Hepatoprotective effect of fraxin against carbon tetrachloride-induced hepatotoxicity in vitro and in vivo through regulating hepatic antioxidant, inflammation response and the MAPK-NF-κB signaling pathway

Fraxin alleviates oral lichen planus by suppressing OCT3-mediated activation of FGF2/NF-κB pathway

Oral lichen planus (OLP) is a carcinogenic chronic inflammatory oral disease, which lacks effective treatments. Fraxin is an active ingredient of the traditional Chinese medicine Qin Pi, which has an anti-inflammatory effect, but its effect on OLP is unclear. The aim of this study was to investigate the therapeutic effect of fraxin on OLP and the underlying mechanism. Human immortalized keratinocytes (HaCat) were incubated with fraxin (10, 20, or 40 µM) for 48 h and then treated with 10 µg/mL LPS for 24 h. Cell viability and apoptosis were detected. Next, the interaction between OCT3 and FGF2 was predicted by online database and verified by Co-IP analysis. Fraxin, Ad-OCT3, sh-OCT3, and sh-FGF2 were, respectively, applied to treat LPS-incubated HaCat cells, and cell viability, apoptosis, and secretion of inflammatory factors were detected with MTT, flow cytometry, and ELISA assays. Then, the involvement of OCT3 and FGF2 in the prevention of fraxin on HaCat cells from LPS-induced cell apoptosis and inflammation was investigated through multiple rescue experiments. In addition, OLP models were constructed in VDR-/- mice and NOD/SCID mice by injecting with human OLP pathological tissue homogenates to verify the therapeutic effect of fraxin on OLP. Fraxin treatment increased cell viability and reduced cell apoptosis and the secretion of IL-6 and TNF-α in a dose-dependent manner. OCT3 was significantly upregulated in oral mucosa tissues of OLP mice. OCT3 silencing inhibited LPS-induced cell apoptosis and secretion of inflammatory factors. Fraxin incubation reduced the expression of OCT3, and OCT3 interacted with FGF2 to upregulate FGF2 protein. FGF2 silencing reduced the expression of p-p65/NF-κB protein and improved LPS-induced cell apoptosis and secretion of inflammatory factors. OCT3 overexpression increased the expression of FGF2 and p-p65/NF-κB proteins, rh-FGF2 aggravated this effect, while FGF2-Neu-Ab reversed this effect. The results of in vivo experiments showed that fraxin alleviated cell apoptosis and inflammation in oral buccal mucosa tissues of OLP mice. Fraxin inhibited cell apoptosis and inflammation by suppressing OCT3-mediated activation of the FGF2/NF-κB pathway, alleviating the progression of OLP.

Fraxini cortex: Progresses in phytochemistry, pharmacology and ethnomedicinal uses

ETHNOPHARMACOLOGICAL RELEVANCE

Fraxini cortex, which has been widely used as a traditional Chinese medicine for 2000 years, is made from the dried bark of four plant species: Fraxinus chinensis subsp. rhynchophylla (Hance) A.E.Murray, Fraxinus chinensis Roxb., Fraxinus chinensis subsp. chinensis and Fraxinus stylosa Lingelsh.. In Chinese traditional medicine, it possesses the properties of heat-clearing and dampness-drying, asthma relief and cough suppression, as well as vision improvement. It is utilized for treating bacterial disorders, enteritis, leukorrhea, chronic bronitis, painful red eyes with swelling, lacrimation due to windward exposure, psoriasis, and other diseases or related symptoms.

AIM OF THE STUDY

Fraxini cortex is abundant in chemical constituents and has garnered significant attention from plant chemists, particularly regarding coumarins, as evidenced by the recently identified three coumarin compounds. Considering the current dearth of systematic reporting on studies pertaining to Fraxini cortex, herein we provide a comprehensive summary of the advancements in phytochemistry, pharmacology, detection methods, and ethnomedicinal applications of Fraxini cortex.

MATERIALS AND METHODS

We conducted a comprehensive search across online data sources (Web of Science, Public Medicine (PubMed), China National Knowledge Infrastructure (CNKI), as well as Chinese dissertations) and traditional Chinese medicine classics to gather the necessary literature resources for this review.

RESULTS

Briefly, The Fraxini cortex yielded a total of 132 phytochemicals, including coumarins, lignans, secoiridoids, phenylethanol glycosides, flavonoids, triterpenoids, and other compounds. Among them, the main active ingredients are coumarins which possess a diverse range of pharmacological activities such as anti-inflammatory effects, anti-tumor properties, prevention of tissue fibrosis and oxidation damage as well as cardioprotective effects.

CONCLUSIONS

All types of research conducted on Fraxini cortex, particularly in the field of ethnopharmacology, phytochemistry, and pharmacology, have been thoroughly reviewed. However, certain traditional applications and pharmacological activities of Fraxini cortex lack scientific evaluation or convincing evidence due to incomplete methodologies and ambiguous results, as well as a lack of clinical data. To validate its pharmacological activity, clinical efficacy, and safety profile, a systematic and comprehensive research evaluation is imperative. As an important traditional Chinese medicine, Fraxini cortex should be further explored to facilitate the development of novel drugs and therapeutics for various diseases. Greater attention should be given to how it can be better utilized.

Pharmacological Activities of Plant-Derived Fraxin with Molecular Mechanisms: A Comprehensive Review

Fruits and vegetables serve not only as sources of nutrition but also as medicinal agents for the treatment of diverse diseases and maladies. These dietary components are significant resources of phytochemicals that demonstrate therapeutic properties against many illnesses. Fraxin is a naturally occurring coumarin glycoside mainly present in various species of Fraxinus genera, having a multitude of therapeutic uses against various diseases and disorders. This study focuses to investigate the pharmacological activities, botanical sources, and biopharmaceutical profile of the phytochemical fraxin based on different preclinical and non-clinical studies to show the scientific evidence and to evaluate the underlying molecular mechanisms of the therapeutic effects against various ailments. For this, data was searched and collected (as of February 15, 2024) in a variety of credible electronic databases, including PubMed/Medline, Scopus, Springer Link, ScienceDirect, Wiley Online, Web of Science, and Google Scholar. The findings demonstrated favorable outcomes in relation to a range of diseases or medical conditions, including inflammation, neurodegenerative disorders such as cerebral ischemia-reperfusion (I/R) and depression, viral infection, as well as diabetic nephropathy. The phytochemical also showed protective effects such as osteoprotective, renoprotective, pulmoprotective, hepatoprotective, and gastroprotective effects due to its antioxidant capacity. Fraxin has a great capability to diminish oxidative stress-related damage in different organs by stimulating the antioxidant enzymes, downregulating nuclear factor kappa B and NLRP3, and triggering the Nrf2/ARE signaling pathways. Fraxin exhibited poor oral bioavailability because of reduced absorption and a wide distribution into tissues of different organs. However, extensive research is required to decipher the biopharmaceutical profiles, and clinical studies are necessary to establish the efficacy of the natural compound as a reliable therapeutic agent.

Anti-cytokine Storm Activity of Fraxin, Quercetin, and their Combination on Lipopolysaccharide-Induced Cytokine Storm in Mice: Implications in COVID-19

Background

Cytokine release syndrome (CRS) is the leading cause of mortality in advanced stages of coronavirus patients. This study examined the prophylactic effects of fraxin, quercetin, and a combination of fraxin+quercetin (FQ) on lipopolysaccharide-induced mice.

Methods

Sixty mice were divided into six groups (n=10) as follows: control, LPS only, fraxin (120 mg/Kg), quercetin (100 mg/Kg), dexamethasone (5 mg/Kg), and FQ. All treatments were administered intraperitoneally (IP) one hour before induction by LPS (5 mg/Kg) IP injection. Twenty-four hours later, the mice were euthanized. Interleukin one beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were quantified using an enzyme-linked immunosorbent assay (ELISA), and lung and kidney tissues were examined for histopathological alterations. This study was conducted at Al-Nahrain University, Baghdad, Iraq, in 2022.

Results

FQ reduced IL-1β (P<0.001). All treatments significantly suppressed IL-6, fraxin, quercetin, dexamethasone, and FQ, all with P<0.001. The TNF-α level was reduced more with dexamethasone (P<0.001) and quercetin (P<0.001). Histopathological scores were significantly reduced mainly by quercetin and FQ in the lungs with scores of 12.30±0.20 (P=0.093), and 15.70±0.20 (P=0.531), respectively. The scores were 13±0.26 (P=0.074) and 15±0.26 (P=0.222) for quercetin and FQ in the kidneys, respectively.

Conclusion

All used treatments reduced proinflammatory cytokine levels and protected against LPS-induced tissue damage.

Chemical characterisation of essential oil from Sambucus williamsii Hance leaves and its hepatoprotective effects

This study is the first to examine the effect of leaves of Sambucus williamsii Hance essential oil on acute liver injury. According to gas chromatography-mass spectrometry analysis, the major constituents of S. williamsii essential oil (SEO)were (S)-falcarinol (62.66%), 17-pentatriacontene (7.78%) and tetrapentacontane (8.64%). Mice were pre-treated with SEO for 6 days followed by inducing liver injury with CCl4. The results indicated that SEO protected the liver against CCl4-induced injuries. Elevated levels of alanine-aminotransferase (ALT), aspartate amino-transferase (AST), alkaline phosphatase (ALP) in serum were significantly reduced on SEO pre-treatment. SEO pre-treatment significantly inhibited the oxidative stress and inflammation. Furthermore, toll-like receptor-4 (TLR4)/nuclear factor kappa-B (NF-κB) signalling pathways were significantly modulated by SEO in the liver tissue. The findings demonstrate that the essential oil of S. williamsii has enhancing the resistance to CCl4-induced liver injury.

Harmine ameliorates CCl4-induced acute liver injury through suppression of autophagy and inflammation

CCl4-induced acute liver injury (ALI) is characterized by heightened autophagy, inflammation, and oxidative damage. Accumulating evidence suggests that harmine exerts beneficial effects in countering CCl4-induced ALI by mitigating inflammation and oxidative stress. However, the impact of autophagy on CCl4-induced ALI and the protective role of harmine remain unclear. This study aimed to investigate the potential protective effects of harmine against CCl4-induced ALI in mice by suppressing autophagy and inflammation. Male Kunming mice were orally administered harmine or bifendate for seven days. Subsequently, one hour after the final administration, the model group and treatment groups were intraperitoneally injected with CCl4 to induce ALI. The findings revealed that harmine significantly reduced the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum, and ameliorated the liver histopathological changes induced by CCl4. Furthermore, harmine diminished the levels of TNF-α and IL-6, restored the levels of glutathione (GSH) and superoxide dismutase (SOD), and suppressed the production of nitric oxide (NO) and malondialdehyde (MDA) in the liver. Mechanistically, harmine down-regulated LC3B II/I, p38 MAPK, TLR4, and NF-κB levels, while upregulating p62, Bcl-2, Beclin1, ULK1, and p-mTOR expression. In conclusion, harmine mitigated CCl4-induced ALI by inhibiting autophagy and inflammation through the p38 MAPK/mTOR autophagy pathway, the Bcl-2/Beclin1 pathway, and the TLR4/NF-κB pathway.

Fraxin in Combination with Dexamethasone Attenuates LPS-Induced Liver and Heart Injury and Their Anticytokine Activity in Mice

Background

Cytokine storm syndrome (CSS) is a major cause of morbidity and mortality in people suffering from hyperinflammatory status, which diverse etiological factors, including pathogens, therapeutic interventions, malignancies, and autoimmune disorders, can instigate. Since there is limited research on the antioxidant properties of fraxin and no studies have investigated its potential as an anticytokine storm agent, it is important to note that most studies have primarily focused on proinflammatory cytokines such as IL-1β, IL-6, and TNFα during cytokine storm. However, little research discusses the role of chemokines, particularly IL-8, during cytokine storms. Therefore, further investigation is warranted into the role of fraxin as an anticytokine storm agent and the involvement of IL-8 in cytokine storms. The present study examines the preventive efficacy of fraxin and the combination of fraxin and dexamethasone (FD) in mitigating lipopolysaccharide-induced systemic inflammation in mice caused by Escherichia coli, 055: B5.

Methods

Five groups of ten mice were randomly assigned: LPS only group (5 mg/kg, intraperitoneally i.p.), control (normal saline N.S. 1 ml/kg, i.p.), concentrations were selected based on previous literature, fraxin (120 mg/kg, i.p.), dexamethasone (5 mg/kg, i.p.), fraxin + dexamethasone (FD) (60 mg/kg + 2.5 mg/kg, i.p.), administered one hour before LPS injection (5 mg/kg,i.p.), animals were euthanized next day, and interleukin-8 (IL-8) was quantified in serum using an enzyme-linked immunosorbent assay. The liver and heart tissues underwent histopathological analysis to assess morphological changes. For data analysis using ANOVA and Tukey post hoc tests, the Kruskal-Wallis and Mann-Whitney U tests were employed to analyze the histological results.

Results

A significant decline in IL-8 levels was recorded in the treatment groups almost to the same degree (p < 0.001), and the percentage of inhibition of IL-8 for fraxin, dexamethasone, and FD was 93%.92.4%, and 93%, respectively, compared to the LPS-only group. Histopathological scores were significantly reduced in liver and heart tissue (P < 0.05).

Conclusions

All interventions used in this study significantly reduced interleukin-8 (IL-8) levels and reduced LPS-induced liver and cardiac damage. The combination (FD) did not result in an evident superiority of either agent. More research is required to identify the possible usefulness of these agents in treating hyperinflammatory diseases, such as cytokine storms, in future clinical practice.

Fraxin inhibits melanogenesis by suppressing the ERK/MAPK pathway and antagonizes oxidative stress by activating the NRF2 pathway

Hyperpigmentation disorders, such as melasma and freckles, are highly prevalent and draw increasing attention. Patients thus tend to seek effective and safe cosmetic whitening agents. Fraxin, a bioactive substance extracted from Cortex Fraxini, possesses anti-inflammation and antioxidant properties. In this study, we further explored the anti-melanogenic activities of fraxin were explored in vitro and in vivo. We found that pretreatment with fraxin decreased the melanin content of MNT1 cells and zebrafishes. In MNT1 cells, melanogenesis-related proteins, such as MITF, TYR, TYRP1, and DCT were down-regulated and tyrosinase activity was reduced under fraxin treatment. Further exploration of the mechanism revealed that fraxin could inhibit the phosphorylation of ERK, which is closely related to melanogenesis. Besides, fraxin also protected MNT1 cells from H2O2-induced apoptosis via scavenging reactive oxygen species (ROS) in cells. Further experimentation revealed that fraxin could activate NRF2 and upregulate antioxidase CAT and HO-1. In conclusion, fraxin could be an effective agent with anti-melanogenesis and antioxidant properties for hyperpigmentation disorders.

Comparison of physicochemical characteristics, antioxidant and immunomodulatory activities of polysaccharides from wine grapes

In this study, an efficient ultrasonic-assisted extraction method was used for the extraction and optimization of four wine grape polysaccharides. A three-level, three-factor Box Behnken Design combined with the response surface approach was used to optimize the extraction conditions. Their physicochemical properties, molecular structure, antioxidant activity, immunomodulatory activity and hepatoprotective effects were examined and compared. These findings suggest that the four wine grape polysaccharides share similar basic structural features and monosaccharide composition. Furthermore, four wine grape polysaccharides exhibited antioxidant and immunomodulatory activities in a concentration-dependent manner. Moldova (MD) polysaccharide displayed better antioxidant activity and immunomodulatory ability. Furthermore, MD polysaccharide has a significant therapeutic effect on CCl₄-induced rat liver injury by improving the antioxidant defense system and inhibiting oxidative stress, indicating that MD has a hepatoprotective effect. Taken together, the MD wine grape polysaccharide may have potential applications in prevention of liver disease in the functional food and pharmaceutical industries.

Rosmarinic acid exerts anti-inflammatory effect and relieves oxidative stress via Nrf2 activation in carbon tetrachloride-induced liver damage

Background

Rosmarinic acid (RA) has biological and pharmaceutical properties and shows hepatoprotective potential. However, the hepatoprotective mechanism of RA needs to be further elucidated in vivo and in vitro.

Objective

This study was aimed to evaluate the protective effect of RA on carbon tetrachloride (CCl₄)-induced liver injury and elucidate the hepatoprotective mechanism of RA in vivo and in vitro.

Design

In vivo, the mice were orally administrated with RA (10, 20, and 40 mg/kg bw) daily for 28 consecutive days, and 1% CCl₄ (5 mL/kg bw, dissolved in peanut oil) was used to induce liver injury. In vitro, the big rat liver (BRL) hepatocytes were pretreated with RA (0.2, 0.4, and 0.8 mg/mL) for 3 h, and then the hepatocytes were treated with CC1₄ (final concentration, 14 mM) for 3 h to induce cell injury. The related indexes, including hepatic function, oxidative stress, protein expression of nuclear-factor erythroid 2-related factor 2 (Nrf2) pathway, inflammation, histopathological change, hepatocyte apoptosis, and mitochondrial membrane potential, were evaluated.

Results

Oral administration of RA to mice considerably decreased the CCl₄-induced elevation of serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), triacylglycerols (TG), total cholesterol (TC), total bilirubin (TBIL), hepatic reactive oxygen species (ROS), malondialdehyde (MDA), nitric oxide (NO), 8-hydroxydeoxyguanosine (8-OHdG), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8). RA also increased the levels of hepatic glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) and the protein expressions of Nrf2, quinine oxidoreductase (NQO1), and heme oxygenease-1 (HO-1). Histopathological examinations indicated that RA (20 and 40 mg/kg bw) alleviated the liver tissue injury induced by CCl₄. Moreover, RA inhibited the hepatocyte apoptosis caused by CCl₄ based on TUNEL assay. In vitro, RA pretreatment remarkably recovered the cell viability and reduced the CCl₄-induced elevation of AST, ALT, lactate dehydrogenase (LDH), ROS, and 8-OHdG. Immunohistochemistry staining demonstrated that pretreatment with RA markedly inhibited the expression of IL-6, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and Caspase-3 in CCl₄-treated hepatocytes. Additionally, RA pretreatment significantly decreased the elevation of mitochondrial membrane potential in CCl₄-treated hepatocytes.

Conclusions

RA exerted a protective effect against CCl₄-induced liver injury in mice through activating Nrf2 signaling pathway, reducing antioxidant damage, suppressing inflammatory response, and inhibiting hepatocyte apoptosis. RA could attenuate BRL hepatocyte ROS production, DNA oxidative damage, inflammatory response, and apoptosis induced by CCl₄ exposure.

Preventive Effect of Flavonoid Extract from the Peel of Gonggan (Citrus reticulata Blanco Var. Gonggan) on CCl4-Induced Acute Liver Injury in Mice

Objective

Citrus peel, a waste product of citrus consumption and processing, is rich in flavonoids. This study aimed to study the protective effect of flavonoid extract from the peel of gonggan (Citrus reticulata Blanco var. gonggan) on acute chemical liver injury.

Materials and Methods

We established a chemical liver injury model induced by carbon tetrachloride (CCl₄) in mice. The flavonoid composition in gonggan (Citrus reticulata Blanco var. gonggan) peel was detected by HPLC. The histopathological sections of liver, related biochemical indicators in serum and liver, and related genes were examined to evaluate the protective effect of gonggan peel flavonoid extract (GPFE).

Results

The results showed that GPFE contained narirutin, hesperidin, nobiletin, tangeretin, and 5-demethylnobiletin. After 14 days of intragastric administration of GPFE, the result showed GPFE could reduce the increase in liver index, serum alanine aminotransferase (ALT), and aspartate transaminase (AST) levels caused by CCl₄. At the same time, pathological sections of liver confirmed that GPFE alleviated the damage to liver tissue. Moreover, biochemical indicator results showed that GPFE increased the activities of superoxide dismutase (SOD) and catalase (CAT) in liver tissue and reduced the content of malondialdehyde (MDA). Also, it reduced the levels of inflammation factors: tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin (IL)-1β, and IL-6. In addition, q-PCR results showed that GPFE upregulated mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), copper/zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), glutathione peroxidase (GSH-Px), γ-glutamylcysteine synthetase (γ-GCS), CAT, and downregulated IL-6 and TNF-α mRNA expression levels. The mechanism of GPFE may be related to the inhibition of oxidative stress and inflammation.

Conclusion

The experiment indicates GPFE has a good protective effect on acute chemical liver injury in mice induced by CCl₄ via antioxidant and anti-inflammatory pathways.

Fraxin prevents knee osteoarthritis through inhibiting chondrocyte apoptosis in an experimental rat osteoarthritis model

BACKGROUND

Current treatments of osteoarthritis are unsatisfied, a new approach towards the treatment of osteoarthritis is urged considering the state at present.

OBJECTIVES

The objective of this study is to investigate the effect of fraxin on knee OA in a rat model and probe into the possible molecular mechanism.

METHODS

Primary Murine Chondrocytes were isolated and cell apoptosis analyses were performed. Rat OA models were established using meniscectomy method and allocated into three groups. Knee joint specimens were collected for qRT-PCR, western blotting and histological analysis. Statistical analyses were processed by using a SPSS.

RESULTS

The apoptosis rate of fraxin group is significantly reduced compared with the OA group or the control group. Fraxin remarkably down-regulated the expression of cleaved-Caspase-3 while significantly up-regulated the expression of Bcl-2, both on mRNA and protein levels. Toluidine blue stain results show relatively lighter articular cartilage damage compared with OA group.

CONCLUSION

Fraxin prevents knee osteoarthritis by inhibiting chondrocyte apoptosis, which makes it a potential candidate as an anti-OA drug for clinical use.

Hepatoprotective Effect of Apigenin Against Liver Injury via the Non-canonical NF-κB Pathway In Vivo and In Vitro

Apigenin, a flavonoid found in many plants, has various biological properties. We aimed to investigate the anti-inflammatory and anti-oxidative activity of apigenin against carbon tetrachloride (CCl₄)-induced acute liver injury in mice and hydrogen peroxide (H₂O₂)-induced oxidative stress in HepG2 cells and possible mechanism. In vivo, apigenin significantly reduced alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity in serum of mice challenged by CCl₄ and markedly alleviated the lipid peroxidation as indicated by the increased level of superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidases (GSH-Px) and catalase (CAT), and the decreased malondialdehyde (MDA) in liver tissue. Apigenin also ameliorated inflammation by downregulating tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and upregulating IL-10. Consistently, the elevated ALT and AST level; the impaired balance between SOD, GSH activity, and excessive ROS; and the increased gene expression of TNF-α and IL-6 resulting from H₂O₂-induced oxidative stress were restored by apigenin. Moreover, the results from Western blot, real-time qPCR, and immunofluorescence assay indicated that apigenin enhanced the activity of TNF receptor-associated factor (TRAF) 2/3 and cellular inhibitor of apoptosis protein (c-IAP) 1, ameliorated NF-κB-inducing kinase (NIK), and mediated the nuclear translocation of NF-κB2, therefore had an inhibitory effect on the non-canonical NF-κB pathway which was activated in both models. siNIK canceled the protective effect of apigenin on H₂O₂-induced HepG2 cells. Altogether, our results demonstrated that apigenin mitigated liver injury by ameliorating inflammation and oxidative stress through suppression of the non-canonical NF-κB pathway, indicating the potential of apigenin for treatment of the liver injury.

The novel nanocomplexes containing deoxycholic acid-grafted chitosan and oleanolic acid displays the hepatoprotective effect against CCl4-induced liver injury in vivo

Chemical liver injury threatens seriously human health, along with the shortage of efficiency and low-toxicity drugs. Herein, the novel oral nanocomplexes composed of deoxycholic acid-grafted chitosan and oleanolic acid were constructed to reverse the CCl₄-induced acute liver damage in mice. Results indicated core-shell nanocomplexes, maintained by the hydrophobic interaction between deoxycholic acid and oleanolic acid, could be dissociated in the intestine. Notably, the nanocomplexes possessed superior hepatoprotective effect in vivo, possibly due to the synergistic effect between grafted chitosan and oleanolic acid. Mechanism investigations suggested that nanocomplexes reversed CCl₄-induced liver injury through improving hepatic antioxidant capacity via NrF2/Keap1 pathway and regulating inflammation response via NF-κB signaling pathway. The novel oral nanocomplexes represent an effective strategy for chemical liver injury therapy.

Hepatoprotective effect of apolipoprotein A4 against carbon tetrachloride induced acute liver injury through mediating hepatic antioxidant and inflammation response in mice

Apolipoprotein A4 (ApoA4) regulates lipid and glucose metabolism and exerts anti-inflammatory effects in atherogenesis and colitis. The present study explored the presumed protective role of ApoA4 in carbon tetrachloride (CCl4)-induced acute liver injury (ALI) in mice. The ALI model in wild type (WT), ApoA4 knock-out (ApoA4-KO) and ApoA4 transgenic (ApoA4-TG) mice was induced by a single intraperitoneal administration of CCl4. Liver and blood were harvested from mice to assess liver functions, immunohistological changes, immune cell populations and cytokine profiles. ApoA4 deficiency aggravated, and ApoA4 overexpression alleviated CCl4-inflicted liver damage by controlling levels of anti-oxidant enzymes. ApoA4 deletion increased the recruitment of monocytes/macrophages into the injured liver and upregulated the plasma levels of IL-6, TNF-α and MCP-1, but lower IL-10 and IFN-γ. ApoA4 over-expression rescued this effect and resulted in lower percentages of monocytes/macrophages and dendritic cells, the ratio of blood pro-inflammatory to anti-inflammatory monocytes and reduced plasma concentrations of IL-6, but enhanced IL-10 and IFN-γ. We propose ApoA4 as a potential new therapeutic target for the management of liver damage.

Polydeoxyribonucleotide Exerts Protective Effect Against CCl4-Induced Acute Liver Injury Through Inactivation of NF-κB/MAPK Signaling Pathway in Mice

Acute liver injury (ALI) causes life-threatening clinical problem, and its underlying etiology includes inflammation and apoptosis. An adenosine A_2A receptor agonist, polydeoxyribonucleotide (PDRN), exhibits anti-inflammatory and anti-apoptotic effects by inhibiting the secretion of pro-inflammatory cytokines. In the current study, the protective effect of PDRN against carbon tetrachloride (CCl₄)-induced ALI was investigated using mice. For the induction of ALI, mice received intraperitoneal injection of CCl₄ twice over seven days. Mice from the PDRN-treated groups received an intraperitoneal injection of 200 μL saline containing PDRN (8 mg/kg), once a day for seven days, starting on day 1 after the first CCl₄ injection. In order to confirm that the action of PDRN occurs through the adenosine A_2A receptor, 8 mg/kg 3,7-dimethyl-1-propargylxanthine (DMPX), an adenosine A_2A receptor antagonist, was treated with PDRN. Administration of CCl₄ impaired liver tissue and increased the liver index and histopathologic score. The expression of pro-inflammatory cytokines was increased, and apoptosis was induced by the administration of CCl₄. Administration of CCl₄ activated nuclear factor-kappa B (NF-κB) and facilitated phosphorylation of signaling factors in mitogen-activated protein kinase (MAPK). In contrast, PDRN treatment suppressed the secretion of pro-inflammatory cytokines and inhibited apoptosis. PDRN treatment inactivated NF-κB and suppressed phosphorylation of signaling factors in MAPK. As a result, liver index and histopathologic score were reduced by PDRN treatment. When PDRN was treated with DMPX, the anti-inflammatory and anti-apoptotic effect of PDRN disappeared. Therefore, PDRN can be used as an effective therapeutic agent for acute liver damage.

Coumarins as Modulators of the Keap1/Nrf2/ARE Signaling Pathway

The Keap1/Nrf2/ARE system is a central defensive mechanism against oxidative stress which plays a key role in the pathogenesis and progression of many diseases. Nrf2 is a redox-sensitive transcription factor controlling a variety of downstream antioxidant and cytodefensive genes. Nrf2 has a powerful anti-inflammatory activity mediated via modulating NF-κB. Therefore, pharmacological activation of Nrf2 is a promising therapeutic strategy for the treatment/prevention of several diseases that are underlined by both oxidative stress and inflammation. Coumarins are natural products with promising pharmacological activities, including antioxidant, anticancer, antimicrobial, and anti-inflammatory efficacies. Coumarins are found in many plants, fungi, and bacteria and have been widely used as complementary and alternative medicines. Some coumarins have shown an ability to activate Nrf2 signaling in different cells and animal models. The present review compiles the research findings of seventeen coumarin derivatives of plant origin (imperatorin, visnagin, urolithin B, urolithin A, scopoletin, esculin, esculetin, umbelliferone, fraxetin, fraxin, daphnetin, anomalin, wedelolactone, glycycoumarin, osthole, hydrangenol, and isoimperatorin) as antioxidant and anti-inflammatory agents, emphasizing the role of Nrf2 activation in their pharmacological activities. Additionally, molecular docking simulations were utilized to investigate the potential binding mode of these coumarins with Keap1 as a strategy to disrupt Keap1/Nrf2 protein-protein interaction and activate Nrf2 signaling.

Indole-3-Carbinol Derivative DIM Mitigates Carbon Tetrachloride-Induced Acute Liver Injury in Mice by Inhibiting Inflammatory Response, Apoptosis and Regulating Oxidative Stress

3,3'-Diindolylmethane (DIM), a metabolic product of indole-3-carbinol extracted from cruciferous vegetables exhibits anti-inflammatory and anti-cancer properties. Earlier, the product has been demonstrated to possess anti-fibrotic properties; however, its protective effects on liver injury have not been clearly elucidated. In this study, we postulated the effects and molecular mechanisms of action of DIM on carbon tetrachloride (CCl4)-induced liver injury in mice. Acute liver injury was induced by a single intraperitoneal administration of CCl4 (1 ml/kg) into mice. DIM was injected via subcutaneous route for three days at various doses (2.5, 5 and 10 mg/kg) before CCl4 injection. Mice were sacrificed and serum was collected for quantification of serum transaminases. The liver was collected and weighed. Treatment with DIM significantly reduced serum transaminases levels (AST and ALT), tumor necrosis factor-α (TNF-α) and reactive oxygen species (ROS). CCl4- induced apoptosis was inhibited by DIM treatment by the reduction in the levels of cleaved caspase-3 and Bcl2 associated X protein (Bax). DIM treated mice significantly restored Cytochrome P450 2E1, nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression in CCl4 treated mice. In addition, DIM downregulated overexpression of hepatic nuclear factor kappa B (NF-κB) and inhibited CCl4 mediated apoptosis. Our results suggest that the protective effects of DIM against CCl4- induced liver injury are due to the inhibition of ROS, reduction of pro-inflammatory mediators and apoptosis.

Fraxin Alleviates LPS-Induced ARDS by Downregulating Inflammatory Responses and Oxidative Damages and Reducing Pulmonary Vascular Permeability

Acute respiratory distress syndrome (ARDS) is a severe acute disease that threatens human health, and few drugs that can effectively treat this disease are available. Fraxin, one of the main active ingredients of Cortex Fraxini, a Chinese herbal medicine, has presented various pharmacological and biological activities. However, the effects of fraxin on ARDS have yet to be reported. In the present study, the protective effect of fraxin in lipopolysaccharide (LPS)-induced ARDS in a mouse model was analyzed. Results from the hematoxylin and eosin staining showed that fraxin might alleviate pathological changes in the lung tissues of mice with ARDS. ELISA and Western blot results revealed that fraxin might inhibit the production of inflammatory factors, namely, IL-6, TNF-α, and IL-1β, and the activation of NF-κB and MAPK signaling pathways in the lungs. Thus, the inflammatory responses were reduced. Fraxin might inhibit the increase in reactive oxygen species (ROS) and malondialdehyde (MDA), a product of lipid peroxidation in lung tissues. Fraxin might increase the superoxide dismutase (SOD) activity to avoid oxidative damage. Vascular permeability was also assessed through Evans blue dye tissue extravasation and fluorescein isothiocyanate-labeled albumin (FITC-albumin) leakage. Fraxin might inhibit the increase in pulmonary vascular permeability and relieve pulmonary edema. Fraxin was also related to the inhibition of the increase in matrix metalloproteinase-9, which is a glycocalyx-degrading enzyme, and the relief of damages to the endothelial glycocalyx. Thus, fraxin elicited protective effects on mice with LPS-induced ARDS and might be used as a drug to cure ARDS induced by Gram-negative bacterial infection.

Preventive effects of fraxin on ischemia/reperfusion-induced acute kidney injury in rats

AIM

Kidney ischemia reperfusion (IR) injury is an important health problem resulting in acute kidney failure. The oxidative stress and inflammatory process are the underlying mechanisms of IR injury. It has been purposed in this study to research the possible protective effects of fraxin on kidney injury induced by IR.

MATERIAL AND METHODS

32 Sprague Dawley male rats were divided into 4 groups. The groups were organized as follows; sham, IR, IR + fraxin 10 mg/kg, and IR + 50 mg/kg fraxin groups. Some oxidant, antioxidant and inflammatory parameters were evaluated in kidney tissues removed at the end of our experimental study.

KEY FINDINGS

It was detected that the oxidant and proinflammatory markers increased and antioxidant parameters decreased in IR group but the results significantly reversed in treatment groups compared to IR group. And also, 8-OHdG, NF-κB, HAVCR1 immunopositivities were at severe levels and these results attenuated in IR fraxin + 10 mg/kg, and IR + fraxin 50 mg/kg groups.

SIGNIFICANCE

These presented results have shown that fraxin performed protective effects against kidney injury induced by IR.

Brassica rapa Polysaccharides Ameliorate CCl4 -Induced Acute Liver Injury in Mice through Inhibiting Inflammatory Apoptotic Response and Oxidative Stress

Brassica rapa L., also called NIUMA, is used empirically in Tibetan medicine for its antioxidant, anti-inflammatory and antiradiation activities. This study explored the hepatoprotective effects of B. rapa polysaccharides (BRPs) on acute liver injury induced by carbon tetrachloride (CCl₄ ) in mice and the underlying mechanisms. Mice were treated with CCl₄ after the oral administration of BRPs (55, 110 and 220 mg/kg) or bifendate (100 mg/kg) for 7 days. Blood and liver samples of mice were collected for analysis after 24 h. The ALP, ALT and AST levels and the biological activities of SOD, MDA and GSH-Px were measured. Histopathological changes in the liver were determined through hematoxylin and eosin staining. Moreover, TNF-α, IL-1β and IL-6 expression levels were detected by commercial reagent kits. Finally, Western blot analysis was used to check the relative expression levels of caspase-3, p-JAK2 and p-STAT3. The BRP pre-treatment significantly decreased the enzymatic activities of ALT, ALP and AST in the serum, markedly increased the activities of SOD and GSH-Px in the liver and reduced the MDA concentration in the liver. BRPs alleviated hepatocyte injury and markedly inhibited the expression of TNF-α, IL-1β and IL-6, also downregulating the CCl₄ -induced hepatic tissue expression of caspase-3. Furthermore, BRPs inhibited the JAK2/STAT3 signaling pathway in a dose-dependent manner in the liver. This study demonstrated that BRPs exert hepatoprotective effect against the CCl₄ -induced liver injury via modulating the apoptotic and inflammatory responses and downregulating the JAK2/STAT3 signaling pathway. Therefore, B. rapa could be considered a hepatoprotective medicine.

Fraxin inhibits lipopolysaccharide-induced inflammatory cytokines and protects against endotoxic shock in mice

Fraxin, the effective component isolated from Cortex Fraxini, has been reported to have anti-inflammation effects. The aim of this study was to explore the effect of fraxin on lipopolysaccharide (LPS)-induced endotoxic shock in mice. We used Kunming male mice to establish the model, and we found that fraxin could improve the survival rate of the LPS-induced mice. Histopathological study showed that fraxin could mitigate the injuries in LPS-induced lung and liver tissues. The levels of tumour necrosis factor-α and interleukin-6 both in serum and lung, liver tissues, and the productions of nitric oxide (NO), aspartate transaminase and alanine transaminase in serum were decreased by fraxin. Western blot assay demonstrated that the pretreatment with fraxin could downregulate LPS-induced protein expressions of nuclear factor-kappa B (NF-κB) and NLRP3 inflammatory corpuscle signalling pathways. Overall, fraxin had protective effects on LPS-induced endotoxic shock mice and the possible mechanisms might activate through NF-κB and NLRP3 inflammatory corpuscle signalling pathways.

Combination of metformin and luteolin synergistically protects carbon tetrachloride-induced hepatotoxicity: Mechanism involves antioxidant, anti-inflammatory, antiapoptotic, and Nrf2/HO-1 signaling pathway

Liver diseases are one of the fatal disorders due to the vital role of the liver. Carbon tetrachloride (CCl₄ ) is the most perceived chemical substance utilized in developing models of hepatic damage. Metformin (Met) is a potent antidiabetic and redox modulatory agent that has shown anticancer and protective effects on various organs. Therefore, addition of therapy with natural antioxidative agents or herbal extracts shows defensive impacts against different injuries inside the body. Luteolin (Lut) can be found in several customary Chinese remedies. It has been reported for various pharmacological actions such as antitumor, antioxidative, and anti-inflammatory impacts. Here, the liver injury rat model was established using CCl₄ (1.00 mL/kg body weight) in vivo. The protective roles of Met and Lut separately or in combination were observed in hepatotoxicity induced by CCl₄ . The result was shown that both Met and Lut, while individually used, were normally active in diminishing CCl₄ -caused hepatotoxicity. The combination of two drugs performed synergistically to improve liver damage caused by CCl₄ , as shown by the considerably improved liver dysfunction. Met and Lut showed highly antioxidative effects on CCl₄ -treated rats moderately by increasing the activities and expression of the antioxidant enzymes. Along with this, a combination of Met and Lut significantly suppressed inflammatory responses, which is evidenced by the reduced level of inflammatory cytokines together with interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6). Additionally, CCl₄ -agitated apoptosis was intensely reduced by Met and Lut through reducing cleaved caspase-3 and Bax (pro-apoptotic factor) while increasing Bcl-2 (antiapoptotic factor) signaling pathways. Cotreatments of Met and Lut upregulated nuclear factor erythroid 2-related factor 2 (NRF2) and heme oxygenase-1 (HO-1) expression in the CCl₄ -intoxicated rat's liver. The above result recommended that combination of Met and Lut may have a substantial potential and synergizing impact against CCl₄ -induced hepatotoxicity.

Protective effect of free phenolics from Lycopus lucidus Turcz. root on carbon tetrachloride-induced liver injury in vivo and in vitro

Protective effect of free phenolics from Lycopus lucidus Turcz. root (FPLR) on CCl₄-induced hepatotoxicity in vivo and in vitro was first evaluated. Oral administration of FPLR (100 mg/kg bw) to mice significantly reduced the CCl₄-induced elevation of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, triacylglycerols, total cholesterol, and total bilirubin. FPLR also increased the hepatic GSH contents and antioxidant enzyme activities of SOD and CAT and decreased the hepatic MDA level. Histopathological examinations further confirmed that the FPLR could protect the liver from CCl₄-induced damage. Further research indicated that FPLR prevented the DNA fragmentation caused by CCl₄ based on TUNEL assay. Moreover, immunohistochemistry staining demonstrated that pretreatment with FPLR significantly inhibited the elevation of hepatic TNF-α, IL-6, IL-8, iNOS, COX-2, and Caspase-3 in CCl₄-treated mice. In vitro experiments showed that FPLR remarkably reduced BRL hepatocyte apoptosis and damage caused by CCl₄ treatment. These findings indicate that FPLR could be developed as a functional food or medication for therapeutic purpose and prevention of hepatic injury.

Matrix Remodeling Associated 7 Deficiency Alleviates Carbon Tetrachloride-Induced Acute Liver Injury in Mice

Matrix remodeling associated 7 (MXRA7) was first noted to co-express with a group of matrix remodeling related genes, and its biological functions had remained unclear. In this study, we investigated the presumed function of MXRA7 in a carbon tetrachloride (CCl₄)-induced acute liver injury model in mice. Wild-type, MXRA7^−/− mice, and mice that were pulsed with hydrodynamic injection of vehicle or MXRA7-harboring plasmids were challenged with a single dose of CCl₄ for injury induction. The sera, spleens, and livers were harvested from mice for assay of cytokines/chemokines expression, cellular responses, or histological features. We found that MXRA7 deficiency alleviated, and MXRA7 overexpression aggravated liver damage in CCl₄-challenged mice. FACS analysis showed that MXRA7 deficiency reduced the recruitment of neutrophils through downregulation the expression of CXCL1 and CXCL2 in liver, decreased the number of CD8⁺ T cells in liver and spleen, suppressed the release of IFNγ and TNFα from T cells, and decreased IFNγ in serum and liver. Western blot assay demonstrated that MXRA7 deficiency suppressed the activation of MAPK pathway and AKT/NF-κB pathway, respectively. Lastly, MXRA7 deficiency or overexpression regulated the expression of two matrix remodeling-related genes (fibronectin and TIMP1) in the liver. We concluded that MXRA7 was an active player in CCl₄-induced liver injury, hypothetically by mediating the inflammation or immune compartments and matrix remodeling processes. Further exploration of MXRA7 as a possible new therapeutic target for management of inflammation-mediated liver injury was discussed.