Protective role of Vitamin E pre-treatment on N-nitrosodiethylamine induced oxidative stress in rat liver

Nitrosamine compounds are known hepatic carcinogens. In the metabolism of nitrosamines, such as N-nitrosodiethylamine (NDEA), there is evidence of the formation of reactive oxygen species (ROS) resulting in oxidative stress, which may be one of the factors in the etiology of cancer. The formation of ROS may alter the antioxidant system, while the presence of Vitamin E may counteract NDEA induced oxidative stress. This study was planned to determine whether pre-treatment with Vitamin E (40 mg/kg body weight, i.p., twice a week for 4 weeks) to NDEA induced rats provides protection against oxidative stress in liver caused by the carcinogen. A single necrogenic dose of NDEA (200mg/kg body weight) was administered i.p. to the male albino rats with or without Vitamin E pre-treatment and the animals were sacrificed on Days 7, 14 or 21 after the administration of NDEA. The result showed enhanced levels of hepatic lipid peroxidation (LPO) and conjugated dienes of NDEA treated rats as the indices of oxidative stress, however, Vitamin E pre-treated rats administered NDEA showed decreased LPO and conjugated dienes (Day 21). Superoxide dismutase (SOD) activity in liver was not altered significantly in NDEA treated rats with or without Vitamin E pre-treatment. Catalase (CAT) activity was inhibited with NDEA treatment, however, Vitamin E pre-treatment showed recovery in hepatic CAT activity (Days 14 and 21). Total and Se-glutathione peroxidase (GSH-Px) activities and glutathione-S-transferase (GST) activity in liver increased in NDEA treated rats irrespective of Vitamin E pre-treatment. Glutathione reductase (GSH-R) activity as well as total glutathione (GSH) content in liver decreased in NDEA treated animals, both of which were recovered in Vitamin E pre-treated rats administered NDEA. Activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were increased significantly following NDEA treatment to rats with or without Vitamin E pre-treatment. The activities of AST and ALT enzymes were significantly reduced on Days 14 and 21 and ALP activity was reduced on Day 21 in NDEA+Vitamin E treated animals when compared to NDEA treated alone. LDH enzyme activity was normalized on Day 14 in Vitamin E pre-treated animals administered NDEA. However, the AST, ALT and ALP enzyme activities remained high in all treatment groups as compared to control group. Normal control and Vitamin E treated alone rats revealed normal histology of liver. On the other hand, NDEA treated animals showed alterations in normal hepatic histoarchitecture, which comprised of necrosis and vacuolization of the cells. However, the rats treated with Vitamin E+NDEA showed that the liver cells were normal, with very little necrosis (Day 21). This study concludes that the pre-treatment with Vitamin E prior to the administration of NDEA, reduced the degree of oxidative stress, although this vitamin produced only slight changes in the hepatic injury, in a time-dependent manner.     

Protective effect of ascorbic acid against oxidative stress induced by inorganic arsenic in liver and kidney of rat

Ascorbic acid treatment in arsenic trioxide treated rats increased arsenic excretion, inhibited lipid peroxidation, improved GSH status, regulated GSSG turnover and also restored glutathione-S-transferases activity in liver and kidney. Suitable mechanisms leading to ascorbic acid protection have been discussed. Upregulation of GSH dependent enzymes was found to be necessary for a protective effect. Protection is finally attributed to higher GSH levels observed in the liver and kidney of ascorbic acid and inorganic arsenic treated rats. It is also concluded that ascorbic acid protection is influenced by gender dependent factors. Arsenic poisoning is a global problem now. Gender differences need to be considered while applying therapeutic measures.     

Protective effect of silymarin on oxidative stress in rat brain

Brain is susceptible to oxidative stress and it is associated with age-related brain dysfunction. Previously, we have pointed out a dramatic decrease of glutathione levels in the rat brain after acetaminophen (APAP) oral administration overdose. Silymarin (SM) is a mixture of bioactive flavonolignans isolated from Silybum marianum (L.) Gaertn., employed usually in the treatment of alcoholic liver disease and as anti-hepatotoxic agent in humans. In this study, we have evaluated the effect of SM on enzymatic and non enzymatic antioxidant defensive systems in rat brain after APAP-induced damage. Male albino Wistar rats were treated with SM (200 mg/kg/die orally) for three days, or with APAP single oral administration (3 g/kg) or with SM (200 mg/kg/die orally) for 3 days and APAP single oral administration (3 g/kg) at third day. Successively the following parameters were measured: reduced and oxidized glutathione (GSH and GSSG), ascorbic acid (AA), enzymatic activity variations of superoxide dismutase (SOD) and malondialdehyde levels (MDA). Our results showed a significant decrease of GSH levels, AA levels and SOD activity and an increase of MDA and GSSG levels after APAP administration. After SM administration GSH and AA significantly increase and SOD activity was significantly enhanced. In the SM+APAP group, GSH values significantly increase and the others parameters remained unchanged respect to control values. These results suggest that SM may to protect the SNC by oxidative damage for its ability to prevent lipid peroxidation and replenishing the GSH levels.     

Protective role of erdosteine on vancomycin-induced oxidative stress in rat liver

Drug-induced liver toxicity is a common cause of liver injury. This study was designed to elucidate whether high dose vancomycin (VCM) induces oxidative stress in liver and to investigate the protective effects of erdosteine, an expectorant agent. Twenty-two young Wistar rats were divided into three groups as follows: control group, VCM, and VCM plus erdosteine. VCM was administered intraperitoneally in the dosage of 200 mg/kg twice daily for 7 days. Erdosteine was administered orally administered once a day at a dose of 10 mg/kg body weight. The activities of antioxidant enzymes such as superoxide dismutase and catalase as well as the concentration of malondialdehyde, as an indicator of lipid peroxidation, were measured to evaluate oxidative stress in homogenates of the liver. VCM administration increased malondialdehyde levels (p < 0.001), superoxide dismutase (p < 0.01) and catalase (p < 0.001) activities. Erdosteine co-administration with VCM injections caused significantly decreased malondialdehyde levels (p < 0.001), superoxide dismutase (p < 0.01) and catalase (p < 0.001) activities in liver tissue when compared with VCM alone. It can be concluded that erdosteine may prevent VCM-induced oxidative changes in liver by reducing reactive oxygen species.     

Protective effect of vitamin E in dimethoate and malathion induced oxidative stress in rat erythrocytes

Organophosphate (OP) pesticides such as dimethoate and malathion intoxication has been shown to produce oxidative stress due to the generation of free radicals and alter the antioxidant defense system in erythrocytes. It is possible that vitamin E being present at the cell membrane site may prevent OP-induced oxidative damage. In the present study, rats were pretreated orally with vitamin E (250 mg/kg body wt, twice a week for 6 weeks) prior to oral administration of a single low dose of dimethoate and/or malathion (0.01% LD(50)). The result showed that treatment with OP increased lipid peroxidation (LPO) in erythrocytes, however, vitamin E pretreated rats administered OP's showed decreased LPO in erythrocytes. The increase in the activities of superoxide dismutase (SOD) and catalase (CAT) and total-SH content in erythrocytes from dimethoate and/or malathion treated rats as compared to control appears to be a response towards increased oxidative stress. Vitamin E pretreated animals administered OP's showed a lowering in these parameters as compared to OP treated rats which indicates that vitamin E provide protection against OP-induced oxidative stress. The glutathione-S-transferase (GST) activity in erythrocytes was inhibited in OP intoxicated rats which partially recovered in vitamin E pretreated animals administered OP's. Inhibition in erythrocyte and serum acetylcholinesterase (AChE) activity was not relieved in vitamin E pretreated rats administered OP's probably due to the competitive nature of enzyme inhibition by OP's. The results show that vitamin E may amelierate OP-induced oxidative stress by decreasing LPO and altering antioxidant defense system in erthrocytes.     

Protective effect of Montilla-Moriles appellation red wine on oxidative stress induced by streptozotocin in the rat

This study evaluated the protective effect of Montilla-Moriles appellation red wine (Cordoba, Spain) on oxidative stress, course and intensity of symptoms in experimental diabetes induced by the injection of streptozotocin in male Wistar rats. The rats were injected with a single dose of streptozotocin (60 mg/kg i.p.) and given water and red wine separately. After 4 weeks of treatment, blood samples were obtained to determine sugar and fructosamine concentrations in blood plasma, serum insulin concentration, and percentage of glycosylated hemoglobin in blood. The kidney, liver, and pancreas were removed to determine lipid peroxidation levels, reduced glutathione content, and antioxidative enzyme activity. A significant increase of glucose concentration in urine was found in the rats after injecting the streptozotocin. The administration of red wine before streptozotocin elevated reduced glutathione content and antioxidative enzyme activity, while lowering the lipid peroxidation level. Moreover, the red wine induced decreased levels of glycemia, plasma fructosamine and percentage of glycosylated hemoglobin, while increasing levels of insulin. These data suggest that red wine has a protective effect against oxidative stress and diabetes induced by streptozotocin.     

Protective effect of acetyl-L-carnitine against oxidative stress induced by antiretroviral drugs

Both HIV infection per se and antiretroviral drugs might contribute to oxidative stress and mitochondrial dysfunctions. In this study we assess zidovudine, stavudine and didanosine on U937 and CEM cell lines. All these drugs induced apoptosis and increased intracellular hydrogen peroxide but not superoxide anions. The addition of acetyl-l-carnitine (ALC) was able to prevent the pro-oxidant effect of the drugs tested. Supplementation with ALC, deficient in certain cohorts of HIV-infected individuals, especially on high active antiretroviral therapy regimen, has been associated with favourable effects. These data suggest that one of these effects could be a direct anti-oxidant action.     

甘草提取物对鼠肝线粒体氧化损伤的保护作用

用60%乙醇回流甘草,得粗提物(RG0),经AB-8大孔树脂纯化RG0得到甘草精提物(RG1),并对RG0和RG1主要活性成分的含量进行测定。为研究RG0和RG1对鼠肝线粒体氧化损伤的保护作用,用Vc-Fe2+诱导线粒体损伤,测定RG0和RG1对ATP酶的活性、线粒体肿胀度和蛋白质羰基含量的影响;用H2O2-Fe2+体系诱导线粒体脂质过氧化,测定RG0和RG1对丙三醛(MDA)含量的影响;用NBT法测定RG0和RG1抑制线粒体产生超氧阴离子的作用。结果显示:RG0和RG1可以显著地抑制线粒体的氧化损伤,并能防止线粒体肿胀和ATP酶活力下降,降低蛋白质羰基化水平,以及具有有效清除线粒体产生的超氧阴离子自由基的作用。因此,RG0和RG1对鼠肝线粒体的氧化损伤具有良好的保护作用,RG1的作用比RG0好。     

Protective effect of aminoguanidine against oxidative stress and bladder injury in cyclophosphamide‐induced hemorrhagic cystitis in rat

Cyclophosphamide (CP) is an antineoplastic agent that is used for the treatment of many neoplastic diseases. Hemorrhagic cystitis (HC) is a major dose limiting side effect of CP. Recent studies show that aminogaunidine, an inhibitor of inducible nitric oxide synthase is a potent antioxidant and prevents changes caused by oxidative stress such as depletion of antioxidant activity and tissue injury. The purpose of the study is to investigate the effect of aminoguanidine on parameters of oxidative stress, antioxidant enzymes and bladder injury caused by CP. Adult male rats were randomly divided into four groups. Control rats were administered saline; the AG control group received 200 mg/kg body wt of aminoguanidine; The CP group received a single injection of CP at the dose of 150 mg/kg body wt intraperitoneally. The CP + AG group received aminoguanidine (200 mg/kg body wt) intraperitoneally 1 h before the administration of CP. The rats were sacrificed 16 h after CP/saline administration. The bladder was used for light microscopic studies and biochemical studies. The markers of oxidative damage including protein carbonyl content, protein thiol, malondialdehyde and conjugated dienes were assayed in the homogenates along with the activities of the antioxidant enzymes, superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase and glutathione S transferase. In the bladders of CP treated rats edema of lamina propria with epithelial and sub‐epithelial hemorrhage was seen. All the parameters of oxidative stress that were studied were significantly elevated in the bladders of CP treated rats. The activities of the antioxidant enzymes were significantly lowered in the bladders of CP treated rats. Aminoguanidine pretreatment prevented CP‐induced oxidative stress, decrease in the activities of anti‐oxidant enzymes and reduced bladder damage. The results of the present study suggest the antioxidant role for aminoguanidine in CP‐induced bladder damage. Copyright © 2008 John Wiley & Sons, Ltd.     

Protective effect of Embelia ribes Burm on methionine-induced hyperhomocysteinemia and oxidative stress in rat brain

The present study was aimed to find out the protective effect of ethanolic extract of E. ribes fruits on homocysteine, lactate dehydrogenase (LDH) and lipid profile in serum, lipid peroxidation (LPO) and non-enzymatic antioxidant glutathione (GSH) levels in brain homogenates and histopathological examination of brain tissue in methionine (1 g/kg body weight, orally for 30 days) induced hyperhomocysteinemic rats. A significant increase in homocysteine, LDH, total cholesterol, triglycerides, low density lipoprotein (LDL-C) and very low density lipoprotein (VLDL-C) levels was observed in serum. Increased LPO levels in brain homogenates with reduced serum high density lipoprotein (HDL-C) levels and decreased GSH content were other salient features observed in methionine treated pathogenic control rats. Administration of ethanolic E. ribes extract (100 mg/kg body weight, orally) for 30 days to methionine-induced hyperhomocysteinemic rats produced a significant decrease in the levels of homocysteine, LDH, total cholesterol, triglycerides, LDL-C, VLDL-C in serum and LPO levels in brain homogenates with significant increase in serum HDL-C levels and GSH content in brain homogenates, when compared with pathogenic control rats. Biochemical observations were further substantiated with histological examination of brain. Degenerative changes of neuronal cells in methionine treated rats were minimized to near normal morphology by ethanolic E. ribes extract administration as evident by histopathological examination. The results provide clear evidence for the first time, that ethanolic E. ribes extract treatment enhances the antioxidant defense against methionine-induced hyperhomocysteinemia and oxidative stress in brain.     

Copper-mediated oxidative stress in rat liver

Copper is an essential trace element with various biological functions. Excess copper, however, is extremely toxic, leading to many pathological conditions that are consistent with oxidative damage to membranes and molecules. Exposure to high levels of copper results in various changes in the tissues. In liver, hypertrophy of hepatocytes, hepatitis, hepatocellular necrosis, and hepatocellular death are the results. Lipid peroxidation causes dysfunction in the cell membrane, decreased fluidity, inactivation of receptors and enzymes, and changes ion permeability. In this study, we aimed to determine the effect of copper on oxidative and antioxidative substances in plasma and liver tissue in a rat model. Sixteen male Sprague—Dawley rats were divided into two groups: Group 1 rats included control rats given tap water. Group 2 rats were given water containing copper in a dose of 100 μg/mL. All rats were sacrificed at 4 wk under ether anesthesia. Plasma and liver superoxide dismutase (SOD) activities, plasma and liver MDA (malondialdehyde) levels, and liver glutathione (GSH) levels were studied. Plasma and liver SOD activities were found to be higher in group 2 than those in group 1. Although plasma MDA levels were higher in group 2, MDA levels in liver tissues were comparable. Liver tissue glutathione levels were lower in group 2. It was concluded that although copper is needed in trace amounts, an excess amount is toxic for the organism. It increases lipid peroxidation and depletes GSH reserves, which makes the organism more vulnerable to other oxidative challenges.     

Melatonin reduces oxidative stress induced by ochratoxin A in rat liver and kidney

Melatonin (MEL) displays antioxidant and free radical scavenger properties. In the present study, the effect of MEL on the oxidative stress induced by ochratoxin A (OTA) administration in rats was investigated. Four groups of 15 rats each were used: controls, MEL-treated rats (5 mg/kg body mass), OTA-treated rats (250 μg/kg) and MEL+OTA-treated rats. After 4 weeks of treatment, the levels of malondialdehyde (MDA), a lipid peroxidation product (LPO) were measured in serum and homogenates of liver and kidney. Also, the levels of glutathione (GSH), and activities of glutathione reductase (GR), glutathione peroxidase (GSPx), superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) in liver and kidney were determined. In OTA-treated rats, the levels of LPO in serum and in both liver and kidney were significantly increased compared to levels in controls. Concomitantly, the levels of GSH and enzyme activities of SOD, CAT, GSPx and GR in both liver and kidney were significantly decreased in comparison with controls. In rats received MEL+OTA, the changes in the levels of LPO in serum and in liver and kidney were not statistically significant compared to controls. Concomitantly, the levels of GSPx, GR and GST activities in both liver and kidney tissues were significantly increased in comparison with controls. Similar increases in GSPx, GR and GST activities were also observed in MEL-treated rats when compared with controls. In conclusion, the oxidative stress may be a major mechanism for the toxicity of OTA. MEL has a protective effect against OTA toxicity through an inhibition of the oxidative damage and stimulation of GST activities. Thus, clinical application of melatonin as therapy should be considered in cases of ochratoxicosis.     

Melatonin protects against taurolithocholic‐induced oxidative stress in rat liver

Cholestasis, encountered in a variety of clinical disorders, is characterized by intracellular accumulation of toxic bile acids in the liver. Furthermore, oxidative stress plays an important role in the pathogenesis of bile acids. Taurolithocholic acid (TLC) was revealed in previous studies as the most pro‐oxidative bile acid. Melatonin, a well‐known antioxidant, is a safe and widely used therapeutic agent. Herein, we investigated the hepatoprotective role of melatonin on lipid and protein oxidation induced by TLC alone and in combination with FeCl₃ and ascorbic acid in rat liver homogenates and hepatic membranes. The lipid peroxidation products, malondialdehyde and 4‐hydroxyalkenals (MDA + 4‐HDA), and carbonyl levels were quantified as indices of oxidative damage to hepatic lipids and proteins, respectively. In the current study, the rise in MDA + 4‐HDA levels induced by TLC was inhibited by melatonin in a concentration‐dependent manner in both liver homogenates and in hepatic membranes. Melatonin also had protective effects against structural damage to proteins induced by TLC in membranes. These results suggest that the indoleamine melatonin may potentially act as a protective agent in the therapy of those diseases that involve bile acid toxicity. J. Cell. Biochem. 110: 1219–1225, 2010. Published 2010 Wiley‐Liss, Inc.     

Adaptations to oxidative stress induced by vitamin E deficiency in rat liver

Vitamin E deficiency in rats led to a sequence of antioxidant defense adaptations in the liver. After three weeks, α-tocopherol concentration was 5% of control, but ascorbate and ubiquinol concentrations were 2- to 3-fold greater than control. During the early phase of adaptation no differences in markers of lipid peroxidation were observed, but the activities of both cytochrome b5 reductase and glucose-6-phosphate dehydrogenase were significantly greater in deficient livers. By nine weeks, accumulation of lipid peroxidation end products began to occur along with declining concentrations of ascorbate, and higher NQO1 activities. At twelve weeks, rat growth ceased, and both lipid peroxidation products and cytosolic calcium-independent phospholipase A2 reached maximum concentrations. Thus, in growing rats the changes progressed from increases in both ubiquinol and quinone reductases through accumulation of lipid peroxidation products and loss of endogenous antioxidants to finally induction of lipid metabolizing enzymes and cessation of rat growth.     

束缚应激对D-氨基半乳糖联合脂多糖诱导小鼠肝损伤的保护作用

目的探讨束缚应激对D-氨基半乳糖联合脂多糖（D–galactosamine and lipopolysaccharide combination,D＋L）诱导的小鼠肝损伤的保护作用。方法正常BALB/c小鼠随机分为正常对照组（con）、应激对照组（str）、模型组（D＋L）、束缚应激组（D＋L＋str）。con组小鼠常规饲养;str组小鼠给予定时定量的束缚应激;D＋L组小鼠腹腔注射D-氨基半乳糖和脂多糖的混合溶液,1次/2天;D＋L＋str组小鼠腹腔注射等量D＋L混合液后,给予与str组相同的束缚应激。第8周,各组小鼠取血检测血清AST、ALT,肝脏固定后HE及Masson染色观察小鼠肝脏结构、细胞形态及纤维化程度。结果第8周D＋L＋str组与D＋L组小鼠相比,血清ALT和AST显著降低（P〈0.01）,AST/ALT显著增高（P〈0.01）;HE及Masson染色显示,D＋L组小鼠肝小叶结构紊乱,出现结节性增生及大量上皮细胞核浓缩、溶解、坏死,枯否氏细胞浸润,而D＋L＋str组未见明显病理变化;纤维化程度评分显示,D＋L＋str组与D＋L组小鼠相比,病理评分与纤维显色吸光度值均显著降低（P〈0.05）。结论束缚应激对D＋L诱导的小鼠肝损伤具有一定保护作用。     

Protective effect of hesperidin on nicotine induced toxicity in rats

Nicotine administration (2.5 mg/kg of body weight, sc, 5 days a week for 22 weeks) enhanced lipid peroxidative indices (thiobarbituric acid reactive substances and hydroperoxides) accompanied by a significant increase in the marker enzymes alanine transaminase, aspartate transaminase, alkaline phosphatase and lactate dehydrogenase and elevated levels of cholesterol, triglycerides, phospholipids and free fatty acids in Wistar rats. There was a significant protection by hesperidin administration at different doses (25, 50, 75, 100 and 150 mg/kg body weight) in nicotine-treated rats. However, the effect of hesperidin was more significant at 25mg/kg dose. The results suggest that hesperidin exerts the protective effects by modulating the extent of lipid peroxidation. The results are supported by histopathological observations of lung, liver and kidney.     

Protective effect of daidzein against streptozotocin‐induced Alzheimer's disease via improving cognitive dysfunction and oxidative stress in rat model

Oxidative stress is performing an essential role in developing Alzheimer's disease (AD), and age‐related disorder and other neurodegenerative diseases. In existing research, we have aimed at investigating the daidzein (4′,7‐dihydroxyisoflavone) effect (10 and 20 mg/kg of body weight), as a free radical scavenger and antioxidant in streptozotocin (STZ) infused AD in rat model. Daidzein treatment led to significant improvement in intracerebroventricular‐streptozotocin (ICV‐STZ)‐induced memory and learning impairments that was evaluated by Morris water maze test and spontaneous locomotor activity. It significantly restored the alterations in malondialdehyde, catalase, superoxide dismutase, and reduced glutathione levels. In addition, histopathological observations in cerebral cortex and hippocampal areas confirmed the neuroprotective effect of daidzein. These outcomes provide experimental proof showing preventive effect of daidzein on memory, learning dysfunction and oxidative stress in case of ICV‐STZ rats. In conclusion, daidzein offers a potential treatment module for various neurodegenerative disorders with regard to mental deficits like AD.     

Protective effect of the octadecaneuropeptide on hydrogen peroxide-induced oxidative stress and cell death in cultured rat astrocytes

Oxidative stress, resulting from accumulation of reactive oxygen species (ROS), plays a critical role on astrocyte death associated with neurodegenerative diseases. Astroglial cells produce endozepines, a family of biologically active peptides that have been implicated in cell protection. Thus, the purpose of the present study was to investigate the potential protective effect of one of the endozepines, the octadecaneuropeptide ODN, on hydrogen peroxide (H(2) O(2) )-induced oxidative stress and cell death in rat astrocytes. Incubation of cultured astrocytes with graded concentrations of H(2) O(2) for 1 h provoked a dose-dependent reduction of the number of living cells as evaluated by lactate dehydrogenase assay. The cytotoxic effect of H(2) O(2) was associated with morphological modifications that were characteristic of apoptotic cell death. H(2) O(2) -treated cells exhibited high level of ROS associated with a reduction of both superoxide dismutases (SOD) and catalase activities. Pre-treatment of astrocytes with low concentrations of ODN dose-dependently prevented cell death induced by H(2) O(2) . This effect was accompanied by a marked attenuation of ROS accumulation, reduction of mitochondrial membrane potential and activation of caspase 3 activity. ODN stimulated SOD and catalase activities in a concentration-dependent manner, and blocked H(2) O(2) -evoked inhibition of SOD and catalase activities. Blockers of SOD and catalase suppressed the effect of ODN on cell survival. Taken together, these data demonstrate for the first time that ODN is a potent protective agent that prevents oxidative stress-induced apoptotic cell death.     

Protective effect of Piper longum L. on oxidative stress induced injury and cellular abnormality in adriamycin induced cardiotoxicity in rats

Effect of methanolic extract of fruits of P. longum (PLM) on the biochemical changes, tissue peroxidative damage and abnormal antioxidant levels in adriamycin (ADR) induced cardiotoxicity in Wistar rats was investigated. PLM was administered to Wistar albino rats in two different doses, by gastric gavage (250 mg/kg and 500 mg/kg) for 21 days followed by ip ADR (15 mg/kg) on 21st day. ADR administration showed significant decrease in the activities of marker enzymes aspartate transaminase, alanine transaminase, lactate dehydrogenase and creatine kinase in heart with a concomitant increase in their activities in serum. A significant increase in lipid peroxide levels in heart of ADR treated rats was also observed. Pretreatment with PLM ameliorated the effect of ADR on lipid peroxide formation and restored activities of marker enzymes. Activities of myocardial antioxidant enzymes like catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase along with reduced glutathione were significantly lowered due to cardiotoxicity in rats administered with ADR. PLM pretreatment augmented these endogenous antioxidants. Histopathological studies of heart revealed degenerative changes and cellular infiltrations in rats administered with ADR and pretreatment with PLM reduced the intensity of such lesions. The results indicate that PLM administration offers significant protection against ADR induced oxidative stress and reduces the cardiotoxicity by virtue of its antioxidant activity.