Ethanol-induced Oxidative Damage Research Articles

Polyphenols in Eucalyptus leaves improved the egg and meat qualities and protected against ethanol-induced oxidative damage in laying hens.

Polyphenols in Eucalyptus leaves (PE) were value resources due to various pharmacological activities, but data on the effect on laying hens are very scare. This study was conducted to determine the effect of PE on the laying performance, egg traits, meat quality, antioxidant status and liver tissues of laying hens. One hundred and twenty 256-day-old Yueqinhuang laying hens were randomly assigned to four treatment groups (different levels of PE at 0, 0.5, 0.8 and 1.2g/kg diet) for 63days with 15 replicates per group. Addition of 0.8g/kg PE not only improved the egg trait by increasing the eggshell thickness and decreasing MDA production and cholesterol content in the egg yolk, but also significantly enhanced meat quality of hens, as suggested by the increase pH45min (p<.01) and a* value, and decrease drip loss rate (p<.01). Meanwhile, under acute ethanol-induced oxidative damage condition, supplementation of 0.8g/kg PE enhanced the serum antioxidant status by increasing enzymatic activities (GSH-PX, T-SOD, T-AOC), inhibited oxidative damage and provided protective effect to liver tissue. In conclusion, addition of 0.8g/kg PE not only improved the egg traits and meat quality without obvious adverse effects, but also increased the serum antioxidant status of the hens and protected their liver tissue from ethanol-induced oxidative damage. This study indicated that PE could be utilized as an effective feed additive for laying hens to improve health performance and egg traits.

Autophagy protects gastric mucosal epithelial cells from ethanol-induced oxidative damage via mTOR signaling pathway.

Alcohol abuse is an important cause of gastric mucosal epithelial cell injury and gastric ulcers. A number of studies have demonstrated that autophagy, an evolutionarily conserved cellular mechanism, has a protective effect on cell survival. However, it is not known whether autophagy can protect gastric mucosal epithelial cells against the toxic effects of ethanol. In the present study, gastric mucosal epithelial cells (GES-1 cells) and Wistar rats were treated with ethanol to detect the adaptive response of autophagy. Our results demonstrated that ethanol exposure induced gastric mucosal epithelial cell damage, which was accompanied by the downregulation of mTOR signaling pathway and activation of autophagy. Suppression of autophagy with pharmacological agents resulted in a significant increase of GES-1 cell apoptosis and gastric mucosa injury, suggesting that autophagy could protect cells from ethanol toxicity. Furthermore, we evaluated the cellular oxidative stress response following ethanol treatment and found that autophagy induced by ethanol inhibited generation of reactive oxygen species and degradation of antioxidant and lipid peroxidation. In conclusion, these findings provide evidence that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate oxidative damage induced by ethanol in gastric mucosal epithelial cells. Therefore, modifying autophagy may provide a therapeutic strategy against alcoholic gastric mucosa injury. Impact statement The effect and mechanism of autophagy on ethanol-induced cell damage remain controversial. In this manuscript, we report the results of our study demonstrating that autophagy can protect gastric mucosal epithelial cells against ethanol toxicity invitro and invivo. We have shown that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate ethanol-induced oxidative damage in gastric mucosal epithelial cells. This study brings new and important insights into the mechanism of alcoholic gastric mucosal injury and may provide an avenue for future therapeutic strategies.

Iron-Mediated Lysosomal Membrane Permeabilization in Ethanol-Induced Hepatic Oxidative Damage and Apoptosis: Protective Effects of Quercetin.

Iron, in its free ferrous states, can catalyze Fenton reaction to produce OH∙, which is recognized as a crucial role in the pathogenesis of alcoholic liver diseases (ALD). As a result of continuous decomposition of iron-containing compounds, lysosomes contain a pool of redox-active iron. To investigate the important role of intralysosomal iron in alcoholic liver injury and the potential protection of quercetin, male C57BL/6J mice fed by Lieber De Carli diets containing ethanol (30% of total calories) were cotreated by quercetin or deferoxamine (DFO) for 15 weeks and ethanol-incubated mice primary hepatocytes were pretreated with FeCl3, DFO, and bafilomycin A1 at their optimal concentrations and exposure times. Chronic ethanol consumption caused an evident increase in lysosomal redox-active iron accompanying sustained oxidative damage. Iron-mediated ROS could trigger lysosomal membrane permeabilization (LMP) and subsequent mitochondria apoptosis. The hepatotoxicity was attenuated by reducing lysosomal iron while being exacerbated by escalating lysosomal iron. Quercetin substantially alleviated the alcoholic liver oxidative damage and apoptosis by decreasing lysosome iron and ameliorating iron-mediated LMP, which provided a new prospective of the use of quercetin against ALD.

Safety Evaluation, in Vitro and in Vivo Antioxidant Activity of the Flavonoid-Rich Extract from Maydis stigma

This study aimed to assess the acute toxicity and safety of flavonoid-rich extract from Maydis stigma (FMS) in mice. The in vitro antioxidant activity of FMS was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethyl-benzthiazoline-6-sulphonate) (ABTS) scavenging assays. Furthermore, the in vivo antioxidant of FMS against ethanol-induced oxidative damage in mice was determined by analysis of the serum total superoxide dismutase (T-SOD) activity, malondialdehyde (MDA) content, liver tissue glutathione (GSH) content, and protein carbonyl (PC) content in liver tissue. The oral administration of FMS at doses of 30 g/kg did not cause death in mice, and there were no significant biologically adverse effects in mice. These results indicated that the median lethal dose (LD50) is higher than this dose. The IC50 values of FMS for the DPPH and ABTS scavenging activity were 50.73 and 0.23 mg/mL, respectively. Meanwhile, FMS could significantly enhance T-SOD activity, reduce MDA content in the serum, increase GSH content, and decrease PC content in the liver tissue at the tested doses (25, 50, 100, 200 mg/kg·day). These results indicate that FMS can be generally regarded as safe and used potentially as a bioactive source of natural antioxidants.

Sodium selenite/selenium nanoparticles (SeNPs) protect cardiomyoblasts and zebrafish embryos against ethanol induced oxidative stress

Alcoholic cardiomyopathy is the damage caused to the heart muscles due to high level of alcohol consumption resulting in enlargement and inflammation of the heart. Selenium is an important trace element that is beneficial to human health. Selenium protects the cells by preventing the formation of free radicals in the body. In the present study, protein mediated synthesis of SeNPs was investigated. Two different sizes of SeNPs were synthesized using BSA and keratin. The synthesized SeNPs were characterized by scanning electron microscopy (SEM) with elemental composition analysis Energy Dispersive X-ray spectroscopy(EDX) and X-ray diffraction (XRD). This study demonstrates the in vitro and in vivo antioxidative effects of sodium selenite and SeNPs. Further selenium and SeNPs were evaluated for their ability to protect against 1% ethanol induced oxidative stress in H9C2 cell line. The selenium and SeNPs were found to reduce the 1% ethanol-induced oxidative damage through scavenging intracellular reactive oxygen species. The selenium and SeNPs could also prevent pericardial edema induced ethanol treatment and reduced apoptosis and cell death in zebrafish embryos. The results indicate that selenium and SeNPs could potentially be used as an additive in alcoholic beverage industry to control the cardiomyopathy.

Hepatoprotective Effect of the Macrotyloma uniflorum Seed (Horse gram) in Ethanol-Induced Hepatic Damage in Rats

Macrotyloma uniflorum is a lesser known bean consumed as a whole seed or sprout in India. The protective effect of a hydroalcoholic extract of the seeds of Macrotyloma uniflorum (MUSE) in ethanol-induced hepatotoxicity was investigated in rats. Liver damage was induced in rats by administering ethanol (4 g/kg, 20 % w/v p.o.) once daily for 21 days. MUSE (250 mg/kg and 500 mg/kg) and the reference drug silymarin (100 mg/kg) were administered orally for 28 days to ethanol treated rats, this treatment beginning 7 days prior to the commencement of ethanol administration. MUSE elicited significant hepatoprotective and antioxidant activity by attenuating the ethanol-elevated levels of serum marker enzymes (aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase), bilirubin, hepatic and serum triglycerides and the lipid peroxidation marker malondialdehyde, and by restoring the ethanol-depleted levels of albumin, total proteins, reduced glutathione and the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. The present findings indicate that hepatoprotective effect of MUSE in ethanol-induced oxidative damage may be due to an augmentation of the endogenous antioxidants and inhibition of lipid peroxidation in liver.

Network pharmacology-based antioxidant effect study of zhi-zi-da-huang decoction for alcoholic liver disease.

Zhi-Zi-Da-Huang decoction (ZZDHD), a classic traditional Chinese medicine (TCM) formula, has been used for centuries to treat alcoholic liver disease. Reliable therapeutics of ZZDHD has also been validated in clinical practice. In this study, molecular docking and network analysis were carried out to explore the antioxidative mechanism of ZZDHD as an effective therapeutic approach to treat alcoholic liver disease. Multiple active compounds of ZZDHD were screened based on four key original enzymes (cytochrome P450 2E1, xanthine oxidase, inducible nitric oxide synthase, and cyclooxygenase-2) involved in ethanol-induced oxidative stress damage. A drug-target network was constructed through network pharmacology analysis, which predicted the relationships of active ingredients to the targets. Some results had been verified by the previous experimental pharmacological studies; meanwhile, it was first reported that xanthine oxidase and eriocitrin, neoeriocitrin, isorhoifolin, and poncirin had interactions. The network pharmacology strategy used provided a forceful tool for searching the mechanism of action of TCM formula and novel bioactive ingredients.

Synergistic effect of Se-methylselenocysteine and vitamin E in ameliorating the acute ethanol-induced oxidative damage in rat

The present study was conduced to investigate the synergistic effects of combined treatments with Se-methylselenocysteine (SeMSC) and vitamin E (Vit E) in reversing oxidative stress induced by ethanol in serum and different tissues of rats. Sixty female rats were randomly divided into six groups for 30 days’ consecutive pretreatments as followed: control (I), physiological saline (II), 2.8μgkg−1 Se as SeMSC (III), 2.8μgkg−1 Se as sodium selenite (Na2SeO3, IV), 5mgkg−1 α-tocopherol as α-tocopherol acetate (Vit E, V), 5mgkg−1 α-tocopherol as α-tocopherol acetate and 2.8μgkg−1 Se as SeMSC (VI). All animals in groups II–VI were treated by ethanol treatment to cause oxidative stress. After 6h of ethanol treatment, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), the contents of total antioxidant capacity (T-AOC), malondialdehyde (MDA), glutathione (GSH) and carbonyl protein (CP) in the serum, liver, heart and kidney were measured. The result showed that the individual SeSMC, Na2SeO3 and vitamin E could effectively increase the SOD, T-AOC, GSH-Px and GSH contents as well as significantly decrease the MDA and CP concentrations in the tissues of ethanol-induced rats. At the same dose on different forms of Se, SeMSC showed greater antioxidant activity than Na2SeO3. Moreover, group VI (SeMSC and α-tocopherol acetate) showed much better antioxidant activity than individual group III (SeMSC) and V (α-tocopherol acetate) due to the synergistic effect.

Pyrroloquinoline quinone-secreting probiotic Escherichia coli Nissle 1917 ameliorates ethanol-induced oxidative damage and hyperlipidemia in rats.

Chronic ethanol (EtOH) consumption is associated with oxidative tissue damage, decrease in antioxidant enzyme activities, and increase in hepatic and plasma lipids. This study investigates the effect of modified probiotic Escherichia coli Nissle 1917 (EcN) secreting pyrroloquinoline quinone (PQQ) against EtOH-induced metabolic disorder in rats. Male Charles Foster rats were gavaged with EtOH (5 g/kg body weight [acute study] and 3 g/kg body weight per day for 10 weeks [chronic study]). Pretreatment of PQQ, vitamin C, and PQQ-secreting EcN prevented acute EtOH-induced oxidative damage in rats reflected by reduced lipid peroxidation in blood and liver and increased hepatic reduced glutathione. However, PQQ given externally was found to be most effective against acute EtOH toxicity. In the chronic study, rats treated with PQQ-secreting EcN showed remarkable reduction in oxidative tissue damage (liver, colon, blood, and kidney) with significant increase in antioxidant enzyme activities as compared to only EtOH-treated rats. Additionally, these rats had significantly lowered hepatic and plasma lipid levels with concomitant reduction in mRNA expression of fatty acid synthase (0.5-fold) and increase in mRNA expression of acyl coenzyme A oxidase (2.4-fold) in hepatic tissue. Antioxidant and hyperlipidemic effects of PQQ-secreting EcN are correlated with increased colonic short chain fatty acids (SCFAs; i.e., acetate, propionate, and butyrate) levels, and PQQ concentration in fecal samples (2-fold) and liver (4-fold). Extracted PQQ and vitamin C were given once a week, but they did not exhibit any ameliorative effect against chronic EtOH toxicity. Accumulated PQQ in tissues prevents hepatic and systemic oxidative damage. PQQ along with SCFAs reduced hyperlipidemia, which can be correlated with changes in mRNA expression of hepatic lipid metabolizing genes. Our study suggests that endogenous generation of PQQ by EcN could be an effective strategy in preventing alcoholic liver disease.

The effects of caloric restriction against ethanol-induced oxidative and nitrosative cardiotoxicity and plasma lipids in rats

Caloric restriction (CR) prevents or delays a wide range of aging-related diseases possibly through alleviation of oxidative stress. The aim of our study was to examine the effect of CR on oxidative and nitrosative cardiac damage in rats, induced by acute ethanol intoxication. Male Wistar rats were divided into following groups: control; calorie-restricted groups with intake of 60-70% (CR60-70) and 40-50% of daily energy needs (CR40-50); ethanol-treated group (E); calorie-restricted, ethanol-treated groups (CR60-70 + E, CR40-50 + E). Ethanol was administered in five doses of 2 g/kg every 12 h, while the duration of CR was five weeks before ethanol treatment. Malondialdehyde level was significantly lower in CR60-70 + E and significantly higher in CR40-50 + E vs. control. Nitrite and nitrate level was significantly higher in CR40-50 + E compared to control group. Activity of total superoxide dismutase (SOD) and its isoenzyme, copper/zinc-SOD (Cu/ZnSOD), was significantly higher in CR60-70 + E and lower in CR40-50 + E vs. control. Activity of manganese-SOD (MnSOD), that is also SOD isoenzyme, was significantly lower in CR40-50 + E compared to control group. Plasma content of sulfhydryl (SH) groups was significantly higher in CR60-70 group vs. control. Plasma concentration of total cholesterol, triacylglycerol, low-density lipoproteins and high-density lipoproteins was significantly lower in CR60-70 group compared to control values. Food restriction to 60-70% of daily energy needs has a protective effect on acute ethanol-induced oxidative and nitrosative cardiac damage, at least partly due to alleviation of ethanol-induced decrease in SOD activity, while restriction to 40-50% of energy needs aggravates lipid peroxidation and nitrosative stress.

Carbon monoxide alleviates ethanol-induced oxidative damage and inflammatory stress through activating p38 MAPK pathway

Stress-inducible protein heme oxygenase-1(HO-1) is well-appreciative to counteract oxidative damage and inflammatory stress involving the pathogenesis of alcoholic liver diseases (ALD). The potential role and signaling pathways of HO-1 metabolite carbon monoxide (CO), however, still remained unclear. To explore the precise mechanisms, ethanol-dosed adult male Balb/c mice (5.0g/kg.bw.) or ethanol-incubated primary rat hepatocytes (100mmol/L) were pretreated by tricarbonyldichlororuthenium (II) dimmer (CORM-2, 8mg/kg for mice or 20μmol/L for hepatocytes), as well as other pharmacological reagents. Our data showed that CO released from HO-1 induction by quercetin prevented ethanol-derived oxidative injury, which was abolished by CO scavenger hemoglobin. The protection was mimicked by CORM-2 with the attenuation of GSH depletion, SOD inactivation, MDA overproduction, and the leakage of AST, ALT or LDH in serum and culture medium induced by ethanol. Moreover, CORM-2 injection or incubation stimulated p38 phosphorylation and suppressed abnormal Tnfa and IL-6, accompanying the alleviation of redox imbalance induced by ethanol and aggravated by inflammatory factors. The protective role of CORM-2 was abolished by SB203580 (p38 inhibitor) but not by PD98059 (ERK inhibitor) or SP600125 (JNK inhibitor). Thus, HO-1 released CO prevented ethanol-elicited hepatic oxidative damage and inflammatory stress through activating p38 MAPK pathway, suggesting a potential therapeutic role of gaseous signal molecule on ALD induced by naturally occurring phytochemicals.

Gastroprotective, cytoprotective and antioxidant effects of Oleum cinnamomi on ethanol induced damage

Peptic ulcer disease is a gastrointestinal disorder defined by mucosal damage and free oxygen radicals associated with peptic ulcer and gastritis. Cinnamon is a traditional herb used for many diseases and it has also effects as an antioxidant, anti-inflammatory, antispasmodic and anti-ulcerative. Our research is based on oxidative stress and effects of Oleum cinnamomi on stomach, liver and kidney disorders induced by ethanol. In our experiment, 2-3month old male Sprague-Dawley rats were used. One hour before the mucosal damage induced by 70% ethanol, O. cinnamomi (2.5ml/kg) was added into the groups. Gastric pH, analysis of gastric mucus and ulcer index were calculated from samples obtained from the stomach. Superoxide dismutase (SOD), malondialdehyde and catalase (CAT) levels were determined in stomach, liver and kidney homogenates and erythrocyte hemolysate. Histopathological examination of stomach, liver and kidney were determined with H&E staining. The non-treated ulcerative group showed higher scores than the control group which was treated with O. cinnamomi, when ulcer scores, gastric mucus and pH level of stomach are compared. Increased lipid peroxidation levels were observed in the liver, kidney and erythrocyte hemolysate. SOD activity was decreased in liver whereas increased in stomach of ethanol treated ulcerative groups. CAT levels were increased in stomach and liver of ethanol treated rats. Histopathological findings showed that ethanol treatment cause multiply organ damage such as stomach, liver and kidney injury. O. cinnamomi treatment protected these tissues from ethanol-induced damage. Consequently, the current investigation shows that O. cinnamomi has protective effects on ethanol-induced oxidative and mucosal damage.

Gastroprotective mechanism of Bauhinia thonningii Schum

Ethnopharmacological relevanceBauhinia thonningii Schum. (Cesalpiniaceae) is locally known as Tambarib and used to treat various diseases including gastric ulcer. Aim of the studyThe current study aims to evaluate the gastroprotecive mechanism(s) of methanolic (MEBT) and chloroform (CEBT) extracts of Bauhinia thonningii leaves on ethanol-induced gastric ulceration. Materials and methodsGastric acidity, quantification and histochemistry of mucus, gross and microscopic examination, nitric oxide, lipid peroxidation, 2D gel electrophoresis, mass spectroscopy and biochemical tests were utilized to assess the mechanism(s) underlying the gastroprotective effects of MEBT and CEBT. Effect of these extracts into lipopolysaccharide/interferon-γ stimulated rodent cells were done in vitro. In vitro and in vivo toxicity studies were also conducted. Antioxidant activities of MEBT and CEBT were examined using DPPH, FRAP and ORAC assays. Phytochemical analyses of MEBT and CEBT were conducted using chemical and spectroscopic methods. ResultsGross and histological features confirmed the anti-ulcerogenic properties of Bauhinia thonningii. Gastroprotective mechanism of MEBT was observed to be mediated through the modulation of PAS-reactive substances, MDA and proteomics biomarkers (creatine kinase, malate dehydrogenase, ATP synthase, actin and thioredoxin). MEBT and CEBT showed no significant in vitro and in vivo effects on nitric oxide. Methanolic extract (MEBT) showed superior gastroprotective effects, polyphenolic content and antioxidant activities compared to CEBT. The plant extracts showed no in vitro or in vivo toxicity. ConclusionIt could be concluded that MEBT possesses anti-ulcer activity, which could be attributed to the inhibition of ethanol-induced oxidative damage and the intervention in proteomic pathways but not the nitric oxide pathway.

벌나무 열수 및 에탄올 추출물의 항산화 활성 및 알코올 분해능

벌나무의 에탄올 및 열수 추출물을 각각 제조하여 추출물별 항산화 활성을 비교하고, in vitro 및 in vivo에서의 알코올 분해능을 검토하였다. 벌나무 열수 및 에탄올 추출물의 총 폴리페놀 함량은 각각 171.93±2.2 μg/mg, 152.69±1.25μg/mg, 총 플라보노이드 함량은 각각 7.51±1.34 μg/mg,5.01±0.83 μg/mg이었고, FRAP값은 각각 1.75±0.32 μM/μg, 1.67±0.28 μM/μg으로 나타났다. 벌나무 열수 및 에탄올 추출물은 DPPH 및 ABTS에 대해 높은 소거활성을 보였고, 지질과산화 억제활성이 높음을 알 수 있었다. 벌나무 열수추출물은 HepG2 세포에서 알코올에 대한 in vitro에서의 간세포 보호 효과가 있었고, 또한 알코올을 투여한 rat에서 벌나무 추출물을 투여하면 알코올 투여 30분이 경과한 후 알코올 투여군보다 혈중 알코올 함량이 유의적으로 저하되었다. 따라서 벌나무 추출물은 높은 항산화 작용을 하며, 알코올분해 작용 및 알코올에 대한 간 보호 효과가 높은 것으로 생각된다.

Antioxidant Effect of Livomap, A Polyherbal Formulation on Ethanol Induced Hepatotoxicity in Albino Wistar Rats

The present study was designed to evaluate the antioxidant activity of Livomap on ethanol induced hepatotoxicity in albino wistar rats. A total of 30 rats were divided into five groups of six rats in each group. Group 1 served as normal control, Group 2 - normal rat + livomap (50mg/Kg), Group 3 - ethanol control rats, Group 4 - ethanol + livomap (25mg/Kg) and Group 5 - ethanol + livomap (50mg/Kg). The liver toxicity was induced by the administration of ethanol to the animals at a dose of 3 g/kg orally for 35 days. During the period, livomap was coadministered to the rats at doses of 25 and 50 mg/kg for 35 days. Ethanol induced rats exhibited significant increase in the levels of lipid peroxidative products and decrease in the levels of antioxidants. Co-administration of livomap to ethanol-induced rats significantly minimized the alterations in the levels of lipid peroxidation products and antioxidants. Results suggest that livomap might be beneficial in alleviating ethanol-induced oxidative damage and may be attributed to the antioxidant property of polyherbal formulation.

Bilirubin participates in protecting of heme oxygenase-1 induction by quercetin against ethanol hepatotoxicity in cultured rat hepatocytes

To attenuate alcohol liver disease (ALD) is extremely urgent since ALD has been emerged as a major liver disease. The aim of the present study is to investigate the hepatoprotective effect against ethanol-induced injury of bilirubin, a product of heme metabolism degradation via HO and biliverdin reductase catalysis. Ethanol-incubated primary rat hepatocytes (100 mmol/L) were treated by quercetin, bilirubin, inflammatory factors, and/or HO-1 inducer/inhibitor for 24 h, and the cellular damage was assayed. Quercetin lowered ethanol-induced glutathione depletion and superoxide dismutase inactivation, inhibited the overproduction of malondialdehyde and reactive oxygen species, and decreased the leakage of cellular aspartate aminotransferase and lactate dehydrogenase, accompanying the normalization of bilirubin level. The effect of quercetin was mimicked by exogenous bilirubin in a dose-dependent manner to some extent (within 25 μmol/L) and pharmacological HO-1 inducer hemin, but abolished by HO-1 inhibitor zinc protoporphyrin-IX. Inflammatory challenge of TNF-α plus IL-6 further aggravated ethanol-induced oxidative damage, which was also attenuated by bilirubin in part. These findings shed a light on the anti-oxidative and anti-inflammatory role of bilirubin released from quercetin/HO-1 and biliverdin reductase pathway against ethanol hepatotoxicity and highlight a prospective strategy of nutritional intervention for ALD by naturally occurring quercetin to induce HO-1 with the release of bioactive end-products.

Antioxidant and hepatoprotective effect of Garcinia indica fruit rind in ethanolinduced hepatic damage in rodents

The protective effects of aqueous extracts of the fruit rind of Garcinia indica (GIE) on ethanol-induced hepatotoxicity and the probable mechanisms involved in this protection were investigated in rats. Liver damage was induced in rats by administering ethanol (5 g/kg, 20% w/v p.o.) once daily for 21 days. GIE at 400 mg/kg and 800 mg/kg and the reference drug silymarin (200 mg/kg) were administered orally for 28 days to ethanol treated rats, this treatment beginning 7 days prior to the commencement of ethanol administration. Levels of marker enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP)), triglyceride (sTG), albumin (Alb) and total protein (TP) were evaluated in serum. Antioxidant parameters (reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR)), hepatic triglycerides (hTG) and the lipid peroxidation marker malondialdehyde (MDA) were determined in liver. GIE and silymarin elicited significant hepatoprotective activity by attenuating the ethanol–elevated levels of AST, ALT, ALP, sTG, hTG and MDA and restored the ethanol-depleted levels of GSH, SOD, CAT, GPx, GR, Alb and TP. GIE 800 mg/kg demonstrated greater hepatoprotection than GIE 400 mg/kg. The present findings indicate that hepatoprotective effects of GIE in ethanol-induced oxidative damage may be due to an augmentation of the endogenous antioxidants and inhibition of lipid peroxidation in liver.

Hepatoprotective effects of purified oleuropein from olive leaf extract against ethanol-induced damages in the rat

Summary Olives and olive oil contain large amounts of oleuropein. This phenolic compound is responsible for their bitter taste and pungent aroma and has been recognized as a powerful hypotensive, hypoglycemic and antioxidant agent. Thus, the aim of the present study was to evaluate the antioxidant properties of oleuropein on ethanol-induced oxidative damage and to examine its beneficial effects on liver function. Thirty-two adult male Sprague-Dawley rats were divided into four equal groups: the first group served as untreated control. The second group of rats were given ethanol (4 g/kg) orally. Group 3 received oral oleuropein (15 mg/kg). The final group of rats were fed ethanol (4 g/kg), 120 min after oral administration of oleuropein (15 mg/kg). All of the treatments were applied for 4 weeks via gavage. Administration of ethanol to rats induced toxicity in their liver, as shown by the significant elevation in the serum levels of transaminases, total cholesterol as well as liver histopathological findings. Elevation of glutathione peroxidase activity, the hepatic main antioxidant enzyme, and total glutathione was observed to suppress oxidative stress in the ethanol group. TBARS (an indicator of lipid peroxidation) concentration is also increased in ethanol-treated rats. In contrast, oleuropein during ethanol treatment in rats resulted in a higher antiperoxidative enzyme activity, catalase, and inhibited toxicity to the liver, as monitored by the reduction in ALT and AST levels and TBARS concentration. It is suggested that oleuropein possesses beneficial antioxidant effects against ethanol-induced liver toxicity, and therefore use of olive leaf extract may have prophylactic value in reducing the common complications resulting from oxidative stress in alcoholism.

Acute ethanol intake induces superoxide anion generation and mitogen-activated protein kinase phosphorylation in rat aorta: A role for angiotensin type 1 receptor

Ethanol intake is associated with increase in blood pressure, through unknown mechanisms. We hypothesized that acute ethanol intake enhances vascular oxidative stress and induces vascular dysfunction through renin–angiotensin system (RAS) activation. Ethanol (1g/kg; p.o. gavage) effects were assessed within 30min in male Wistar rats. The transient decrease in blood pressure induced by ethanol was not affected by the previous administration of losartan (10mg/kg; p.o. gavage), a selective AT1 receptor antagonist. Acute ethanol intake increased plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels. Ethanol induced systemic and vascular oxidative stress, evidenced by increased plasma thiobarbituric acid-reacting substances (TBARS) levels, NAD(P)H oxidase‐mediated vascular generation of superoxide anion and p47phox translocation (cytosol to membrane). These effects were prevented by losartan. Isolated aortas from ethanol-treated rats displayed increased p38MAPK and SAPK/JNK phosphorylation. Losartan inhibited ethanol-induced increase in the phosphorylation of these kinases. Ethanol intake decreased acetylcholine-induced relaxation and increased phenylephrine-induced contraction in endothelium-intact aortas. Ethanol significantly decreased plasma and aortic nitrate levels. These changes in vascular reactivity and in the end product of endogenous nitric oxide metabolism were not affected by losartan. Our study provides novel evidence that acute ethanol intake stimulates RAS activity and induces vascular oxidative stress and redox-signaling activation through AT1-dependent mechanisms. These findings highlight the importance of RAS in acute ethanol-induced oxidative damage.

Biochemical and immunological basis of silymarin effect, a milk thistle (Silybum marianum) against ethanol-induced oxidative damage

Ethanol metabolism induces generation of excessive amount of reactive oxygen species (ROS) which results in immune dysfunction. We examined the efficacy of silymarin on ethanol-induced oxidative stress, immunomodulatory activity, and vascular function in mice blood. Effectiveness of silymarin was compared with potent antioxidant ascorbic acid. In the present study, 8- to 10-week-old male BALB/c mice (20–30 g) were divided into the four groups of six each. One group were fed with ethanol (1.6 g/kg body weight), while second group were fed with ethanol (1.6 g/kg body weight) and silybin (250 mg/kg body weight), and the third group were exposed to ethanol (250 mg/kg body weight) and ascorbic acid (250 mg/kg body weight) per day for 12 weeks. The control group was fed with isocaloric glucose solution instead of ethanol. Ethanol exposure significantly increased thiobarbituric acid reactive substance (TBARS) and nitrite levels besides glutathione-S-transferase (GST) activity, and significantly decreased reduced glutathione (GSH) content and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx) in whole blood hemolyzate, while silymarin treatment significantly normalized these altered parameters. Silymarin significantly prevented ethanol-induced, elevated activities of interleukin (IL)-10, tumor necrosis factor (TNF)-α, γ interferon (IFN-γ), vascular endothelial growth factor (VEGF)-A, and transforming growth factor (TGF)-β1, as well as decreased IL-4 activity in mice blood. These results were comparable with the activity of ascorbic acid.