Ellagic acid ameliorates nickel induced biochemical alterations: diminution of oxidative stress

Low Dose of Nickel and Benzo [a] Anthracene in Rat-Diet, Induce Apoptosis, Fibrosis, and Initiate Carcinogenesis in Liver via NF-Ƙβ Pathway

Environmental contaminants such as polycyclic aromatic hydrocarbon (PAH) and heavy metals are major contaminants of food such as fish thus serving as source of exposure to human. This study was designed to evaluate the carcinogenic risk and other risks associated with long-term consumption of environmentally relevant dose of nickel and benzo [a] anthracene in rats. Thirty-six (36) male rats weighing between 80 and 100 g were assigned into 6 groups of 6 animals each; normal, nickel-, and benzo [a] anthracene-exposed groups for 12 and 24 weeks, respectively. Micronucleus and comet analyses were done in the blood, liver, and bone marrow. Liver function, redox, and inflammatory markers (AST, ALT, GGT, SOD, GSH, MDA, protein carbonyl, protein thiol, total protein, IL-10, 1L-1β, TNF-α, TGF-β NF-Ƙβ, and 8-oxodeoxyguansine) were analysed by standard methods. Immuno-histochemical quantification of Bax, Bcl2, and Erk 1/2 as well as mRNA expression of cyclin D1 was done in liver. From the results, weight gain was observed in varying degrees throughout the exposure period. The polychromatic erythrocytes/normochromatic erythrocytes ratio > 0.2 indicates no cytotoxic effects on the bone marrow. Percentage-MnPCE in blood significantly (p < 0.05) increased throughout exposure duration. Percentage tail DNA in blood was significantly (< 0.05) increased at weeks 20 and 24 in the exposed groups and in liver at weeks 12 (16.22 ± 0.47) and 24 (17.00 ± 0.36) of nickel-exposed rats. The aspartate amino transferase (AST):alanine amino transferase (ALT) ratio indicated fatty liver disease in the benzo [a] anthracene (0.90) and acute liver injury in the nickel (> 10 times greater than the upper limits of the reference group) exposed groups during the first 12 weeks. Observation from the histological and cytological data of the liver revealed the presence of inflammation, fibrosis, and high nuclear/cytoplasmic ratio, respectively, in the nickel and benzo [a] anthracene groups. Only benzo [a] anthracene induced liver oxidative stress with significant (p < 0.05) decrease in SOD (0.64 ± 0.02) activity and increase in protein carbonyl (7.60 ± 0.80 × 10-5) and MDA (57.10 ± 6.64) concentration after 24 weeks. Benzo [a] anthracene up-regulated the cyclin D1 expression and significantly (p < 0.05) increased the levels of the cytokines. Nickel and benzo [a] anthracene significantly (p < 0.05) increased the Bax (183.45 ± 6.50 and 199.76 ± 10.04) and Erk 1/2 (108.25 ± 6.41 and 136.74 ± 4.22) levels when compared with the control (37.43 ± 22.22 and 60.37 ± 17.86), respectively. Overall result showed that the toxic effects of nickel and benzo [a] anthracene might involve fibrosis, cirrhosis, apoptosis, and inflammation of the liver. As clearly demonstrated in this study, benzo [a] anthracene after the 24 weeks of exposure stimulates carcinogenic process by suppressing the liver antioxidant capacity, altering apoptotic, cell proliferation, and differentiation pathways.

Unlocking the Therapeutic Potential of Ellagic Acid for Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis

Obesity is in epidemic proportions in many parts of the world, contributing to increasing rates of non-alcoholic fatty liver disease (NAFLD). NAFLD represents a range of conditions from the initial stage of fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to severe fibrosis, through to hepatocellular carcinoma. There currently exists no treatment for the long-term management of NAFLD/NASH, however, dietary interventions have been investigated for the treatment of NASH, including several polyphenolic compounds. Ellagic acid is one such polyphenolic compound. Nutraceutical food abundant in ellagic acid undergoes initial hydrolysis to free ellagic acid within the stomach and small intestine. The proposed mechanism of action of ellagic acid extends beyond its initial therapeutic potential, as it is further broken down by the gut microbiome into urolithin. Both ellagic acid and urolithin have been found to alleviate oxidative stress, inflammation, and fibrosis, which are associated with NAFLD/NASH. While progress has been made in understanding the pharmacological and biological activity of ellagic acid and its involvement in NAFLD/NASH, it has yet to be fully elucidated. Thus, the aim of this review is to summarise the currently available literature elucidating the therapeutic potential of ellagic acid and its microbial-derived metabolite urolithin in NAFLD/NASH.

Protective activities of ellagic acid and urolithins against kidney toxicity of environmental pollutants: A review

Oxidative stress and inflammation are two possible mechanisms related to nephrotoxicity caused by environmental pollutants. Ellagic acid, a powerful antioxidant phytochemical, may have great relevance in mitigating pollutant-induced nephrotoxicity and preventing the progression of kidney disease. This review discusses the latest findings on the protective effects of ellagic acid, its metabolic derivatives, the urolithins, against kidney toxicity caused by heavy metals, pesticides, mycotoxins, and organic air pollutants. We describe the chelating, antioxidant, anti-inflammatory, antifibrotic, antiautophagic, and antiapoptotic properties of ellagic acid to attenuate nephrotoxicity. Furthermore, we present the molecular targets and signaling pathways that are regulated by these antioxidants, and suggest some others that should be explored. Nevertheless, the number of reports is still limited to establish the efficacy of ellagic acid against kidney damage induced by environmental pollutants. Therefore, additional preclinical studies on this topic are required, as well as the development of well-designed clinical trials.

Ellagic acid ameliorates hexavalent chromium-induced renal toxicity by attenuating oxidative stress, suppressing TNF-α and protecting mitochondria

Nephrotoxicity is an important adverse effect of oxidative stress induced by hexavalent chromium [Cr(VI)]. The effect of ellagic acid, a dietary polyphenolic compound with potent antioxidant activity, was investigated in Cr(VI)-induced kidney injury. Six groups of male Wistar rats were treated intragastrically with vehicle or ellagic acid (15 and 30 mg/kg) for 10 days. On day 10, rats received saline or Cr(VI) (K₂Cr₂O₇ 15 mg/kg) subcutaneously. Cr(VI) significantly increased kidney weight, affected kidney function assessed by biomarkers in blood and urine (protein, creatinine and urea nitrogen), caused histological changes (tubular injury and glomerular capillary tuft damage), increased markers of oxidative stress and reduced the activity of antioxidant enzymes. In addition, Cr(VI) altered mitochondrial ultrastructure, impaired mitochondrial respiration, increased lipid peroxidation, and inhibited the function of mitochondrial enzymes. Pretreatment with ellagic acid (30 mg/kg) attenuated all the aforementioned alterations. Furthermore, we explored whether ellagic acid might regulate the tumor necrosis factor-alpha (TNF-α)/receptor-interacting protein kinase 3 (RIPK3) pathway, reducing Cr(VI)-induced tubular necrosis. Cr(VI) upregulated both TNF-α and RIPK3, but ellagic acid only decreased TNF-α levels, having no effect on RIPK3 content. Therefore, understanding the mechanisms through which Cr(VI) promotes necroptosis is crucial for future studies, in order to design strategies to mitigate kidney damage. In conclusion, ellagic acid attenuated Cr(VI)-induced renal alterations by preventing oxidative stress, supporting enzymatic activities, suppressing TNF-α, and preserving mitochondrial ultrastructure and function, most likely due to its antioxidant properties.

The Use of Ellagic Acid and Annona Muricata Improves Semen Quality in Men with High-Risk Papillomavirus Infection

Background: Few data are currently available on the treatment of patients with HPV infection. In particular, there is no agreement on the use of antioxidants in these patients. Ellagic acid and annona muricata appear to improve HPV clearance in infected women. However, it is presently unknown whether they could enhance the clearance of HPV infection in infertile male patients. Aim: To evaluate the effects of a commercially available combined compound containing ellagic acid and annona muricata on semen quality in patients with documented papillomavirus (HPV) infection, and on the frequency of HPV DNA detection in seminal fluid after treatment. In addition, anti-sperm antibodies and the percentage of spermatozoa with fragmented DNA were evaluated. Materials and methods: This was a retrospective case-control study including patients attending our center for infertility. Fifty selected patients who were positive for high risk (HR)-HPV with available semen analysis results were consecutively enrolled. Patients were classified into two groups, according to the clinician’s decision to either administer ellagic acid 100 mg and annona muricata 100 mg (combined tablet formulation) for a period of three months (Group A; 25 patients), or to re-evaluate HPV DNA after a period of active surveillance only (protected sexual intercourse) (Group B; 25 patients). Results: Group A patients had a mean age of 31.0  ±  11.0 years, while Group B was 33.0  ±  8.0 years old (p  > 0.05). After three months of treatment with ellagic acid and annona muricata, all conventional seminal parameters improved more significantly in Group A than in Group B patients: sperm concentration = 45 mil/mL vs. 20 mil/mL (p < 0.05); sperm progressive motility = 45% vs. 18% (p < 0.05); and normal sperm morphology = 18% vs. 6% (p < 0.05). After the treatment, the frequency of persistence of HPV DNA in the seminal fluid was significantly lower in Group A patients compared to those in Group B (12/25 = 48% vs. 22/25 = 88%; p < 0.05). Finally, after 3 months, Group A showed a significant reduction in anti-sperm antibodies and in the percentage of spermatozoa with fragmented DNA. Conclusion: The results of this study demonstrate, for the first time, the effects of a commercially available combined compound containing ellagic acid and annona muricata on semen quality in patients with HR-HPV infection, and that this therapy is also associated with a significant reduction in the persistence of HPV DNA in the seminal fluid.

Effect of ellagic acid and mesocarp extract of Punica granatum on productive and reproductive performances of laying hens

In the present study, we determined the potential effects of ellagic acid and mesocarp extract of Punica granatum on the productive and reproduction performance of laying hens. Five treatment groups were setup: (1) control group (without ellagic acid), (2) 50 mg of ellagic acid, (3) 100 mg of ellagic acid, (4) 200 mg of ellagic acid, and (5) mesocarp extract of P. granatum. All the groups were investigated for feed intake, body weight, egg production, egg quality, fertility, hatchability, antioxidant status of serum and liver, lipid peroxidation, and antibacterial activities. Egg production, feed intake, and bodyweight were significantly increased (p < 0.05) with 100 mg of ellagic acid and P. granatum extract while no significant effect was observed on albumen and yolk weight, yolk index, yolk color, egg-shape index, and Haugh unit. Both ellagic acid and P. granatum extract significantly improved hatchability while 100 and 200 mg/kg of ellagic acid numerically decreased fertility. Besides, ellagic acid (100 mg/kg) and P. granatum extract significantly decreased malondialdehyde concentration and increased total antioxidant capacity, glutathione peroxidase, and total superoxide dismutase in serum and liver samples of laying hens (p < 0.05). The lipid peroxidation was decreased among the treatment groups, with 100 mg of ellagic acid and P. granatum extract showed the best activity. Moreover, ellagic acid demonstrated strong killing activity against Escherichia coli and Staphylococcus aureus while it was ineffective against methicillin-resistant S. aureus. Our results conclude that ellagic acid and P. granatum promoted egg production, hatchability, and antioxidant enzyme activities of the laying hens.

Ellagic Acid: A Review on Its Natural Sources, Chemical Stability, and Therapeutic Potential

Ellagic acid (EA) is a bioactive polyphenolic compound naturally occurring as secondary metabolite in many plant taxa. EA content is considerable in pomegranate (Punica granatum L.) and in wood and bark of some tree species. Structurally, EA is a dilactone of hexahydroxydiphenic acid (HHDP), a dimeric gallic acid derivative, produced mainly by hydrolysis of ellagitannins, a widely distributed group of secondary metabolites. EA is attracting attention due to its antioxidant, anti-inflammatory, antimutagenic, and antiproliferative properties. EA displayed pharmacological effects in various in vitro and in vivo model systems. Furthermore, EA has also been well documented for its antiallergic, antiatherosclerotic, cardioprotective, hepatoprotective, nephroprotective, and neuroprotective properties. This review reports on the health-promoting effects of EA, along with possible mechanisms of its action in maintaining the health status, by summarizing the literature related to the therapeutic potential of this polyphenolic in the treatment of several human diseases.

Mitochondrial respiratory chain inhibition and Na+K+ATPase dysfunction are determinant factors modulating the toxicity of nickel in the brain of indian catfish Clarias batrachus L

Nickel is a potential neurotoxic pollutant inflicting damage in living organisms, including fish, mainly through oxidative stress. Previous studies have demonstrated the impact of nickel toxicity on mitochondrial function, but there remain lacunae on the damage inflicted at mitochondrial respiratory level. Deficient mitochondrial function usually affects the activities of important adenosinetriphosphatases responsible for the maintenance of normal neuronal function, namely Na⁺K⁺ATPase, as explored in our study. Previous reports demonstrated the dysfunction of this enzyme upon nickel exposure but the contributing factors for the inhibition of this enzyme remained unexplored. The main purpose of this study was to elucidate the impact of nickel neurotoxicity on mitochondrial respiratory complexes and Na⁺K⁺ATPase in the piscine brain and to determine the contributing factors that had an impact on the same. Adult Clarias batrachus were exposed to nickel treated water at 10% and 20% of the 96 h LC50 value (41 mg.l^–1) respectively and sampled on 20, 40 and 60 days. Exposure of fish brain to nickel led to partial inhibition of complex IV of mitochondrial respiratory chain, however, the activities of complex I, II and III remained unaltered. This partial inhibition of mitochondrial respiratory chain might have been sufficient to lower mitochondrial energy production in mitochondria that contributed to the partial dysfunction of Na⁺K⁺ATPase. Besides energy depletion other contributing factors were involved in the dysfunction of this enzyme, like loss of thiol groups for enzyme activity and lipid peroxidation-derived end products that might have induced conformational and functional changes. However, providing direct evidence for such conformational and functional changes of Na⁺K⁺ATPase was beyond the scope of the present study. In addition, immunoblotting results also showed a decrease in Na⁺K⁺ATPase protein expression highlighting the impact of nickel neurotoxicity on the expression of the enzyme itself. The implication of the inhibition of mitochondrial respiration and Na⁺K⁺ATPase dysfunction was the neuronal death as evidenced by enhanced caspase-3 and caspase-9 activities. Thus, this study established the deleterious impact of nickel neurotoxicity on mitochondrial functions in the piscine brain and identified probable contributing factors that can act concurrently in the inhibition of Na⁺K⁺ATPase. This study also provided a vital clue about the specific areas that the therapeutic agents should target to counter nickel neurotoxicity.

Ellagic Acid Suppresses the Oxidative Stress Induced by Dietary-Oxidized Tallow

Dietary tallow was thermally oxidized at 180°C in an open fryer. The oxidized tallow (OT) and unoxidized tallow were characterized for oxidation parameters and fatty acid composition using GC-MS. Tallow samples were fed to rabbits along with 50, 100, and 150 mg/kg/day of ellagic acid (EA) for three weeks. Results revealed that the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) significantly increased, while radical scavenging activity (RSA) of the tallow decreased significantly with oxidation. GC-MS analysis showed eight fatty acids in the tallow samples, where palmitic acid (48.5-49.7 g/100 g), linoleic acid (18.7-23.7 g/100 g), stearic acid (13.5-15.6 g/100 g), and margaric acid (6.32-6.42 g/100 g) were the major fatty acids. Animal studies showed that oxidized tallow (OT) alone or in combination with EA significantly altered the body weight of the rabbits. Serum biochemical parameters and renal function tests were affected by OT and ameliorated by EA. The toxic effects of OT on haematological indices were minimized by EA. The supplementation of OT alone had significant effects on the liver structure and functions. The coadministration of EA reduced the toxic properties of OT on the liver, by increasing the antioxidant (GSH) system. The rabbit heart was also affected by the OT, which was ameliorated by EA supplementation. These results suggested that the supplementation of EA was beneficial against the OT-induced oxidative stress and may be considered for foods containing oxidized lipids.

Ellagic acid in suppressing in vivo and in vitro oxidative stresses

Oxidative stress is a biological condition produced by a variety of factors, causing several chronic diseases. Oxidative stress was, therefore, treated with natural antioxidants, such as ellagic acid (EA). EA has a major role in protecting against different diseases associated with oxidative stress. This review critically discussed the antioxidant role of EA in biological systems. The in vitro and in vivo studies have confirmed the protective role of EA in suppressing oxidative stress. The review also discussed the mechanism of EA in suppressing of oxidative stress, which showed that EA activates specific endogenous antioxidant enzymes and suppresses specific genes responsible for inflammation, diseases, or disturbance of biochemical systems. The amount of EA used and duration, which plays a significant role in the treatment of oxidative stress has been discussed. In conclusion, EA is a strong natural antioxidant, which possesses the suppressing power of oxidative stress in biological systems.

Chelating effects of carnosine in ameliorating nickel-induced nephrotoxicity in rats

The kidney is one of the main organs affected by nickel toxicity. We investigated the protective effects of carnosine on nickel-induced oxidative stress in kidney of rats. Animals received NiSO₄ (20 mg·kg^-1·day^-1 intragastrically) and (or) carnosine (10 mg·kg^-1·day^-1 intragastrically) for 21 days and then were evaluated for biochemical, molecular, and histopathological alterations. Nickel caused an increase in renal levels of malondialdehyde and a decrease in reduced glutathione, catalase, and superoxide dismutase levels and total antioxidant capacity. Carnosine prevented the prooxidant and antioxidant imbalance induced by nickel. Nickel-treated rats showed an increase in serum creatinine, urea, and uric acid with a concomitant decrease in albumin. Nickel markedly accumulated in kidney of exposed rats, but its concentration was effectively reduced by carnosine treatment. Carnosine corrected the biochemical abnormalities and the elevated renal TNF-α and IL-6 levels in the nickel-treated group. It also attenuated nickel-induced abnormalities in renal architecture. Although carnosine showed antioxidant and anti-inflammatory effects in renal tissue of nickel-exposed rats, we cannot clearly attribute the protective effect of carnosine to these effects. Instead, the beneficial effect of carnosine observed in the current study may be due to chelation between nickel and carnosine. Thus, carnosine may represent a therapeutic option to protect against nickel-induced nephrotoxicity that deserves further consideration and examination.

Effects of diallyl tetrasulfide on cadmium-induced oxidative damage in the liver of rats

The protective efficacy of diallyl tetrasulfide (DTS) from garlic on liver injury induced by cadmium (Cd) was investigated. In this study, Cd (3 mg/kg body weight) was administered subcutaneously for 3 weeks to induce toxicity. DTS was administered orally (10, 20 and 40 mg/kg body weight) for 3 weeks with subcutaneous (sc) injection of Cd. Cd-induced liver damage was evidenced from increased activities of serum hepatic enzymes, namely aspartate transaminase, alanine transaminase, alkaline phosphatase and lactate dehydrogenase, with significant elevation of lipid peroxidation indices (thiobarbituric acid reactive substances and hydroperoxides) and protein carbonyl groups in the liver. Rats subjected to Cd toxicity also showed a decline in the levels of total thiols, reduced glutathione (GSH), vitamin C and vitamin E, accompanied by an increased accumulation of Cd, and significantly decreased activities of superoxide dismutase, catalase (CAT), glutathione peroxidase, glutathione-S-transferase (GST), glutathione reductase, and glucose-6-phosphate dehydrogenase in the liver. Administration of DTS at 40 mg/kg body weight significantly normalised the activities of hepatic marker enzymes, compared to other doses of DTS (10 and 20 mg/kg body weight). In addition, DTS (40 mg/kg body weight) significantly reduced the accumulation of Cd and the level of lipid peroxidation, and restored the level of antioxidant defense in the liver. Histological studies also showed that administration of DTS to Cd-treated rats resulted in a marked improvement of hepatocytes morphology with mild portal inflammation. Our results suggest that DTS might play a vital role in protecting Cd-induced oxidative damage in the liver. Human & Experimental Toxicology(2007) 26, 527—534

The Effects of Ellagic Acid upon Brain Cells: A Mechanistic View and Future Directions

Ellagic acid (EA, 2,3,7,8-tetrahydroxy-chromeno; C14H6O8) is a polyphenol derived from fruits (pomegranates, berries) and nuts. EA exhibits antioxidant capacity and induces anti-inflammatory actions in several mammalian tissues. EA has been characterized as a possible neuroprotective agent, but the number of reports is still limited to conclude whether and how EA exerts neuroprotection in humans. In this regard, performing additional studies considering the potential beneficial and/or toxicological roles for EA on brain cells would be an important step towards fully understanding of when and how EA may be securely utilized by humans as a neuroprotective agent. The aim of the present work is to discuss data related to the neuronal and glial effects of EA and the mechanisms underlying such events. Moreover, future directions are suggested as a potential guide to be utilized by researchers interested in investigating the neuronal and glial actions of EA hereafter.

Effects of ellagic acid on copper, zinc, and biochemical values in serum and liver of experimental cholestatic rats

Ellagic acid (EA) is a natural polyphenolic compound. Although, modulator effects of EA on copper (Cu) and zinc (Zn) levels in some liver diseases have been reported in experimental animals, its effects in obstructive jaundice (OJ) has not been clarified. We aimed to evaluate potential effects of EA on Cu and Zn levels in liver and serum of cholestatic rats. Forty Wistar albino rats were equally divided into four groups. First group was used as controls. Second group received EA (60 mg(-1) kg(-1) day(-1)) for 8 days. Third was OJ group, and fourth group was OJ plus EA group. After 8 days, blood and liver samples were obtained. Higher serum and liver Cu and lower serum and liver Zn levels were found in OJ group (p < 0.05) compared with other groups. However, these differences reached to significant levels for Cu in serum and for Zn in lever. Higher serum copper levels were decreased, and lower liver Zn levels were increased by EA treatment in cholestatic rats (p < 0.05). Also, higher Cu/Zn ratio in OJ group was decreased by EA treatment both in liver (p < 0.05) and in serum (p < 0.05). Significantly higher serum bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase values were found in OJ and OJ + EA groups compared with the control and EA groups (p < 0.05). In conclusion, result of the current study indicated that ellagic acid has modulator effects on Cu and Zn levels in liver and serum of cholestatic rats.

Hepatoprotective effect of morin on ethanol-induced hepatotoxicity in rats

Morin is a flavonoid that exists in nature and is the major component of traditional medicinal herbs. Here we evaluated morin for its hepatoprotective effect against chronic ethanol-induced biochemical changes in male Wistar rats. Ethanol administration (7.9 g/kg bwt) for 60 days induced hepatic and renal damage by increasing oxidative stress and decreasing antioxidant levels. The status of lipid peroxidation (thiobarbituric reactive substances (TBARS) and hydroperoxides (HP)), antioxidant (vitamin C, vitamin E, GSH), serum hepatic markers (AST, ALT, ALP, GGT, bilirubin), and renal markers (urea, creatinine) were assessed as biochemical endpoints to determine the hepatic protective effect of morin. Oral administration of morin (100 mg/kg b.w) to alcohol-intoxicated rats for 30 days showed significant decreases in lipid peroxidation and restoration of antioxidant, hepatic, and renal markers to normal. Histopathologic observations of liver were also in correlation with biochemical parameters. The results indicate that morin might be beneficial in ameliorating alcohol-induced oxidative damage in rat liver.

Subchronic exposure to ellagic acid impairs cytotoxic T-cell function and suppresses humoral immunity in mice

Ellagic acid (EA) is present in a variety of foods such as grapes, strawberries, raspberries, and nuts. It is a dietary plant phenol that has been shown to inhibit oxidative stress and chemical carcinogenesis. Although several studies have examined the protective mechanisms of dietary EA including the induction of detoxifying enzymes, regulation of cell cycle, chelation of nickel, and prevention of DNA methylation, none have addressed the role of EA in immunological surveillance. This study investigates the status of immune function in B6C3F1 mice exposed continuously to EA in drinking water at 0.5, 1.0, or 2.0 mg/kg/day for 28 days. Although this range of exposure is above the estimated human daily intake (approximately 940 microg/day for 70 kg person or 13.4 microg/kg/day), these levels would not be unreasonable if EA were used as a dietary supplement or as a chemotherapeutic agent. Previous reports have demonstrated the anticarcinogenic effects of EA at levels 10- to 250-fold greater than those applied in this study. Immunological parameters assessed included natural killer (NK) cell activity, cytotoxic T lymphocyte (CTL) activity, IgM antibody plaque forming cell (PFC) response, thymus, spleen, kidney, and liver mass, and total cellularity for the thymus and spleen. Subchronic exposure to EA for 28 days in drinking water caused significant suppression of specific IgM antibody responses in the 2.0 mg/kg EA treatment group and suppressed cytotoxic T-cell function in the 0.5 and 1.0 mg/kg EA treatment groups. All other immunological parameters were within normal ranges. Kidney and liver mass were not altered after treatment with EA. The results from this study indicate that EA suppressed both IgM antibody responses and CTLs. These observations suggest important implications on human health should EA be prescribed as a chemotherapeutic agent or a preventative dietary supplement for cancer.

Plasma lipid peroxidation and erythrocyte antioxidants status in workers exposed to nickel

The objectives were to investigate the plasma lipid peroxidation and erythrocyte antioxidants status in workers exposed to nickel. The study groups comprised 69 nickel plating workers and 50 office workers residing in the same city, but away from the place of work of the study group subjects, considered as control group. Urinary nickel concentration was determined by graphite furnace atomic absorption spectrophotometry. The plasma lipid peroxidation and erythrocyte antioxidants were measured by spectrophotmetric methods. The plasma lipid peroxidation level was significantly increased in nickel-platers and their helpers as compared with controls. Erythrocyte antioxidants were significantly decreased in the nickel-platers compared with the controls. The level of plasma lipid peroxidation was positively and erythrocyte antioxidants were negatively and significantly correlated with the urine nickel levels. Multiple regression analysis assessed the oxidative stress associated with nickel and other potential confounding factors such as body mass index, the consumption of green vegetables, coffee, tea, smoking and alcohol consumption. Analysis showed that the lifestyle confounding factors: the consumption of green vegetables, smoking and alcohol, were not significantly associated with oxidative stress. The exposure to nickel, body mass index and coffee consumption were significantly associated with oxidative stress. The results show that the increased plasma lipid peroxidation and decreased erythrocyte antioxidants levels observed in nickel-exposed workers could be used as biomarkers of oxidative stress.

Inhibition of cadmium-induced oxidative injury in rat primary astrocytes by the addition of antioxidants and the reduction of intracellular calcium

Exposure of the brain to cadmium ions (Cd(2+)) is believed to lead to neurological disorders of the central nervous system (CNS). In this study, we tested the hypothesis that astrocytes, the major CNS-supporting cells, are resistant to Cd(2+)-induced injury compared with cortical neurons and microglia (CNS macrophages). However, treatment with CdCl(2) for 24 h at concentrations higher than 20 microM substantially induced astrocytic cytotoxicity, which also resulted from long-term exposure to 5 microM of CdCl(2). Intracellular calcium levels were found to rapidly increase after the addition of CdCl(2) into astrocytes, which led to a rise in reactive oxygen species (ROS) and to mitochondrial impairment. In accordance, preexposure to the extracellular calcium chelator EGTA effectively reduced ROS production and increased survival of Cd(2+)-treated astrocytes. Adenovirus-mediated transfer of superoxide dismutase (SOD) or glutathione peroxidase (GPx) genes increased survival of Cd(2+)-exposed astrocytes. In addition, increased ROS generation and astrocytic cell death due to Cd(2+) exposure was inhibited when astrocytes were treated with the polyphenolic compound ellagic acid (EA). Taken together, Cd(2+)-induced astrocytic cell death resulted from disrupted calcium homeostasis and an increase in ROS. Moreover, our findings demonstrate that enhancement of the activity of intracellular antioxidant enzymes and supplementation with a phenolic compound, a natural antioxidant, improves survival of Cd(2+)-primed astrocytes. This information provides a useful approach for treating Cd(2+)-induced CNS neurological disorders.

Protective role of zinc pretreatment in hepatotoxicity induced by halothane

BACKGROUND AND OBJECTIVE

This study was designed to determine the protective effects of zinc on halothane induced hepatotoxicity.

METHODS

Forty-five male Sprague-Dawley rats were divided into three groups. The halothane group received normal drinking water and diet; the zinc-halothane group received 227 mg L(-1) zinc sulphate in the drinking water and diet for 2 weeks; and the control group received normal diet and water. At the end of 2 weeks, rats were housed in an anaesthesia box and 1 MAC (minimum alveolar concentration)halothane was administered at 6 L min(-1) in room air for 2 h. This was repeated 48 h later. After the rats were sacrificed, we measured alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gammaglutamyl transpeptidase, glutathione-S-transferase, serum electrolytes and bilirubin in samples. The degree of liver toxicity was assessed by light microscopic examination.

RESULTS

We demonstrated a reduction of alanine aminotransferase, aspartate amino transferase, glutathione-S-transferase levels and a reduction in liver damage in the zinc-halothane group.

CONCLUSION

The study concludes that zinc has the potential to alleviate the toxic effects of halothane in rat liver.

Dietary berries and ellagic acid prevent oxidative DNA damage and modulate expression of DNA repair genes

DNA damage is a pre-requisite for the initiation of cancer and agents that reduce this damage are useful in cancer prevention. In this study, we evaluated the ability of whole berries and berry phytochemical, ellagic acid to reduce endogenous oxidative DNA damage. Ellagic acid was selected based on >95% inhibition of 8-oxodeoxyguosine (8-oxodG) and other unidentified oxidative DNA adducts induced by 4-hydroxy-17ss-estradiol and CuCl(2) in vitro. Inhibition of the latter occurred at lower concentrations (10 microM) than that for 8-oxodG (100 microM). In the in vivo study, female CD-1 mice (n=6) were fed either a control diet or diet supplemented with ellagic acid (400 ppm) and dehydrated berries (5% w/w) with varying ellagic acid contents - blueberry (low), strawberry (medium) and red raspberry (high), for 3 weeks. Blueberry and strawberry diets showed moderate reductions in endogenous DNA adducts (25%). However, both red raspberry and ellagic acid diets showed a significant reduction of 59% (p < 0.001) and 48% (p < 0.01), respectively. Both diets also resulted in a 3-8 fold over-expression of genes involved in DNA repair such as xeroderma pigmentosum group A complementing protein (XPA), DNA excision repair protein (ERCC5) and DNA ligase III (DNL3). These results suggest that red raspberry and ellagic acid reduce endogenous oxidative DNA damage by mechanisms which may involve increase in DNA repair.

Modulation by ellagic acid of DCA-induced developmental toxicity in the zebrafish (Danio rerio)

The ability of ellagic acid (EA) to modulate dichloroacetic acid (DCA)-induced developmental toxicity and oxidative damage was examined in zebrafish embryos. Embryos were exposed to 20 mM EA administered concomitantly with 32 mM DCA at 4 hours postfertilization (hpf) and 20 h later. Embryos were observed through 144 hpf for developmental malformations, and production of superoxide anion (SA) and nitric oxide (NO) was determined in embryonic homogenates. DCA was shown to produce developmental abnormalities and significant levels of SA and NO in zebrafish embryos. EA exposure alleviated the developmental malformations observed in treated embryos and decreased the levels of SA and NO in those same embryos. Less than 10% of DCA + EA exposed embryos showed developmental malformations compared to 100% of embryos treated with DCA alone. Animals in this group that developed malformations were shown to have fewer defects than those treated with DCA only. Taken together, the results confirm the involvement of oxidative stress in the developmental toxicity of DCA in zebrafish embryos, and suggest possible protection against those effects with the use of antioxidants.

Chemomodulatory effects of Terminalia chebula against nickel chloride induced oxidative stress and tumor promotion response in male Wistar rats

Nickel, a major environmental pollutant is a known potent nephrotoxic agent. In this communication we report the chemopreventive effect of Terminalia chebula on nickel chloride (NiCl(2)) induced renal oxidative stress, toxicity and cell proliferation response in male Wistar rats. Administration of NiCl(2) (250micromoL Ni/kg body weight) to male Wistar rats resulted in an increase in the reduced renal glutathione content (GSH), glutathione-S-transferase (GST), glutathione reductase (GR), lipid peroxidation (LPO), H(2)O(2) generation, blood urea nitrogen (BUN) and serum creatinine with a concomitant decrease in the activity of glutathione peroxidase (p<0.001). Nickel chloride (NiCl(2)) treatment also induced tumor promotion markers, viz., ornithine decarboxylase (ODC) activity and thymidine [(3)H] incorporation into renal DNA (p<0.001). Prophylactic treatment of rats with T. chebula (25mg/kg body weight and 50mg/kg body weight) daily for one week resulted in the diminution of NiCl(2) mediated damage as evident from the down regulation of glutathione content, GST, GR, LPO, H(2)O(2) generation, BUN, serum creatinine, DNA synthesis (p<0.001) and ODC activity (p<0.01) with concomitant restoration of GPx activity. Thus, the present investigation suggests that T. chebula extract could be used as therapeutic agent for cancer prevention as evident from this study where it blocks or suppresses the events associated with chemical carcinogenesis.

Oxidative stress due to nickel toxicity in the liver of protein-deficient rats

This study was designed to determine the oxidative stress induced by nickel sulfate in the liver in the protein-deficient rats. Nickel sulfate in the dose of 800 mg/L in drinking water was administrated to Sprauge Dawley (SD) rats as well as protein-deficient rats for a total duration of 8 weeks. The effects of nickel treatment and protein deficiency separately and in combination were studied on rat liver antioxidant defense system enzymes like catalase, glutathione peroxidase (GPX), glutathione reductase (GR), superoxide dismutase (SOD), reduced glutathione (GSH), and glutathione-S-transferase (GST), as well as on lipid peroxidation (LPO). The investigations revealed a significant increase in the activity of enzymes, which include catalase, Gpx, GR and GST, and in the levels with LPO following nickel treatment in combination with protein deficiency. On the contrary, feeding to control rats resulted in a significant depression in the levels of SOD and GSH. However, nickel treatment to normal rats caused a significant increase in the activity of enzymes catalase and GST and in the levels of LPO, whereas the levels of GSH get significantly depressed. Further, nickel treatment to protein-deficient rats did not cause any additional alteration in the status of liver antioxidants as were observed in conditions of protein deficiency.

Protective role of zinc in nickel induced hepatotoxicity in rats

This study was planned to determine the protective role of zinc, if any, in attenuating the toxicity induced by nickel sulfate in rat liver. Female Sprague Dawley (SD) rats received either nickel alone in the dose of 800 mg/l in drinking water, zinc alone in the dose of 227 mg/l in drinking water, and nickel plus zinc or drinking water alone for a total duration of eight weeks. The effects of different treatments were studied on various parameters in rat liver which include antioxidant enzymes, levels of nickel and zinc and histoarchitecture at the light microscopic level. Further, the activities of hepatic marker enzymes AST and ALT were also studied in rat serum. Nickel treatment to the normal control animals, resulted in a significant increase in lipid peroxidation and enzyme activities of catalase and glutathione-S-transferase. On the contrary, nickel treatment to normal rats caused a significant inhibition in the levels of reduced glutathione. Superoxide dismutase activity was found to be decreased which however was not significant. Interestingly, when Zn was supplemented to nickel treated rats, the activities of catalase, and glutathione-S-transferase and the levels of GSH and lipid peroxidation came back to within normal limits. Activities of serum AST and ALT were increased significantly following nickel treatment to normal rats. Simultaneous zinc administration to nickel treated rats tended to restore the altered levels of AST and ALT. Normal control and zinc treated animals revealed normal histology of liver. On the other hand, nickel treated animals showed alterations in normal hepatic histoarchitecture which comprise of vacuolization of the hepatocytes and dilatation of sinusoids as well as increase in the number of bi-nucleated cells. Administration of zinc to nickel treated rats resulted in marked improvement in the structure of hepatocytes, thus emphasizing the protective potential of zinc in restoring the altered hepatic histoarchitecture. The nickel administration to normal rats indicated increased concentrations of nickel and decreased concentrations of zinc. However, zinc effectively brought the altered levels of nickel and zinc to within normal range. The study concludes that zinc has the potential in alleviating the toxic effects of nickel in rat liver because of its property to induce metallothionein (S-rich protein) as a free radical scavenger, or its indirect action in reducing the levels of oxygen reactive species.

Stages of activation of hepatic stellate cells: effects of ellagic acid, an inhibiter of liver fibrosis, on their differentiation in culture

To further explore that hepatic stellate cell (HSC) activation results in physiological protection against environmental insult, the profile of differentiation of HSC has been examined upon treatment with ellagic acid (EA), a plant-derived antioxidant that shows multiple protective effects during liver disease. Sparse rat liver cell cultures were grown in media containing EA (3, 6, 30 and 100 microg/ml) and, as controls, without EA, and inspected until day 7 in culture. The cells were double-labelled with antibodies against glial fibrillary acidic protein (GFAP) and smooth muscle alpha-actin (SMAA), marker proteins of quiescent and activated HSC, respectively. In EA-free culture conditions, the quiescent (SMAA-/GFAP+) HSC transiently acquired a semi-activated (SMAA+/GFAP+), phenotype and were further transformed into activated (SMAA+/GFAP-), pleomorphic HSC. Up to a concentration of 30 microg/ml, EA induced an early synthesis of SMAA in all HSC and inhibited their morphologic differentiation and individual growth throughout the culture period. At a concentration of 6 microg/ml, EA supported the semi-activated (SMAA+/GFAP+) phenotype of HSC throughout the culture period, whereas treatment with high EA concentrations (30 microg/ml) resulted in an early loss of GFAP expression.

IN CONCLUSION

(i) the uniform response of HSC to EA by mild activation adds functional significance to cellular features preceding the transformation of HSC to myofibroblasts; (ii) the high sensitivity of HSC to EA treatment suggests their involvement in any mechanisms of protection by this antioxidant; (iii) the maintenance of HSC morphology might be one of the factors playing a role in the prevention or slowing down of liver fibrosis; (iv) because the effects of EA are concentration- and time-dependent, an arbitrary usage of this antioxidant is a matter of potential concern; (v) the various patterns of HSC activation observed might correspond to distinct activities of these cells, which, in turn, might lead to different outcomes of liver fibrosis.

Glyceryl trinitrate, a nitric oxide donor, abrogates ferric nitrilotriacetate-induced oxidative stress and renal damage

Ferric nitrilotriacetate (Fe-NTA), a common water pollutant and a known renal carcinogen, acts through the generation of oxidative stress and hyperproliferative response. In the present study, we show that the nitric oxide (NO) generated by the administration of glyceryl trinitrate (GTN) affords protection against Fe-NTA-induced oxidative stress and proliferative response. Administration of Fe-NTA resulted in a significant (P<0.001) depletion of renal glutathione (GSH) content with concomitant increase in lipid peroxidation and elevated tissue damage marker release in serum. Parallel to these changes, Fe-NTA also caused down-regulation of GSH metabolizing enzymes including glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase and several fold induction in ornithine decarboxylase (ODC) activity and rate of DNA synthesis. Subsequent exogenous administration of GTN at doses of 3 and 6mg/kg body weight resulted in significant (P<0.001) recovery of GSH metabolizing enzymes and amelioration of tissue GSH content, in a dose-dependent manner. GTN administration also inhibited malondialdehyde (MDA) formation, induction of ODC activity, enhanced rate of DNA synthesis, and pathological deterioration in a dose-dependent fashion. Further, administration of NO inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), exacerbated Fe-NTA-induced oxidative tissue injury, hyperproliferative response, and pathological damage. Overall, the study suggests that NO administration subsequent to Fe-NTA affords protection against ROS-mediated damage induced by Fe-NTA.

Nigella sativa (black cumin) ameliorates potassium bromate-induced early events of carcinogenesis: diminution of oxidative stress

Potassium bromate (KBrO3) is a potent nephrotoxic agent. In this paper, we report the chemopreventive effect of Nigella sativa (black cumin) on KBrO3-mediated renal oxidative stress, toxicity and tumor promotion response in rats. KBrO3 (125 mg/kg body weight, intraperitoneally) enhances lipid peroxidation, gamma-glutamyl transpeptidase, hydrogen peroxide and xanthine oxidase with reduction in the activities of renal antioxidant enzymes and renal glutathione content. A marked increase in blood urea nitrogen and serum creatinine has also been observed. KBrO3 treatment also enhances ornithine decarboxylase (ODC) activity and [3H] thymidine incorporation into renal DNA. Prophylaxis of rats orally with Nigella sativa extract (50 mg/kg body weight and 100 mg/kg body weight) resulted in a significant decrease in renal microsomal lipid peroxidation (P < 0.001), gamma-glutamyl transpeptidase (P < 0.001), H2O2 (P < 0.001) and xanthine oxidase (P < 0.05). There was significant recovery of renal glutathione content (P < 0.01) and antioxidant enzymes (P < 0.001). There was also reversal in the enhancement of blood urea nitrogen, serum creatinine, renal ODC activity and DNA synthesis (P < 0.001). Data suggest that Nigella sativa is a potent chemopreventive agent and may suppress KBrO3-mediated renal oxidative stress, toxicity and tumour promotion response in rats.