Plasma Total Antioxidant Activity Research Articles

Effectiveness of moderate green tea consumption on antioxidative status and plasma lipid profile in humans

The antioxidant activity of green tea (GT) has been extensively studied; however, the results obtained from dietary intervention studies are controversial. In the present study we investigated the effect of the addition of two cups of GT (containing approximately 250 mg of total catechins) to a controlled diet in a group of healthy volunteers with respect to a group following the same controlled diet but not consuming GT. Antioxidant status and lipid profile in plasma, the resistance from oxidative damage to lipid and DNA, and the activity of glutathione peroxidase (GPX) in isolated lymphocytes were measured at the beginning and the end of the trial. After 42 days, consumption of GT caused a significant increase in plasma total antioxidant activity [from 1.79 to 1.98 μmol Trolox equivalent (TE)/ml, P<.001], significant decreases in plasma peroxides level (from 412 to 288 Carr U, P<.05) and induced DNA oxidative damage in lymphocytes (from 14.2% to 10.1% of DNA in tail, P<.05), a moderate although significant decrease in LDL cholesterol (from 119.9 to 106.6 mg/dL, P<.05) with respect to control. The present study suggests the ability of GT, consumed within a balanced controlled diet, to improve overall the antioxidative status and to protect against oxidative damage in humans.

Evaluation of nitrosative and oxidative stress in Behçet disease

Plasma nitrotyrosine and nitrite/nitrate levels as markers of nitrosative stress and plasma malondialdehyde (MDA) and protein carbonyl as markers of oxidative stress were determined in patients with Behcet disease (BD). To evaluate the balance between oxidant and antioxidant systems in these patients, we measured erythrocyte lysate CuZn superoxide dismutase (CuZn SOD) activity, plasma sulfhydryl (SH) values and total antioxidant activity. We also determined levels of plasma C-reactive protein (CRP), a key marker of inflammation, and compared them with those of healthy subjects. We found plasma nitrotyrosine levels of BD patients to be increased, indicating that nitrosative stress may occur in these patients. Plasma MDA and CRP levels in BD patients were found to be significantly higher than those in control group. However, plasma SH levels were decreased. No changes were observed in the other measured parameters of the patient group compared with the controls. These data suggest the possible involvement of nitric oxide (NO) together with reactive oxygen substances (ROS) in the pathogenesis of BD.

Comparative Analysis of the Renoprotective Effects of Pentoxifylline and Vitamin E on Streptozotocin-Induced Diabetes Mellitus

Background: Oxidative stress (OxS) induced by diabetes plays an important role in the development of diabetic nephropathy. Studies have shown that antioxidants are beneficial in its reduction. Vitamin E has been documented as providing the most improvement in the antioxidative status. Recently, pentoxifylline (PTX) has been proposed to have antioxidant properties. Aim: The aim of the study was to assess the ability of two antioxidants to reduce lipid peroxidation and renal hypertrophy in vivo. Methods: Diabetes was induced by streptozotocin (STZ) in rats. Treatment groups 7were divided as follows: healthy (H), diabetic without treatment (STZ), PTX treated group (STZ + PTX), and vitamin E supplemented (STZ + E) group. At 8 weeks, kidneys were removed; one was homogenized to quantify lipoperoxide levels (LPOS), and the other was used to study the morphological changes by electron microscopy (EM). Additionally, plasma total antioxidant activity (TAA) was quantified. Results: A reduction in LPOS was observed in both groups: PTX and vitamin E with regard to STZ group. PTX increased TAA compared to STZ + E, which restored it to its normal values. However, both treatments reduced the LPO/TAA ratio to lower basal levels; hence, similar results were obtained in terms of correcting functional parameters. Structural changes in STZ rats included a glomerular membrane thickening, podocyte flattening, as well as loss of fenestration in the endothelial layer. All these changes were less aggressive for treated rats. Conclusions: Vitamin E and PTX have potential therapeutic properties that may help to retard the rate of deterioration of diabetic kidneys.

Health promotion by flavonoids, tocopherols, tocotrienols, and other phenols: direct or indirect effects? Antioxidant or not?

Foods and beverages rich in phenolic compounds, especially flavonoids, have often been associated with decreased risk of developing several diseases. However, it remains unclear whether this protective effect is attributable to the phenols or to other agents in the diet. Alleged health-promoting effects of flavonoids are usually attributed to their powerful antioxidant activities, but evidence for in vivo antioxidant effects of flavonoids is confusing and equivocal. This may be because maximal plasma concentrations, even after extensive flavonoid intake, may be low (insufficient to exert significant systemic antioxidant effects) and because flavonoid metabolites tend to have decreased antioxidant activity. Reports of substantial increases in plasma total antioxidant activity after flavonoid intake must be interpreted with caution; findings may be attributable to changes in urate concentrations. However, phenols might exert direct effects within the gastrointestinal tract, because of the high concentrations present. These effects could include binding of prooxidant iron, scavenging of reactive nitrogen, chlorine, and oxygen species, and perhaps inhibition of cyclooxygenases and lipoxygenases. Our measurements of flavonoids and other phenols in human fecal water are consistent with this concept. We argue that tocopherols and tocotrienols may also exert direct beneficial effects in the gastrointestinal tract and that their return to the gastrointestinal tract by the liver through the bile may be physiologically advantageous.

Comparative Analysis of the Renoprotective Effects of Pentoxifylline and Vitamin E on Streptozotocin-Induced Diabetes Mellitus

Oxidative stress (OxS) induced by diabetes plays an important role in the development of diabetic nephropathy. Studies have shown that antioxidants are beneficial in its reduction. Vitamin E has been documented as providing the most improvement in the antioxidative status. Recently, pentoxifylline (PTX) has been proposed to have antioxidant properties. The aim of the study was to assess the ability of two antioxidants to reduce lipid peroxidation and renal hypertrophy in vivo. Diabetes was induced by streptozotocin (STZ) in rats. Treatment groups were divided as follows: healthy (H), diabetic without treatment (STZ), PTX treated group (STZ+PTX), and vitamin E supplemented (STZ+E) group. At 8 weeks, kidneys were removed; one was homogenized to quantify lipoperoxide levels (LPOS), and the other was used to study the morphological changes by electron microscopy (EM). Additionally, plasma total antioxidant activity (TAA) was quantified. A reduction in LPOS was observed in both groups: PTX and vitamin E with regard to STZ group. PTX increased TAA compared to STZ+E, which restored it to its normal values. However, both treatments reduced the LPO/TAA ratio to lower basal levels; hence, similar results were obtained in terms of correcting functional parameters. Structural changes in STZ rats included a glomerular membrane thickening, podocyte flattening, as well as loss of fenestration in the endothelial layer. All these changes were less aggressive for treated rats. Vitamin E and PTX have potential therapeutic properties that may help to retard the rate of deterioration of diabetic kidneys.

Improved FIA-ABTS Method for Antioxidant Capacity Determination in Different Biological Samples

In order to evaluate the actual antioxidant features of foods, beverages and also plasma from patients, a number of assays have been developed in the last few years to determine the so called total antioxidant activity (TAA), intended as the cumulative capacity of a biological sample to scavenge free radicals. Most of the assays partially failed in obtaining a good reproducibility when using plasma because it is composed of a large number of substances, some of which are present at very high concentrations and possess masking features. For these reasons we have improved the widely known ABTS method by means of a FIA system where both temperature and dispersion of sample and reagent were strictly controlled. We found that temperature may be a critical aspect in the measurement of plasma TAA whilst its influence may be less important in the assay of non-complex biological samples. We demonstrated that also the reaction time may be critical, depending on the nature of the substance employed. Data confirmed the high TAA of a methylsalicylate-containing mouthrinse as well as the negligible TAA offered by the chlorhexidine containing one. White wines (Verdicchio) also displayed interesting TAA values. The improved method was useful to screen rapidly, without dilution, with very limited handling of the sample and with high repeatability the TAA of plasma in addition to chemical products, beverages and non-complex biological mixtures.

Plasma antioxidant vitamin status of periparturient cows supplemented with α-tocopherol and β-carotene

Eighteen crossbred cows in their advance pregnancy were distributed into three equal groups. Group I was kept as control, whereas, groups II and III were supplemented with 1000 IU dl-α-tocopheryl acetate (Vitamin E) and 1000 IU dl-α-tocopheryl acetate + 300 mg β-carotene per cow per day, respectively, from 30 days prepartum to 2 weeks postpartum. Blood samples were collected at 30, 20, 10 and 5 days prepartum, at calving and 3, 7 and 12 days postpartum. Vitamin E and β-carotene contents of feeds offered and blood samples were estimated using HPLC. Total Vitamin E and β-carotene intake in the three respective groups was 185, 1185, 1185 IU per day and 397, 397, 697 mg per day. Plasma α-tocopherol concentration at 30 days prepartum was 3.62, 2.74 and 4.10 μg/ml which decreased by 56.6, 17.8 and 33.6% on the day of parturition in the three respective groups. Higher plasma α-tocopherol in groups II and III at calving helped to regain normal plasma Vitamin E status of 3.0 μg/ml for better immune function, within 2 weeks, whereas, unsupplemented cows could not reach this level during this period. Decrease in plasma retinol and β-carotene concentrations was observed in cows of all the groups on the day of parturition which continued to decrease further up to 7 days post-calving in unsupplemented cows (groups I and II), whereas, these levels were maintained in group III cows. Plasma retinol and β-carotene levels were higher in group III cows. Total antioxidant activity of plasma did not differ among groups. The data indicated that the extent of decrease in the levels of α-tocopherol, retinol and β-carotene at parturition can be reduced by supplementing these vitamins during dry period in order to improve their immunity status.

Pentoxifylline Diminishes the Oxidative Damage to Renal Tissue Induced by Streptozotocin in the Rat

Oxidative damage has been suggested to be a contributing factor in the development to diabetic nephropathy (DN). Recently, there has been evidence that pentoxifylline (PTX) has free radical-scavenging properties; thus, its antiinflammatory and renoprotective effects may be related to a reduction in reactive oxygen species production. It is likely that the pharmacological effects of PTX include an antioxidant mechanism as shown in in vitro assays. The aim of this study was to evaluate whether the reported renoprotective effects of PTX could be the result of its antioxidant actions in streptozotocin (STZ)-induced DN in rats. The administration of PTX over a period of 8 weeks, in addition to displaying renoprotective effects, caused a significant reduction in lipoperoxide levels (LPOS) in the diabetic kidney (P < 0.05), compared to untreated rats. These levels were comparable to those in the healthy kidney of experimental animals (P > 0.05). All untreated STZ rats exhibited an increase in LPOS as opposed to healthy controls (H) (P < 0.001). The total antioxidant activity (TAA) in plasma was increased significantly already after 2 days of STZ (P < 0.05). When we examined the progression of TAA in STZ rats, there was a significant decrease over 8 weeks (P < 0.05). PTX treatment caused an increase in TAA when compared to untreated STZ rats (P < 0.05). Renal hypertrophy was less evident in PTX-treated STZ than in untreated STZ rats, evaluated by kidney weight/body weight ratio. These results indicate that PTX decreases the oxidative damage induced by these experimental procedures and may increase antioxidant defense mechanisms in STZ-induced diabetes in rats.

Total and corrected antioxidant capacity in hemodialyzed patients.

BackgroundOxidative stress may play a critical role in the vascular disease of end stage renal failure and hemodialysis patients. Studies, analyzing either discrete analytes and antioxidant substances, or the integrated total antioxidant activity of human plasma during hemodialysis, give contradictory results.MethodsRecently, we have introduced a new automated method for the determination of Total Antioxidant Capacity (TAC) of human plasma. We have serially measured TAC and corrected TAC (cTAC: after subtraction of the interactions due to endogenous uric acid, bilirubin and albumin) in 10 patients before the onset of the dialysis session, 10 min, 30 min, 1 h, 2 h and 3 h into the procedure and after completion of the session.ResultsOur results indicate that TAC decreases, reaching minimum levels at 2 h. However, corrected TAC increases with t1/2 of about 30 min. We then repeated the measurements in 65 patients undergoing dialysis with different filters (36 patients with ethylene vinyl alcohol copolymer resin filter -Eval-, 23 patients with two polysulfone filters -10 with F6 and 13 with PSN140-, and 6 patients with hemophan filters). Three specimens were collected (0, 30, 240 min). The results of this second group confirm our initial results, while no significant difference was observed using either filter.ConclusionsOur results are discussed under the point of view of possible mechanisms of modification of endogenous antioxidants, and the interaction of lipid- and water-soluble antioxidants.

Antioxidant status of rats receiving lycopene in different doses.

Oral treatment with lycopene (per os) in doses of 10 or 50 mg/kg for 2 weeks led to accumulation of lycopene in the liver, liver microsomes, and blood plasma, increased total plasma antioxidant activity, inhibited LPO in the liver, and decreased solubilization of lysosomal enzymes. Lycopene had no effect on ex vivo resistance of liver microsomes to LPO and activities of antioxidant enzymes in the liver.

Effect of Vitamin E Supplementation on Plasma Antioxidant Vitamins and Immunity Status of Crossbred Cows

Twenty crossbred (HF×Tharparkar) dry pregnant cows were divided into four equal groups. They were supplemented with 1,000 I.U. α-tocopheryl acetate from 0 (group I), 15 (group II), 30 (group III) and 60 (group IV) days before parturition to 1month of lactation. All the cows were kept under similar feeding and management conditions. Blood plasma samples collected on specific days were analyzed for α-tocopherol, retinol, total antioxidant activity (FRAP), immunoglobulin and calcium. Plasma α-tocopherol concentration at 30 days prepartum averaged 3.5, 4.1, 4.4 and 3.9 µg/ml and decreased by 50.0, 41.4, 34.1 and 33.3 percent on the day of parturition in the four respective groups. After calving, plasma vitamin E started to recover earlier in groups II, III and IV as compared to group I. Mean plasma α-tocopherol concentration at 21 days postpartum was significantly higher in groups II, III and IV (2.9, 3.5 and 3.1 µg/ml) compared to group I (1.9 µg/ml) cows. Plasma retinol concentration also showed a substantial decrease in all the groups on the day of calving but recovered to its normal value at 3 weeks postpartum. Plasma total antioxidant activity averaged 901, 895, 859 and 875 µmol/l in the four respective groups on 30 days prepartum and decreased on the day of calving in all the groups, but the decrease was less in groups III and IV. Plasma immunoglobulin concentration was higher in group IV, followed by groups III, II and I, respectively, showing better immune status of vitamin E supplemented cows due to less oxidative stress. Supplementation of vitamin E resulted in higher plasma calcium concentration. The data showed that vitamin E supplementation should be started at least 30 days prepartum to reduce oxidative stress in periparturient cows. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 11 : 1614-1618)

Influence of amalgam fillings on Hg levels and total antioxidant activity in plasma of healthy donors

In order to evaluate the influence of specific factors on mercury (P-Hg) levels and antioxidant power (P-FRAP) in human plasma, 26 healthy donors were examined by a dentist, their plasma analyzed for Hg by atomic absorption spectrometry and for total antioxidant activity by FRAP method. Hg plasma concentration was found to be correlated with the number of amalgam fillings, suggesting that Hg released from fillings is a source of Hg in non-occupational exposed subjects. P-FRAP correlated negatively with P-Hg suggesting a pro-oxidant role of the Hg released from amalgam fillings. Though age by itself was not significantly correlated with P-FRAP, when considered together with P-Hg in multivariate analysis, it was found to be a major related cofactor. Multivariate analysis showed no influence of fish consumption or cigarette smoking on P-FRAP.

Effect of capsaicin on dynamics of neutrophil functional activity in Wistar rat venous blood.

Capsaicin in neurotoxic dose produced phasic changes in functional activity of sensory neuropeptides and venous blood neutrophils of Wistar rats. At the early terms after capsaicin injections, the sensitivity of neutrophils to bacterial stimuli decreased against the background of neuropeptide release from the sensory terminals. After 2 weeks, activity of neutrophils assessed by NBT-test increased against the background of depletion of neuropeptide stores, while total antioxidant activity of venous plasma decreased. On day 21 of capsaicin treatment, when the content of neuropeptides returned to the baseline level, functional activity of neutrophils decreased and plasma antioxidant activity returned to the control level.

End-of-life care-related publications in cardiology journals

ingestion on the antioxidant capacity of serum. Clin Chem 1995;41:32–35. 16. Wayner DD, Burton GW, Ingold KU, Barclay LR, Locke SJ. The relative contributions of vitamin E, urate, ascorbate and proteins to the total peroxyl radical-trapping antioxidant activity of human blood plasma. Biochim Biophys Acta 1987;924:408–419. 17. Day A, Stansbie D. Cardioprotective effect of red wine may be mediated by urate. Clin Chem 1995;41:1319–1320. 18. Hayek T, Fuhrman B, Vaya J, Rosenblat M, Belinky P, Coleman R, Elis A, Aviram M. Reduced progression of atherosclerosis in apolipoprotein E-deficient mice following consumption of red wine, or its polyphenols quercetin or catechin, is associated with reduced susceptibility of LDL to oxidation and aggregation. Arterioscler Thromb 1997;17:2744–2752. 19. Stein JH, Keevil JG, Wiebe DA, Aeschlimann S, Folts JD. Purple grape juice improves endothelial function and reduces the susceptibility of LDL cholesterol to oxidation in patients with coronary artery disease. Circulation 1999;100:1050–1055.

Genetic contributions to plasma total antioxidant activity.

Oxidative stress plays important roles in a wide spectrum of pathological processes, such as atherosclerosis. Although several environmental factors are documented to influence redox metabolism, relatively little is known about genetic effects. In the present study, we evaluated genetic contributions to variation in plasma total antioxidant status (TAS), a measure of peroxyl-scavenging capacity, in 1337 members of 40 Mexican American families. TAS levels were significantly lower in women than in men (1.675+/-0.004 versus 1.805+/-0.005 mmol/L, respectively; P<0.001), and there was a significant decline of TAS levels with age in men but not in women (P<0.01 for the interaction). Quantitative genetic analysis indicated the heritability of TAS levels to be 0.509+/-0.052; ie, approximately 51% of the residual variance (after covariate adjustment) in TAS levels was due to the additive effects of genes (P<0.001). We have further observed a significant gene-by-smoking interaction (P<0.05). Additive genetic effects account for 83% of the residual phenotypic variance in TAS levels among smokers, but they account for only 49% in nonsmokers. However, genes contributing to TAS variation are the same in smokers and nonsmokers. Our study for the first time demonstrates that TAS, an indicator of redox homeostasis, is under strong genetic control, especially among smokers. With appropriate tools, such as genome screening, it should be possible to localize genes that regulate redox homeostasis and, ultimately, identify the DNA sequence variants predisposing subjects to oxidative damage.

Effect of disturbed plasma oxidant homeostasis on hemopoietic differentiation of polypotent bone marrow stem cells in mice treated with dipyridamole.

The choice of hemopoietic differentiation by polypotent bone marrow stem cells was studied by morphological and chemiluminescent methods. This choice occurred on day 7 after heterotopic bone marrow transplantation and dipyridamole administration, under the effect of oxidative homeostasis imbalance in the plasma. Dipyridamole increased total antioxidant activity and 10-fold reduced the intensity of free radical oxidation. Disaggregation therapy with dipyridamole reduced platelet count in the peripheral blood and decreased total plasma antioxidant activity.

The Risk Factors For Diabetic Complications

The major late complications of diabetes mellitus can be classified into those attributable to atherosclerosis (heart attacks, stroke, and peripheral vascular disease) and to microvascular disease (diabetic polyneuropathy [DPN], retinopathy, and nephropathy). The risk factors for diabetic polyneuropathy had not previously been adequately assessed by: 1) assessing representative population‐based cohorts; 2) assessing DPN comprehensively and quantitatively; 3) expressing nerve tests as a percentile and normal deviate value correcting for anthropometric characteristics as based on study of a randomly selected normal subject cohort from which neurologic disease had been excluded; 4) assessing risk factors serially over time; and 5) performing multivariate analysis of risk factors. For DPN we have found that the risk factors are: 1) markers of diabetic microvessel disease (diabetic retinopathy, 24‐hour proteinuria, or 24‐hour microalbuminuria); 2) chronic hyperglycemic exposure; and 3) type of DM. Excluding markers of microvessel disease and type of DM we found that the highest correlation coefficients were obtained by glycated hemoglobin (GH) × duration of DM 1/2 × 18/age of onset DM (lowest score = 1) × total plasma antioxidant activity. Similarly, major determinants for diabetic retinopathy and nephropathy also are GH × duration of DM. These results provide strong supportive evidence that the product of chronic hyperglycemic (especially GH) exposure × duration of DM are the main determinants of the diabetic complications of retinopathy, nephropathy, and neuropathy.

Tomato consumption does not affect the total antioxidant capacity of plasma

This study was performed to evaluate the effect of tomato intake on total antioxidant activity of plasma measured by the radical trapping antioxidant parameter assay in 11 healthy female subjects. After 7 d of a diet low in carotenoids and free from lycopene, subjects ate 25 g tomato puree daily (containing 7.0 mg lycopene and 0.25 mg β-carotene) for 14 consecutive days. At the beginning and end of tomato supplementation, the carotenoid plasma concentration and the total antioxidant activity of plasma were assessed. Before tomato puree consumption, mean ± SE total lycopene and β-carotene plasma concentrations were 0.13 ± 0.02 μmol/L and 0.24 ± 0.04 μmol/L, respectively. After tomato puree supplementation, both concentrations increased significantly (0.57 ± 0.06 μmol/L, P < 0.0001 for total lycopene, and 0.31 ± 0.04 μmol/L, P = 0.0036 for β-carotene); however, total plasma antioxidant capacity values did not change significantly. From our results, intake of a food rich in carotenoids does not seem to modify the antioxidant capacity of plasma as evaluated by the radical trapping antioxidant parameter assay.

Influencia de la presencia de sofocos durante la menopausia sobre el metabolismo del óxido nítrico. Efecto del tratamiento hormonal sustitutivo

To asses if the hot flushes during the menopause are associated to alterations in the metabolism of nitric oxide, total antioxidant activity and other biochemical parameters. To evaluate the effect of hormone replacement therapy (HRT) in the metabolism of nitric oxide, total antioxidant activity and biochemistry in menopausal women with and without hot flushes. Experimental study. This study included 29 healthy menopausal women with hot flushes (12 with HRT) and 20 without them (6 with HRT), 45-55 years old, with duration of menopause ranging from 1 to 5 years. Control group included 14 fertile women. Determinations of estradiol, nitrite-nitrate, total antioxidant activity and basic analytic, were performed before previous and after 4-6 month of HRT therapy. Previously to HRT, hot flushes were associated to smaller level of total antioxidant activity (p < 0.05) in plasma, without differences in nitrite-nitrate concentrations. HRT was associated to increase in total antioxidant activity level and nitrite-nitrate concentrations (p < 0.05) in menopausal women, with and without hot flushes. Hot flushes during the menopause indicate a high level of oxidative stress and a higher cardiovascular risk. HRT decreased the oxidative stress level and increased the nitric oxide derivate metabolites in menopausal women with and without hot flushes.

Role of Bilirubin in the Regulation of the Total Peroxyl Radical Trapping Antioxidant Activity of Plasma in Sickle Cell Disease

Alpha-tocopherol and bilirubin antioxidant properties were evaluated in sickle cell disease. The total peroxyl radical trapping antioxidant activity of plasma (TRAP) was measured with a polarographic method using hemin as oxidative stress initiator. The TRAP was not correlated with plasma alpha-tocopherol concentration. The TRAP was correlated with plasma total bilirubin concentration [TRAP = 8.1 (total bilirubin) +363.7 (r = 0.67)] and the correlation was even better with the sum (alpha-tocopherol + total bilirubin) plasma concentration [TRAP = 9.1(alpha-tocopherol + total bilirubin)+ 170.5(r = 0.77)]. The alpha-tocopherol contribution in the antioxidant capacity of plasma was significant but bilirubin level acted as the limiting factor of plasma antioxidant capacity in sickle cell anemia. This result can be explained by the antioxidant property of bilirubin but also by coantioxidant activity towards oxidized alpha-tocopherol.