Measurement Of Total Antioxidant Capacity Research Articles

Oxidant and antioxidant parameters in patients with Brucella canis

The aim of this study was to evaluate the oxidative status in patient with Brucella canis (B. canis) and healthy controls by measurement of total antioxidant capacity (TAC) and total oxidant capacity (TOS), and calculation of oxidative stress index (OSI). Six patients with B. canis and 6 healthy control subjects were included in this study. Diagnosis of B. canis was made by rapid slide agglutination test (RSAT) and Modified Plate Agglutination Test (MPAT). The serum samples of B. canis positive patients and controls were used for measurement of TAC and TOS levels. The TOS and OSI index were significantly higher in brucellosis positive patients than control group (p<0.001 and p<0.0001, respectively), while TAC level was found similar in patient and control groups. Findings of this study have shown that B. canis generate low TOS and OSI index in man compared with smooth Brucella species infection. This difference may help to provide understanding about the pathogenesis of B. canis infection in man.

Quantitative determination of low molecular weight antioxidants and their effects on different antioxidants in chicken blood plasma

Antioxidants in the body are in balance, and form a network that protects living organisms against oxidative stress. To prove this hypothesis, we developed suitable methods for assessing the amount of antioxidants and their antioxidant activity in the chickens’ plasma, which enable us to explain the overall anti-oxidant status of the animals during the controlled industrial raise. The effects of exogenous coenzyme Q10, and α-lipoic acid on the reduction of oxidative stress in the animal body were assessed. The physical and the health conditions of chickens during the raising period of 40 days were followed. The benefits of additives were estimated through the measured concentrations of selected low molecular weight antioxi-dants (coenzyme Q10, α-lipoic acid, α-tocopherol, lutein and zeaxathin) and antioxidant enzymes (super-oxide dismutase, glutathione reductase), cholesterol and glucose in plasma and measurements of total antioxidant capacity. Quantitative analyses of selected substances were done with different chromatographic, spectroscopic and electrometric methods. The addition of antioxidants has positive effects on the acts of antioxidant network.

Exercise modulation of total antioxidant capacity (TAC): towards a molecular signature of healthy aging

The objective of this article was to review the biochemical basis of the total antioxidant capacity (TAC) test and its applications to exercise science and promotion of healthy aging. Measurement of TAC allows evaluation of the antioxidant content of muscle, heart and other exercise-target organs. Acute non-regular physical exercise and body exposition to higher altitude have been associated with a considerable decrease of blood TAC. However, regular practice of physical activity and exercise is associated with improved antioxidant response increasing TAC levels. TAC methodologies did not address lipophylic antioxidants and have some other limitations. However, TAC is useful as a complementary test for the evaluation of antiperoxidation assays and blood, erythrocyte and cytosolic antioxidant enzyme assays (glutathion reductase, glutathion peroxidase, superoxide dismutase and catalase). Exercise induces both molecular antioxidant and hormetic responses which have been suggested to be linked with a healthy aging.

The effect of intravenous iron therapy on total antioxidant capacity in patients with iron deficiency anemia

Objectives: Parenteral iron is used for patients who are either unable to absorb oral iron or who have increasing anemia despite adequate doses of per oral iron. Parenteral iron preparations are clearly effective, but concerns have been raised regarding adverse events and potentially long-term toxicity. So, in this study we aimed to investigate the effect of intravenous iron therapy on acute antioxidant capacity. Materials and methods: Totally 36 patients with iron deficiency anemia and 20 healthy controls were included in the study. Prior to iron infusion to subjects, blood samples were obtained for measurement of total antioxidant capacity. Then patients received 100 mg intravenous iron sucrose in an hour. And at the first hour after the infusion was completed, the blood samples were repeated. Results: Before the treatment total antioxidant capacity was significantly lower in anemic patients (280±34 μmol/L) than in control group (365±58 μmol/L) (p=0.001). Significantly decreased total antioxidant capacity (264±35 μmol/L) was found after the iron treatment (p=0.01). No adverse events related to intravenous iron were observed. Conclusion: In this study, we observed that intravenously administered iron sucrose in 100 mg dose and also iron deficiency anemia itself, caused increased oxidative stress.

Total antioxidant capacity and total oxidant status after surfactant treatment in preterm infants with respiratory distress syndrome

Oxidative damage is important in the pathogenesis of respiratory distress syndrome (RDS). However, data on the effect of surfactant therapy on oxidative stress in vivo are limited. We aimed to evaluate the oxidant/antioxidant status in preterm infants with RDS via measurement of total antioxidant capacity (TAC) and total oxidant status (TOS), to determine the effect of surfactant on oxidant/antioxidant balance and to assess the association between TAC, TOS and clinical outcomes of the patients. Sixty-nine infants with RDS were included. Blood samples for determining TAC and TOS were collected before and 48 h after surfactant treatment. TAC and TOS levels were analysed in serum. Patients were followed up until discharge or death. Post-surfactant TAC levels were significantly higher than pre-surfactant TAC levels (P = 0.029). TAC/TOS ratio significantly increased after surfactant treatment (P = 0.018). Infants <28 weeks of gestational age had lower levels of baseline TAC than those ≥28 weeks of gestational age (P = 0.020), whereas TOS levels were similar. Baseline TAC/TOS ratio was lower in infants who died in the study period than those who survived (P = 0.023). After controlling gestational age, baseline TAC levels were significantly and inversely correlated with the duration of total respiratory support (r = -0.343; P = 0.009) and hospitalization (r = -0.341; P = 0.009). TAC or TOS levels were not associated with the development of bronchopulmonary dysplasia or other complications as determined during the investigation period. Oxidant-antioxidant balance shifts in favour of the antioxidant system after surfactant treatment. Lower TAC/TOS ratio in preterm infants may be associated with increased mortality.

Evaluation of oxidative status in patients with hyperthyroidism

Data on the antioxidant levels enzyme in patients with hyperthyroidism are limited and conflicting. Therefore, the objective of this study was to evaluate the oxidative status using an automated method in patients with hyperthyroidism. Thirty-six subjects with hyperthyroidism and 30 healthy controls were enrolled in this study. Serum oxidative status was determined via measurement of total antioxidant capacity (TAC) and total oxidant status (TOS) and calculation of oxidative stress index (OSI). Serum TAC levels were significantly lower in patients with hyperthyroidism than controls (P=0.002), while serum TOS levels and OSI values were significantly higher (P=0.008, 0.004; respectively). Serum TAC levels were correlated with TSH levels (rho=0.223, P=0.032), FT3 levels (rho=-0.434, P=0.002) and FT4 levels (rho=-0.363, P=0.003) in patients. Further, TOS levels and OSI values were correlated with TSH levels (rho=-0.245, P=0.037; rho=-0.312, P=0.011, respectively), FT3 levels (rho=0.293, P=0.017, rho=0.505, P=0.002, respectively), and FT4 levels (rho=0.302, P=0.006, rho=0.321, P=0.008, respectively) in patients. Duration of disease was significantly correlated with OSI values in patients (rho=0.420, P=0.011), while no correlation with serum TAC levels and TOS levels (P>0.05). Oxidants are increased and antioxidants are decreased in patients with hyperthyroidism; as a result, the oxidative-antioxidative balance is shifted to the oxidative side. Increased oxidative stress may play a role in the pathogenesis of hyperthyroidism. It is believed that supplementation of antioxidant vitamins such as vitamins C and E may be helpful for these patients.

Sequential injection analysis with electrochemical detection as a tool for economic and rapid evaluation of total antioxidant capacity

This work presents a new flow-based coupled electrochemical technique for evaluation of “total antioxidant capacity (TAC)”. A sequential injection (SI) with amperometric detection was applied to the TAC analysis of commercial instant ginger infusion beverages using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. Besides having chromogenic properties, the ABTS reagent behaves as an electroactive species at the glassy carbon electrode in phosphate buffer pH 7.0, the decrease of the cathodic current signal of the ABTS+ radical after reaction with antioxidants can be monitored. The SI system, furnished with an in-house electrochemical detection cell (ECD), was optimized with respect to the applied potential, sample and reagent volume, and flow rate to the detector. Gallic acid was used as the standard antioxidant and the capacity was reported as gallic acid equivalent (GAE) unit. TAC measurements of ginger infusions at the optimum condition were performed using the proposed technique and also with the classical batch spectrophotometric ABTS assay. TAC values obtained from our method and the standard method are in good agreement (r2=0.956). The SI-amperometric technique provided satisfactory precision (4.11% RSD) with rapid sample throughput (40samplesh−1). Also using this method, the consumption of the expensive ABTS reagent was greatly reduced.

Contribution of environment and genetics to oxidative stress in pancreatic cancer (PC) patients (pts).

211 Background: Several risk factors have been identified as contributors to PC development, including tobacco and alcohol use, and exposure to environmental chemicals. A common denominator of these risk factors is the ability to induce oxidative stress/damage. An individual's genetic makeup may also contribute to oxidative stress, as oxidative stress/damage genes exhibit single nucleotide polymorphisms (SNPs), which can alter protein expression or activity. The goal of this study was to (1) determine if increased oxidative stress/damage is observed in PC pts and (2) to assess the contribution of environmental and genetic factors to oxidative stress/damage parameters. Methods: An oxidative stress/damage profile was generated from blood samples of newly diagnosed PC pts (n=20), from non-cohabiting genetic relatives (n=20) and/or from non-genetic relatives living in the same household (n=20). This profile consisted of measurement of total antioxidant capacity (Trolox equivalent antioxidant capacity, TEAC), direct and oxidative DNA damage (COMET), and malondialdehyde (MDA) levels. Expression of SNPs in selected oxidative stress/response genes was also evaluated. Environmental and dietary/lifestyle information was collected using a detailed questionnaire. Results: PC pts, when compared to healthy nonrelated but cohabitating relatives, displayed a significant increase in direct DNA damage (p=0.002), while oxidative DNA damage, TEAC and MDA levels were similar. When comparing PC pts to healthy genetic relatives, increased levels of TEAC, direct and oxidative DNA damage approached or were statistically significant (p = 0.061, 0.002, and 0.062 respectively). Analysis of 26 selected SNPs in oxidative stress/ damage genes in the PC pts vs healthy controls revealed that expression of CYP2A6 (L160H), rs1801272, and TNF (-308G&gt;A), rs1800629, approached statistical significance (p=0.05 and 0.20 respectively). Conclusions: Increased oxidative DNA damage observed in PC pts vs healthy related, but non-cohabitating relatives, suggests that environmental exposures contribute to oxidative stress. In combination with a specific genetic background, environmental influences may increase the risk of PC. No significant financial relationships to disclose.

Umbilical cord oxidative stress in infants of diabetic mothers and its relation to maternal hyperglycemia

There is growing body of evidence that oxidative stress plays an important role in the pathogenesis of diabetes mellitus (DM) and in development of maternal and fetal complications of diabetic pregnancies. The aim of the present study was to investigate total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) in infants of diabetic mothers (IDM) and to reveal the influence of maternal hyperglycemia on these parameters. A prospective controlled study was conducted between March 2010 and November 2010. Umbilical cord blood was taken from IDM and controls for TAC and TOS measurement, and OSI was calculated. IDM were divided into two groups, either of mothers treated with insulin during pregnancy or of those treated with a carbohydrate-restricted diet. Thirty-six IDM and 14 infants born to non-diabetic mothers were enrolled. Infants of insulin-treated mothers (group 1) and infants of mothers managed with a carbohydrate-restricted diet (group 2) had significantly higher TOS (p < 0.001 and p = 0.001, respectively) and OSI (p < 0.001 and p = 0.001, respectively) levels compared to controls. However, TAC levels were similar in all three groups. Maternal HbA(1c) values were correlated to TOS (p < 0.001, r = 0.694) and OSI (p < 0.001, r = 0.683). Oxidative stress is increased in IDM, and a significant relation exists between the degree of maternal hyperglycemia in pregnancy and oxidative stress in the newborn at birth.

Thorough Study of Reactivity of Various Compound Classes toward the Folin−Ciocalteu Reagent

A thorough study was done to test the reactivity of the Folin-Ciocalteu (F-C) reagent toward various compound classes. Over 80 compounds were tested. Compound classes included phenols, thiols, vitamins, amino acids, proteins, nucleotide bases, unsaturated fatty acids, carbohydrates, organic acids, inorganic ions, metal complexes, aldehydes, and ketones. All phenols, proteins, and thiols tested were reactive toward the reagent. Many vitamin derivatives were also reactive, as were the inorganic ions Fe(+2), Mn(2+), I(-), and SO(3)(2-). Other compounds showing reactivity included the nucleotide base guanine and the trioses glyceraldehyde and dihydroxyacetone. Copper complexation enhanced the reactivity of salicylate derivatives toward the reagent, whereas zinc complexation did not. Several amino acids and sugars that were reported to be reactive toward the F-C reagent in earlier studies were found not to be reactive in this study, at least in the concentrations used. Reaction kinetics of each compound with the F-C reagent were also measured. Most compounds tested showed a biphasic kinetic pattern with half-lives under 1 min. Trolox and ascorbic acid displayed a rapid monophasic pattern in which the reaction reached end point within 1 min. In summary, this study has shown that the F-C reagent is significantly reactive toward other compounds besides phenols. As other investigators have suggested, the F-C assay should be seen as a measure of total antioxidant capacity rather than phenolic content. Because phenolics are the most abundant antioxidants in most plants, it gives a rough approximation of total phenolic content in most cases.

Contribution of polyphenols to the total antioxidant capacity of pomegranate and grape juices

Pomegranate juice (PJ) and grape juice (GJ) have comparable ORAC assay values, but PJ is more potent than GJ in other in vitro measures of Total Antioxidant Capacity (TAC). We examined the basis for these differences in the ORAC, FRAP, and DPPH assays. Juices were fractionated into their sugar, organic acid, neutral phenol, and anthocyanin components to assess the contribution of each to their TAC. Polyphenol fractions contributed ≥75% of the TAC for both juices. For PJ, neutral phenols contributed the most to ORAC, FRAP, and DPPH values with 50, 49, and 46% of TAC of the whole juice, respectively; GJ anthocyanins contributed the most with 53, 47, and 49%, respectively. The contribution of PJ polyphenols to FRAP values was 56% greater than GJ. The contribution of PJ polyphenols to ORAC values were 42% less than GJ. The ORAC/FRAP ratio of GJ neutral phenols and anthocyanin fractions were ≥1.5‐fold higher than those of PJ fractions, while ORAC/DPPH ratios were 3.5‐fold larger. Fraction recombination revealed interactions were dependent upon the assay. Sugars and organic acids antagonized PJ polyphenols in the DPPH assay by 50% and the GJ ORAC value by 22%. Therefore, the differential TAC of PJ and GJ can be attributed to the larger intrinsic electron transfer capacity but smaller hydrogen transfer capacity of PJ phenols and anthocyanins than GJ. Supported by the USDA and POM Wonderful LLC. BWB was supported by NIGMS K12GM074869.

Development and validation of an algorithm to establish a total antioxidant capacity database of U.S. diet

The present study was designed to develop and validate an algorithm to estimate total antioxidant capacity (TAC) of the U.S. diet. Vitamin C equivalent antioxidant capacities (VCEAC) of individual antioxidant nutrients and 50 popular antioxidant‐rich food items in the U.S. diet were determined by 2,2′‐azino‐bis‐3‐ethylbenzthiazoline‐6‐sulphonic acid (ABTS) assay. According to the algorithm, theoretical TAC for each food item was calculated as the sum of the product of antioxidant content and antioxidant capacities of individual antioxidant nutrients. The top ten TAC food items in the U.S. diet according to standard serving size were blueberry &gt; plum &gt; green tea &gt; strawberry &gt; green tea (decaffeinated) &gt; red wine &gt; grape juice &gt; black tea &gt; cherry &gt; grape. Major contributors to TAC were total phenolics (r = 0.952, p &lt; 0.001) and flavonoids content (r = 0.827, p &lt; 0.001) of 50 food items. Theoretical TAC was positively correlated with experimental TAC (r = 0.833, p &lt; 0.01) and with TAC from the USDA database for the oxygen radical absorbance capacity (ORAC) (r = 0.484, p &lt; 0.01, n = 44). This study validates that TAC measurement based on VCEAC can be employed to establish a TAC database of the U.S. diet. In future studies, TAC of the U.S. diet can be calculated and linked to biomarkers of chronic disease.Grant Funding Source: Supported by Beginning Grant in Aid (BGIA) No. 0865092E from the American Heart Association and University of Connecticut Faculty Large Grant

Modified cerium(IV)-based antioxidant capacity (CERAC) assay with selectivity over citric acid and simple sugars

A Ce(IV)-based reducing capacity (CERAC) assay was developed to measure the total antioxidant capacity (TAC) of foods, in which Ce(IV) would selectively oxidize antioxidant compounds but not citric acid and reducing sugars. The redox potential of the Ce(IV) oxidant was fine-tuned in 0.3 M H 2SO 4 + 0.7 M Na 2SO 4 aqueous medium for selective oxidation. In the classical Ce(IV)-based assay for which the name CERAC was proposed, the presence of citric acid (at 1.5 × 10 −5 M) caused approximately 25% reduction in Ce(IV) (at 2.0 × 10 −4 M) recovery, whereas in the present method, the presence of citric acid (at 1.0 × 10 −4 M) caused negligible error in the TAC measurement of quercetin. The trolox equivalent antioxidant capacity (TEAC) values in the order of quercetin > rutin > gallic acid > catechin > caffeic acid ≥ ferulic acid > naringenin ≥ naringin > trolox ≥ ascorbic acid were established with the proposed method and were found to be compatible with those found with other antioxidant assays. It is noteworthy that naringin and rutin were also hydrolyzed in the acidic medium of the method so as to exert their full antioxidant capacity not measured by other TAC assays. The proposed TAC assay with Ce(IV) is simple, low-cost, rapid, and can be easily applied in modestly equipped conventional laboratories.

Oxidant/Antioxidant Status of Patients with Diabetic and Senile Cataract

ABSTRACTThe aim of the present study is to evaluate the relationship of total antioxidant capacity, total oxidant status, oxidative stres and total free sulfydryl groups in patients with diabetic and nondiabetic senil cataract.The study was carried out on venous blood samples from 70 subjects admitted to the ophtalmology clinic of a research hospital. Of these, 25 were senile Type 2 diabetic patients with cataract who were using oral hypoglycemic agents or insülin. Fourty-five patients with nondiabetic senile cataract comprised the control group. Total oxidant status (TOS), total antioxidant capacity (TAC) and total free -SH levels were measured in sera of patients with cataract. Serum TAS and TOS levels were determined using a novel automated measurement method. Oxidative status was determined using TAC and TOS measurement and with the calculation of oxidative stres index.TOS and OSI levels were significantly higher in diabetic cataract than senile cataract (p=0.008, p=0.013), respectively. TAC and total free -SH levels were similiar in the two groups (p = 0.17, p=0.54). Free sulfydryl groups levels are consistent with TAC.The results of present study suggest that TOS and intensity of the oxidative stress in diabetic patients are higher, compared to other age-related cataract patients without diabetes. Since oxidative stress is important in development of diabetic complications, increased TOS and oxidative stress might have a role in the pathophysiology of diabetic cataract.

Efficient Assay for Total Antioxidant Capacity in Human Plasma Using a 96-Well Microplate

In the present study, we tried to establish an efficient assay for total antioxidant capacity (TAC) in human plasma using a 96-well microplate. TAC was assessed using lag time by antioxidants against the myoglobin-induced oxidation of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) with hydrogen peroxide, and expressed as Trolox equivalent. The linearity of the calibration curve with Trolox was maintained with the Trolox concentration range from 2.5 µM to 25 µM (R2 = 0.997). The assay was applied to the measurement of TAC in healthy human plasma. Coefficient of variation in intraday assay was 2.4%. Difference was not observed in interday assay. Plasma TAC of men ((569 ± 41) µM Trolox equivalent; n = 6) was higher than that of women ((430 ± 28) µM Trolox equivalent; n = 4). After the vegetable juice was drunk for 1 week, the increase in plasma TAC was observed in almost all the volunteers. In summary, we developed the efficient assay for plasma TAC using a 96-well microplate.

Evaluation of oxidative stress, antioxidants and prolactin in infertile women.

The objective of the study was to estimate the serum concentrations of oxidative stress markers-lipid hydroperoxide (MDA-Malondialdehyde), lactate dehydrogenase (LDH), nitrite; and ferric reducing antioxidant power (FRAP) - a measure of total antioxidant capacity in serum. Serum nitrite levels were high in fertile women than in infertile women (p<0.001), whereas MDA was high in infertile women than in fertile group (p<0.018). On classifying the entire group of women with infertility based on the etiology, serum MDA and LDH levels were higher in women with infertility due to unexplained factor than in women with other causes contributing to infertility compared to controls (p<0.001, p<0.02). A positive correlation among serum prolactin and nitrite suggested that hyperprolactinemia could contribute to infertility by inducing oxidative damage. Serum FRAP levels showed no significant difference in the groups studied. Lipid peroxidation was high in women with unexplained infertility which may be due to hyperprolactinemia.

Rapid measurement of total antioxidant capacity in plants

There is growing interest in measuring the antioxidant status of plant tissues. This protocol describes the oxygen radical absorbance capacity (ORAC) assay, which measures antioxidant inhibition of peroxyl radical-induced oxidations and is a measure of total antioxidant capacity. The assay is performed in a microplate and is assessed with a 96-well multi-detection plate reader. Total antioxidant capacity of 64 experimental samples can easily be analyzed in 1 d. This assay is presented along with rapid assays for total phenolic content and total ascorbate content. Overall, these assays provide a general diagnostic tool of the antioxidant capacity in leaf tissue extracts.

Progressive augmentation and long‐term facilitation of ventilation is mitigated following a reduction in oxidative stress in individuals with obstructive sleep apnea

Purpose: To determine whether oxidative stress impacts on progressive augmentation (PA) and long-term facilitation (LTF) of minute ventilation in subjects with obstructive sleep apnea (OSA) during wakefulness after exposure to intermittent hypoxia (IH). Methods: Six male OSA subjects were exposed to IH on two occasions. The IH protocol consisted of 12-4 minute episodes of hypoxia (PETO2 −50 mmHg, PETCO2 -sustained at 4 mmHg above resting values) separated by 4 minute recovery periods. The recovery period following the last episode was 30 minutes. Prior to exposure to IH subjects were treated with an antioxidant cocktail (Aox) on one occasion and a placebo (Plb) on another. Peripheral venous blood was sampled before and after IH on both occasions to obtain measures of total antioxidant capacity. Results: Total antioxidant capacity was increased following treatment with Aox (Plb vs. Aox - 2.6 ± 0.5 vs. 3.7 ± 0.7 mM Trolox Equivalents; p < 0.04). Baseline levels of minute ventilation and carbon dioxide following treatment with Plb and Aox were similar (19.9 ± 3.8 vs. 16.6 ± 1.1 L/min; 44.2 ± 1.1 vs. 44.2 ± 1.2 mmHg). The ventilatory response to the last IH episode was greater compared to the initial episode following Plb, but not after treatment with Aox (Plb - 2.04 ± 0.13 vs. 1.70 ± 0.09 fraction of baseline, p < 0.001; Aox - 1.86 ± 0.12 vs.1.80 ± 0.08 fraction of baseline). Moreover, LTF of minute ventilation was evident following IH on both occasions. However, LTF was significantly greater following Plb compared to Aox (1.48 ± 0.04 vs. 1.28 ± 0.03 fraction of baseline, p < 0.02). Conclusions: PA and LTF of minute ventilation are evident in subjects with OSA during wakefulness if carbon dioxide is sustained above resting levels. The emergence of these phenomena is impacted by levels of oxidative stress.

Evaluation of antioxidant capacity of some fruit and vegetable foods: efficiency of extraction of a sequence of solvents

AbstractAll methods for assessing the total antioxidant capacity (TAC) of food samples are strongly affected by the solvents used during extraction. In recent years a sequential solvent extraction procedure utilising water and acetone has been widely used for TAC measurements of foods. To better understand the efficiency of this procedure in terms of the amount of extracted antioxidants and the subsequent measurement of TAC, two vegetables (onion and spinach) and two fruits (orange and tomato) were sequentially extracted with water, acetone and chloroform. Each extract fraction was analysed separately for its content of known antioxidant compounds by specific procedures and for its TAC by the Trolox equivalent antioxidant capacity assay. The results showed that the compounds in the water and acetone extracts were the main contributors to TAC. The chloroform extracts did not contribute to TAC, with the exception of the spinach extract, owing to the presence of low levels of carotenoids. In conclusion, the analysed extraction procedure was more effective for foods rich in water‐soluble antioxidants than for those rich in lipid‐soluble antioxidants. Copyright © 2006 Society of Chemical Industry

A simple automated procedure for thiol measurement in human serum samples

Thiol groups have been described as the main responsible for antioxidative effects of plasmatic proteins. Also, thiol serum levels have shown a positive correlation with total antioxidant capacity (TAC) in many studies. Measurement of TAC by substract oxidation-based methods have been widely used as a reference to measure antioxidant status; however, in many cases these methods are inexact or imprecise, usually when performed by manual procedures. In this paper we describe a simple automated procedure for the determination of total thiols in serum, which was based on Ellman’s method. It was correlated with several markers of oxidative/antioxidative status, such as TAC and thiobarbituric acid reactive substance test (TBARs). Serum thiol levels were correlated positively with TAC (r = 0.298, p < 0.001) and negatively with TBARs levels (r = -0.330, p < 0.001). The novel automated procedure for thiol groups measurement can be a great tool in estimation of antioxidant status together with TAC assay. This procedure makes the determination of total thiol groups in large scale possible in clinical chemistry or research laboratories where this approach is necessary.