Hepatoprotective effects of aqueous leaf extract and crude isolates of Murraya koenigii against in vitro ethanol-induced hepatotoxicity model

Medicinal plants constitute a principal health care resource corroborating their gradual acceptance by the global population. The ethno medicinal plant, Murraya koeniggi (Curry-leaf tree) as is native to India exhibits diverse biological activities. Unpublished data from our laboratory revealed hepatoprotective activity of its crude aqueous extract against ethanol-induced hepatotoxicity in experimental animals. Chronic ethanol consumption diminishes the cellular antioxidant levels through free radical induced injury causing hepatitis and cirrhosis with mortality in severe cases. This provided a rationale for studying its mechanistic approaches in terms of modulation of antioxidant defenses for probable hepatoprotective activity against ethanol-induced hepatotoxicity in vitro.Based on the inhibitory concentration (IC₅₀) obtained from the cell viability assay, graded concentrations of 100 μg/ml and 500 μg/ml of aqueous extract (WE), isolated carbazole alkaloids (CA) and tannin (T) fraction were chosen to study the hepatoprotective activity against ethanol-induced hepatotoxicity using liver carcinoma cell lines (Hep G₂). Their antioxidant activity with anti-lipid peroxidation potential (LPO), effects on protein content, liver metabolizing enzymes viz., glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and the morphology of the cells were studied as parameters of hepatoprotection.The tannins and the carbazole alkaloids from the aqueous extract exhibited excellent hepatoprotective activity with respect to the different parameters studied and maintained normal morphology even after ethanolic challenge to the cells as comparable to the protection offered by the standard drug l-ornithine l-aspartate (LOLA).The modulating effect of the aqueous extract and isolates on liver metabolizing enzymes, reduction in lipid peroxidation and decreased cellular damage were found to contribute to the hepatoprotective activity.     

Hepatoprotective activity of cultured mycelium of Morel mushroom,Morchella esculenta

The hepatoprotective activity of cultured mycelium of morel mushroom Morchella esculenta against CCl₄ and ethanol induced chronic hepatotoxicity was investigated. Hepatotoxicity was induced by challenging the animals with CCl₄ (1:5, v/v, 3.75 ml/kg body weight, i.p., 30 doses) and ethanol (36%, v/v, 6 ml/animal, p.o., 35 doses) and the extract was administered at two concentrations (250 and 500 mg/kg body weight). Hepatoprotection was evaluated by determining the activities of liver function marker enzymes and antioxidant status of liver and also by histopathological observations of liver tissue. Administration of both ethanol and CCl₄ elevated the levels of liver function enzymes, GOT, GPT and ALP in serum drastically. The treatment with the extract decreased the elevated serum GOT, GPT and ALP activities in a dose dependent manner. The extract also restored the depleted levels of antioxidants in liver consequent to CCl₄ and ethanol challenge. The results indicated that aqueous-ethanolic extract of M. esculenta mycelium possessed significant hepatoprotective activity. The conclusion is also supported by the biochemical determinations and histopathological observations. The findings thus suggest the potential therapeutic use of morel mushroom mycelium as a novel hepatoprotective agent.     

Hepatoprotective and antioxidant potential of ferulic acid against acetaminophen-induced liver damage in mice

In the present study, we aimed to investigate the hepatoprotective and antioxidant potential of ferulic acid against acetaminophen-induced liver damage in mice. Hepatotoxicity was induced in mice by single dose of acetaminophen (900 mg/kg body weight i.p.). Ferulic acid (80 mg/kg body weight i.p.) and silymarin (25 mg/kg/body weight i.p.) were administered 30 min after the injection of acetaminophen. After 4 h, the mice were killed; liver markers (aspartate transaminase, alanine transaminase, alkaline phosphatase, and total bilirubin) were estimated in serum, while the lipid peroxidation and antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and glutathione) were determined in liver homogenate. Liver markers (aspartate transaminase, alanine transaminase, alkaline phosphatase, and total bilirubin) and lipid peroxidation levels were found to be increased in mice exposed to acetaminophen, whereas the antioxidant status was found to be depleted compared to that of the control group. However, ferulic acid administration (80 mg/kg body weight i.p.) to acetaminophen-intoxicated mice significantly reverse (p?<?0.05) the above-mentioned changes similar to the positive drug silymarin as evidenced in liver histology. The results clearly exhibit that ferulic acid possesses promising hepatoprotective potential.     

Antioxidant and hepatoprotective activity appraisal of four selected Fumaria species and their total phenol and flavonoid quantities

Fumaria species (Fumariaceae) have been recorded to be used traditionally against liver-related disorders in many countries including Turkey. Oxidative stress is also known to be strongly associated with hepatic problems. Consequently, in the current study, the ethanol extracts of four Fumaria species; F. cilicica Hausskn., F. densiflora DC., F. kralikii Jordan and F. parviflora Lam. growing in Turkey were initially screened for their in vitro antioxidant activities by three methods; 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test, Fe⁺²-ferrozine test system for metal chelating test and ferric-ion reducing antioxidant power (FRAP) at 250, 500 and 1000 μg/ml concentrations. Then, each of the ethanol extracts was fractionated into petroleum ether, chloroform, ethyl acetate and methanol fractions and their antioxidant activities were estimated by DPPH radical scavenging and xanthine oxidase inhibition tests at 1000 μg/ml. In both tests, the chloroform and ethyl acetate fractions of F. cilicica were found to be the most active and were further investigated in in vivo hepatoprotective activity experiment against toxicity induced by CCl₄. Total phenol and flavonoid quantities of the ethanol extracts were determined spectrophotometrically using Folin-Ciocalteau's and AlCl₃ reagents, respectively. Our data revealed that the chloroform and ethyl acetate fractions of F. cilicica did not have hepatoprotective effect and the ethanol extracts exerted low antioxidant activity. Although protective effect of some Fumaria species in hepatic diseases was shown in several previous studies, this record seems to be not pertinent for F. cilicica.     

In vitro antioxidant and protective effects of corn peptides on ethanol-induced damage in HepG2 cells

To assess the effect of corn peptides (CPs) as an antioxidant on ethanol (EtOH)-induced oxidative stress in HepG2 cells, the cells were preincubated with CPs for 4?h before treated with EtOH. Methyl thiazolyl tetrazolium and flow cytometry assay were performed to detect the viability of CP-treated HepG2 cells and control cells. The activities of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by corresponding kits, respectively. The results showed that treatment with 300?mmol/L EtOH for 24?h resulted in a death of around 50% of the HepG2 cells. Pretreatments of appropriate concentrations of CPs (more than 5?mg/mL, particularly at 20?mg/mL) significantly prevented EtOH-induced cytotoxicity and reduced the increase of ALT, AST, LDH and MDA contents, as well as inhibited the reduction of SOD contents in the HepG2 cells, indicating that CPs protected the cells from oxidative damage induced by EtOH metabolism, and thus had a great application potential in hepatoprotective nutraceuticals.     

<Emphasis Type="Italic">Celastrus orbiculatus</Emphasis> extracts induce apoptosis in mTOR-overexpressed human hepatocellular carcinoma HepG2 cells

Background

Celastrus orbiculatus (Celastraceae) are used as traditional Chinese medicine to treat inflammation and cancer. This study aims to evaluate the effect of Celastrus orbiculatus extract (COE) on the apoptosis in human hepatic carcinoma HepG2 cells with mTOR overexpression.

Methods

The stable expression of mTOR in HepG2 cells (HepG2/mTOR⁺) were established by lipofectin transfection of GV238-mTOR recombinant plasmids and further antibiotic selection. Human hepatic carcinoma HepG2/mTOR⁺ cells were treated with different concentrations (20, 40, 80, 160, and 320?μg/mL) of COE for 24?h. The cell proliferation upon COE treatment was detected by MTT. Apoptosis was measured by Flow Cytometry. The activity of mTOR signaling pathway was detected by Western Blotting.

Results

COE significantly inhibited the proliferation of HepG2/mTOR⁺ cells. The expression levels of Bax and Caspase-3 protein were increased in the HepG2/mTOR⁺ cells in a dose-dependent manner. The proteins expression of Bcl2, Bcl-2?L12, mTOR, phospho-mTOR, 4EBP1, phospho-4EBP1, P70S6k, and phospho-P70S6k in HepG2/mTOR⁺ cells were reduced in dose-dependent manners. Furthermore, COE and mTOR inhibitor rapamycin (RAPA) synergistically induced apoptosis in HepG2/mTOR⁺ cells by regulating apoptosis-related proteins and inhibiting mTOR signaling pathways.

Conclusion

COE could inhibit the proliferation of HepG2/mTOR⁺ cells, and induce the cell apoptosis. The mechanisms may be related to the regulation of the expression of Bcl-2, Bcl-2?L12, and mTOR signaling pathways. These data suggest that COE may be a potential treatment for human hepatocellular carcinoma.

     

Polyphenols from the extract and fraction of <Emphasis Type="Italic">T. indica</Emphasis> seeds protected HepG2 cells against oxidative stress

Background

Tamarindus indica L. (T. indica) or locally known as “asam jawa” belongs to the family Leguminosae. T. indica seeds as by-products from the fruits were previously reported to contain high polyphenolic content. However, identification of their bioactive polyphenols using recent technologies is less well researched but nonetheless important. Hence, it was the aim of this study to provide further information on the polyphenolic content and antioxidant activities as well as to identify and quantify its bioactive polyphenols.

Methods

T. indica seeds were extracted with methanol and were then fractionated with different compositions of hexane, ethyl acetate and methanol. Polyphenolic contents were measured using Folin-Ciocalteu assay while antioxidant activities were measured using DPPH radical scavenging and ferric reducing (FRAP) activities. The cytotoxic activities of the crude extract and the active fraction were evaluated in HepG2 cells using MTT assay. The cells were then pre-treated with the IC₂₀ concentrations and induced with H₂O₂ before measuring their cellular antioxidant activities including FRAP, DPPH, lipid peroxidation, ROS generation and antioxidant enzymes, SOD, GPx and CAT. Analyses of polyphenols in the crude extract and its active fraction were done using UHPLC and NMR.

Results

Amongst the 7 isolated fractions, fraction F3 showed the highest polyphenolic content and antioxidant activities. When HepG2 cells were treated with fraction F3 or the crude extract, the former demonstrated higher antioxidant activities. F3 also showed stronger inhibition of lipid peroxidation and ROS generation, and enhanced activities of SOD, GPx and CAT of HepG2 cells following H₂O₂-induced oxidative damage. UHPLC analyses revealed the presence of catechin, procyanidin B2, caffeic acid, ferulic acid, chloramphenicol, myricetin, morin, quercetin, apigenin and kaempferol, in the crude seed extract of T. indica. UHPLC and NMR analyses identified the presence of caffeic acid in fraction F3. Our studies were the first to report caffeic acid as the active polyphenol isolated from T. indica seeds which likely contributed to the potent antioxidant defense system of HepG2 cells.

Conclusion

Results from this study indicate that caffeic acid together with other polyphenols in T. indica seeds can enhance the antioxidant activities of treated HepG2 cells which can provide protection against oxidative damage.

     

Assessing the protective effect of Crassocephalum vitellinum against Rifampicin-induced hepatotoxicity in Wistar rats

BackgroundCrassocephalum vitellinum is widely used by traditional medical practitioners and local people in East Africa to manage a large number of ailments including hepatitis ¹. However, its hepatoprotective effects had not been evaluated prior to this study. The aim of this study was to assess the effect of an ethanolic leaf extract of Crassocephalum vitellinum against rifampicin-induced liver toxicity in Wistar rats.MethodsIncreasing doses of an ethanolic leaf extract of C. vitellinum were administered to Wistar rats daily for 35 days, together with rifampicin given orally as suspension. After the treatment period, Assessment of hepatoprotective activity was done by analysis of serum levels of biochemical and histopathological effects on the liver.ResultsThe results showed that administration of C. vitellinum extract significantly prevented drug- induced increase in serum levels of liver biomarker enzymes and also decreased the hepatocellular necrosis and inflammatory cells infiltration.ConclusionThe plant extract loweres the liver biomarker enzymes (ALT, ALP, AST) and preserves the histomorphology of the hepatocytes which is suggestive that the plant possess hepatoprotective properties.     

Mangiferin, a natural polyphenol protects the hepatic damage in mice caused by CCl4 intoxication

Mangiferin is a natural polyphenolic (C-glucoxyl xanthone) antioxidant present in the bark, fruits, roots and leaves of Mangifera indica Linn. In the present study, we investigated the protective effect of mangiferin against carbon tetrachloride (CCl₄)-induced hepatotoxicity in mice and compared it with silymarin, a standard hepatoprotective drug. The pretreatment of mangiferin (30?mg/kg body weight, i.p.) has shown it to possess a significant protective effect by lowering the serum aspartate and alanine aminotransferases, alkaline phosphatase, bilirubin and inflammatory mediator TNF-α. This hepatoprotective action was confirmed by histological observation. In addition, pretreatment of mangiferin prevented the elevation of hepatic malondialdehyde formation and the depletion of antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and total reduced glutathione) activity in the liver of CCl₄-injected mice. The results suggest that mangiferin exhibits potent hepatoprotective effects on CCl₄-induced liver damages in mice.     

Histamine Dihydrochloride Protects Against Early Alcohol-Induced Liver Injury in a Rat Model

Inflammation of the liver may be caused by a variety of factors that include infectious agents and toxins. Reactive oxygen species (ROS) generated by the NADPH oxidase in Kupffer cells and infiltrating leukocytes play an important role in the pathogenesis of early alcohol-induced hepatitis. Histamine dihydrochloride (histamine) suppresses the generation of ROS through the histamine type-2 receptor (H2 receptor). Histamine was studied as a potential protective treatment against early alcohol-induced liver injury in an experimental hepatitis model. Female Wistar rats were given ethanol (5 g/kg) intragastrically by gavage once daily for 4 weeks, while a control group not receiving ethanol was fed an isocaloric high-fat diet. Animals receiving ethanol had elevated serum levels of alanine and aspartate transaminase (ALT/AST) and developed steatosis, inflammation, and necrosis of the liver. Histamine treatment (0.5 or 5.0 mg/kg, twice daily) protected against this liver injury as evident by normal serum transaminase levels and significantly reduced liver pathology scores. Ranitidine (10 mg/kg), an H2 receptor antagonist, blocked the protective effect of histamine, indicating that the histamine effect is predominantly mediated through the H2 receptor. In conclusion, these results suggest that histamine protects against early alcohol-induced liver injury in rats.     

Hot water extract of Chlorella vulgaris induced DNA damage and apoptosis

OBJECTIVES:

The aim of this study was to determine the antiproliferative and apoptotic effects of hot water extracts of Chlorella vulgaris on hepatoma cell line HepG2.

INTRODUCTION:

The search for food and spices that can induce apoptosis in cancer cells has been a major study interest in the last decade. Chlorella vulgaris, a unicellular green algae, has been reported to have antioxidant and anti‐cancer properties. However, its chemopreventive effects in inhibiting the growth of cancer cells have not been studied in great detail.

METHODS:

HepG2 liver cancer cells and WRL68 normal liver cells were treated with various concentrations (0‐4 mg/ml) of hot water extract of C. vulgaris after 24 hours incubation. Apoptosis rate was evaluated by TUNEL assay while DNA damage was assessed by Comet assay. Apoptosis proteins were evaluated by Western blot analysis.

RESULTS:

Chlorella vulgaris decreased the number of viable HepG2 cells in a dose dependent manner (p < 0.05), with an IC₅₀ of 1.6 mg/ml. DNA damage as measured by Comet assay was increased in HepG2 cells at all concentrations of Chlorella vulgaris tested. Evaluation of apoptosis by TUNEL assay showed that Chlorella vulgaris induced a higher apoptotic rate (70%) in HepG2 cells compared to normal liver cells, WRL68 (15%). Western blot analysis showed increased expression of pro‐ apoptotic proteins P53, Bax and caspase‐3 in the HepG2 cells compared to normal liver cells WRL68, and decreased expression of the anti‐apoptotic protein Bcl‐2.

CONCLUSIONS:

Chlorella vulgaris may have anti‐cancer effects by inducing apoptosis signaling cascades via an increased expression of P53, Bax and caspase‐3 proteins and through a reduction of Bcl‐2 protein, which subsequently lead to increased DNA damage and apoptosis.     

Antihepatotoxic Effect of Tadehaginoside,Extracted from Tadehagi triquetrum (L.), Against CCl4-Lesioned Rats Through Activating the Nrf2 Signaling Pathway and Attenuating the Inflammatory Response

Recently, an increasing number of studies suggest that oxidative stress and inflammation are associated with hepatocellular injuries. Thus, we aimed to evaluate the potential hepatoprotective role of tadehaginoside (TA) on liver lesions induced by carbon tetrachloride (CCl₄). The results in vitro suggested that TA dose-dependently suppressed the cell proliferation of HepG2 cells, whereas the phosphorylated level of IκBα in cells was effectively inactivated. The study in vivo showed that TA significantly lowered the serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), immunoglobulin E (IgE), and leukotriene (LT) in CCl₄-lesioned rats. Pathological examination indicated that CCl₄-induced hepatocellular damage was effectively mitigated by TA treatment. Meanwhile, the contents of γ-glutamylcysteine synthetase (γ-GCS), glutathione (GSH), and catalase (CAT) in liver tissue were gradually elevated. In addition, cytochrome c oxidase (COX) mRNA expression in hepatocytes was markedly upregulated, and nuclear factor E2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keapl) levels were progressively increased. Furthermore, the tumor necrosis factor alpha (TNF-α) and nuclear factor-kappa B (NF-κB)-expressed protein were downregulated. These findings demonstrate that tadehaginoside effectively protects against CCl₄-induced oxidative injury and inflammatory reaction in hepatocytes, in which the underlying mechanisms are involved in activating the Nrf2 signaling pathway and inhibiting the NF-κB pathway, thereby attenuating oxidative stress and reducing the inflammation in liver cells.     

In vitro antioxidant and cytotoxicity activities of selected indigenous South African medicinal plants

BackgroundMedicinal plants are regarded as a large source of phytochemicals that may have anticancer properties. This could lead to the development of innovative drugs or alternative therapy against cancer.ObjectiveThis study was designed to determine the antioxidant and cytotoxicity effect of 5 selected indigenous South African medicinal plants namely; Bulbine frutescens, Bulbine natalensis, Chlorophytum comosum, Kniphofia uvaria, and Tulbaghia violacea.MethodPhytochemical extracts namely; methanol, 50%, 100% ethanol, and water extracts were prepared from the root and shoot of the plants. The antioxidant effect of methanol extracts of the plant materials was performed using a DPPH assay. A preliminary cytotoxicity screening of the phytochemical extracts in the human colon (Caco-2), cervical (HeLa), and hepatocellular (HepG2) cell lines were determined followed by the half-maximal inhibitory concentration (IC50) using MTT assay.ResultThe methanol root extract of B. natalensis and B. frutescens (33.20% and 26.33% respectively) and shoot extract of K. uvaria (17.10%) showed the highest antioxidant. Out of the 5 plants, only 100% ethanol extract of C. comosum, K. uvaria, and T. violacea caused more than 80% cytotoxicity in HepG2 and Caco-2 cell lines. The shoot of B. frutescens (10.43 µg/ml), K. uvaria (23.0 µg/ml), and root of C. comosum (23.77 µg/ml) were the most active with the highest cytotoxicity.ConclusionC. comosum, K. uvaria, and T. violacea possess significant cytotoxicity that is promising in developing alternative drugs against colon and liver cancers. Our results provided new pieces of evidence for antioxidant and cytotoxic activities of these plants which could be useful for developing new anticancer therapies.     

低浓度乙醇对人肝癌HepG2细胞的杀伤作用

目的探讨低浓度乙醇对人肝癌Hep G2细胞的杀伤作用,及其作用机制。方法以体外培养的人肝癌Hep G2细胞为研究对象,MTT法检测细胞毒性,吖啶橙(AO)、溴化乙锭(EB)染色观察细胞凋亡形态,2’,7’-二氢二氯荧光黄双乙酸钠(DCFH-DA)法检测Hep G2细胞内活性氧族(ROS)水平,罗丹明123(Rh123)染色检测线粒体膜电位变化,免疫荧光法检测Caspase-9表达,流式细胞术检测细胞凋亡率。结果 MTT显示,低浓度乙醇呈时间依赖性和剂量依赖性抑制Hep G2细胞增殖,1.0、1.6mol/L乙醇作用6h后,细胞内ROS、Caspase-9荧光强度均显著高于对照组(P0.01,n=20),Rh123荧光强度显著低于对照组(P0.01,n=20);高内涵活细胞成像系统可见细胞核固缩呈圆珠状凋亡特征;流式细胞术显示,1.0mol/L乙醇作用6h可诱导27.92%Hep G2细胞凋亡,5.4%细胞坏死;1.6mol/L乙醇作用6h可诱导31.22%Hep G2细胞凋亡,15.1%Hep G2细胞坏死。结论低浓度乙醇可通过升高细胞内ROS水平,降低线粒体膜电位,上调Caspase-9表达,通过线粒体途径诱导Hep G2细胞凋亡。     

Interleukin-22-Induced Antimicrobial Phospholipase A2 Group IIA Mediates Protective Innate Immunity of Nonhematopoietic Cells against Listeria monocytogenes

Listeria monocytogenes is a bacterial pathogen which establishes intracellular parasitism in various cells, including macrophages and nonhematopoietic cells, such as hepatocytes. It has been reported that several proinflammatory cytokines have pivotal roles in innate protection against L. monocytogenes infection. We found that a proinflammatory cytokine, interleukin 22 (IL-22), was expressed by CD3⁺ CD4⁺ T cells at an early stage of L. monocytogenes infection in mice. To assess the influence of IL-22 on L. monocytogenes infection in hepatocytes, cells of a human hepatocellular carcinoma line, HepG2, were treated with IL-22 before L. monocytogenes infection in vitro. Gene expression analysis of the IL-22-treated HepG2 cells identified phospholipase A2 group IIA (PLA2G2A) as an upregulated antimicrobial molecule. Addition of recombinant PLA2G2A to the HepG2 culture significantly suppressed L. monocytogenes infection. Culture supernatant of the IL-22-treated HepG2 cells contained bactericidal activity against L. monocytogenes, and the activity was abrogated by a specific PLA2G2A inhibitor, demonstrating that HepG2 cells secreted PLA2G2A, which killed extracellular L. monocytogenes. Furthermore, colocalization of PLA2G2A and L. monocytogenes was detected in the IL-22-treated infected HepG2 cells, which suggests involvement of PLA2G2A in the mechanism of intracellular killing of L. monocytogenes by HepG2 cells. These results suggest that IL-22 induced at an early stage of L. monocytogenes infection enhances innate immunity against L. monocytogenes in the liver by stimulating hepatocytes to produce an antimicrobial molecule, PLA2G2A.     

Estrogen suppresses heptatic IκB expression during short-term alcohol exposure

Objective

To assess the effects of sex steroids on hepatic inflammatory pathways in short-term chronically ethanol-fed rats.

Methods

Ovariectomized female Wistar rats (8–12?weeks old, n?=?8 per treatment group) were implanted with osmotic pumps releasing 17β-estradiol (20?μg/24?h) or testosterone (25?μg/24?h) and fed liquid diets with or without ethanol (8?% w/v) for two?weeks. Hepatic expression of IκBα/β, TNF-α, and IL-6 mRNA was examined by real-time PCR. Liver (nuclear) NFκB, IκBα and β, IL-6, and IL-6Rα protein expression was examined by enzyme-linked immunosorbent assay (ELISA) or Western blot.

Results

Estrogen alone induced greater steatosis, NFκB translocation, TNF-α mRNA, as well as IL-6, and IL-6R protein. Alcohol consumption along with estrogen treatment further increased steatosis, NFκB translocation, TNF-α mRNA, and IL-6 protein. Conversely, neither estrogen nor ethanol consumption induced IκBα or IκBβ mRNA or protein expression, while testosterone robustly induced these inhibitory proteins regardless of treatment.

Conclusions

Estrogen exposure enhances alcohol-induced liver inflammation, and the anti-inflammatory effects of testosterone in the liver might be related to induction of IκB. Elevated inflammation in response to estrogen may overwhelm the regenerative influence of IL-6 in liver, leading to increased steatosis and greater liver damage.     

Involvement of P450s and nuclear receptors in the hepatoprotective effect of quercetin on liver injury by bacterial lipopolysaccharide

Abstract

Objective: Quercetin (Que), a flavonoid, possesses anti-inflammatory and antioxidant properties. It has been shown to protect against liver injury induced by various factors. This study was designed to investigate the underlying mechanism of its protective effect against lipopolysaccharide (LPS)- induced liver damage.

Methods: Mice were pretreated with Que for 7 consecutive days and then exposed to LPS. To study the hepatoprotective effect of Que, oxidative stress parameters, inflammatory cytokine levels in liver and serum liver function indexes were examined. Protein and mRNA expression of nuclear orphan receptors and cytochrome P450 enzymes were measured by Western Blotting and qPCR, respectively.

Results: Que significantly reduced circulating ALT, AST, ALP, and ameliorated LPS-induced histological alterations. In addition, Que obviously decreased markers of oxidative stress and pro-inflammatory cytokines. Furthermore, Que carried out the hepatoprotective effect via regulation of the expression of nuclear orphan receptors (CAR, PXR) and cytochrome P450 enzymes (CYP1A2, CYP2E1, CYP2D22, CYP3A11).

Conclusions: Our findings suggested that Que pretreatment could ameliorate LPS-induced liver injury.     

Hepatoprotective effects of pecan nut shells on ethanol-induced liver damage

The hepatoprotective activity of the aqueous extract of the shells of pecan nut was investigated against ethanol-induced liver damage. This by-product of the food industry is popularly used to treat toxicological diseases. We evaluated the phytochemical properties of pecan shell aqueous extract (AE) and its in vitro and ex vivo antioxidant activity. The AE was found to have a high content of total polyphenols (192.4 ± 1.9 mg GAE/g), condensed tannins (58.4 ± 2.2 mg CE/g), and antioxidant capacity, and it inhibited Fe²⁺-induced lipid peroxidation (LP) in vitro. Rats chronically treated with ethanol (Et) had increased plasmatic transaminases (ALT, AST) and gamma glutamyl transpeptidase (GGT) levels (96%, 59.13% and 465.9%, respectively), which were effectively prevented (87; 41 and 383%) by the extract (1:40, w/v). In liver, ethanol consumption increased the LP (121%) and decreased such antioxidant defenses as glutathione (GSH) (33%) and superoxide dismutase (SOD) (47%) levels, causing genotoxicity in erythrocytes. Treatment with pecan shell AE prevented the development of LP (43%), GSH and SOD depletion (33% and 109%, respectively) and ethanol-induced erythrocyte genotoxicity. Catalase activity in the liver was unchanged by ethanol but was increased by the extract (47% and 73% in AE and AE + Et, respectively). Therefore, pecan shells may be an economic agent to treat liver diseases related to ethanol consumption.     

Hepatoprotective effect of acetonic and methanolic extracts of Heterotheca inuloides against CCl4-induced toxicity in rats

A model of hepatotoxicity by carbon tetrachloride (CCl₄) in rats was used in order to evaluate the protective potential of the acetonic and methanolic extracts of Heterotheca inuloides. Pretreatment with the two H. inuloides extracts attenuated the increase in the activity of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) observed in CCl₄-induced liver injury. The protective effect was confirmed by the analysis of tissue slides stained with hematoxylin-eosin and periodic acid/Schiff’s reagent. Additionally, the two extracts are scavengers to the superoxide radical as was observed by electron paramagnetic resonance. Due to the fact that the methanolic extract resulted in a better protective effect in the previous experiments, it was used to investigate in more detail the mechanism of hepatoprotection. Quercetin, one of the main components of the extract, with known hepatoprotective and antioxidant activity was used as a positive control. Pretreatment of animals with the methanolic extract or quercetin, was associated with the prevention of 4-hydroxynonenal and 3-nitrotyrosine increase in the liver, two markers of oxidative stress. Furthermore, the decrease in the activity of several antioxidant enzymes including superoxide dismutase, catalase and glutathione peroxidase in CCl₄-induced liver injury was alleviated by the pretreatment with H. inuloides methanolic extract or quercetin. These results suggest that the hepatoprotective capacity of H. inuloides methanolic extract is associated with its antioxidant properties, which would also explain the biomedical properties attributed to this plant.