) with hydrophobic side chains exhibited the most potent NO inhibitory activity (IC₅₀ = 19.32 and 16.63 μM, respectively), showing stronger inhibitory effect on the production of pro- inflammatory cytokines tumor necrosis factor (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) than indomethacin and celecoxib at 10 μM. The structure-activity relationships (SARs) suggested that the 7-O-amide unit was buried in a medium-sized hydrophobic cavity of the bound receptor. Furthermore, compound 4d could also significantly suppress the expression of inducible nitric oxide synthase enzymes (iNOS) and cyclooxygenase-2 (COX-2), through the nuclear factor-kappa B (NF-κB) signaling pathway.