Changes In Antioxidant System Research Articles

Antioxidant Systems in Sunflower as Affected by Oxalic Acid

Changes in antioxidant systems in sunflower (Helianthus annuus L.) inbred lines were studied in relation to different concentrations (0, 2, 3 and 4 mM) of oxalic acid. A great variability of the total superoxide dismutase (SOD) activity was observed in different genotypes after application of oxalic acid. Genotypes showing no change in SOD activity, as well as those with decreased and increased activities, have been found. The highest guaiacol peroxidase (GPX) activity was recorded in the leaves of Ha-26A genotype where the activity of SOD was low. In genotypes with increased GPX activity the malonyldialdehyde content was low. The increase in reduced glutathione content occured in almost all of the genotypes studied with the increase in oxalate concentration. Some genotypes such as PR-ST-3B, showed distinctive and combined activity of several antioxidant systems. Also, obtained results for the content of total phenols support the idea of using soluble phenols as molecular markers and confirm the hypothesis of the defensive role of these compounds in plants.

Protective Effect of Modified Glucomannans against Changes in Antioxidant Systems of Quail Egg and Embryo due to Aurofusarin Consumption

The aim of this study was to evaluate effects of modified glucomannan (Mycosorb) on the antioxidant profile of egg yolk and tissues of newly hatched quail after aurofusarin inclusion in the maternal diet. Fifty-four 45 day-old Japanese quail were divided into three groups and were fed a corn-soya diet balanced in all nutrients ad libitum. The diet of the experimental quail was supplemented with aurofusarin at the level of 26.4 mg/kg feed in the form of Fusarium graminearum culture enriched with aurofusarin or with aurofusarin plus Mycosorb at 1 g/kg feed. Eggs obtained after 8 weeks of feeding were analysed and incubated in standard conditions of 37.5°C/55% RH. Samples of quail tissues were collected from newly hatched quail. The main carotenoids, retinol, retinyl esters and malondialdehyde were analysed by HPLC-based methods. Inclusion of aurofusarin in the maternal diet was associated with decreased carotenoid and vitamin A concentrations in egg yolk and liver of newly-hatched quail. Furthermore, lipid peroxidation in quail tissues was enhanced. Inclusion of modified glucomannan (Mycosorb) in the toxin-contaminated diet provided a significant protective effect against changes in antioxidant composition in the egg yolk and liver. It is suggested that a combination of mycotoxin adsorbents and natural antioxidants could be the next step in counteracting mycotoxins in animal feed.

Early contrast sensitivity loss and oxidative damage in healthy heavy smokers

AbstractObjective: The purpose of this study was 1) to evaluate visual functions and the activities of antioxidant enzymes in plasma and erythrocytes in smokers in comparison with non‐smokers, 2) to evaluate the correlations between visual functions and the oxidant/antioxidant system. We hypothesized that the changes in antioxidant system and consequently lipid peroxidation depend on smoking may affect sophisticated visual tests including contrast sensitivity (CS) and pattern visual evoked potentials (PVEP)Subjects: This non‐randomised control study included 24 chronic, heavy smokers who were smoking more than 20 cigarettes per day at least for last 10 years. Sixteen age and sex‐matched, healthy, non‐smokers were taken as controls. All volunteer subjects were accumulated from the outpatient clinic. To rule out the effect of alcoholism and malnutrition, we chose young, healthy heavy smokers who maintained adequate diet and who had no alcohol consumption history.Following visual acuity and color vision tests, all subjects were applied to CS and PVEP tests. Values of CS, N75‐P100 amplitude and P100 wave latency were compared between the study and control subjects. Superoxide dismutase (SOD) and catalase (CAT) activities in plasma and erythrocytes were determined by spectrophotometer. Plasma malondialdehyde (MDA) level, as an end product of lipid peroxidation, was assessed by spectrofluorometric method.Results: CS was determined to be significantly reduced in smokers compared to non‐smokers, although central vision and PVEP responses were not affected. Erythrocyte SOD activity and plasma MDA levels were significantly increased in smokers compared to controls. There were positive correlations between plasma SOD and erythrocyte SOD; CS and erythrocyte SOD; and CS and plasma SOD.Conclusions: The results suggest the possible association between early CS loss and increase in antioxidant enzyme activities thus reflecting an increased oxidative damage due to cumulative effect of chronic smoking. Elevated concentrations of lipid peroxidation products in the plasma of smokers may directly show the increased oxidative damage in these subjects.

Cadmium-Induced Changes in Antioxidative Systems, Hydrogen Peroxide Content, and Differentiation in Scots Pine Roots

Cadmium-Induced Changes in Antioxidative Systems, Hydrogen Peroxide Content, and Differentiation in Scots Pine Roots

Cadmium-induced changes in antioxidative systems, hydrogen peroxide content, and differentiation in Scots pine roots.

To investigate whether Cd induces common plant defense pathways or unspecific necrosis, the temporal sequence of physiological reactions, including hydrogen peroxide (H(2)O(2)) production, changes in ascorbate-glutathione-related antioxidant systems, secondary metabolism (peroxidases, phenolics, and lignification), and developmental changes, was characterized in roots of hydroponically grown Scots pine (Pinus sylvestris) seedlings. Cd (50 microM, 6 h) initially increased superoxide dismutase, inhibited the systems involved in H(2)O(2) removal (glutathione/glutathione reductase, catalase [CAT], and ascorbate peroxidase [APX]), and caused H(2)O(2) accumulation. Elongation of the roots was completely inhibited within 12 h. After 24 h, glutathione reductase activities recovered to control levels; APX and CAT were stimulated by factors of 5.5 and 1.5. Cell death was increased. After 48 h, nonspecific peroxidases and lignification were increased, and APX and CAT activities were decreased. Histochemical analysis showed that soluble phenolics accumulated in the cytosol of Cd-treated roots but lignification was confined to newly formed protoxylem elements, which were found in the region of the root tip that normally constitutes the elongation zone. Roots exposed to 5 microM Cd showed less pronounced responses and only a small decrease in the elongation rate. These results suggest that in cells challenged by Cd at concentrations exceeding the detoxification capacity, H(2)O(2) accumulated because of an imbalance of redox systems. This, in turn, may have triggered the developmental program leading to xylogenesis. In conclusion, Cd did not cause necrotic injury in root tips but appeared to expedite differentiation, thus leading to accelerated aging.

In vivo changes in antioxidant systems and protective role of melatonin and a combination of vitamin C and vitamin E on oxidative damage in erythrocytes induced by chlorpyrifos-ethyl in rats.

Reactive oxygen species (ROS) may be involved in the toxicity of chlorpyrifos-ethyl (CE) [O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl)phosphorothioate]. We have, therefore, examined the in vivo effects of CE on the rat erythrocyte antioxidant system and evaluated the ameliorating effects of melatonin and a combination of vitamin E and vitamin C on the oxidative damage induced by CE. The experimental groups were: (1) control group, (2) CE-treated group (CE), (3) vitamin E plus vitamin C treatment group (Vit), (4) melatonin-treated group (Mel), (5) vitamin E plus vitamin C plus CE treatment group (Vit + CE), and (6) melatonin plus CE treatment group (Mel + CE). Vitamin E and vitamin C were administered intramuscularly once a day for 6 consecutive days at 150 and 200 mg/kg, respectively, in the Vit and Vit + CE groups. Melatonin was administered intramuscularly at 10 mg/kg per day for 6 consecutive days in the Mel and Mel + CE groups. At the end of the fifth day, the rats of CE, Vit + CE and Mel + CE groups were treated orally with the first of two equal doses of 41 mg/kg CE, the second oral dose being given 21 h later. Blood samples were taken 24 h after the first CE administration. Levels of thiobarbituric acid reactive substance (TBARS), antioxidant defence potential (AOP), and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were determined in erythrocytes. In comparison with the control group, oral administration of CE significantly (P < 0.05) stimulated TBARS activity while significantly (P < 0.05) inhibiting AOP and the activities of SOD and CAT. However, GSH-Px activity remained unchanged by CE treatment. Treatment with melatonin and vitamins E plus C significantly (P < 0.05) reduced the CE-induced increase of TBARS, and overcame the inhibitory effect of CE on SOD and CAT, but not on AOP. Melatonin treatment significantly (P < 0.05) increased only GSH-Px activity, irrespective of the effect of CE. These results suggest that CE treatment increases in vivo lipid peroxidation and decreases antioxidant defence by increasing oxidative stress in erythrocytes of rats, and melatonin and a combination of vitamin E and vitamin C can reduce this lipoperoxidative effect.

Nitrogen dependent changes in antioxidant system and in fatty acid composition of chloroplast membranes from Coffea arabica L. plants submitted to high irradiance

In the present work we investigated the contribution of N availability to the changes in some antioxidant systems and in fatty acid composition of chloroplast membranes, in order to evaluate their role in the high light acclimation in coffee plants. Young coffee ( Coffea arabica L. cv. Catuaı́) plants, grown under low irradiance (up to 150 μmol m −2 s −1) with high (2 N), medium (1 N) and low (0 N) N availability, were exposed to high irradiance (up to 1500 μmol m −2 s −1) for a maximal period of 15 days. Changes in several parameters were monitored during that period in the two top pairs of mature leaves. The formation rate of superoxide (O 2 ⋅−) estimated by ESR ( K f) did not differ among N-treatments before the onset of high light, but increased 70 and 30% in 0 N and 1 N plants, respectively, and decreased 33% in 2 N plants by the end of the stress. By this time, the chloroplastic activities of Cu,Zn-superoxide dismutase (Cu,Zn-SOD), ascorbate peroxidase (APer) and glutathione reductase (GRed) increased, respectively, 18, 225 and 138% in 2 N plants. The 0 N plants presented a 120% increase in Cu,Zn-SOD activity (which agrees with the higher K f of O 2 ⋅−) and a 68% decrease in APer activity, suggesting an increase in H 2O 2 levels, while GRed activity decreased 20%. The total carotenoid content was higher in 2 N plants and increased (about 20%) only in these plants by the end of stress. After 12 days of high irradiance, the total fatty acid (TFA) content increased about 30% in 2 N and 1 N plants, but did not significantly change in 0 N plants. In 2 N and 1 N plants a preferential synthesis of palmitic acid (16:0) and a decrease in the linolenic acid (18:3) percentage caused a decrease in the unsaturation level, which may have made the chloroplast membranes less susceptible to peroxidation. The N dependent changes observed in 2 N (and to a lesser extent in 1 N) plants could represent adaptive features under the new high irradiance conditions, which increased the protection of the chloroplast structures against photooxidative stress.

Vitamin E administration attenuates the tri-iodothyronine-induced modification of heart electrical activity in the rat.

This work was designed to determine whether the thyroid-hormone-induced modifications of heart electrical activity are, at least in part, due to increased free radical production. For this study, 60-day-old euthyroid, hyperthyroid and hyperthyroid vitamin-E-treated rats were used. Hyperthyroidism, elicited by a 10 day treatment with tri-iodothyronine, induced an increase in lipid peroxidation without changing the level of antioxidants. Intraperitoneal vitamin administration to hyperthyroid rats led to a reduction in lipid peroxidation and a non-significant increase in antioxidant level. The hyperthyroid state was also associated with an increase in heart rate measured in vivo and a decrease in the duration of the ventricular action potential recorded in vitro. Administration of vitamin E attenuated the thyroid-hormone-induced changes in heart rate and action potential duration, which were, however, significantly different from those of the control euthyroid rats. These results suggest that vitamin E protects hyperthyroid heart against lipid peroxidation by mechanisms that may be independent of the changes in antioxidant systems. Moreover, the reduction in the tri-iodothyronine effects on heart electrophysiological properties indicates that such effects are mediated, at least in part, through a membrane modification, probably related to increased lipid peroxidation, involving a free radical mechanism.

Mechanisms of chilling‐induced oxidative stress injury and tolerance in developing maize seedlings: changes in antioxidant system, oxidation of proteins and lipids, and protease activities

SummaryThe mechanisms involved in chilling injury or tolerance in developing maize seedlings subjected to low temperature stress have been investigated. Although acclimation‐induced chilling tolerance was developmentally regulated, no tolerance was observed in non‐acclimated developing seedlings subjected to 7 days of 4°C stress. Consistent with previous results, chilling induced oxidative stress in the seedlings. Whereas acclimated seedlings had elevated levels (35–120%) of antioxidant enzymes, such as catalase, glutathione reductase and guaiacol peroxidase, non‐acclimated seedlings had lower levels of these enzyme activities during chilling conditions. The increase in the activity of mitochondrial catalase3 isozyme, a major anti‐oxidant enzyme in maize, was due to an increase in cat3 transcripts and CAT3 protein, as indicated by Northern and Western blot analyses. Besides, non‐acclimated seedlings had increased levels of oxidized proteins (two to threefold) and lipids (35–65%) during chilling and recovery compared with control or acclimated seedlings. Low‐temperature stress also inhibited two proteases, endopeptidase and aminopeptidase, by 35% in non‐acclimated seedlings. Since seedlings treated with prooxidants also promoted the oxidation of proteins and lipids and the inhibition of proteases, it was concluded that in vivo generated oxidative stress was likely responsible for affecting these processes. These results provide a correlative evidence to suggest that: (i) in non‐acclimated seedlings, chilling injury was partly due to the build up of reactive oxygen species (ROS) that promoted the oxidation of proteins and lipids and inhibited protease activity; (ii) in acclimated seedlings, chilling tolerance was partly due to an enhanced anti‐oxidant system that prevented the accumulation of ROS and therefore, prevented the oxidation of proteins and lipids and the inhibition of protease activities during 4°C stress and recovery.

Antioxidant systems in normal pregnancy and in pregnancy-induced hypertension

Increased free radical activity has been implicated in the pathogenesis of pregnancy-induced hypertension. This article investigates whether changes in antioxidant systems contribute to this condition. Two extracellular (plasma thiols and ceruloplasmin) and two intracellular (red blood cell lysate thiols and red blood cell superoxide dismutase) antioxidant markers were assayed in 25 nonpregnant women, 16 pregnant women with normal blood pressure, 19 women with pregnancy-induced hypertension, and 13 women with proteinuric pregnancy-induced hypertension. In the normotensive pregnant group (in comparison with the nonpregnant group) the plasma thiol level was reduced (p < 0.001) and the ceruloplasmin level raised (p < 0.005), suggesting increased free radical activity. The lysate thiol level increased (p < 0.005), which may reflect a compensatory protective response. In the hypertensive pregnant groups the lysate thiol rise was not present. These red blood cells may be more prone to oxidative stress. Whether this situation is a cause or an effect of oxidative stress in pregnancy-induced hypertension has yet to be elucidated. (AM J OBSTET GYNECOL 1991;165:1701-4.)

Glutathione depletion: Its effects on other antioxidant systems and hepatocellular damage

1. The mechanisms of the liver damage produced by three glutathione (GSH)-depleting agents, bromobenzene, allyl alcohol and diethyl maleate, were investigated. 2. With each toxin liver necrosis was accompanied by lipid peroxidation that developed only after severe depletion of GSH. 3. Changes in antioxidant systems by alpha-tocopherol (vitamin E) and ascorbic acid were studied. A decrease in the hepatic level of vitamin E, and a change in the redox state of vitamin C (increase in oxidized over reduced form) were evident whenever extensive lipid peroxidation developed. However, in the case of bromobenzene intoxication these alterations preceded lipid peroxidation, and may be an index of oxidative stress leading to subsequent membrane damage. 4. Experiments carried out with vitamin E-deficient or supplemented diets indicated that pathological phenomena occurring as a consequence of GSH depletion depend on hepatic levels of vitamin E. In vitamin E-deficient animals, lipid peroxidation and liver necrosis appeared earlier than in animals fed the control diet. In animals fed a vitamin E-supplemented diet, bromobenzene and allyl alcohol had only limited toxicity, and diethyl maleate none, in spite of similar hepatic GSH depletion. Thus, vitamin E may largely modulate the expression of toxicity by GSH-depleting agents.