Antioxidant status of liver, erythrocytes, and blood serum of rats in acute methanol intoxication

Radical Scavenging Activities of Lagerstroemia speciosa (L.) Pers. Petal Extracts and its hepato-protection in CCl4-intoxicated mice

BACKGROUND

Lagerstroemia speciosa (L.) Pers. has medicinal importance. Bioactive phytochemicals isolated from different parts of L. speciosa, have revealed hypoglycemic, antibacterial, anti-inflammatory, antioxidant and hepato protective properties. Despite one report from Philippines detailing the use of L. speciosa as curative for fever and as well as diuretic, there is no experimental evidence about the hepatoprotective activity of the flower extracts.

METHODS

Several spectroscopic methods, including GC-MS, were used to characterize phytochemicals present in the petal extract of L. speciosa. Ethanol extract of petals was evaluated for anti-oxidant and free radical scavenging properties by using methods related to hydrogen atom transfer, single electron transfer, reducing power, and metal chelation. This study has also revealed the in vitro antioxidant and in vivo hepatoprotective properties of petal extract against carbon tetra chloride (CCl₄)-induced liver toxicity in Swiss albino mice. Hepatoprotection in CCl₄ -intoxicated mice was studied with the aid of histology and different enzymatic and non-enzymatic markers of liver damage. Cytotoxicity tests were done using murein spleenocytes and cancareous cell lines, MCF7 and HepG2.

RESULT

GCMS of the extract has revealed the presence of several potential antioxidant compounds, of them γ-Sitosterol and 1,2,3-Benzenetriol (Pyrogallol) were the predominant ones. The antioxidants activities of the flower-extract were significantly higher than curcumin (in terms of Nitric oxide scavenging activity; p = 0.0028) or ascorbic acid (in terms of 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) assay; p = 0.0022). The damage control by the flower extract can be attributed to the reduction in lipid peroxidation and restoration of catalase activity. In vitro cytotoxicity tests have shown that the flower extract did not affect growth and survivability of the cell lines. It left beyond doubt that a flower of L. speciosa is a reservoir of antioxidant and hepatoprotective agents capable of reversing the damage inflicted by CCl₄-intoxication.

CONCLUSION

Results from the present study may be used in developing a potential hepato-protective health drink enriched with antioxidants from Lagerstroemia speciosa (L.) Pers.

Carthamus red from Carthamus tinctorius L. exerts antioxidant and hepatoprotective effect against CCl(4)-induced liver damage in rats via the Nrf2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Carthamus red isolated from safflower (Carthamus tinctorius L., a Chinese traditional medicine) is evaluated for antioxidant and hepatoprotective activity.

MATERIALS AND METHODS

Carthamus red was isolated from a Na2CO3 extract of safflower and its analysis was carried out by HPLC/MS. Acute toxicity study was determined and the antioxidant activity was investigated using various established in vitro systems. An in vivo study against CCl4-induced liver injury was also conducted and compared with that of silymarin, a known hepatoprotective drug.

RESULTS

Carthamus red did not show any toxicity and mortality up to 2000mg/kg dose, and it showed strong antioxidant ability in vitro. In the in vivo study, carthamus red treatment lowered the serum levels of ALT, AST, ALP and total protein in liver damage rat models. Meanwhile, Nrf2, GSTα and NQO1 expressions were up-regulated at the protein level by carthamus red intervention. Additionally, the activities of antioxidant enzymes and level of GSH were elevated by carthamus red intervention, while the content of TBARS, which is an oxidative stress marker, was lessened. HE stain analysis showed that the condition of liver damage was mitigated.

CONCLUSION

This study demonstrates that carthamus red may serve as a candidate with strong a hepatoprotective effect and antioxidant activity in liver damage.

Identification of superoxide dismutase as a potential urinary marker of carbon tetrachloride-induced hepatic toxicity

The aim of this study was the identification of a novel protein marker of hepatotoxicity in rat urine. Rats were dosed by gavage with carbon tetrachloride (CCl(4)) to induce acute liver injury. Surface enhanced laser desorption/ionisation (SELDI) ProteinChip technology revealed the appearance of a 15.7 kDa protein in the CCl(4)-treated rat urine. One-dimensional sodium dodecyl sulphate polyacrylamide electrophoresis (SDS-PAGE) identified an 18.4 kDa protein in the CCl(4)-treated rat urine. The appearance of either protein was coincident over a time course during which they first appeared at 12h post-dosing, peaked at 36h and had disappeared again within 3 days post-dosing. The protein was identified by in-gel digestion and nano-electrospray (nano-ES)-tandem mass spectrometry as Cu/Zn superoxide dismutase (SOD-1). SOD activity was found to be increased by 61.4-fold in CCl(4)-treated rat urine. Western blots of tissue homogenates from the rats revealed a time-dependent loss of SOD-1 from the livers of CCl(4)-treated rats matching the time course of SOD-1 appearance in urine. SOD-1 is not specifically located in liver; however, its appearance in urine in response to acute CCl(4)-induced hepatotoxicity is a novel finding; this coupled with loss from the liver following injury suggests urinary SOD-1 may be a potential marker of hepatotoxicity.

Effect of methanol-induced oxidative stress on the neuroimmune system of experimental rats

It is well known that the nervous system has increased susceptibility to methanol intoxication. The present study reveals the effect of methanol intoxication on antioxidant status, lipid peroxidation and DNA integrity in hypothalamic-pituitary-adrenal (HPA) axis organs and spleen. Non-specific and specific immune functions were analyzed. In addition, open field behavior, plasma corticosterone level and blood methanol level were estimated. Male Wistar albino rats were intoxicated with methanol (2.37 g/kg b.wt., i.p.) for 1 day, 15 and 30 days. Administration of methanol showed significant increase in enzymatic (superoxide dismutase, catalase, glutathione peroxidase), non-enzymatic (reduced glutathione and Vitamin C) antioxidants and lipid peroxidation (LPO) in hypothalamus and adrenal gland of day 1 group. However, decrease in enzymatic and non-enzymatic antioxidants with concomitant increase in LPO level were observed in 15 and 30 days groups. Plasma corticosterone level was significantly increased in day 1 and 15 days groups whereas, 30 days methanol intoxication group showed considerable decrease in corticosterone level compared with control animals. Cell-mediated immune response of footpad thickness was significantly decreased with an increased leukocyte migration inhibition. Humoral immune response of antibody titers was elevated in methanol-intoxicated groups. Neutrophil functions, adherence and phagocytic index (PI) were found to be significantly decreases. Furthermore, significant increase in the avidity index and nitro blue tetrozolium reduction was observed in the methanol exposed animals. Day 1 methanol exposed group showed increased PI compared to the control ones. Methanol exposure for 30 days showed an increased DNA fragmentation in the hypothalamus, adrenal glands, and spleen. In conclusion, exposure to methanol-induced oxidative stress disturbs the HPA-axis function altering the level of corticosterone, which lead to varied non-specific and specific immune response in experimental rats.

Quercetin, a flavonoid antioxidant, prevents and protects against ethanol-induced oxidative stress in mouse liver

This study evaluates whether quercetin (25, 50 and 75 mg/kg body weight) treatment has a protective effect on the pro-oxidant-antioxidant state following chronic ethanol treatment in mice. Pretreatment (quercetin 25, 50 and 75 mg/kg body weight for 15 d+co-treatment of ethanol 18%+quercetin for 15 d and ethanol 18% for the 15 d) increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH) in comparison to the ethanol group. No significant differences from the ethanol group were observed in the group after post-treatment (ethanol 18% for 30 d+quercetin 25, 50 and 75 mg/kg body weight for 15 d) with quercetin. A significant increase in lipid peroxidation (malondialdehyde, MDA) products was observed in liver tissue after administration of ethanol, which was attenuated by pre- and post-treatment with a high dose of quercetin. GSH levels increased and oxidized glutathione (GSSG) levels decreased in groups of ethanol-exposed mice that received quercetin for 15 d prior to ethanol exposure. In conclusion, pre-treatment of quercetin may protect against ethanol-induced oxidative stress by directly quenching lipid peroxides and indirectly by enhancing the production of the endogenous antioxidant GSH. There was no protective effect on post-treatment with quercetin.

In vitro effect of methanol on folate-deficient rat hepatocytes

Methanol is primarily metabolized by oxidation to formaldehyde and then to formic acid. These processes are accompanied by formation of superoxide anion and hydrogen peroxide. This paper reports the in vitro antioxidant effect of vitamin E on isolated hepatocytes of folic acid deficient rats rendered so as to emulate a human hepatocyte model. These hepatocytes were treated with 320 microM of methanol per million cells and incubated for 30 min. The microsomal fraction of these hepatocytes showed a decreased level of superoxide dismutase (SOD), with increase in lipid peroxidation (LPO) shown by increase in recorded levels of malondialdehyde (MDA). Catalase activity was shown to be increased. Levels of reduced glutathione (GSH) were decreased and the activity of glutathione peroxidase (GSH-Px) and of glutathione reductase (GSSG-R) were not altered. The hepatocytes of folate deficient rats pretreated with vitamin E, when subjected to methanol treatment, showed no significant change in SOD levels and a significant decrease in MDA levels. The catalase activity in this group of animals showed a highly significant decrease. These animals had normal levels of GSH, while a significant fall in GSH-Px and GSSG-R levels were observed. These results suggest that Vitamin E exerts a protective effect on hepatocytes by acting as a free radical scavenger, proving its usefulness in treating methanol toxicity.

Candidate tumour suppressor genes at 11q23-q24 in breast cancer: evidence of alterations in PIG8, a gene involved in p53-induced apoptosis

One of the most consistently deleted chromosomal regions in solid tumours is 11q23-q25, which consequently has been postulated to harbour one or more tumour suppressor loci. Despite large efforts to identify the responsible genes, the goal remains elusive, but as knowledge accumulates new candidates are emerging. The present study was undertaken in an attempt to assess the possible implication of four genes residing at 11q23-q24, in a population of early onset breast cancer (n=41). The coding sequence of PIG8, CHK1, LOH11CR2A and PPP2R1B were screened for mutations using the protein truncation test or single-strand conformational polymorphism, in combination with direct DNA sequencing. Varying proportions of alterations were detected, ranging from 6% in PPP2R1B to 39% in PIG8. Many of these changes were deletions, in some cases corresponding to complete exons, thus likely to represent splice variants, while others were presumed to arise from aberrant splicing, since they occurred at sites with resemblance to exon/intron borders. Considering only bona fide mutations, the highest alteration frequency (17%) was again found in PIG8. Most of these alterations were likely to have an adverse impact on the translated protein as they either altered the reading frame or affected phylogenetically conserved residues. Our data represent the first evidence of alterations in the PIG8 gene in human malignancies, a finding that substantiates its role as a potential tumour suppressor gene as suggested by its involvement in p53-induced apoptosis.

Alcohol and aldehyde dehydrogenase activity in the stomach and small intestine of rats poisoned with methanol

The activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) were measured with fluorogenic naphthaldehydes in the stomach and small intestine homogenates of rats dosed with 6 g methanol/kg bw after 6, 12, 24 h and 2, 5, 7 days. After intoxication with a sublethal dose, the ADH activity measured with these naphthaldehydes and ALDH activities in the stomach and small intestine were significantly decreased. This inhibition is stronger in the stomach and probably depends on cell damage and protein denaturation. We conclude that the activity measured with 6-methoxy-2-naphthaldehyde (MONAL-62) may be due to the activity of rat ADH-1 isoenzyme, and the activity detected with 4-methoxy-1-naphthaldehyde (MONAL-41) to the activity of rat ADH-2 isoenzyme.

Protective effect of N-acetylcysteine on rat liver cell membrane during methanol intoxication

Methanol is oxidized in-vivo to formaldehyde and then to formate, and these processes are accompanied by the generation of free radicals. We have studied the effect of N-acetylcysteine on liver cell membrane from rats intoxicated with methanol (3.0 g kg(-1)). Evaluation of the effect was achieved by several methods. Lipid peroxidation and surface charge density were measured. An ultrastructural study of the liver cells was undertaken. The concentration of marker enzymes of liver damage (alanine aminotransferase and aspartate aminotransferase) in blood serum was measured. Methanol administration caused an increase in lipid peroxidation products (approximately 30%) as well as in surface charge density (approximately 60%). This might have resulted in the membrane liver cell damage visible under electron microscopy and a leak of alanine aminotransferase and aspartate aminotransferase into the blood (increase of approximately 70 and 50%, respectively). Ingestion of N-acetylcysteine with methanol partially prevented these methanol-induced changes. Compared with the control group, lipid peroxidation was increased by approximately 3% and surface charge density by approximately 30%. Alanine aminotransferase and aspartate aminotransferase activity increased by 9 and 8%, respectively, compared with the control group. The results suggested that N-acetylcysteine was an effective antioxidant in methanol intoxication. It may have efficacy in protecting free radical damage to liver cells following methanol intoxication.

Influence of trolox derivative and N-acetylcysteine on surface charge density of erythrocytes in methanol intoxicated rats

Methanol is oxidized in vivo to formaldehyde and then to formate and these processes are accompanied by free radicals generation. This paper reports the effect of antioxidants: trolox derivative (U-83836E) and N-acetylcysteine (NAC) on lipid peroxidation, surface charge density and hematological parameters of erythrocytes from rats intoxicated with methanol (3.0 g/kg body weight). Methanol administration caused increase in erythrocyte lipid peroxidation products and changes in surface charge density. Ingestion of methanol with U-83836E and NAC partially prevented these methanol-induced changes. This suggests that U83836E and NAC act as effective antioxidants and free radicals scavengers. They may have efficacy in protecting free radical damage to erythrocytes following methanol intoxication.

Protective effect of N-acetylcysteine on reduced glutathione, reduced glutathione-related enzymes and lipid peroxidation in methanol intoxication

The primary metabolic appropriation of methanol is oxidation to formaldehyde and then to formate. These processes are accompanied by formation of superoxide anion and hydrogen peroxide. This paper reports data on the effect of N-acetylcysteine (NAC) on reduced glutathione (GSH) and on activity of some GSH-metabolising enzymes in the liver, erythrocytes and serum of rats intoxicated with methanol (3 g/kg b.w.) during 7 days after intoxication. Methanol administration, increasing concentration of the lipid peroxidation products, decreased the liver glutathione-peroxidase and glutathione reductase (GSSG-R) activities, GSH concentration and total antioxidant status (TAS). The use of NAC after methanol ingestion apparently diminished lipid peroxidation, elevated the GSH level in the liver and erythrocytes, and increased activity of GSH-related enzymes in the serum, erythrocytes and in the liver. These results suggest that NAC exerts its protective effect by acting as a precursor for glutathione, the main low molecular antioxidant and as a free radical scavenger.

Trolox-derivative antioxidant protects against methanol-induced damage

This paper reports data on the effect of a new antioxidant, U-83836E, on the lipid peroxidation and antioxidant status of liver, red blood cells (RBCs) and blood serum of rats intoxicated with methanol (3.0 g/kg body weight). Methanol administration slightly increased the levels of peroxidation products in the liver, and markedly increased them in RBCs and serum. In contrast, glutathione-peroxidase, glutathione-reductase activity, reduced glutathione concentration and total antioxidant status were decreased. The use of U-83836E, containing a trolox ring, appeared to be beneficial in reducing lipid peroxidation products and in partially in preventing the decrease in glutathione and antioxidant enzymes induced by methanol in liver and serum. These results show that antioxidant U-83836E may partially prevent methanol toxicity.