Tinospora cordifolia induces enzymes of carcinogen/drug metabolism and antioxidant system, and inhibits lipid peroxidation in mice

The present study is an effort to identify a potent chemopreventive agent against various diseases (including cancer) in which oxidative stress plays an important causative role. Here, we investigated the effect of a hydroalcoholic (80% ethanol: 20% distilled water) extract of aerial roots of Tinospora cordifolia (50 and 100mg/kg body wt./day for 2 weeks) on carcinogen/drug metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione (GSH) content, lactate dehydrogenase and lipid peroxidation in liver of 8-week-old Swiss albino mice. The modulatory effect of the extract was also examined on extrahepatic organs, i.e., lung, kidney and forestomach, for the activities of GSH S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD) and catalase. Significant increases in the levels of acid-soluble sulfhydryl (-SH) and cytochrome P(450) contents, and enzyme activities of cytochrome P(450) reductase, cytochrome b(5) reductase, GST, DTD, SOD, catalase, GSH peroxidase (GPX) and GSH reductase (GR) were observed in the liver. Both treated groups showed decreased malondialdehyde (MDA) formation. In lung SOD, catalase and GST; in kidney SOD and catalase; and in forestomach SOD, DTD and GST showed significant increase at both dose levels of treatment. BHA (0.75%, w/w in diet), a pure antioxidant compound, was used as a positive control. This group showed increase in hepatic levels of GSH content, cytochrome b(5), DTD, GST, GR and catalase, whereas MDA formation was inhibited significantly. In the BHA-treated group, the lung and kidney showed increased levels of catalase, DTD and GST, whereas SOD was significantly increased in the kidney and forestomach; the latter also showed an increase in the activities of DTD and GST. The enhanced GSH level and enzyme activities involved in xenobiotic metabolism and maintaining antioxidant status of cells are suggestive of a chemopreventive efficacy of T. cordifolia against chemotoxicity, including carcinogenicity, which warrants further investigation of active principle (s) present in the extract responsible for the observed effects employing various carcinogenesis models.     

Modulatory effect of Urtica dioica L. (Urticaceae) leaf extract on biotransformation enzyme systems, antioxidant enzymes, lactate dehydrogenase and lipid peroxidation in mice.

The effects of two doses (50 and 100 mg/kg body wt given orally for 14 days) of an ethanol-water (80%-20%) extract of Urtica dioica L. and butylated hydroxyanisole (BHA) were investigated, for phase I and phase II enzymes, antioxidant enzymes, lactate dehydrogenase, lipid peroxidation and sulfhydryl groups in the liver of Swiss albino mice (8-9 weeks old). A modulatory effect of two doses and BHA was also observed for the activities of glutathione S-transferase, DT-diaphorase, superoxide dismutase and catalase in the kidney, lung and forestomach, as compared with the control group. The activities of cytochrome b5 (cyt b5), NADH-cytochrome b5 reductase (cyt b5 R), glutathione S-transferase (GST), DT-diaphorase (DTD), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT) showed a significant increase in the liver at both dose levels of extract. Both extract-treated showed significantly lower activity of cytochrome P450 (cyt P450), lactate dehydrogenase (LDH), NADPH-cytochrome P450 reductase (cyt P450 R), total sulfhydryl groups (T-SH), nonprotein sulfhydryl groups (NP-SH) and protein-bound sulfhydryl groups (PB-SH). BHA-treated Swiss albino mice showed a notable increase in levels of cyt b5, DTD, T-SH, PB-SH, GPx, GR, and SOD in the liver while, LDH, cyt P450, cyt P450 R, Cyt b5 R, GST, NP-SH, and CAT levels were reduced significantly as compared to control values. The extract was effective in inducing GST, DTD, SOD and CAT activity in the forestomach and SOD and CAT activity in the lung at both dose levels. BHA-treated Swiss albino mice induced DTD, GST and all antioxidative parameters in the kidney, lung and forestomach.     

Modulatory influence of Brassica compestris Linn var sarson on phase-II carcinogen metabolizing enzymes and glutathione levels in mice

The present study reports the modulatory influence of 95% ethanolic extract from the seeds of B. compestris on the activity of phase-II enzymes such as glutathione S-transferase (GST), DT-diaphorase (DTD) and reduced glutathione (GSH) level in the skin, lung, kidney and forestomach of the mouse. Oral treatment with the seed extract at 800 mg/kg body wt. for 15 days significantly elevated GST in lung and forestomach and DT-diaphorase in forestomach and skin and GSH level in lung, kidney forestomach and skin. The lower dose 400 mg/kg body wt was effective only in inducing GST and DT-diaphorase activity in forestomach and reduced glutathione level in lung. The findings suggest that B. compestris seed extract may block or suppress the events associated with chemical carcinogenesis at least in part, by inducing metabolic detoxification of the carcinogen.     

Chemomodulatory action of Aloe vera on the profiles of enzymes associated with carcinogen metabolism and antioxidant status regulation in mice.

The effect of two doses (30 microl and 60 microl/day/mice daily for 14 days) of the fresh leaf pulp extract of Aloe vera was examined on carcinogen-metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of mice. The modulatory effect of the pulp extract was also examined on extrahepatic organs (lung, kidney and forestomach) for the activities of glutathione S-transferase, DT-diophorase, superoxide dismutase and catalase. The positive control mice were treated with butylated hydroxyanisole (BHA). Significant increases in the levels of acid soluble sulfhydryl (-SH) content, NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase, glutathione S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX) and glutathione reductase (GR) were observed in the liver. Aloe vera significantly reduced the levels of cytochrome P450 and cytochrome b5. Thus, Aloe vera is clearly an inducer of phase-II enzyme system. Treatment with both doses of Aloe caused a decrease in malondialdehyde (MDA) formation and the activity of lactate dehydrogenase in the liver, suggesting its role in protection against prooxidant-induced membrane and cellular damage. The microsomal and cytosolic protein was significantly enhanced by Aloe vera, indicating the possibility of its involvement in the induction of protein synthesis. BHA, an antioxidant compound, provided the authenticity of our assay protocol and response of animals against modulator. The pulp extract was effective in inducing GST, DTD, SOD and catalase as measured in extrahepatic organs. Thus, besides liver, other organs (lung, kidney and forestomach) were also influenced favorably by Aloe vera in order to detoxify reactive metabolites, including chemical carcinogens and drugs.     

Modulatory effect of Henna leaf (Lawsonia inermis) on drug metabolising phase I and phase II enzymes,antioxidant enzymes,lipid peroxidation and chemically induced skin and forestomach papillomagenesis in mice

Henna leaf (Lawsonia inermis), commonly known as Mehndi is cultivated throughout India and is a very popular natural dye to color hand and hair. It is an integral part of indigenous culture, and is also known for its medicinal value. The effect of 200 and 400 mg/kg body weight of 80% ethanolic extract of the fresh leaves of Lawsonia inermis were examined on drug metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of 7 weeks old Swiss albino mice. Also anticarcinogenic potential of Henna leaf extract was studied adopting the protocol of benzo(a)pyrene induced forestomach and 7,12 dimethylbenz(a)anthracene (DMBA)-initiated and croton oil-promoted skin papillomagenesis. Our primary findings reveal the duel-acting nature of henna leaf as deduced from its potential to induce only the phase-II enzyme activity, associated mainly with carcinogen detoxification in liver of mice and inhibit the phase I enzyme activities. The hepatic glutathione S-transferase and DT-diaphorase specific activities were elevated above basal (p < 0.005) level by Lawsonia inermis extract treatment. With reference to antioxidant enzymes the investigated doses were effective in increasing the hepatic glutathione reductase (GR), superoxide dismutase (SOD) and catalase activities significantly (from p < 0.05 to p < 0.005) at both the dose levels. Reduced glutathione (GSH) measured as non-protein sulphydryl was found to be significantly elevated in liver (p < 0.005) and in all the extrahepatic organs studied (from p < 0.05 to p < 0.005). Among the extrahepatic organs examined (forestomach, kidney and lung) glutathione S-transferase and DT-diaphorase level were increased in a dose independent manner (from p < 0.05 to p < 0.005). Chemopreventive response was measured by the average number of papillomas per mouse (tumor burden) as well as percentage of tumor bearing animals and tumor multiplicity. There was a significant inhibition of tumor burden in both the tumor model systems studied (from p < 0.01 to p < 0.001). Tumor incidence was also reduced by both the doses used in our experiment in both the model systems.     

Chemomodulation of carcinogen metabolising enzymes,antioxidant profiles and skin and fore-stomach papillomagenesis by Spirulina platensis

Numerous reports have revealed an inverse association between consumption of some selective natural products and risk of developing cancer. In the present study the effect of 250 and 500 mg/kg body weight of Spirulina was examined on drug metabolising phase I and phase II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of 7-week-old Swiss albino mice. The implications of these biochemical alterations have been further evaluated adopting the protocol of benzo(a)pyrene induced forestomach and 7,12 dimethylbenz(a)anthracene (DMBA) initiated and croton oil promoted skin papillomagenesis. Our primary findings reveal the Monofunctional nature of Spirulina as deduced from its potential to induce only the phase II enzyme activities associated mainly with carcinogen detoxification. The glutathione S-transferase and DT-diaphorase specific activities were induced in hepatic and all the extrahepatic organs examined (lung, kidney and forestomach) by Spirulina pretreatment (significance level being from p < 0.05 to p < 0.005) except for the low dose treatment in forestomach. With reference to antioxidant enzymes viz., superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and reduced glutathione were increased significantly by both the chosen doses of Spirulina from p < 0.01 to p < 0.005. Chemopreventive response was quantitated by the average number of papillomas per effective mouse (tumor burden) as well as percentage of tumor bearing animals. There was a significant inhibition of tumor burden as well as tumor incidence in both the tumor model systems studied. In the skin tumor studies tumor burden was reduced from 4.86 to 1.20 and 1.15 by the low and high dose treatment respectively. In stomach tumor studies tumor burden was 2.05 and 1.73 by the low and high doses of Spirulina treatment against 3.73 that of control.     

Chemomodulatory efficacy of basil leaf (Ocimum basilicum) on drug metabolizing and antioxidant enzymes, and on carcinogen-induced skin and forestomach papillomagenesis.

Basil or sweet basil (Ocimum basilicum) is cultivated throughout India and is known for its medicinal value. The effects of doses of 200 and 400 mg/kg body weight of hydroalcoholic extract (80% ethanol, 20% water) of the fresh leaves of Ocimum basilicum on xenobiotic metabolizing Phase I and Phase II enzymes, antioxidant enzymes, Glutathione content, Lactate dehydrogenase and lipid peroxidation in the liver of 8-9 weeks old Swiss albino mice were examined. Furthermore, the anticarcinogenic potential of basil leaf extract was studied, using the model of Benzo(a)pyrene-induced forestomach and 7,12 dimethyl benz(a)anthracene (DMBA)-initiated skin papillomagenesis. The hepatic glutathione S-transferase and DT-diaphorase specific activities were elevated above basal level by basil leaf treatment (from p < 0.005 to p < 0.001). Basil leaf extract was very effective in elevating antioxidant enzyme response by increasing significantly the hepatic glutathione reductase (GR) (p < 0.005), superoxide dismutase (SOD) (p < 0.05), and catalase activities (p < 0.005). Reduced glutathione (GSH), the major intracellular antioxidant, showed a significant elevation in the liver (p < 0.005) and also in all the extrahepatic organs (from p < 0.05 to p < 0.005). In the forestomach, kidney and lung, glutathione S-transferase and DT-diaphorase levels were augmented significantly, varying from p < 0.01 to p < 0.001. There were significant decreases in lipid peroxidation and lactate dehydrogenase activity. Chemopreventive response was evident from the reduced tumor burden (the average number of papillomas/mouse, p < 0.005 to p < 0.001), as well as from the reduced percentage of tumor bearing-animals. Basil leaf, as deduced from the results, augmented mainly the Phase II enzyme activity that is associated with detoxification of xenobiotics, while inhibiting the Phase I enzyme activity. There was an induction in antioxidant level that correlates with the significant reduction of lipid peroxidation and lactate dehydrogenase formation. Moreover, Basil leaf extract was highly effective in inhibiting carcinogen-induced tumor incidence in both the tumor models at peri-initiational level.     

Black tea polyphenols modulate xenobiotic-metabolizing enzymes,oxidative stress and adduct formation in a rat hepatocarcinogenesis model

The present study was designed to investigate the modulatory effects of black tea polyphenols (Polyphenon-B) on phase I and phase II xenobiotic-metabolizing enzymes and oxidative stress in a rat model of hepatocellular carcinoma (HCC). Liver tumours induced in male Sprague-Dawley rats by dietary administration of ρ-dimethylaminoazobenzene (DAB) increased cytochrome P450 (total and CYP1A1, 1A2 and 2B isoforms), cytochrome b₅, cytochrome b₅ reductase, glutathione S-transferase (GST total and GST-P isoform) and gamma-glutamyltranspeptidase (GGT) with decrease in quinone reductase (QR). This was accompanied by enhanced lipid and protein oxidation and compromised antioxidant defences associated with increased expression of the oxidative stress markers 4-hydroxynonenal (4-HNE), anti-hexanoyl lysine (HEL), dibromotyrosine (DiBrY) and 8-hydroxy 2-deoxyguanosine (8-OHdG). Dietary administration of Polyphenon-B effectively suppressed DAB-induced hepatocarcinogenesis, as evidenced by reduced preneoplastic and neoplastic lesions, modulation of xenobiotic-metabolizing enzymes and amelioration of oxidative stress. Thus, it can be concluded that Polyphenon-B acts as an effective chemopreventive agent by modulating xenobiotic-metabolizing enzymes and mitigating oxidative stress in an in vivo model of hepatocarcinogenesis.     

Chemopreventive effect of piperine on mitochondrial TCA cycle and phase-I and glutathione-metabolizing enzymes in benzo(a)pyrene induced lung carcinogenesis in Swiss albino mice

Piperine is a major component of black (Piper nigrum Linn) and long pepper (Piper longum Linn) used widely in various systems of traditional medicine. We have evaluated the effect of piperine on mitochondrial tricarboxylic acid cycle and phase I and glutathione-metabolizing enzymes in Benzo(a)pyrene induced experimental lung carcinogenesis in swiss albino mice. Lung cancer bearing mice showed a significant decrease in the activities of mitochondrial enzymes-isocitrate dehydrogenase (ICDH), -ketoglutarate dehydrogenase (KDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) and significantly increased NADPH-Cytochorome reductase (NADPH-C reductase), cytochrome P450 (cyt-p450) and cytochrome b5(cyt-b5). The activities of glutathione-metabolizing enzymes glutathione peroxidase(GPx), glutathione reductase (GR) and glucose-6-phospho dehydrogenase(G6PDH) were significantly lowered in lung-cancer bearing mice when compared with control mice. Piperine supplementation to tumour-induced animals significantly lowered the phase-I enzymes (NADPH-C reductase, cyt-p450 and cyt-b5)) and there was a rise in glutathione-metabolizing enzymes (GPx, GR and G6PDH), which indicated an antitumour and anti-cancer effect. Comparison of normal control mice and mice administered piperine only as drug control showed no significant variations in enzyme activities. Piprine administration to benzo(a)pyrene induced animals significantly increased the activities of mitochondrial enzymes, thereby suggesting its role in mitochondrial energy production.     

Changes in glutathione-related enzymes in tumor-bearing mice after cisplatin treatment

The effect of cisplatin on five glutathione-related enzymes was studied in liver, kidney, and Dalton lymphoma cells of tumor-bearing mice. In liver, the activities of glutathione S-transferase, glutathione peroxidase, catalase, and superoxide dismutase decreased approximately 30–40%, 60–67%, 35–50% and 70–80% respectively, while glutathione reductase increased about 36–45% after cisplatin treatment. In kidney, catalase activity decreased by 47–82% at all time points (24–96 h) of cisplatin treatment, while glutathione S-transferase activity decreased significantly (~24%) mainly at 72 h of treatment. An increase in glutathione reductase (~1.5–2.5 times), glutathione peroxidase (significant at 24 h, 47%), and superoxide dismutase (~15–60%) was noted in kidney after the treatment. In Dalton lymphoma cells, the activities of glutathione S-transferase, glutathione peroxidase, and catalase decreased very distinctly (~2–5, 2–5 and 5–11 times, respectively) at all time points, but glutathione reductase decreased significantly only at 72 h of cisplatin treatment. Interestingly, the superoxide dismutase activity in Dalton lymphoma cells increased initially at 24–48 h and then decreased (~60%) during later periods (72–96 h) of treatment. Cisplatin treatment caused a decrease in glutathione level in Dalton lymphoma cells (~14–20%) and kidney (~18–28%) but no change in liver. In view of the results, a definite correlation with the changes in glutathione concentrations and enzymatic activities in a tissue could not be firmly derived. It is suggested that the changes in various glutathione-related enzymes and glutathione levels in the tissues of the host during cisplatin-mediated chemotherapy could affect cellular antioxidant defense potential, which may play an important contributory role in cisplatin-mediated toxicity, particularly nephrotoxicity, and anticancer activity in the host. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of arsenic (AsIII) on glutathione-dependent enzymes in liver and kidney of the freshwater fish Channa punctatus

The possible role of glutathione-dependent enzymes in the liver and kidney of the freshwater fish Channa punctatus has been studied after exposure to arsenic trioxide for different durations. Activities of glutathione-S-transferases, glutathione peroxidase, glutathione reductase, and catalase decreased in the liver and kidney as a result of the initial increase in arsenic concentration in the liver and kidney. However, during longer exposures, a decline in arsenic concentration corresponded with improved enzyme activity. Because arsenic manifests its toxicity by inducing oxidative stress, the antioxidant enzymes, especially the glutathione-dependent enzymes, play a protective role in arsenic toxicity.     

Effect of Terminalia chebula aqueous extract on oxidative stress and antioxidant status in the liver and kidney of young and aged rats

We evaluated the preventive effects of Terminalia chebula (T. chebula) aqueous extract on oxidative and antioxidative status in liver and kidney of aged rats compared to young albino rats. The concentrations of malondialdehyde (MDA), lipofuscin (LF), protein carbonyls (PCO), activities of xantione oxidase (XO), manganese‐superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione‐S‐transferase (GST), and glucose‐6‐phosphate dehydrogenase (G6PDH), levels of glutathione (GSH), vitamin C and vitamin E were used as biomarkers. In the liver and kidney of aged animals, enhanced oxidative stress was accompanied by compromised antioxidant defences. Administration of aqueous extract of T. cheubla effectively modulated oxidative stress and enhanced antioxidant status in the liver and kidney of aged rats. The results of the present study demonstrate that aqueous extract of T. cheubla inhibits the development of age‐induced damages by protecting against oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.     

Antioxidant status in herbaceous plants growing under elevated CO2 in mini-FACE rings

Here we present studies on the antioxidant status of a semi-natural grassland community, permanently growing in mini-FACE rings under elevated concentrations of atmospheric CO₂ (560 μmol mol⁻¹). In general, in leaves of Dactylis glomerata L. and Trifolium repens L., no differences between ambient and elevated CO₂ were detected as concerns protein content, activity of oxidant-scavenging enzymes (catalase, superoxide dismutase, ascorbate peroxidase and guaiacol peroxidase), and lipid peroxidation. The activity of antioxidant-regenerating enzymes (monodehydroascorbate reductase, dehydroascorbate reductase and glutathione disulfide reductase) and the content of antioxidants (ascorbic acid, dehydroascorbic acid, reduced glutathione and glutathione disulfide) showed remarkable variability between leaves from plants grown in ambient and CO₂-enriched mini-FACE rings. Thus, in general it can be concluded that the effects of elevated CO₂ at environmentally relevant concentrations on the leaf antioxidant status of a grassland community are extremely variable, species-specific and rather limited.     

Methyl jasmonate and salicylic acid elicitation induces ginsenosides accumulation, enzymatic and non-enzymatic antioxidant in suspension culture Panax ginseng roots in bioreactors

The effects of methyl jasmonate (MJ) and salicylic acid (SA) on changes of the activities of major antioxidant enzymes, superoxide anion accumulation (O₂ ⁻), ascorbate, total glutathione (TG), malondialdehyde (MDA) content and ginsenoside accumulation were investigated in ginseng roots (Panax ginseng L.) in 4 l (working volume) air lift bioreactors. Single treatment of 200 μM MJ and SA to P. ginseng roots enhanced ginsenoside accumulation compared to the control and harvested 3, 5, 7 and 9 days after treatment. MJ and SA treatment induced an oxidative stress in P. ginseng roots, as shown by an increase in lipid peroxidation due to rise in O₂ ⁻ accumulation. Activity of superoxide dismutase (SOD) was inhibited in MJ-treated roots, while the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), SOD, guaiacol peroxidase (G-POD), glutathione peroxidase (GPx) and glutathione reductase (GR) were induced in SA-treated roots. A strong decrease in the activity of catalase (CAT) was obtained in both MJ- and SA-treated roots. Activities of ascorbate peroxidase (APX) and glutathione S transferase (GST) were higher in MJ than SA while the contents of reduced ascorbate (ASC), redox state (ASC/(ASC+DHA)) and TG were higher in SA- than MJ-treated roots while oxidized ascorbate (DHA) decreased in both cases. The result of these analyses suggests that roots are better protected against the O₂ ⁻ stress, thus mitigating MJ and SA stress. The information obtained in this work is useful for efficient large-scale production of ginsenoside by plant-root cultures.     

Hepatoprotective activity of <Emphasis Type="BoldItalic">Tribulus terrestris</Emphasis> extract against acetaminophen-induced toxicity in a freshwater fish (<Emphasis Type="BoldItalic">Oreochromis mossambicus</Emphasis>)

The potential protective role of Tribulus terrestris in acetaminophen-induced hepatotoxicity in Oreochromis mossambicus was investigated. The effect of oral exposure of acetaminophen (500 mg/kg) in O. mossambicus at 24-h duration was evaluated. The plant extract (250 mg/kg) showed a remarkable hepatoprotective activity against acetaminophen-induced hepatotoxicity. It was judged from the tissue-damaging level and antioxidant levels in liver, gill, muscle and kidney tissues. Further acetaminophen impact induced a significant rise in the tissue-damaging level, and the antioxidant level was discernible from the enzyme activity modulations such as glutamate oxaloacetic transaminase, glutamate pyruvic transaminase, alkaline phosphatase, acid phosphatase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, lipid peroxidase and reduced glutathione. The levels of all these enzymes have significantly (p < 0.05) increased in acetaminophen-treated fish tissues. The elevated levels of these enzymes were significantly controlled by the treatment of T. terrestris extract (250 kg/mg). Histopathological changes of liver, gill and muscle samples were compared with respective controls. The results of the present study specify the hepatoprotective and antioxidant properties of T. terrestris against acetaminophen-induced toxicity in freshwater fish, O. mossambicus.     

Alteration of antioxidant status following sympathectomy: Differential effects of modified plasma levels of adrenaline and noradrenaline

The influence of altered levels of endogenous catecholamines following adrenalectomy or 6-hydroxydopamine (6-OH) treatment (alone or in combination) on enzymatic (glutathione reductase, catalase, glutathione peroxidase and Cu,Zn superoxide dismutase) and non-enzymatic (glutathione) antioxidant components of heart, liver, kidney, lung and erythrocytes in male Wistar rats was investigated. Functional antioxidant status was assessed in terms of susceptibility to t-butylhydroperoxide-induced sulfhydryl group oxidation (an indirect measure of glutathione depletion) and lipid peroxidation, as measured by thiobarbituric acid-reactive substance (TBARS) formation. Reduced levels of adrenaline and noradrenaline resulted from adrenalectomy and 6-OH treatment, respectively, while a combination of these treatments led to a reduction in the levels of both catecholamines. Adrenalectomy was associated with alterations in glutathione reductase activity in the heart and liver (increased). 6-OH treatment alone produced an elevation in glutathione reductase activity only in the heart. In adrenalectomized animals, 6-OH treatment produced no further increases in glutathione reductase activities of heart or liver. In lung, however, the combination of adrenalectomy and 6-OH treatment caused an elevation in both glutathione peroxidase and glutathione reductase activities. Glutathione levels of liver alone were elevated following adrenalectomy, while those of erythrocytes and liver (but not other tissues investigated) were increased by the combination of adrenalectomy and 6-OH treatment. The kidney was relatively resistant to the effects of sympathectomy and showed no changes in any of the antioxidant components measured. Adrenalectomy alone or in combination with 6-OH produced an increase in susceptibility to peroxide-induced sulfhydryl group oxidation only in the heart. 6-OH treatment caused a reduction in peroxide-induced TBARS formation only in the kidney. Both adrenalectomy and the combination of adrenalectomy and 6-OH treatment were associated with reduced TBARS formation in the liver, lung and kidney, but not heart. Results from this study demonstrate that the effects of sympathectomy on antioxidant status vary among tissues. Differences between adrenalectomy and 6-OH treatment on antioxidant components are suggestive of differential actions of adrenaline and noradrenaline on tissue antioxidant status which may have important implications under conditions associated with elevations in levels of these catecholamines including chronic stress and myocardial infarction.     

Chemoprevention of mammary tumorigenesis and chemomodulation of the antioxidative enzymes and peroxidative damage in prepubertal Sprague Dawley rats by Biochanin A

Although chemopreventive action of Biochanin A against various cancers including that of prostate, breast, colon, and fore-stomach has been reported earlier, none of the studies was made in prepubertal subjects. The present study appears to be the first one on prepubertal rats that indicates the efficacy of the test compound in the prevention of tumorigenesis. The antioxidative status and xenobiotic metabolism were also evaluated to understand the mechanism of Biochanin A induced prevention of cancer. For the tumorigenesis study 500 μg/g bwt of Biochanin A or vehicle dimethyl sulfoxide (DMSO) s.c, was injected at 16th, 18th, and 20th days post-partum followed by the administration of dimethylbenz[a]nthracene (DMBA) (80 μg/g bwt) at 50th day. In another set of experiments, to study the involvement of peroxidative process in the mechanism of action of test compound, different antioxidant parameters were studied following the administration of two different doses of Biochanin A (0.5 and 50 mg/kg bwt, through oral gavage for 10 days) in the prepubertal rats from day 16 post-partum. Results showed a significant reduction in the mammary tumors (more than 40%) in Biochanin A treated animals, as compared to animals treated with DMBA only. Spectrophotometric enzyme estimations revealed that the specific activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione transferase (GST), DT-diaphorase (DTD), and reduced glutathione (GSH) levels were increased, whereas specific activities of lactate dehydrogenase (LDH) and lipid peroxidation (LPO) were decreased significantly, both in liver as well as in mammary gland, in animals treated with Biochanin A prepubertally. These results reveal the possible involvement of the antioxidative and metabolic enzymes in the suppression of cancer burden and incidence in a prepubertal rat model suggesting that the intake of this phytoestrogen at an early stage may help in lowering the risk of mammary tumor.     

Interactions of betulinic acid with xenobiotic metabolizing and antioxidative enzymes in DMBA-treated Sprague Dawley female rats

Cancer chemoprevention is related to classical epidemiology and involves the use of agents that inhibit, delay, or reverse the carcinogenesis that occurs as a result of accumulation of mutations and increased proliferation. Betulinic acid is known for its cytotoxic effects against a panel of cancer cell lines. In the present study, interactions of betulinic acid (BA) with xenobiotic metabolizing enzymes including mixed function oxidases (cytochrome b5, P420, P450, NADPH cytochrome P450 reductase, and NADH cytochrome b5 reductase), phase II enzymes (GST, DT-diaphorase, γ-glutamyl transpeptidase), LDH, antioxidative enzymes (glutathione reductase, SOD, catalase, ascorbate peroxidase, and guaiacol peroxidase), and lipid peroxidation are studied alone as well as in the presence of 7,12 dimethylbenzanthracene (DMBA)—a potent carcinogen using Sprague Dawley female rats. The effect of BA on reduced glutathione content and protein content is also taken into consideration. It has been found that administration of BA decreased the level of mixed function oxidases that are involved in the conversion of carcinogen to electrophile, elevated the level of phase II enzymes which participated in the removal of electrophiles by sulfation, conjugation etc. It has been found that BA effectively removed or neutralized the reactive species by the action of phase II enzymes and such an effect was reflected from the specific activities of antioxidative enzymes which were found to be lower as compared to positive control (DMBA-treated group) and in some cases even that of untreated control. BA was also found to have a pronounced effect in protecting the animals from lipid peroxidation as evident from the reduced levels of TBARS, conjugated diene, and lipid hydroperoxide formation. This study highlights the role of BA in modulating the activities of xenobiotic and antioxidative enzymes that have putative roles in cancer initiation and proliferation.     

Biomarkers of oxidative stress for in vivo assessment of toxicological effects of iron oxide nanoparticles

Iron oxide nanoparticles (Fe₂O₃-IONPs) have revolutionized the industry by significant economic and scientific impacts. Enormous increase in the usage of IONPs has raised concerns about their unseen adverse effects. In the current study, we investigated the effects of IONPs and its bulk on oxidative stress biomarkers, histopathology and biodistribution in rats after 28 days repeated oral treatment at 30, 300 and 1000 mg/kg body weight (b.w.). IONPs size in dry, wet forms and crystallinity was determined using TEM, DLS and XRD. The investigation of oxidative stress biomarkers demonstrated significant increase in lipid peroxidation and decrease in reduced glutathione content in the liver, kidney and the brain of the treated groups in a dose dependant manner. Further, antioxidant enzymes catalase, glutathione S transferase, glutathione peroxidase and glutathione reductase activities were significantly elevated along with significant decrease in superoxide dismutase activity in treated rat organs. ICP-OES analysis revealed dose and size dependant accumulation of IONPs in the liver followed by kidney and the brain than bulk. Moreover, accumulation of IONPs at high dose brought pathological changes only in liver. A large fraction of IONPs was eliminated in urine. Bulk material was substantially excreted in faeces than IONPs suggesting increased absorption of IONPs. In conclusion accumulated IONPs and bulk in organs trigger free radical generation, leading to the induction of oxidative stress condition in rats. The results obtained highlight the importance of toxicity assessments in evaluating the efficiency of IONPs for the safe implementation for diversified applications.     

The influence of chromium chloride consumption on lipid peroxidation and activity of the antioxidant defense in rat tissues

The effect of food supplementation with chromium (CrCl₃ · 6H₂O) on intensity of peroxide processes and activity of antioxidant enzymes has been investigated in some rat tissues. Food supplementation with 200 μg/kg CrCl₃ · 6H₂O for 30 days resulted in the increase of tissue chromium. The tissue chromium content of chromium-treated rats decreased in the following order: spleen, heart, kidney, lung, brain, liver, skeletal muscles. All organs and tissues (except skeletal muscles) of chromium-treated rats were characterized by decreased content of lipid peroxidation (LPO) products: hydroperoxides and thiobarbituric acid reactive substances (TBARS). The maximal reduction in LPO products was observed in spleen, kidney, liver, and lung. Treatment with chromium also caused an increase in the activity of glutathione peroxidase, glutathione reductase, and calatase in all tissues and organs studied. In the brain and kidney an increase in the content of reduced glutathione was observed. Superoxide dismutase activity was higher in myocardium and skeletal muscles, basically equal in lung and liver, while in other organs (brain, kidney, spleen) of experimental animals it was lower than in control animals. Results of this study suggest that chromium exhibits tissue/organ-specific regulatory effects on enzymes of the antioxidant defense