Alteration of DMBA-induced oxidative stress by additive action of a modified indigenous preparation--Kalpaamruthaa

The present study investigated the protective efficacy of the novel preparation named as Kalpaamruthaa (KA, includes Semecarpus anacardium Linn nut milk extract (SA), dried powder of Phyllanthus emblica fruit and honey) on the peroxidative damage and abnormal antioxidant levels in the hepatic mitochondrial fraction of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma rats. Female Sprague-Dawley rats of weight 180+/-10 g were categorized into six groups. Three groups were administered DMBA (25 mg/rat dissolved in olive oil, orally) to induce mammary carcinoma. One of these groups received KA treatment (300 mg/kg b.wt., orally) and other group received SA (200 mg/kg b.wt., orally) for 14 days after 90 days of DMBA induction. Vehicle-treated control and drug control groups were also included. The hepatic mitochondrial fraction of untreated DMBA rats showed 2.96-fold increase in MDA content when compared to control rats and abnormal changes in the activities/levels of mitochondrial enzymic (superoxide dismutase, glutathione peroxidase and glutathione reductase) and non-enzymic (glutathione, vitamin C and vitamin E) antioxidants were observed. DMBA-treated rats also showed decline in the activities of mitochondrial enzymes such as succinate dehydrogenase, alpha-ketoglutarate dehydrogenase, malate dehydrogenase and isocitrate dehydrogenase. In contrast, rats treated with SA and KA showed normal lipid peroxidation antioxidant defenses and mitochondrial enzymes, thereby showing the protection rendered by SA and KA. Although, KA treatment exhibited more profound effect in inhibiting DMBA-induced oxidative stress than sole SA treatment. Results of the study indicate that the anticarcinogenic activity of KA during DMBA-initiated mammary carcinogenesis is mediated through alteration of hepatic antioxidant status as well as modulation of TCA cycle enzymes. On the basis of the observed results, KA can be considered as a readily accessible, promising and novel cancer chemopreventive agent.     

Efficacy of caffeic acid in preventing nickel induced oxidative damage in liver of rats

Nickel (Ni), a major environmental pollutant, is known for its wide toxic manifestations. In the present study caffeic acid (CA), one of the most commonly occurring phenolic acids in fruits, grains and dietary supplements, was evaluated for its protective effect against the Ni induced oxidative damage in liver. In this investigation, Ni (20 mg/kg body weight) was administered intraperitoneally for 20 days to induce toxicity. CA was administered orally (15, 30 and 60 mg/kg body weight) for 20 days with intraperitoneal administration of Ni. Ni induced liver damage was clearly shown by the increased activities of serum hepatic enzymes namely aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT) and lactate dehydrogenase (LDH) along with increased elevation of lipid peroxidation indices (thiobarbituric reactive acid substances (TBARS) and lipid hydroperoxides). The toxic effect of Ni was also indicated by significantly decreased levels of enzymatic (superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx) and glutathione S-transferase (GST)) and non-enzymatic antioxidants (glutathione (GSH), vitamin C and vitamin E). CA administered at a dose of 60 mg/kg body weight significantly reversed the activities of hepatic marker enzymes to their near normal levels when compared with other two doses. In addition, CA significantly reduced lipid peroxidation and restored the levels of antioxidant defense in the liver. All these changes were supported by histological observations. The results indicate that CA may be beneficial in ameliorating the Ni induced oxidative damage in the liver of rats.     

Non-invasive in vivo magnetic resonance imaging assessment of acute aflatoxin B1 hepatotoxicity in rats

Acute aflatoxin B1 (AFB1)-induced hepatotoxicity was assessed in vivo in male Sprague-Dawley rats (150-300 g) using magnetic resonance imaging (MRI). MRI results were compared to serum enzyme levels, histology and electron microscopy. Twenty-four hours following intraperitoneal delivery of AFB1 (3 mg/kg body weight in a saline/dimethyl sulfoxide (DMSO; 0.03 ml/kg body weight) solution), regions of damage, characterised by increased proton signal intensities in T2-weighted images, were observed in the vicinity of the hepatic portal vein (HPV) and in the right medial regions of the liver. Image analysis of regions of apparent damage around the HPV and right medial regions, following 24 h of AFB1 exposure, indicated statistically significant (P<0.05) increases in proton image signal intensities, when compared to saline/DMSO-treated rats. No significant difference in proton image signal intensities were observed 1-2 h following AFB1 exposure. Twenty-four hours following AFB1 exposure, histopathological assessment was characterised by portal/central vein/artery congestion, sinusoid congestion, nuclear pyknosis and karyolysis, and hepatocyte vacuolation; electron microscopy (EM) examination indicated nuclear debris, swollen cytoplasmic compartments, vacuolation, and the disappearance of the smooth endoplasmic reticulum, and elevated levels of serum aspartate aminotransferase and alanine aminotransferase were found to be significantly different (P<0.01) than controls.     

2-(Allylthio)pyrazine inhibition of aflatoxin B1-induced hepatocarcinogenesis in rats.

2-(Allylthio)pyrazine (2-AP), a synthetic pyrazine derivative with an allylsulfur moiety, has hepatoprotective effects against toxicants. Effect of 2-AP on hepatic tumorigenesis in association with glutathione S-transferase (GST) induction was examined in rats exposed to aflatoxin B1 (AFB1). Both AFB1-DNA adduct formation in the liver and urinary elimination of 8,9-dihydro-8-(N7-guanyl)-9-hydroxy-aflatoxin B1 (AFB1-N7-guanine) adduct were also determined. Male Sprague Dawley rats were treated with 2-AP at the daily oral doses of 10, 25 and 50 mg/kg for 16 consecutive days, during which four repeated doses of AFB1 (1.0 mg/kg) were given to the animals. Rats were then subjected to two-thirds of hepatectomy, followed by administration of phenobarbital (PB). Focal areas of hepatocellular alteration were identified after 44 days and preneoplastic foci expressing the placental form of glutathione S-transferase P (GST-P) were quantified by immunostaining of liver sections. 2-AP reduced the volume of liver occupied by GST-P foci by 65-96%. Under these experimental conditions, 2-AP treatment resulted in significant elevations in GST activity in the liver. Levels of radiolabeled AFB1 covalently bound to hepatic DNA, RNA and proteins were significantly reduced in rats treated with 2-AP for 5 days. 2-AP pretreatment also caused a 45% reduction in the urinary elimination of AFB1-N7-guanine adduct over the 24-h postdosing period. The present findings demonstrated that 2-AP exhibited protective effects against AFB1-induced hepatocarcinogenesis in rats with a marked decrease in the level of AFB1-DNA adduct. Reduction of hepatic DNA adducts might result from elevations of activity of GST, which catalyzes detoxification of the carcinogen.     

The interaction of aflatoxin B1 with vitamin K, phenylbutazone, and sulfamethoxine in rats

The interactions of aflatoxin B1 (AFB1) with vitamin K, phenylbutazone, and sulfamethoxine were investigated in albino rats. Vitamin K (5 mg/kg) was able to completely suppress the increase in whole blood clotting time caused by AFB1 (25 micrograms/kg). Phenylbutazone (50 mg/kg) and sulfamethoxine (50 mg/kg) also significantly (P less than 0.05) lowered the increased clotting time caused by AFB1. Equilibrium dialysis was performed on rat plasma (4 mg/ml protein content) to investigate the displacement of AFB1 (3 micrograms) from its bound form by vitamin K (250 micrograms), phenylbutazone (2500 micrograms), and sulfamethoxine (2500 micrograms). Phenylbutazone and sulfamethoxine significantly (P less than 0.05) displaced AFB1 from rat plasma protein. Histopathological examinations performed on the liver, kidneys, and spleen of control and treated rats showed that none of the drugs used appeared to offer any significant organ protection against AFB1 except in the spleen.     

Antioxidant DL-alpha lipoic acid as an attenuator of adriamycin induced hepatotoxicity in rat model

Protective efficacy of DL-alpha lipoic acid on adriamycin induced hepatotoxicity was evaluated in rats. Adriamycin toxicity, induced by a single injection (ip; 15 mg/kg body wt), was expressed by an elevation in alanine transaminase, aspartate transaminase, bilirubin levels in serum and alkaline phosphatase, lactate dehydrogenase, alanine transaminase, aspartate transaminase activity in hepatic tissue. Adriamycin produced significant increase in malondialdehyde levels indicating tissue lipid peroxidation and potentially inhibiting the activity of antioxidant, reduced glutathione and antioxidant enzymes, catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, glucose-6-phosphate dehydrogenase. The present results showed that pretreatment with lipoic acid [75 mg/kg body wt/day (ip), 24 h prior to administration of adriamycin] significantly restored various cellular activity suggesting the antioxidant potential of lipoic acid in ameliorating the hepatotoxicity induced by adriamycin.     

alpha-Tocopherol protects against alpha-naphthylisothiocyanate-induced hepatotoxicity in rats less effectively than melatonin

The protective effect of alpha-tocopherol (alpha-Toc), which exerts antioxidant and anti-inflammatory actions, against alpha-naphthylisothiocyanate (ANIT)-induced hepatotoxicity in rats was compared with that of melatonin because orally administered melatonin is known to protect against ANIT-induced hepatotoxicity in rats through its antioxidant and anti-inflammatory actions. Rats intoxicated once with ANIT (75 mg/kg, intraperitoneal (i.p.)) showed liver cell damage and biliary cell damage with cholestasis at 24 h, but not 12 h, after intoxication. ANIT-intoxicated rats received alpha-Toc (100 or 250 mg/kg) or melatonin (100 mg/kg) orally at 12 h after intoxication. The alpha-Toc administration protected against liver cell damage in ANIT-intoxicated rats, while the melatonin administration protected against both liver cell damage and biliary cell damage with cholestasis. ANIT-intoxicated rats had increased hepatic lipid peroxide concentration and myeloperoxidase activity at 12 and 24 h after intoxication. ANIT-intoxicated rats also had increased serum alpha-Toc and non-esterified fatty acid (NEFA) concentrations at 12 and 24 h after intoxication and increased serum triglyceride and total cholesterol concentrations at 24h. The administration of alpha-Toc to ANIT-intoxicated rats increased the hepatic alpha-Toc concentration with further increase in the serum alpha-Toc concentration and attenuated the increased hepatic lipid peroxide concentration and myeloperoxidase activity and serum NEFA concentration at 24 h after intoxication. The melatonin administration did not affect the hepatic alpha-Toc concentration but attenuated the increased hepatic lipid peroxide concentration and myeloperoxidase activity and serum alpha-Toc, NEFA, triglyceride, and total cholesterol concentrations at 24 h after ANIT intoxication. These results indicate that orally administered alpha-Toc protects against ANIT-induced hepatotoxicity in rats possibly through its antioxidant and anti-inflammatory actions less effectively than orally administered melatonin.     

Protective effect of aqueous garlic extract against lead-induced hepatic injury in rats

Effect of aqueous extract of garlic on hepatic injury due to lead-induced oxidative stress in experimental rats has been investigated. Lead acetate (LA) at a dose of 15 mg/kg body wt was administered ip to rats for 7 consecutive days to induce hepatic injury. Freshly prepared aqueous garlic extract (AGE) at a dose of 50 mg/kg body wt was fed orally to rats 1 h before LA treatment for similar period. LA treatment caused hepatic injury as evident from increased activities of serum glutamate pyruvate transaminase (SGPT) and alkaline phosphatase (ALP), increased serum bilirubin level and damage in the tissue morphology. Lead-induced oxidative stress in liver was evident from increased levels of lipid peroxidation and reduced glutathione. The decreased activity of superoxide dismutase (SOD) and an increased activity of catalase as well as an increased activity of xanthine oxidase (XO) indicate generation and possible accumulation of reactive oxygen intermediates. Furthermore, altered activities of lactate dehydrogenase (LDH), isocitrate dehydrogenase (ICDH), alpha-keto glutarate dehydrogenase (alpha-KGDH) and succinate dehydrogenase (SDH) also indicate an impaired substrate utilization and generation of oxidative stress. All these changes were found to be mitigated when the rats were pre-treated with the AGE. Results indicate that AGE has the potential to ameliorate lead-induced hepatic injury due to oxidative stress in rats. The protective effects may be due to the antioxidant properties of AGE and may have future therapeutic relevance.     

Mitigating role of lupeol and lupeol linoleate on hepatic lipemic-oxidative injury and lipoprotein peroxidation in experimental hypercholesterolemia

In the present study, the role of pentacyclic triterpenes, lupeol and its ester lupeol linoleate, was studied in relation to hepatic oxidative abnormalities and lipoprotein peroxidation in hypercholesterolemic rats. Hypercholesterolemia was induced in male Wistar rats by feeding them with high cholesterol diet (4% cholesterol + 1% cholic acid; HCD) for 30 days. Pentacyclic triterpenes, lupeol and lupeol linoleate were supplemented (50 mg/kg body wt/day) during the last 15 days. After the experimental period, there was a significant depression in hepatic activities of antioxidant enzymes, SOD (38.39%), CAT (25.03%) and GPx (30.26%) along with a marked fall in the levels of non-enzymic antioxidant molecules GSH (31.39%), vitamin C (46.07%) and vitamin E (42.28%), with a concomitant increase (p<0.001) in lipid peroxidation and in the activities of serum alkaline phosphatase, lactate dehydrogenase and aminotransferases when compared to controls. Treatment with triterpenes decreased lipid peroxidation and reverted the activities of antioxidants (p<0.001 and p<0.01) and marker enzymes to near control. Histopathological findings further confirmed the hepatoprotective nature of triterpenes by showing the normal architecture in treated rats, as against the fatty cellular changes in HCD fed rats. Further, the susceptibility of apo-B containing lipoprotein to oxidation by copper and Fenton’s reagent was increased in in vitro condition in HCD fed rats, whereas the lipoproteins were less susceptible to oxidation in triterpenes treated animals. Therefore, it may be concluded that lupeol and its ester afford protection against the hepatic abnormalities and lipoprotein peroxidation in hypercholesterolemic rats.     

Protective Effect of Selenium on Aflatoxin B1-Induced Testicular Toxicity in Mice

Aflatoxins have been considered as one of the major risk factors of male infertility, and aflatoxin B1 (AFB1) is the most highly toxic and prevalent member of the aflatoxins family. Selenium (Se), an essential nutritional trace mineral for normal testicular development and male fertility, has received extensive intensive on protective effects of male reproductive system due to its potential antioxidant and activating testosterone synthesis. To investigate the protective effect of Se on AFB1-induced testicular toxicity, the mice were orally administered with AFB1 (0.75 mg/kg) and Se (0.2 mg/kg or 0.4 mg/kg) for 45 days. We found that that Se elevated testes index, sperm functional parameters (concentration, malformation, and motility), and the level of serum testosterone in AFB1-exposed mice. Moreover, our results showed that Se attenuated the AFB1-induced oxidative stress and the reduction of testicular testosterone synthesis enzyme protein expression such as steroidogenic acute regulatory protein (StAR), P450 side-chain cleavage (P450scc), and 17β-hydroxysteroid dehydrogenase (17β-HSD) in AFB1-exposed mice. These results demonstrated that Se conferred protection against AFB1-induced testicular toxicity and can be attributed to its antioxidant and increased testosterone level by stimulating protein expression of StAR and testosterone synthetic enzymes.     

Potential hepatoprotective activity of ononitol monohydrate isolated from Cassia tora L. on carbon tetrachloride induced hepatotoxicity in wistar rats

Ononitol monohydrate, structurally similar to glycoside was isolated from Cassia tora L. leaves. Fifty Male rats were divided into five groups. Group I served as normal control. Group II, III and IV rats were induced hepatotoxicity by CCl₄ administering single dose of CCl₄ on 8th day only. Group III was treated with ononitol monohydrate (20 mg/kg body weight) and group IV was treated with reference drug silymarin (20 mg/kg body weight) both dissolved in corn oil and administering for 8 days. Ononitol monohydrate with corn oil alone was given for 8 days (group V). At the end of the experimental period all the animals were sacrificed and analyzed for biochemical parameters to assess the effect of ononitol monohydrate treatment in CCl₄ induced hepatotoxicity. In in vivo study, ononitol monohydrate decreased the levels of serum transaminase, lipid peroxidation and TNF-α but increased the levels of antioxidant and hepatic glutathione enzyme activities. Compared with reference drug silymarin ononitol monohydrate possessesed high hepatoprotective activity. Histopathological results also suggested the hepatoprotective activity of ononitol monohydrate with no adverse effect. Hence we conclude that ononitol monohydrate is a potent hepatoprotective agent.     

Alleviation of lindane induced toxicity in testis of Swiss mice (Mus musculus) by combined treatment with vitamin C, vitamin E and alpha-lipoic acid

Mitigation of lindane induced toxicity in testis of Swiss mice by combined treatment with vitamin C, vitamin E and alpha-lipoic acid has been evaluated. Male healthy mice (40), 8-10 weeks old were randomly selected and divided into 4 groups, control (C); lindane (L); antioxidant (A) and antioxidant plus lindane (A+L). Group C animals were administered only the vehicle (olive oil); in group L lindane was administered orally at a dose of 40 mg/kg body wt.; in group A combination of antioxidants at a dose of 125 mg/kg body wt.(vitamin C: 50 mg/kg body wt., vitamin E: 50 mg/kg body wt. and alpha-lipoic acid: 25 mg/kg body wt.) was administered orally; in group A+L both antioxidants (125 mg/kg body wt.) and lindane (40 mg/kg body wt.) were administered at their respective doses. In group A+L antioxidants were administered 1 h prior to lindane administration. All treatments were continuously given for 60 days. Histopathological changes due to lindane intoxication indicated shrunken and distorted seminiferous tubules, sparse Leydig cells and blood vessels and atrophy in the tissue. The testis weight also decreased significantly. Lindane treated group showed increased lipid peroxidation, whereas glutathione, glutathione peroxidase, superoxide dismutase, catalase and protein were significantly decreased compared to control. Lindane induced damage was minimized by administration of antioxidants. Results suggest that combined pretreatment with antioxidants can alleviate the damage caused to testis by lindane.     

Silymarin modulates Cisplatin-induced oxidative stress and hepatotoxicity in rats

Cisplatin (CDDP) is a widely used anticancer drug, but at high dose, it can produce undesirable side effects such as hepatotoxicity. Because silymrin has been used to treat liver disorders, the protective effect of silymarin on CDDP-induced hepatotoxicity was evaluated in rats. Hepatotoxicity was determined by changes in serum alanine aminotransferase [ALT] and aspartate aminotransferase [AST], nitric oxide [NO] levels, albumin and calcium levels, and superoxide dismutase [SOD], glutathione peroxidase [GSHPx] activities, glutathione content, malondialdehyde [MDA] and nitric oxide [NO] levels in liver tissue of rats. Male albino rats were divided into four groups, 10 rats in each. In the control group, rats were injected i.p. with 0.2 ml of propylene glycol in saline 75/25 (v/v) for 5 consecutive days [Silymarin was dissolved in 0.2 ml of propylene glycol in saline 75/25 v/v]. The second group were injected with CDDP (7.5 mg /kg, I.P.), whereas animals in the third group were i.p. injected with silymarin at a dose of 100 mg/kg/day for 5 consecutive days. The Fourth group received a daily i.p. injection of silymarin (100 mg/kg/day for 5 days) 1 hr before a single i.p. injection of CDDP (7.5 mg/kg). CDDP hepatotoxicity was manifested biochemically by an increase in serum ALT and AST, elevation of MDA and NO in liver tissues as well as a decrease in GSH and the activities of antioxidant enzymes, including SOD, GSHPx in liver tissues. In addition, marked decrease in serum NO, albumin and calcium levels were observed. Serum ALT, AST, liver NO level, MDA was found to decreased in the combination group in comparison with the CDDP group. The activities of SOD, GSHPx, GSH and serum NO were lower in CDDP group than both the control and CDDP pretreated with silymarin groups. The results obtained suggested that silymarin significantly attenuated the hepatotoxicity as an indirect target of CDDP in an animal model of CDDP-induced nephrotoxicity.     

Immunohistochemical demonstration of decreased L-pyruvate kinase in enzyme altered rat liver lesions produced by different carcinogens

Preneoplastic liver lesions were produced in female Wistar rats by application of 25 mg/kg N-nitrosomorpholine (NNM), 14 mg/kg diethylnitrosamine (DENA), 0.075 mg/kg aflatoxin B1 (AFB1) or 160 mg/kg safrole. These carcinogens were administered in two equal doses 12 and 24 h after partial hepatectomy. The animals then received sodium phenobarbital (0.1% in tap water) for up to 410 days. Numerous altered hepatic foci (AHF) and hyperplastic nodules (HN) were detected enzyme histochemically by their negative ATPase reaction after application of AFB1, DENA and NNM; some AHF and HN were also caused by the weak carcinogen safrole. Immunohistochemically these lesions were also L-pyruvate kinase (L-PK)-negative with a high coincidence with regard to their number and area. These results confirm the role of L-PK, an enzyme affecting the pentose phosphate pathway, as a negative marker of preneoplastic liver lesions.     

Hepatotoxic effects of acetaminophen. Protective properties of tryptophan derivatives

Rat intoxication with acetaminophen (APAP) (500–1500 mg/kg body weight, intragastrically) caused a considerable dose-dependent decrease in reduced glutathione (GSH) level in both liver cell cytoplasm and mitochondria (at the dose 1500 mg/kg body weight by 60% and 33%, respectively). The decrease in cytoplasmic GSH level was more pronounced than in mitochondria. Despite of significant mitochondrial GSH depletion we did not observe any inactivation of the mitochondrial enzymes: succinate dehydrogenase, α-ketoglutarate dehydrogenase, glutathione peroxidase, and also any decrease in the respiratory activity of liver mitochondria isolated from APAP-intoxicated rats. We have investigated hepatoprotector properties of tryptophan derivatives, melatonin and N-acetyl-nitrosotryptophan (a nitric oxide donor). The pineal gland hormone, melatonin, a known antioxidant (10 mg/kg body weight), did not prevent intramitochondrial GSH, but decreased the APAP hepatotoxicity evaluated as the decrease in the activity of marker enzymes of hepatic damage, ALT and AST and total bilirubin content in blood plasma of intoxicated rats, whereas NNT did not exhibit any hepatoprotective effects.     

Activity of Cassia auriculata leaf extract in rats with alcoholic liver injury

This study was undertaken to investigate the effect of Cassia auriculata leaf extract on tissue lipid peroxidation and antioxidant status in experimental hepatotoxicity. Administering ethanol to rats for 60 days resulted in significantly elevated levels of serum total bilirubin, aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) as compared with those of the experimental control rats. Significantly elevated levels of tissue thiobarbituric acid reactive substances (TBARS), hydroperoxides and lowered activities of superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) were also observed on alcohol treatment as compared with those of experimental control rats. Concentration of serum non-enzymic antioxidants such as vitamin E and vitamin C were also significantly lowered on alcohol supplementation. Treatment with Cassia auriculata leaf extract at a dose of 250 mg kg(-1) body weight and 500 mg kg(-1) body weight to rats administered alcohol, lowered the levels of TBARS and hydroperoxides and elevated the activities of SOD and CAT and the levels of reduced GSH in the liver, brain, kidney and intestine significantly compared to unsupplemented alcohol treated rats. Cassia auriculata leaf extract treatment restored the serum vitamin E, and vitamin C levels also to near those of the experimental control animals. Our data indicate that supplementation with Cassia auriculata leaf extract can offer protection against free radical mediated oxidative stress in experimental hepatotoxicity. In addition, histopathological studies of the liver and brain confirmed the beneficial role of Cassia auriculata leaf extract.     

Restorative Effect of Kalpaamruthaa, an Indigenous Preparation, on Oxidative Damage in Mammary Gland Mitochondrial Fraction in Experimental Mammary Carcinoma

Cancer prevention and treatment using phytochemicals have attracted increased interest. Recent studies have shown that Semecarpus anacardium Linn nut milk extract (SA), a promising antioxidant and anticancer drug, exerts its anticancer effect through reducing or quenching reactive oxygen species under different conditions. The present study examined whether Phyllanthus emblica Linn fruit, rich in vitamin C content synergistically in combination can enhance both the antioxidant and anticancer activity of S. anacardium nut milk extract in 7, 12-dimethyl benz[a]anthracene (DMBA)-induced experimental mammary carcinoma in rat model. Female Sprague Dawley rats of 180 ± 10g were categorized into six groups. Three groups were administered DMBA (25mg/rat, orally) dissolved in olive oil to induce mammary carcinoma. One of these groups received Kalpaamruthaa (KA) (300mg/kg b.wt, orally) and other group received SA (200mg/kg b.wt, orally) for 14 days after 90 days of DMBA induction. A vehicle treated control and drug control groups were also included. The mitochondrial fraction of untreated DMBA-induced mammary gland showed 2.61-fold increase in lipid peroxidation level and abnormal changes in the activities/levels of mitochondrial enzymic (superoxide dismutase, glutathione peroxidase and glutathione reductase) and non-enzymic (glutathione, vitamin C and vitamin E) antioxidants were observed. DMBA treated rats also showed decline in the activities of mitochondrial enzymes such as succinate dehydrogenase, malate dehydrogenase, α-ketoglutarate dehydrogenase and isocitrate dehydrogenase. In contrast, rats treated with Kalpaamruthaa showed normal lipid peroxide level and antioxidant defenses. The results of the present study highlight the improved antioxidant property of KA than sole treatment of S. anacardium nut milk extract.     

Effect of vitamin E on monosodium glutamate induced hepatotoxicity and oxidative stress in rats

Monosodium glutamate (MSG), administered to rats (by gavage) at a dose of 0.6 mg/g body weight for 10 days, significantly (P<0.05) induced lipid peroxidation (LPO), decreased reduced glutathione (GSH) level and increased the activities of glutathione-s-transferase (GST), catalase and superoxide dismutase (SOD) in the liver of the animals; these were observed 24 hr after 10 days of administration. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma glutamyl transferase (GGT) were also significantly increased in the serum, on MSG administration. Vitamin E (0.2 mg/g body wt) co-administered with MSG, significantly reduced the LPO, increased the GSH level and decreased the hepatic activities of GST, catalase and SOD. The activities of ALT, AST and GGT in the serum were also significantly reduced. The results showed that MSG at a dose of 0.6 mg/g body wt induced the oxidative stress and hepatotoxicity in rats and vitamin E ameliorated MSG-induced oxidative stress and hepatotoxicity.     

Enhancement of biliary excretion of aflatoxin B(1) and suppression of hepatic ornithine decarboxylase activity by 2-(allylthio)pyrazine in rats.

2-(Allylthio)pyrazine (2-AP), a synthetic pyrazine derivative with an allylsulfur moiety, has protective effects against chemically-induced hepatic toxicity. Previous studies have shown that 2-AP significantly reduces the formation of preneoplastic foci in rats exposed to aflatoxin B(1) (AFB(1)). The present study was designed to determine whether 2-AP could increase the biliary excretion of metabolites of AFB(1) in rats treated with this carcinogen and whether the agent could alter the activity of ornithine decarboxylase (ODC), which is considered to be associated with tumor promotion. Rats were pretreated with 2-AP (p.o.) at a daily dose of 50 mg/kg for 5 consecutive days. AFB(1) (5 mg/kg) was administered intraperitoneally 2 h after the last dose of 2-AP. Amounts of principal AFB(1) metabolites, AFB(1)-glutathione and a glucuronide conjugate secreted in bile juice was increased by 56 and 50%, respectively, after the 2-AP treatment. Levels of radiolabelled AFB(1) covalently bound to calf thymus DNA catalyzed by microsomes obtained from 2-AP-treated rats (10 and 50 mg/kg, for 5 days) were reduced by 47 to 66%. ODC activity in AFB(1)-treated rats was determined by the three-step medium-term hepatocarcinogenesis assay. Rats were treated with 2-AP at the daily doses of 10, 25 and 50 mg/kg for 16 consecutive days. During this period, four repeated doses of AFB(1) (1.0 mg/kg) were given to the animals. Rats were then subjected to two-third partial hepatectomy, followed by administration of phenobarbital. 2-AP inhibited AFB(1)-induced ODC activity by 40 to 66%, as determined at the 44th day. Inhibition of AFB(1)-induced ODC activity by 2-AP in conjunction with acceleration of AFB(1) elimination through metabolic conjugation may contribute to its chemopreventive effects against this carcinogen.