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At least 19 recordsLinked to original sources

PubMed2000

Distribution of lipid-soluble antioxidants in lipoproteins from healthy subjects. I. Correlation with plasma antioxidant levels and composition of lipoproteins.

The concentration of five lipid-soluble antioxidants (gamma- and alpha-tocopherol, lycopene, beta-carotene and ubiquinol-10) was measured in plasma and very low-density, low-density and high-density lipoproteins (VLDL, LDL and HDL) isolated from young healthy normo- cholesterolemic subjects. Alpha-tocopherol was the exclusive antioxidant whose plasma concentration significantly correlated with the absolute concentration of total cholesterol (r =0.541, P<0.001). No correlation was found between plasma concentration and lipoprotein content of alpha-tocopherol and ubiquinol-10, whereas it reached statistically significant values for gamma-tocopherol, lycopene and beta-carotene. The alpha-tocopherol content in VLDL and HDL, but not in LDL, was strictly associated with the relative abundance of cholesterol and phospholipids in the lipoprotein particles. Moreover, the difference between alpha-tocopherol concentration in VLDL and LDL appeared to be strictly related to the differences in cholesterol, phospholipids and triglycerides. The percent distribution of the total plasma pool of antioxidant in each lipoprotein class revealed that gamma- and alpha-tocopherol were roughly equally distributed in LDL and HDL. On the other hand, lycopene, beta-carotene and ubiquinol-10 were preferentially sequestered in LDL. Finally, the absolute and relative concentration of alpha-tocopherol, but not that of other antioxidants, in HDL exhibited a statistically significant correlation with plasma HDL/LDL cholesterol ratio. These findings indicate that: (i) plasma concentrations of major lipid-soluble antioxidants are not always predictive of their levels in lipoproteins and that, within individual lipoprotein classes, (ii) the lipid composition, metabolism and relative plasma concentration may significantly affect their abundance.

Adult↗

PubMed2000

Antioxidant vitamin and mineral supplements for age-related macular degeneration.

BACKGROUND: It has been proposed that antioxidants may prevent cellular damage in the retina by reacting with free radicals produced in the process of light absorption. OBJECTIVES: The objective of this review is to assess the effects of antioxidant vitamin and/or mineral supplementation on the progression of age-related macular degeneration. SEARCH STRATEGY: The Cochrane Eyes and Vision Group specialised registered, the Cochrane Controlled Trials Register - Central, MEDLINE, the Science Citation Index, and the reference lists of relevant articles were searched. Investigators of included studies were contacted. The most recent searches were performed in December 1999. SELECTION CRITERIA: All randomised trials comparing an antioxidant vitamin and/or mineral supplement (alone or in combination) to control in people with age-related macular degeneration were included. DATA COLLECTION AND ANALYSIS: The reviewer extracted data and assessed trial quality. Due to the small number of trials identified, and variable methods of collecting and presenting outcome data, no statistical summary measure was calculated. MAIN RESULTS: Four published, two unpublished and two ongoing trials were identified. Published trials to date have been small and results inconsistent. Adverse effects and quality of life for people with age-related macular degeneration have not been addressed. REVIEWER'S CONCLUSIONS: The question as to whether people with age-related macular degeneration should take antioxidant vitamin or mineral supplements to prevent progression of the disease has not been answered by research to date. The results of ongoing trials are awaited.

Antioxidants↗

PubMed2000

[Antioxidant vitamins - importance for cardiopulmonary prophylaxis. Part II. Antioxidant food supplies - vitamin C and beta-carotene; current experience in antioxidant vitamin usage].

The faith that an oxidizing of LDL is necessary for he foam cell formation is basically for the so called oxidative hypothesis of atherosclerosis. The role of LDL-oxidation for the atherosclerotic plaque formation, as well as its association with inflammatory processes in the vascular wall, are well established. The important conclusion of this hypothesis is the possible role of the antioxidants attenuating atherosclerotic mechanisms. The advances in studying the principal antioxidant vitamins E, C and beta-carotene effects, revealed a great part of their molecular mechanisms, which are not necessarily antioxidative. The important aspects of the cooperative antioxidant action are revealed too, including the so called tocopherol-mediated peroxidation, suggesting the need for the co-antioxidants for effective antioxidant defense. In the recent years many vitamin antioxidant supplementations are used. The epidemiological results of such supplementation do not always reveal the same beneficial effects as expected theoretically or based on the observations made with a diet rich in fruits and vegetables. The present paper generalizes the thought concerning the impact of oxidized LDL in atherosclerosis, as well as mechanisms of action and pharmacokinetiks of the most widely used antioxidant vitamins--E, C and beta-carotene, and the perspectives of their usage in cardiovascular prophylaxy bazed upon the recent experience in antioxidant vitamin supplementation.

Antioxidants↗

PubMed2004

Antioxidant supplementation preserves antioxidant response in physical training and low antioxidant intake.

The present controlled-training double-blind study (supplemented (S) group, n 7; placebo (P) group, n 10) was designed to investigate whether an antioxidant mixture (Se 150 microg, retinyl acetate mg, ascorbic acid 120 mg, alpha-tocopheryl succinate 20 mg) would allow overloaded triathletes to avoid adaptation failure in the antioxidant system [corrected]. Dietary intakes were recorded. The supplement of Se, and vitamins A and E provided 100 % of the French RDA. Four weeks of overloaded training (OT) followed 4 weeks of normal training (NT). After NT and OT, biological studies were conducted at rest and after a duathlon test (run 5 km, cycle 20 km, run 5 km). During the 4-week period of NT, blood levels of GSH levels increased in response to supplementation (P<0.05) and remained elevated during OT. Plasma glutathione peroxidase activity was significantly higher in the S group in all situations after NT and OT (P<0.01). The S group had increased erythrocyte Cu,Zn-superoxide dismutase activity in response to OT (P<0.05). Supplementation significantly reduced (P<0.05) the magnitude in duathlon-induced creatine kinase isoenzyme MB mass increase, which tended to be higher with OT (P=0.09). We conclude that the antioxidant mixture helped to preserve the antioxidant system during an OT-induced stress in subjects with initially low antioxidant intakes. Effects of supplementation during NT and/or OT are shown mostly by the alleviated muscle damage. The effects of the antioxidant mixture were observed for doses that can be provided by a diversified and well-balanced diet. The maintenance of normal nutritional status with regard to the antioxidant intake (Se, vitamins C and E) plays a key role in antioxidant adaptive effects during NT and OT.

Adaptation, Physiological↗

PubMed1999

Antioxidant capacity of oat (Avena sativa L.) extracts. 2. In vitro antioxidant activity and contents of phenolic and tocol antioxidants.

Oat milling fractions were examined for concentrations of total phenolics, tocols, and phenolic acids and in vitro antioxidant activity to determine their potential as dietary antioxidants. Methanolic extracts of pearling fractions, flour and aspirations from flaking, and trichomes had high, intermediate, and low antioxidant activities, respectively, evaluated by the beta-carotene bleaching method. Pearling fractions were also highest in total phenolics and tocols. p-Hydroxybenzoic acid, vanillic acid, caffeic acid, vanillin, p-coumaric acid, and ferulic acid were identified and quantified by HPLC. Three avenanthramides and an unidentified ferulate derivative were also detected. Total phenolic content was significantly correlated with antioxidant activity, and regression equations that predicted antioxidant activity from phenolic and tocol concentrations were calculated. Antioxidant activity, evaluated by beta-carotene bleaching, was correlated with measures of oxygen radical absorbance capacity and low-density lipoprotein oxidation. These data indicate a potential for oat products, especially those enriched in outer layers of the groat, to contribute to dietary intakes of antioxidant phytonutrients.

Antioxidants↗

PubMed1989

Further characterization of human colostral antioxidants: identification of an ascorbate-like element as an antioxidant component and demonstration of antioxidant heterogeneity.

Human colostrum manifests antioxidant properties, being capable of spontaneous reduction of cytochrome c, depletion of polymorphonuclear leukocyte-produced H2O2 and protection of epithelial cells from PMN-mediated detachment. These activities can be electrophoretically concentrated at either 3.5 kD or 50 kD dialysis membranes at mildly alkaline pH. They are progressively lost under increasingly alkaline conditions. They are resistant to 1-mM N-ethylmaleimide. Examination of a series of antioxidant compounds showed that ascorbate manifests several characteristics of colostrum, being able to reduce cytochrome c and deplete H2O2 but not altering PMN-mediated HEp2 cell detachment. Addition of ascorbate oxidase to colostrum decreased its cytochrome c-reducing activity by more than 85%, decreased its H2O2-depleting activity by nearly 50%, but did not alter its ability to protect HEp2 cells, all suggesting heterogeneity of colostral antioxidant activities. Treatment of colostrum with an enzymatic system (xanthine + xanthine oxidase) known to destroy ascorbate's cytochrome c-reducing activity yielded paradoxical results, decreasing colostral cytochrome c reduction in a dose-related manner, while increasing its H2O2-depleting activity. These studies demonstrate that a colostral component similar to ascorbate, a known antioxidant compound is responsible for the majority of colostral cytochrome c-reducing activity, for about half of its H2O2-depleting activity, and little, if any, of its protective effect on HEp2 cells. Thus colostral antioxidant activity is heterogeneous.

Antioxidants↗

PubMed1994

Cloning and sequencing of thiol-specific antioxidant from mammalian brain: alkyl hydroperoxide reductase and thiol-specific antioxidant define a large family of antioxidant enzymes.

A cDNA corresponding to a thiol-specific antioxidant enzyme (TSA) was isolated from a rat brain cDNA library with the use of antibodies to bovine TSA. The cDNA clone encoded an open reading frame capable of encoding a 198-residue polypeptide. The rat and yeast TSA proteins show significant sequence homology to the 21-kDa component (AhpC) of Salmonella typhimurium alkyl hydroperoxide reductase, and we have found that AhpC exhibits TSA activity. AhpC and TSA define a family of > 25 different proteins present in organisms from all kingdoms. The similarity among the family members extends over the entire sequence and ranges between 23% and 98% identity. A majority of the members of the AhpC/TSA family contain two conserved cysteines. At least eight of the genes encoding AhpC/TSA-like polypeptides are found in proximity to genes encoding other oxidoreductase activities, and the expression of several of the homologs has been correlated with pathogenicity. We suggest that the AhpC/TSA family represents a widely distributed class of antioxidant enzymes. We also report that a second family of proteins, defined by the 57-kDa component (AhpF) of alkyl hydroperoxide reductase and by thioredoxin reductase, has expanded to include six additional members.

Amino Acid Sequence↗

PubMed1999

Antioxidant capacity and polyphenolic components of teas: implications for altering in vivo antioxidant status.

The Oxygen Radical Absorbance Capacity (ORAC) assay was used to determine the total antioxidant capacity of tea. Green and black teas (n = 18) had a mean antioxidant capacity of 761.1 +/- 85.3 micromol Trolox Equivalents (TE) per g dry matter. However, their antioxidant capacity varied from 235 micromol to over 1526 micromol Trolox equivalents (TE)/g dry matter, and total phenolics ranged from 32 to 147 mg/g in different commercial teas. One tea phenolics extract had an antioxidant capacity of 4796 micromol TE/g dry matter and 625 mg total phenolics/g. On a dry matter basis, an antioxidant capacity of 761 micromol TE/g is considerably higher than any of the other fruits and vegetables measured in our laboratory. However, since dry tea is not consumed directly, brewing conditions may influence the final antioxidant capacity in the tea as consumed. We tested both green and black teas by placing one tea bag (1.95 g) in 150 ml (5 oz.) of boiling water. In the first brewed cup, approximately 84% of the total antioxidant activity was solubilized within the first 5 min of brewing. An additional 13% of the antioxidant activity was extracted into the second glass of 150 ml with an additional 5 min of brewing. At the dilutions obtained after the first brewing, the tea as consumed would contain approximately 8. 31 micromol TE per ml. This total antioxidant capacity compares to other drinks from fruits and vegetables that had antioxidant capacity values ranging from 1.6 to 15 micromol TE/ml. At these antioxidant levels, consumption of 150 ml of tea could make a significant contribution to the total daily antioxidant capacity intake. (-)-Epicatechin and (+)-catechin, two components from tea, had an antioxidant capacity of 2.36 and 2.49 micromol/micromol or 8. 13 and 8.58 micromol/mg, respectively. In 16 tea samples we observed a mean of 10.0 +/- 0.6 micromol TE/mg total phenolics. Tea can be an important source of what has been referred to as "non-nutrient" antioxidant phytochemicals. However, with the variation that exists in antioxidant capacity with various tea preparations, measures of antioxidant capacity intake are critical to the study of intake and health outcomes and/or biomarkers of health outcomes.

Antioxidants↗

PubMed2003

Antioxidant intake, plasma antioxidants and oxidative stress in a randomized, controlled, parallel, Mediterranean dietary intervention study on patients with rheumatoid arthritis.

BACKGROUND: Previously we have reported that patients with rheumatoid arthritis (RA) obtained a significant reduction in disease activity by adopting a Mediterranean-type diet. The present study was carried out to investigate the antioxidant intake, the plasma levels of antioxidants and a marker of oxidative stress (malondialdehyde) during the study presented earlier. METHODS: RA patients randomized to either a Mediterranean type diet (MD group; n = 26) or a control diet (CD group; n = 25) were compared during a three month dietary intervention study. Their antioxidant intake was assessed by means of diet history interviews and their intake of antioxidant-rich foods by a self-administered questionnaire. The plasma levels of retinol, antioxidants (alpha- and gamma-tocopherol, beta-carotene, lycopene, vitamin C and uric acid) and urinary malondialdehyde (MDA), a marker for oxidative stress, were determined using high performance liquid chromatography. The Student's t-test for independent samples and paired samples were used to test differences between and within groups. For variables with skewed distributions Mann-Whitney U-test and Wilcoxon signed ranks test were performed. To evaluate associations between dietary intake of antioxidants, as well as between disease activity, MDA and antioxidants we used Pearson's product moment correlation or Spearman's rank correlation. RESULTS: The MD group had significantly higher intake frequencies of antioxidant-rich foods, and also higher intakes of vitamin C (p = 0.014), vitamin E (p = 0.007) and selenium (p = 0.004), and a lower intake of retinol (p = 0.049), compared to the CD group. However, the difference between the groups regarding vitamin C intake was not significant when under- and over-reporters were excluded (p = 0.066). There were no changes in urine MDA or in the plasma levels of antioxidants (after p-lipid adjustments of the tocopherol results), from baseline to the end of the study. The levels of retinol, vitamin C and uric acid were negatively correlated to disease activity variables. No correlation was found between antioxidant intake and the plasma levels of antioxidants. CONCLUSIONS: Despite an increase in reported consumption of antioxidant-rich foods during the Mediterranean diet intervention, the levels of plasma antioxidants and urine MDA did not change. However, the plasma levels of vitamin C, retinol and uric acid were inversely correlated to variables related to RA disease activity.

Clinical Trial↗

PubMed2006

The antioxidative power AP--A new quantitative time dependent (2D) parameter for the determination of the antioxidant capacity and reactivity of different plants.

In the last decade, naturally occurring antioxidants continue to play an important role in the food-supplement industry. The content of antioxidants in a plant depends on the species, temperature, humidity, period of growth, harvest month, part of the plant used and many other variables. Herein, we present a new method able to determine the all over antioxidative power (AP) of plant extracts or lyophilised plant parts based on the reducing activity against a stable test radical. The method is performed by ESR spectroscopy and is based on the well-known 1,1-diphenyl-2-picryl-hydrazil (DPPH) method with the major difference that both the antioxidative capacity and the antioxidative activity are used to characterise an antioxidant. The resulting antioxidative power is expressed in antioxidative units (AU), where 1AU corresponds to the activity of a 1 ppm solution of Vitamin C as a benchmark. This method allows a rapid, unexpensive and general applicable technique for the measurement of the antioxidative power of very different kinds of substances. The inclusion of the kinetic behaviour of the reducing process of the antioxidant for the determination of the AP allows the identification of the main antioxidant present in a sample. Herein, we present the application example of seeds, sprouts and adult parts of dandelion, amaranth, quinoa, fenugreek, broccoli, red clover and mugwort, where the AP method permits to characterise the plants with the highest antioxidant capacity and reaction velocity. The method permits to select active plant extracts for the food and nutrition industry.

Antioxidants↗

PubMed2004

Variation in major antioxidants and total antioxidant activity of Yuzu (Citrus junos Sieb ex Tanaka) during maturation and between cultivars.

Epidemiological studies suggest that a high consumption of fruits can reduce the risk of some cancers and cardiovascular disease, and this may be attributable to the antioxidant activity of vitamins and phenolic compounds. The present study investigated the variations in vitamin C, total phenolic, hesperidin, and naringin contents, and total antioxidant activity of yuzu (Citrus junos Sieb ex Tanaka)-which is a popular citrus fruit in Korea and Japan-between cultivars and during maturity. The amounts of phenolics and vitamin C and the antioxidant activity in all tested yuzu cultivars were higher in peel than in flesh. Ripening increased the total antioxidant activity and vitamin C content in both peel and flesh of yuzu. However, the amounts of all total phenolics, hesperidin, and naringin in peel increased with ripening, whereas they decreased slightly in flesh. There was a highly linear relationship between the vitamin C content and the total antioxidant activity in both peel (r(2) = 1.000) and flesh (r(2) =0.998), suggesting that vitamin C plays a key role in the antioxidant activity of yuzu. In addition, the contribution of each antioxidant to the total antioxidant activity of yuzu was determined using a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and is expressed here in terms of the vitamin C equivalent antioxidant capacity (VCEAC). The means of vitamin C, naringin, and hesperidin in yuzu were 90.4, 63.8, and 65.7 mg/100 g fresh yuzu, respectively. The relative VCEAC values of these compounds were in the following order: vitamin C (1.00) > naringin (0.195) > hesperidin (0.162). Therefore, the estimated contribution of each antioxidant to the total antioxidant capacity of 100 g of fresh yuzus is as follows (in mg of VCEAC): vitamin C (90.36 mg) > naringin (12.44 mg) > hesperidin (10.64 mg). Our results indicate that mature yuzu contains higher amounts of vitamin C and phenolics than other citrus fruits and could therefore be used as a significant dietary source of antioxidants.

Antioxidants↗

PubMed2004

Effect of tomato product consumption on the plasma status of antioxidant microconstituents and on the plasma total antioxidant capacity in healthy subjects.

OBJECTIVES: to identify the plasma antioxidant microconstituents mainly affected by tomato product consumption, to check whether tomato product consumption can affect antioxidant status, and to identify tomato-product antioxidant-microconstituents mainly involved in the effect of these products on oxidative stress. DESIGN: Medium-term dietary supplementation study. SETTING: Human Nutrition Laboratory, Clermont-Ferrand, France. SUBJECTS: Twenty healthy young (20 < years < 40), non obese (18 < BMI (kg/m2) < 25), females were recruited by advertisement. All of them completed the study. INTERVENTION: The usual diet of the subjects was supplemented for three weeks with 96 g/day tomato puree. The volunteers then avoided tomato-product-rich foods for a subsequent three-week period. MEASURES OF OUTCOME: Fasting blood samples were collected the day before supplementation, the day after the supplementation period, and the day after the depletion period. The status of several antioxidant microconstituents (plasma microconstituent concentrations), and the antioxidant status (plasma total antioxidant capacity) were assessed. RESULTS: Supplementation with tomato puree significantly increased plasma lycopene, beta-carotene and lutein. Conversely it did not significantly affect plasma vitamin C and E, plasma antioxidant trace metals (Cu, Zn and Se), and plasma total antioxidant capacity. Avoidance of tomato-product-rich foods for three weeks significantly (p < 0.05) decreased plasma lycopene, beta-carotene, lutein and vitamin C, as well as plasma total antioxidant capacity. Plasma total antioxidant capacity, as measured by chemiluminescence, was positively related (p < 0.05) to the status of lycopene, vitamin C and beta-carotene. CONCLUSIONS: Tomato product consumption can affect not only the lycopene status, but also that of other antioxidant microconstituents (beta-carotene and lutein). Lycopene, but also beta-carotene, are apparently the main tomato microconstituents responsible for the effect of tomato products on antioxidant status.

Adult↗

PubMedDate not supplied

Lipoperoxidation induced by hydrogen peroxide in human erythrocyte membranes. 2. Comparison of the antioxidant effect of Ginkgo biloba extract (EGb 761) with those of water-soluble and lipid-soluble antioxidants.

An in vitro model using healthy human erythrocyte suspensions was used to compare the antioxidant effect of standardized Ginkgo biloba extract (EGb 761) with those of water-soluble (ascorbic acid, glutathione and uric acid) and lipid-soluble (alpha-tocopherol and retinol acetate) antioxidants. Lipid peroxidation was induced by hydrogen peroxide in the absence (control) and presence of antioxidants at low (25 micrograms/ml) and high (250 micrograms/ml) concentrations. Malondialdehyde production was determined as the indicator of lipid peroxidation during the incubation period. The results suggest that all of the antioxidants, except ascorbic acid, have antioxidant potential in this system in a concentration-dependent manner. When the antioxidants were compared, EGb 761 was found to be more effective than water-soluble antioxidants, and as effective as lipid-soluble antioxidants. Among the lipid-soluble antioxidants there was no significant difference in potency between alpha-tocopherol and retinol acetate, but uric acid was the most potent of the water-soluble antioxidants. The antioxidant potency of EGb 761 appears to be comparable with that of the well-known antioxidants alpha-tocopherol and retinol acetate.

Adult↗

PubMed2004

The antioxidants and pro-antioxidants network: an overview.

Living beings have evolved over the past two billion years through adaptation, to an increasing atmospheric oxygen concentration, by both taking advantage of oxygen activating function and developing a complex control network. In these regards, potentially damaging species (reactive oxygen, nitrogen and chlorine species) arise as by-products of metabolism and also work as physiological mediators and signalling molecules. Oxidative stress may be an important factor in numerous pathological conditions, i.e. infection if micronutrients are deficient. Levels of these species are controlled by the antioxidant defence system, which is composed by antioxidants and pro-antioxidants. Several components of this system are micronutrients (e.g. vitamins C and E), are dependent upon dietary micronutrients (e.g. CuZn and Mn superoxide dismutase) or are produced by specific endogenous pathways. The antioxidant defences act, to control levels of these species, as a coordinated system where deficiencies in one component may affect the efficiency of the others. In this network some of the components act as direct antioxidants whereas others act indirectly (pro-antioxidants) either by modulation of direct agents or by regulation of the biosynthesis of antioxidant proteins. Thus, entities usually not considered as antioxidants, also act efficiently counteracting damaging effects of oxidative species. In this contest, the design of new molecules that take into account synergistic interactions among different antioxidants, could be useful both to address mechanistic studies and to develop possible therapeutic agents. In this review the principal categories of antioxidants and pro-antioxidants that goes from vitamins through phyto-derivatives to minerals, are critically reviewed, with particular emphasis on structure-function considerations, together with the perspective opened, in the design of possible therapeutic agents, by the antioxidants interplay.

Animals↗

PubMed2006

Modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (abts) method to measure antioxidant capacity of Selected small fruits and comparison to ferric reducing antioxidant power (FRAP) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods.

The measurement of antioxidant capacity in fruits differs from that of other biological samples due to their low pH and very low lipophilic antioxidant capacity. In this report, we present a modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method for fruits and compare its performance with the other commonly used antioxidant methods of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The antioxidant capacity and reaction kinetics of four phenolic compounds, two antioxidant standards, and five fruits were also investigated. The modified ABTS method prepared at a pH of 4.5 with sodium acetate buffer is highly stable and easily applied to fruit samples as compared to the standard (pH 7.4) version. The measured antioxidant capacity of samples varied with the assay method used, pH, and time of reaction. Traditional antioxidant standards (trolox, ascorbic acid) displayed stable, simple reaction kinetics, which allowed end point analysis with all of assays. Of the phenolic compounds examined, chlorogenic and caffeic acids exhibited the most complex reaction kinetics and reaction rates that precluded end point analysis while gallic acid and quercetin reached stable end points. All fruit extracts exhibited complex and varied kinetics and required long reaction times to approach an end point. Because the antioxidant capacity of fruit extracts is a function of the array of individual antioxidants present, accurate comparisons among fruit samples require that reaction times be standardized and of sufficient length to reach steady state conditions and that more than one assay be used to describe the total antioxidant activity of fruit samples.

Antioxidants↗

PubMed2003

The impact of different antioxidant agents alone or in combination on reactive oxygen species, antioxidant enzymes and cytokines in a series of advanced cancer patients at different sites: correlation with disease progression.

In the present study we tested the ability of different antioxidant agents, used alone or in combination, to reduce the reactive oxygen species (ROS) levels and to increase the glutathione peroxidase (GPx) activity. Moreover, we tested the ability of such antioxidant agents to reduce the serum levels of proinflammatory cytokines IL-6 and TNFalpha. Fifty-six advanced stage cancer patients with tumors at different sites were included in the study: they were mainly stage III (12.5%) and stage IV (82.1%). The study was divided into two phases. In the 1st phase 28 patients were divided into five groups and a single different antioxidant agent was administered to each group. The selected antioxidant agents were: alpha lipoic acid or carboxycysteine-lysine salt, amifostine, reduced glutathione, vitamin A plus vitamin E plus Vitamin C. In the 2nd phase of the study 28 patients were divided into five groups and a combination of two different antioxidant agents was administered to each group. The antioxidant treatment was administered for 10 consecutive days. The patients were studied at baseline and after antioxidant treatment. Our results show that all single antioxidants tested were effective in reducing the ROS levels and three of them in increasing GPx activity, too. Among the combinations of antioxidant agents, three were effective in reducing ROS, while three were effective in increasing GPx activity (arm 4 was effective in both instances). Comprehensively, the "antioxidant treatment" was found to be effective both on ROS levels and GPx activity. Moreover, the antioxidant treatment was able to reduce serum levels of IL-6 and TNFalpha. Furthermore, a correlation was shown between the Eastern Cooperative Oncology Group Performance Status of patients and blood levels of ROS, GPx activity, serum levels of proinflammatory cytokines.

Adult↗

PubMed2001

[Dietary antioxidants and total antioxidant status in children with nephrotic syndrome].

UNLABELLED: Several studies indicate the pathophysiological importance of reactive oxygen species in patients with nephrotic syndrome (NS). The present study was designed to determine the effect of dietary antioxidants on antioxidant enzymes (SOD, GPX, GR) activity and on total antioxidant status (TAS) in children with nephrotic syndrome. 36 children with NS (19 with first episode and 17 with relapse of NS) aged 4-16 were included into the study. Total antioxidant status was estimated using two-reagent Randox Total Antioxidant Status test in plasma. All patients had normal blood pressure, normal serum creatinine level and ingested a diet appropriate for age (with individual differences). Total antioxidant status was estimated using two-reagent Randox Total Antioxidant Status test in the plasma. Glutathione peroxidase (GPX), superperoxide dysmutase (SOD) and glutathione reductase (GR) activity was using antioxidant kits (Randox). A 3-day dietary intake record was obtained from each patient and then analyzed with computer program FOOD 2.0. Laboratory investigations were performed before steroid treatment. RESULTS: 1) in children with NS TAS was significantly reduced comparing to controls (0.84 +/- 0.14, 1.21 +/- 0.62 mmol/l, p = 0.002), 2) low manganese intake was found to have negative influence on TAS (TAS = 0.38 + 14.252*Mn, p > 0.001). 3) low intake of all components of antioxidant system was found: zinc (5.6 +/- 3.5 mg/kg b.w./24 h vs 8.6 +/- 4.0 mg/kg b.w./24 h), copper (0.021 +/- 0.013 mg/kg b.w./24 h vs 0.044 +/- 0.014 mg/kg b.w./24 h), manganese (0.029 +/- 0.0021 mg/kg b.w./24 h vs. 0.067 +/- 0.023 mg/kg b.w./24 h), vitamin E (0.15 +/- 0.04 mg/kg b.w./24 h vs 0.26 +/- 0.06 mg/kg b.w./24 h) and vitamin C (0.34 +/- 0.17 mg/kg b.w./24 h vs 0.87 +/- 0.19 mg/kg b.w./24 h). CONCLUSION: In children with NS reduced antioxidant protection maybe partly associated with low intake of some vital components of the antioxidant system.

Adolescent↗

PubMed2005

Response of blood cell antioxidant enzyme defences to antioxidant diet supplementation and to intense exercise.

BACKGROUND: Exhaustive exercise induces oxidative stress. The cellular antioxidant defence systems have demonstrated great adaptation to chronic exercise. AIM: To establish the influence of the antioxidant diet supplementation on the erythrocyte and lymphocyte antioxidant enzyme activities in athletes at basal and post-exercise levels. METHODS: Fifteen amateur trained male athletes were randomly distributed in two groups: control and antioxidant supplemented (90 days' diet supplementation with 500 mg/day vitamin E and 30 mg/day beta-carotene, and the last 15 days also with 1 g/day vitamin C). The study was double blind. Maximal and submaximal exercise tests were performed after three months of diet supplementation. The study was developed during the training and competition season. RESULTS: The sportsmen of the supplemented group presented significantly higher plasmatic final levels of vitamin C, vitamin E and beta-carotene. Erythrocyte glutathione reductase activity significantly decreased in the placebo group but was maintained in the supplemented group after the three months studied. The erythrocyte superoxide dismutase activity increased after the training/competition period in the placebo group. Lymphocyte catalase and glutathione peroxidase activities increased significantly in the supplemented group after the supplementation period but were maintained in the placebo group. No effects of the antioxidant supplementation were observed in the erythrocyte antioxidant enzyme response to the exercise tests. The antioxidant supplementation induced a better adaptation of lymphocyte catalase after submaximal test. CONCLUSIONS: Lymphocytes showed higher sensibility to antioxidant supplementation, improving the response of antioxidant enzymes to training and to acute exercise. In erythrocytes the training adaptations were more important than the antioxidant supplementation effects.

Adaptation, Physiological↗