Protective effect of ethyl acetate fraction of Drynaria quercifolia against CCl4 induced rat liver fibrosis via Nrf2/ARE and NFκB signalling pathway

Mori fructus aqueous extracts attenuates liver injury by inhibiting ferroptosis via the Nrf2 pathway

BACKGROUND

Liver fibrosis and hepatocellular carcinogenesis secondary to liver fibrosis are serious liver diseases with no effective treatments. Mori fructus aqueous extracts (MFAEs) have served as successful treatments for many types of liver injury including fibrosis although the molecular mechanisms are unknown at present.

PURPOSE

To investigate the effect of MFAEs in alleviating acute and chronic liver injury and tried to decipher the underlying mechanism.

METHODS AND RESULTS

Mice were divided into 5 groups (n = 8) for acute (groups: control, 0.3% CCl₄, bifendate (BD), 100 and 200 mg/kg MFAEs, 7 d) and chronic (groups: control, 10% CCl₄, BD, 100 and 200 mg/kg MFAEs, 4 weeks) liver injury study. Each mouse was injected intraperitoneally with 10 µL/g corn oil containing CCl₄ expect the control group. HepG2 cells were used in vitro study. Eighteen communal components were identified by UPLC-LTQ-Orbitrap-MS. We utilized a mouse model for acute and chronic liver injury using CCl₄ and MFAEs administration effectively blocked fibrosis and significantly inhibited inflammation in the liver. MFAEs activated the nuclear factor erythroid derived 2 like 2/heme oxygenase 1 (Nrf2/HO-1) pathway and promoted the synthesis of the antioxidants glutathione (GSH), superoxidedismutase (SOD) and glutathione peroxidase (GSH-Px) that resulted in reduced levels of CCl₄-induced oxidative stress molecules including reactive oxygen species. These extracts administered to mice also inhibited ferroptosis in the liver by regulating the expression of Acyl-CoA synthetase long chain family member 4 (ACSL4), solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4), thus reducing the occurrence of liver fibrosis. Both in vivo and in vitro tests indicated that the mechanism of MFAEs protection against liver fibrosis was linked to activation of Nrf2 signaling. These effects were blocked in vitro by the addition of a specific Nrf2 inhibitor.

CONCLUSION

MFAEs inhibited oxidative stress, ferroptosis and inflammation of the liver by activating Nrf2 signal pathway and provided a significant protective effect against CCl₄-induced liver fibrosis.

Cell-Permeable PROTAC Degraders against KEAP1 Efficiently Suppress Hepatic Stellate Cell Activation through the Antioxidant and Anti-Inflammatory Pathway

Accumulating evidence indicates that oxidative stress and inflammation are involved in the physiopathology of liver fibrogenesis. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor, which regulates the expression of redox regulators to establish cellular redox homeostasis. The Nrf2 modulator can serve as a primary cellular defense against the cytotoxic effects of oxidative stress. We designed a chimeric Keap1-Keap1 peptide (KKP1) based on the proteolysis-targeting chimera technology. The KKP1 peptide not only can efficiently penetrate into the rat hepatic stellate cell line (HSC-T6) cells but also can induce Keap1 protein degradation by the ubiquitination-proteasome degradation pathway, which releases Nrf2 and promotes the transcriptional activity of the Nrf2/antioxidant response element pathway. It then activates the protein expression of the downstream antioxidant factors, the glutamate-cysteine ligase catalytic subunit and heme oxygenase-1 (HO-1). Finally, Keap1 protein degradation inhibits the nuclear factor-kappaB inflammatory signal pathway, the downstream inflammatory factor tumor necrosis factor alpha, and the interleukin-1beta protein expression and further inhibits the expression of the fibrosis biomarker gene. The current research suggests that our designed KKP1 may provide a new avenue for the future treatment of liver fibrosis.

Tandem mass tag-based proteomics analysis reveals the multitarget mechanisms of Phyllanthus emblica against liver fibrosis

Phyllanthus emblica (PE), a traditional multiethnic herbal medicine, is commonly applied to treat liver diseases. Our previous study demonstrated that aqueous extract of PE (AEPE) could alleviate carbon tetrachloride (CCl₄)-induced liver fibrosis in vivo, but the underlying molecular mechanisms are still unclear. The present study was undertaken to clarify the multitarget mechanisms of PE in treating liver fibrosis by proteomics clues. A CCl₄-induced liver fibrosis rat model was established. The anti-liver fibrosis effects of chemical fractions from AEPE were evaluated by serum biochemical indicators and pathological staining. Additionally, tandem mass tag (TMT) - based quantitative proteomics technology was used to detect the hepatic differentially expressed proteins (DEPs). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, gene ontology (GO) enrichment and protein-protein interaction (PPI) network were used to perform bioinformatics analysis of DEPs. Western blot analysis was used to verify the key potential targets regulated by the effective fraction of AEPE. The low-molecular-weight fraction of AEPE (LWPE) was determined to be the optimal anti-liver fibrosis active fraction, that could significantly improve ALT, AST, HA, Col IV, PCIII, LN, Hyp levels and reduce the pathological fibrotic lesion of liver tissue in model rats. A total of 195 DEPs were screened after LWPE intervention. GO analysis showed that the DEPs were related mostly to extracellular matrix organization, actin binding, and extracellular exosomes. KEGG pathway analysis showed that DEPs are mainly related to ECM-receptor interactions, focal adhesion and PI3K-Akt signaling pathway. Combined with the GO, KEGG and Western blot results, COL1A2, ITGAV, TLR2, ACE, and PDGFRB may be potential targets for PE treatment of liver fibrosis. In conclusion, LWPE exerts therapeutic effects through multiple pathways and multiple targets regulation in the treatment of liver fibrosis. This study may provide proteomics clues for the continuation of research on liver fibrosis treatment with PE.

Identification of hepatoprotective traditional Chinese medicines based on the structure–activity relationship, molecular network, and machine learning techniques

The efforts focused on discovering potential hepatoprotective drugs are critical for relieving the burdens caused by liver diseases. Traditional Chinese medicine (TCM) is an important resource for discovering hepatoprotective agents. Currently, there are hundreds of hepatoprotective products derived from TCM available in the literature, providing crucial clues to discover novel potential hepatoprotectants from TCMs based on predictive research. In the current study, a large-scale dataset focused on TCM-induced hepatoprotection was established, including 676 hepatoprotective ingredients and 205 hepatoprotective TCMs. Then, a comprehensive analysis based on the structure–activity relationship, molecular network, and machine learning techniques was performed at molecular and holistic TCM levels, respectively. As a result, we developed an in silico model for predicting the hepatoprotective activity of ingredients derived from TCMs, in which the accuracy exceeded 85%. In addition, we originally proposed a material basis and a drug property-based approach to identify potential hepatoprotective TCMs. Consequently, a total of 12 TCMs were predicted to hold potential hepatoprotective activity, nine of which have been proven to be beneficial to the liver in previous publications. The high rate of consistency between our predictive results and the literature reports demonstrated that our methods were technically sound and reliable. In summary, systematical predictive research focused on the hepatoprotection of TCM was conducted in this work, which would not only assist screening of potential hepatoprotectants from TCMs but also provide a novel research mode for discovering the potential activities of TCMs.

Protective mechanism of traditional Chinese medicine guizhi fuling pills against carbon tetrachloride-induced kidney damage is through inhibiting oxidative stress, inflammation and regulating the intestinal flora

BACKGROUND

Chemical or drug-induced kidney damage has been recognized as a critical cause of kidney failure. The oxidative stress, inflammation, and imbalance of intestinal flora caused by carbon tetrachloride (CCl₄) play a fundamental role in chronic kidney damage. Guizhi Fuling pills (GZFL) is a traditional formula consisting of five traditional Chinese medicinal herbs, which can promote blood circulation and improve kidney function. The underlying mechanisms of GZFL improving kidney damage are not fully understood yet.

AIM

The current study aimed to explore the effects of GZFL on CCl₄-induced kidney damage and intestinal microbiota in mice.

METHODS

Male ICR mice were intraperitoneally administered with 20% CCl₄ (mixed in a ratio of 1:4 in soybean oil) twice a week, for 4 weeks to induce kidney damage. Creatinine (CRE), urea nitrogen, antioxidant enzymes, and inflammatory cytokines were measured and the histology of the kidney, jejunum, and colon examination to assess kidney and intestinal damage. The expressions of nuclear factor-erythroid 2-related factor 2 (Nrf2) family members, nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome in kidney tissues, and the tight junction proteins in colonic tissues were detected by Western blot. The gut microbiota was analyzed through 16S rRNA gene sequencing.

RESULTS

GZFL treatment decreased the serum CRE and urea nitrogen levels. Moreover, GZFL reduced the levels of pro-inflammatory cytokines and increased antioxidant enzyme activities in kidney and colonic tissues. GZFL improved the kidney, jejunum, and colon histology. Furthermore, GZFL inhibited the expressions of NLRP3, ASC, and cleaved-Caspase-1, while Nrf2, HO-1, NQO1, GCLM, and tight junction proteins were increased. The dysbiosis of intestinal microbiota improved after GZFL treatment.

CONCLUSIONS

This study showed that GZFL could improve kidney damage, which might be mainly via the integrated regulations of the Nrf2 pathway, NLRP3 inflammasome, and composition of intestinal microbiota.

Metformin versus Silymarin as Hepatoprotective Agents in Mice Fibrotic Model Caused by Carbon Tetrachloride

OBJECTIVES

To study metformin hepatoprotective effects compared to silymarin on hepatic fibrosis caused by carbon tetrachloride (CCl4) in mice.

MATERIAL AND METHODS

liver fibrosis in mice was achieved by intraperitoneal injection of 2 ml/kg of CCl4 dilution in olive oil [1:9 (v/v)] twice a week for 7 weeks followed by oral treatment with metformin (250 mg/kg/day) or silymarin (100 mg/kg/day) (a standard hepatoprotective drug). The changes that follow liver fibrosis were assessed by measurement of hepatic enzymes (ALT, AST and ALP), histopathological examination using hematoxylin and eosin stain, special stains, and α-smooth muscle actin (α-SMA) immunostaining, measuring oxidative stress markers (MDA, GSH, NOx and MnSOD) and transforming growth factor-beta 1 (TGF-β1) in liver.

RESULTS

liver fibrosis was obviously developed in mice after intraperitoneal injection with CCl4 for 7 weeks. Both silymarin and metformin treatment exhibited a significant decrease in the fibrotic changes and similarly an increase in endogenous antioxidants. Interestingly there is a significant difference between silymarin and metformin regarding both efficacy and potency.

CONCLUSION

These findings highlight the anti-inflammatory, antioxidant and antifibrotic effects of metformin in CCl4-induced hepatic fibrosis in mice, but silymarin is more beneficial.

Effects of novel Fufang Biejia Ruangan Tablets with sheep placenta as substitute for hominis placenta on CCl4-induced liver fibrosis

Objective

Fufang Biejia Ruangan Tablet (FBRT) is widely used for the treatment of liver fibrosis. However, Hominis Placenta (HP), as an important adjuvant of FBRT, has been restricted for medicinal using due to the limited availability, ethical controversy and safety issues. The present study aimed to investigate the therapeutic effects of novel FBRT (N-FBRT) with sheep placenta (SP) as substitute for HP on liver fibrosis and explore its possible mechanisms. Different dosages of SP in N-FBRT were also evaluated.

Methods

Rats were subcutaneously injected with CCl₄ to induce liver fibrosis and then treated with N-FBRT and FBRT. The anti-hepatic fibrosis effect was determined based on biomarkers analysis of liver function and hepatic fibrosis, and the liver pathology was visualized by H&E staining and Masson staining. The oxidative stress and inflammatory cytokines were also detected. Immunohistochemical staining of α-SMA, real time PCR and Western blotting were performed to evaluate hepatic stellate cells (HSCs) activation and TGF-β1/Smad signaling pathway.

Results

N-FBRT and FBRT could ameliorate CCl₄-induced liver fibrosis and improve liver function, as evidenced by lowering serum biomarkers levels of liver function and hepatic fibrosis, and decreasing hepatic Hyp content and collagen deposition, and improving the hepatic morphology and architecture changes. Moreover, the anti-liver fibrosis effect was better when the dosage of SP used in N-FBRT was 1/2 of HP in FBRT. Administration of N-FBRT markedly alleviated oxidative stress and inflammatory cytokines, and inhibited α-SMA expression. Furthermore, the mRNA expression of Col I, Col III, α-SMA and TGF-β1, and proteins expression of α-SMA, TGF-β1, Smad2/3 and p-Smad2/3 were significantly down-regulated by N-FBRT treatment.

Conclusion

SP can be used as substitute for HP to prepare N-FBRT for the treatment of liver fibrosis and the anti-liver fibrosis effect of N-FBRT is achieved by eliminating oxidative stress and inflammation, and inhibiting HSCs activation and ECM production by blocking TGF-β1/Smad signaling pathway.

Lysimachiae Herba Inhibits Inflammatory Reactions and Improves Lipopolysaccharide/D-Galactosamine-Induced Hepatic Injury

This study aimed to determine the anti-inflammatory and hepatoprotective effects of Lysimachiae Herba ethanolic extract (LHE) in lipopolysaccharide (LPS)-stimulated macrophages and in a LPS/D-galactosamine (GalN)-induced acute hepatitis mouse model. Then, the production of inflammatory mediators and the activation of related pathways in macrophages were explored. Finally, we assessed the serum aminotransferase levels and the expression of inflammatory/antioxidant molecules in liver tissues in mice. Results revealed that LHE treatment significantly inhibited the production of inflammatory mediators in LPS-stimulated RAW 264.7 macrophages. Molecular data showed that LHE remarkably increased the activities of the antioxidant pathway and inhibited the phosphorylation of mitogen-activated protein kinase as well as the transcriptional activity of nuclear factor-κB induced by LPS. Furthermore, it prevented acute liver damage caused by LPS/D-GalN-induced hepatitis by inhibiting aminotransferase levels and histopathological changes in mice. Moreover, treatment with LHE significantly inhibited the activation of inflammatory pathways and increased the expression of antioxidant molecules including heme oxygenase-1/Nuclear factor erythroid 2-related factor 2. In conclusion, LHE has potent anti-inflammatory and hepatoprotective effects in LPS-stimulated macrophages and the LPS/D-GalN-induced acute hepatitis mouse model. Thus, it can be a treatment option for inflammation, hepatitis, and liver injury.

Network Pharmacological Analysis and Experimental Validation of the Mechanisms of Action of Si-Ni-San Against Liver Fibrosis

Background: Si-Ni-San (SNS), a commonly used traditional Chinese medicine (TCM) formula, has potency against liver diseases, such as hepatitis and non-alcoholic fatty liver disease (NAFLD). However, the therapeutic efficacy and pharmacological mechanisms of action of SNS against liver fibrosis remain largely unclear. Methods: A carbon tetrachloride (CCl4)-induced liver fibrosis mouse model was adopted for the first time to investigate the beneficial effects of SNS on liver fibrosis. The potential mechanisms of action of SNS were explored using the network pharmacology-based strategy and validated with the aid of diverse assays. Results: SNS treatment reduced collagen and ECM deposition, downregulated fibrosis-related factor (hyaluronic acid and laminin) contents in serum, maintained the morphological structure of liver tissue, and improved liver function in the liver fibrosis model. Based on network pharmacology results, apoptosis, inflammation and angiogenesis, together with the associated pathways (including VEGF, TNF, caspase, PPAR-γ and NF-κB), were identified as the mechanisms underlying the effects of SNS on liver fibrosis. Further in vivo experiments validated the significant mitigatory effects of SNS on inflammatory infiltration and pro-inflammatory cytokine contents (IFNγ, IL-1β and TGF-β1) in liver tissues of mice with liver fibrosis. SNS suppressed pathologic neovascularization as well as levels of VEGFR1, VEGF and VEGFR2 in liver tissues. SNS treatment additionally inhibited hepatic parenchyma cell apoptosis in liver tissues of mice with liver fibrosis and regulated apoptin expression while protecting L02 cells against apoptosis induced by TNF-α and Act D in vitro. Activation of hepatic stellate cells was suppressed and the balance between MMP13 and TIMP1 maintained in vitro by SNS. These activities may be associated with SNS-induced NF-κB suppression and PPAR-γ activation. Conclusion: SNS effectively impedes liver fibrosis progression through alleviating inflammation, ECM accumulation, aberrant angiogenesis and apoptosis of hepatic parenchymal cells along with inhibiting activation of hepatic stellate cells through effects on multiple targets and may thus serve as a novel therapeutic regimen for this condition.

Tectona grandis leaf extract ameliorates hepatic fibrosis: Modulation of TGF- β /Smad signaling pathway and upregulating MMP3/TIMP1 ratio

ETHNOBOTANICAL RELEVANCE

Tectona grandis L.f (or syn: Jatus grandis (L.f.) Kuntze Revis), from family Lamiaceae, also known as Teak, is widely recognized in ayurvedic system of medicine and confer curative potential against inflammation, liver disorders, biliousness, diabetes, bronchitis, leprosy and dysentery. Its leaves are rich source of edible food colorant and reported nontoxic for liver and various organs.

AIM OF STUDY

Hepatic injury progression to liver cirrhosis and cancer is a serious health issue across the world. Currently, anti-fibrotic therapeutic options are limited and expensive with no FDA approved direct anti-hepato-fibrotic drug validated in clinic. Thus, the aim of this study was to understand ameliorative effect of Tectona grandis L.f, leaves in early liver fibrosis.

METHOD AND RESULTS

C57BL/6 mice suffering from CCl4 induced liver injury, were orally administered at three different doses (50, 100 & 200 mg/kg) of Tectona grandis L.f, leaf extract, thrice a week, up to 4 and 8 weeks. Anti-fibrotic effect was evaluated through animal body/liver weight measurements, serological tests (AST, ALT, GSH, MDA and LDH assays), tissue hydroxyproline content, and histochemical analysis (H&E, Masson trichrome, Sirius red and αSMA localization). Moreover, transcriptional and post-transcriptional expression of fibrosis associated biomarkers and TGF-β/Smad cascade were analyzed. It was observed that 100 mg/kg dose optimally downregulated TGF-β1/Smad2 with upregulation of Smad7 and regulated αSMA, Col 1, PDGF, TIMP1 and MMP3 expression, post 8 weeks of treatment. In addition, MMP3/TIMP1 ratio was upregulated to 0.7, 2.5 and 1.7 fold at 50 mg/kg, 100 mg/kg & 200 mg/kg treatments respectively, in comparison to untreated liver fibrosis models. The extract contains gallic acid, caffeic acid, sinapinic acid and myricetin when analyzed through high performance liquid chromatography.

CONCLUSION

Tectona grandis L.f, leaves have potential to ameliorate liver fibrosis induced by CCl4 in mice via modulation of TGF-β1/Smad pathway and upregulated MMP3/TIMP1 ratio.

Novel Antioxidant, Deethylated Ethoxyquin, Protects against Carbon Tetrachloride Induced Hepatotoxicity in Rats by Inhibiting NLRP3 Inflammasome Activation and Apoptosis

Inflammation and an increase in antioxidant responses mediated by oxidative stress play an important role in the pathogenesis of acute liver injury (ALI). We utilized in silico prediction of biological activity spectra for substances (PASS) analysis to estimate the potential biological activity profile of deethylated ethoxyquin (DEQ) and hypothesized that DEQ exhibits antioxidant and anti-inflammatory effects in a rat model of carbon tetrachloride (CCl₄)-induced ALI. Our results demonstrate that DEQ improved liver function which was indicated by the reduction of histopathological liver changes. Treatment with DEQ reduced CCl₄-induced elevation of gene expression, and the activity of antioxidant enzymes (AEs), as well as the expression of transcription factors Nfe2l2 and Nfkb2. Furthermore, DEQ treatment inhibited apoptosis, downregulated gene expression of pro-inflammatory cytokines (Tnf and Il6), cyclooxygenase 2 (Ptgs2), decreased glutathione (GSH) level and myeloperoxidase (MPO) activity in rats with ALI. Notably, DEQ treatment led to an inhibition of CCl₄-induced NLRP3-inflammasome activation which was indicated by the reduced protein expression of IL-1β, caspase-1, and NLRP3 in the liver. Our data suggest that DEQ has a hepatoprotective effect mediated by redox-homeostasis regulation, NLRP3 inflammasome, and apoptosis inhibition, which makes that compound a promising candidate for future clinical studies.

Differential regulation of Nrf2 is linked to elevated inflammation and nitrative stress in monocytes of children with autism

Autism spectrum disorder (ASD) is a very complex neurodevelopmental disorder characterized by deficits in social and communication skills. Innate immune cells like monocytes are believed to play a cardinal role in neuroimmune inflammation and nitrative stress. On the other hand, Nrf2, a basic leucine zipper transcription factor plays a significant role in protecting the immune cells against inflammation and oxidants. However, its role in monocytes of ASD children and typically developing control (TDC) children has not been elucidated in relation with inflammation and nitrative stress. Therefore, this study was undertaken to evaluate Nrf2 expression/activity along with parameters of inflammation (NFkB, IL-6, IL-1β) and nitrative stress (iNOS, nitrotyrosine) in monocytes of ASD/TDC children. Further, sulforaphane (SFN) was utilized as an Nrf2 activator to assess its effect on above said inflammatory and nitrative stress parameters. Our study shows that monocytes of ASD subjects have decreased Nrf2 expression/activity along with increased inflammation and nitrative stress. Further, monocytes from ASD have deficiency in induction of Nrf2 activity upon stimulation with LPS. However, activation of Nrf2 in vitro by SFN reverses LPS-induced effects on inflammation in monocytes by reduction in NFkB signaling. Further, treatment with SFN also reverses LPS-induced effects on nitrative stress (iNOS, nitrotyrosine) in monocytes of ASD subjects. This study propounds the idea that SFN protects against nitrative stress and inflammation by downregulating oxidative stress and inflammation through blockade of NFkB signaling in autistic children. This may be the reason behind reported ameliorative effects of SFN in ASD subjects.

Testosterone propionate activated the Nrf2-ARE pathway in ageing rats and ameliorated the age-related changes in liver

The present study aimed to evaluate the protective efficacy of testosterone propionate (TP) on age-related liver changes via activation of the nuclear factor erythroid 2-related factor 2-antioxidant response element (Nrf2-ARE) pathway in aged rats. Aged rats received subcutaneous injections of TP (2 mg/kg/d, 84 days). Oxidative stress parameters and the expression levels of signal transducer and activator of transcription 5b (STAT5b), Kelch-like ECH associating protein-1 (Keap1), Nrf2, haem oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO1) in liver tissues were examined to check whether the Nrf2-ARE pathway was involved in the age-related changes in liver. Our results showed that TP supplementation alleviated liver morphology, liver function and liver fibrosis; improved oxidative stress parameters; and increased the expression of STAT5b, Nrf2, HO-1 and NQO-1 and decreased the expression of Keap1 in the liver tissues of aged rats. These results suggested that TP increased the expression of STAT5b, and then activated the Nrf2-ARE pathway and promoted antioxidant mechanisms in aged rats. These findings may provide new therapeutic uses for TP in patients with age-related liver changes.

The Nrf2/HO-1 Axis as Targets for Flavanones: Neuroprotection by Pinocembrin, Naringenin, and Eriodictyol

Flavanones are a group of flavonoids that derive from their immediate chalcone precursors through the action of chalcone isomerase enzymes. The Aromatic A and B rings, C4-keto group, and the 15-carbon flavonoid skeleton are all evident in flavanones, but a notable absence of C2-C3 double bond and a lack of oxygenation at C-3 position of the C-ring makes them distinctively different from other groups such as flavonols (e.g., quercetin). On the basis of oxygenation level in the B ring, flavanones can vary from each other as exemplified by pinocembrin (no oxygenation), naringenin (4′-hydroxyl), or eriodictyol (3′,4′-dihydroxyl substitution). These groups are generally weaker free radical scavengers as compared to quercetin and derivatives though eriodictyol has a better free radical scavenging profile within the group due to the presence of the catechol functional moiety. In this communication, their antioxidant potential through the induction of antioxidant defenses is scrutinized. These compounds as exemplified by pinocembrin could induce the nuclear factor erythroid 2-related factor 2- (Nrf2-) heme oxygenase-1 (HO-1) axis leading to amelioration of oxidative stress in cellular and animal models. Their neuroprotective effect through such mechanism is discussed.

Hepatoprotective effects of an Acer tegmentosum Maxim extract through antioxidant activity and the regulation of autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Acer tegmentosum Maxim (AT), the East Asian stripe maple, is an herb used to treat liver disease and is approved as a functional food in Korea. AT protects against hepatic disorders, atopic dermatitis, and diabetes mellitus.

AIM OF THE STUDY

We explored the mechanism of the hepatoprotective effects of AT extract in in vitro and in vivo levels.

MATERIALS AND METHODS

AT extract from Acer tegmentosum Maxim was extracted by hot water. Hepatoprotective effects of AT extract were confirmed using carbon tetrachloride (CCl₄)- or alcohol-induced mouse model, and H₂O₂- or alcohol-induced HepG2 (liver hepatocellular carcinoma cell line) cells by measuring GOT, GPT, TG, and MDA levels. Hematoxylin and eosin (H&E) staining was used to observe the pathological analysis. Cytotoxicity or protective effect of AT extract was confirmed using MTT assay in HepG2 cells. Antioxidant effect of AT extract was measured using DPPH or H₂DCFDA assay. Mechanism study of antioxidant and autophagy was carried out using western blotting and immunofluorescence analysis.

RESULTS

AT extract increased the viability of HepG2 cells treated with H₂O₂ and ethanol, and protected the liver against damage induced by CCl₄ and alcohol. The AT extract increased the levels of nuclear respiratory factor 2 (Nrf2) and heme oxygenase-1 (HO-1). The level of microtubule-associated protein light chain 3 (LC3)-Ⅱ, beclin-1, autophagy-related genes (Atg) such as Atg3 and Atg12-5 as markers of autophagy activation was also increased. Moreover, the AT extract increased activation of mitogen-activated protein kinase (MAPK), which regulated autophagy and HO-1.

CONCLUSION

Therefore, these results indicate that the AT extract has a hepatoprotective effect by increasing antioxidant activity and inducing autophagy.

Lonicera japonica Attenuates Carbon Tetrachloride-Induced Liver Fibrosis in Mice: Molecular Mechanisms of Action

Liver fibrosis is a worldwide clinical issue that generally causes hepatic cirrhosis. Lonicerae Japonicae Flos (dried flower buds of Lonicera japonica Thunb) is a traditional heat-clearing and detoxifying herbal medicine in China. This study aims to observe the protection of the water extract of Lonicerae Japonicae Flos (FL) from carbon tetrachloride (CCl₄)-induced liver fibrosis in mice. Liver fibrosis was induced in mice by intraperitoneal injection of 2 ml/kg CCl₄ twice a week for 4 weeks. FL's attenuation of CCl₄-induced liver fibrosis in mice was evidenced by the results of Masson's trichrome and Sirius red staining, liver hydroxyproline content and serum amount of collagen IV. FL reduced hepatic stellate cells (HSCs) activation and reversed the epithelial-mesenchymal transition (EMT) process in mice treated with CCl₄. FL also alleviated liver oxidative stress injury and enhanced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) anti-oxidant signaling pathway in mice treated with CCl₄. Additionally, the main phenolic acids in FL including chlorogenic acid (CGA) and caffeic acid (CA) both reduced HSCs activation in vitro. In summary, FL attenuates CCl₄-induced liver fibrosis in mice by inhibiting HSCs activation, reversing EMT and reducing liver oxidative stress injury via inducing Nrf2 activation. CGA may be the main active compound contributing to the antifibrotic activity of FL.

Naringenin as a potential immunomodulator in therapeutics

Naringenin, a citrus flavonoid that possesses various biological activities, has emerged as a potential therapeutic agent for the management of a variety of diseases. Studies using cell culture system have shown that naringenin can inhibit inflammatory response in diverse cell types. Moreover, research using various animal models has further demonstrated therapeutic potentials of naringenin in the treatment of several inflammation-related disorders, such as sepsis, fulminant hepatitis, fibrosis and cancer. The mechanism of action of naringenin is not completely understood but recent mechanistic studies revealed that naringenin suppresses inflammatory cytokine production through both transcriptional and post-transcriptional mechanisms. Surprisingly, naringenin not only inhibits cytokine mRNA expression but also promotes lysosome-dependent cytokine protein degradation. This unique property of naringenin stands in sharp contrast with some widely-studied natural products such as apigenin and curcumin, which regulate cytokine production essentially at the transcriptional level. Therefore, naringenin may provide modality for the development of novel anti-inflammatory agent. This review article summarizes our recent studies in understanding how naringenin acts in cells and animal models. Particularly, we will discuss the anti-inflammatory activities of naringenin in various disease context and its potential use, as an immunomodulator, in the treatment of inflammatory related disease.