Measurement Of Antioxidant Capacity Research Articles

Measurement of Phenolic Content and Antioxidant Capacity of Pennyroyal (Mentha pulegium L.) and Microalgae Spirulina platensis Extracted by Steeping, Ultrasonic and Microwave Methods

Now-a-days more attention is drawn to the use of natural compounds over synthetic ones in the production of food dyes and pharmaceutical additives. Among the most important and effective components in diets are antioxidants which protect the body from oxidative stress caused by free radicals. In this study, extracts of microalgae Spirulina platensis: and pennyroyal were prepared via steeping, microwave and ultrasonic methods using two solvents, water and ethanol under controlled conditions. Six treatments including water-steeping, water-microwave, water- ultrasound, ethanol-steeping, ethanol-microwave and ethanol-ultrasound, were prepared and triplicate experiments were performed to determine the following components: flavonoid, total phenols content as well as antioxidant capacity (IC50) of the extracts based on Alcl, follin-ciocaltuea and absorption of radical DPPH (2,2-diphenyl -1-ipicryl hydrasil). The data was analyzed by SPSS version 24 and the means were compared using a multi-range Duncan test at 5% level (p<0.05). The results showed that the ultrasound method had the best efficacy for the extraction of phenolic and antioxidant compounds. The use of the water-ultrasound treatment in the extraction of microalgae resulted in the highest amounts of flavonoids and total phenols and the lowest amounts of IC50 (the greatest radical scavenging activity) compared to the five other treatments. The use of the ethanol-ultrasound treatment in the extraction of pennyroyal produced similar results to the waterultrasound extracted microalgae, showing high amounts of flavonoid, total phenol, and radical scavenging activity. These results revealed that a combination of different extraction methods and different solvents is needed to obtain the best results.

Plasma Total Antioxidant Capacity and Cardiometabolic Risk in Non-Obese and Clinically Healthy Young Adults.

BackgroundThe oxidative biomarkers play an important role in the genesis of cardiometabolic risk-related processes.ObjectiveTo investigate the total antioxidant capacity of plasma and its association with cardiometabolic risk in non-obese and clinically healthy young adults.MethodsUniversity students of the state of Sergipe, Brazil, aged between 18 and 25 years, were recruited for this study from May of 2013 and October of 2014. Anthropometric, clinical and biochemical parameters were measured and analyzed using protocols which were previously standardized and described in the literature. The measurement of plasma total antioxidant capacity was based on the ability that all the antioxidants present in the sample (plasma) have to inhibit the oxidation of the oxidizable substrate ABTS (2,2`- Azino-di-[3-ethylbenzthiazoline sulphonate]) to ABTS•+ by metmyoglobin.ResultsApproximately 25% of the sample presented more than one component of cardiometabolic risk. Low HDL-cholesterol was the most prevalent component. Compared to absence of components, the subjects with at least one component presented greater body weight and waist circumference, higher levels of diastolic blood pressure and fasting glucose, greater total cholesterol/HDL-c ratio, and lower levels of HDL-c (p < 0.05). Fasting glycemia was the only parameter which was associated with total antioxidant capacity (R2 = 0.10; β = 0.17; p = 0.001).ConclusionsThe plasma total antioxidant capacity was not able to predict the cardiometabolic risk components due possibly to the establishment of compensatory mechanisms that become activated in physiological conditions.

Laboratory tests for oxidative stress.

Introduction:Oxidative stress (OS) is considered a significant contributor to male infertility. A number of laboratory techniques have been developed to evaluate oxidative stress in the semen. We review these tests and their current use.Methods:A literature review was performed utilizing the PubMed search engine for articles studying OS etiology and impact on male fertility, and the laboratory tests used in its assessment.Results:The state of OS results from exaggerated production of oxygen-derived free radicals, also known as reactive oxygen species, to an extent overwhelming the body's antioxidant defense mechanisms. Several laboratory tests have been utilized in OS measurement during male fertility evaluation. These tests are classified into direct assays which measure the degree of oxidation within a sperm cell and indirect assays which estimate the detrimental effects of OS. The chemiluminescence assay, flow cytometry, nitroblue tetrazolium assay, and cytochrome c reduction are examples of direct assays while the myeloperoxidase test and measurements of lipid peroxidation, oxidation-reduction potential, and total antioxidant capacity are examples of the indirect assays.Conclusion:OS measurement is an important tool that may help in understanding the pathophysiology of male infertility and provide valuable information that would guide treatment decisions and patient follow-up.

Solid-Phase Extraction Spectrophotometric Determination of Total Antioxidant Capacity in Antioxidant-poor Samples by Using the Ferric-Ferrozine Method.

Ferrozine (FZ) preferentially stabilizes Fe(II) over Fe(III) to raise the ferric reduction potential and oxidize antioxidants. The advantages of the ferric-ferrozine method over other iron-based total antioxidant capacity assays were: (i) higher molar absorptivity and enhanced sensitivity, (ii) lower interference from foreign ions, (iii) wide pH tolerance (iv) additivity of the absorbances for mixtures. Solid-phase extraction (SPE) could be combined with spectrophotometry, because the magenta-colored anionic Fe(II)-FZ complex was quantitatively sorbed on Sephadex QAE A-25 resin. The sensitivity enhancement using the resin enabled us to conduct total antioxidant capacity (TAC) measurements of antioxidant-poor samples. The apparent molar absorptivity, linear concentration range and trolox equivalent antioxidant capacities (TEAC) of certain antioxidants were found. The calibration curves (lines) of trolox, rutin, and rosmarinic acid individually and in herbal infusions-by using the method of standard additions-were parallel, confirming that the added antioxidants did not interact with herbal constituents to cause chemical deviations from Beer's law.

Antioxidant mechanism of black garlic extract involving nuclear factor erythroid 2-like factor 2 pathway.

BACKGROUN/OBJECTIVESAlthough studies have revealed that black garlic is a potent antioxidant, its antioxidant mechanism remains unclear. The objective of this study was to determine black garlic's antioxidant activities and possible antioxidant mechanisms related to nuclear factor erythroid 2-like factor 2 (Nrf2)-Keap1 complex.METHODS/MATERIALSAfter four weeks of feeding rats with a normal fat diet (NF), a high-fat diet (HF), a high-fat diet with 0.5% black garlic extract (HF+BGE 0.5), a high-fat diet with 1.0% black garlic extract (HF+BGE 1.0), or a high-fat diet with 1.5% black garlic extract (HF+BGE 1.5), plasma concentrations of glucose, insulin,homeostatic model assessment of insulin resistance (HOMA-IR) were determined. As oxidative stress indices, plasma concentrations of thiobarbituric acid reactive substances (TBARS) and 8-isoprostaglandin F2α (8-iso-PGF) were determined. To measure antioxidant capacities, plasma total antioxidant capacity (TAC) and activities of antioxidant enzymes in plasma and liver were determined. The mRNA expression levels of antioxidant related proteins such as Nrf2, NAD(P)H: quinone-oxidoreductase-1 (NQO1), heme oxygenase-1 (HO-1), glutathione reductase (GR), and glutathione S-transferase alpha 2 (GSTA2) were examined.RESULTSPlasma glucose level, plasma insulin level, and HOMA-IR in black garlic supplemented groups were significantly (P < 0.05) lower than those in the HF group without dose-dependent effect. Plasma TBARS concentration and TAC in the HF+BGE 1.5 group were significantly decreased compared to those of the HF group. The activities of catalase and glutathione peroxidase were significantly (P < 0.05) increased in the HF+BGE 1.0 and HF+BGE 1.5 groups compared to those of the HF group. The mRNA expression levels of hepatic Nrf2, NQO1, HO-1, and GSTA2 were significantly (P < 0.05) increased in the HF with BGE groups compared to those in the HF group.CONCLUSIONSThe improvements of blood glucose homeostasis and antioxidant systems in rats fed with black garlic extract were related to mRNA expression levels of Nrf2 related genes.

Rapid sensing of antioxidant capacity based on electrochemiluminescence induced by electrochemically generated reactive oxygen species

A simple and rapid electrochemiluminescence (ECL) method for the measurement of antioxidant capacity using a portable ECL device with a screen-printed electrode is described. The ECL method is based on the luminous reaction of reactive oxygen species (ROS), luminol radicals and antioxidants. ROS are generated by the electrochemical reduction of dissolved oxygen and competitively react with the luminol and antioxidants. The ECL intensity depends on the antioxidant capacity because the radicals are neutralized by the antioxidants, suppressing the luminous reaction. An antioxidant standard curve was generated using different concentrations of known amounts of Trolox by ECL measurement and the detection limit for antioxidant capacity was found to be 0.06mM of Trolox. An antioxidant capacity of beverages (22 types) was evaluated by comparing with the standard curve of Trolox. The time necessary for the ECL measurement of antioxidant capacity is only two minutes after combining the sample solution with luminol on a screen-printed electrode.

Optimization of Physical Conditions for the Aqueous Extraction of Antioxidant Compounds from Ginger (Zingiber officinale) Applying a Box-Behnken Design.

Since ancient times, ginger (Zingiber officinale) has been widely used for culinary and medicinal purposes. This rhizome possesses several chemical constituents; most of them present antioxidant capacity due mainly to the presence of phenolic compounds. Thus, the physical conditions for the optimal extraction of antioxidant components of ginger were investigated by applying a Box-Behnken experimental design. Extracts of ginger were prepared using water as solvent in a conventional solid-liquid extraction. The analyzed variables were time (5, 15 and 25min), temperature (20, 55 and 90°C) and sample concentration (2, 6 and 10%). The antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl method and a modified ferric reducing antioxidant power assay while total phenolics were measured by Folin & Ciocalteu's method. The suggested experimental design allowed the acquisition of aqueous extracts of ginger with diverse antioxidant activity (100-555mg Trolox/100g, 147-1237mg Fe2+/100g and 50-332mg gallic acid/100g). Temperature was the determining factor in the extraction of components with antioxidant activity, regardless of time and sample quantity. The optimal physical conditions that allowed the highest antioxidant activity were: 90°C, 15min and 2% of the sample. The correlation value between the antioxidant activity by ferric reducing antioxidant power assay and the content of total phenolics was R2 = 0.83. The experimental design applied allowed the determination of the physical conditions under which ginger aqueous extracts liberate compounds with antioxidant activity. Most of them are of the phenolic type as it was demonstrated through the correlation established between different methods used to measure antioxidant capacity.

Usage of Capillary Isotachophoresis and Antioxidant Capacity Measurement in Analysis of Changes in Coffee Properties After Roasting, Steaming and Decaffeination

The aim of the study was to optimise and validate the method for quantitation of short-chained organic acids in coffee brews by capillary isotachophoresis (ITP). The linearity of the method was satisfactory with R2 from 0.9924 for lactic acid to 0.9998 for acetic acid. The limit of detection (LOD) was from 4.9 μmol L−1 for acetic acid to 24.8 μmol L−1 for lactic acid. Precision of the method was from 0.20 to 2.69 %. This method was successfully applied to determine six organic acids (tartaric, formic, citric, malic, lactic and quinic) in Arabica and Robusta green and roasted coffee brews. The roasting as well as steaming and decaffeination processes of beans influenced degradation of acids (citric and malic) and their formation (quinic, tartaric, lactic and formic) in coffee brews. The influence of coffee processing on the antioxidant capacity of coffee brews was also tested by using the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Folin-Ciocalteu and chelating Fe(II) assays. The roasted coffee brews possessed higher antioxidant capacity than unprocessed coffee brews, excluding chelating activity.

Plant-Based Nutraceutical Increases Plasma Catalase Activity in Healthy Participants: A Small Double-Blind, Randomized, Placebo-Controlled, Proof of Concept Trial

ABSTRACTOxidative stress resulting from dietary, lifestyle and environmental factors is strongly associated with tissue damage and aging. It occurs when there is either an overproduction of reactive oxygen species (i.e., oxidants) or decreased bioavailability of antioxidants that can scavenge them. The objective of this 12-week double-blind placebo-controlled study was to assess the efficacy of a nutraceutical at augmenting antioxidant status. Healthy adults (25–45 y) were randomized to either a treatment group (Product B, n = 23) or a placebo group (control, n = 20). No significant effect of Product B was observed for anthropometric variables or markers of glucose and lipid regulation. Biomarkers of oxidative stress were likewise not altered following the 12-week intervention. Plasma catalase concentrations were significantly elevated following 12 weeks of Product B as compared to the control group (+6.1 vs. −10.3 nmol/min/mL, p = 0.038), whereas other measures of antioxidant capacity were not significantly different between the groups. Product B effectively augmented concentrations of the anti-aging antioxidant catalase in healthy adults.

Comparative analyses and evaluation of the cosmeceutical potential of selected Chlorella strains

In the present study, aqueous extracts from eight Chlorella strains were evaluated towards selected cosmeceutical properties such as enzymatic and non-enzymatic antioxidant capacity, glutathione content, inhibition potency towards skin regulatory enzymes, and cytotoxic effect on human cell lines. The results showed that the Chlorella strains display wide catalytic diversity with different strains exhibiting quite varied antioxidant enzymatic activities. The enzymes glutathione reductase, peroxidase, and superoxide dismutase were found in all strains, whereas only Chlorella minutissima displays glutathione transferase activity. Total antioxidant capacity (TAC) measurements, using the FRAP, ABTS, and DPPH assays, indicated significant differences among strains suggesting a large chemical diversity of antioxidants in Chlorella species. Chlorella minutissima extract showed high inhibitory potency with IC50 23.3 ± 2.5 and 29.2±2.7 μg towards tyrosinase and elastase, respectively, suggesting a potential activity in controlling skin aging, inflammatory process, and pigmentation. Furthermore, the effect of C. minutissima extract on a human hepatoma cell line (Huh-7) was evaluated using cell proliferation assay and qRT-PCR to analyze the expression of marker genes (SOD1, GPx1, GPx2) involved in oxidative stress response. The results established the absence of cytotoxic effects of the aqueous extracts. SOD1, GPx1, and GPx4 expression levels showed a specific profile and appear to be slightly upregulated, downregulated, and remained unaffected, respectively. Taken together, these results demonstrate that Chlorella species can provide promising extracts rich in antioxidants, anti-aging, and skin-whitening ingredients with the potential for use as raw material in cosmetics industry.

Validation of an automated assay for the measurement of cupric reducing antioxidant capacity in serum of dogs.

BackgroundThe objective of the present study was to optimize and validate an automated method to assess the total antioxidant capacity (TAC) in serum of dogs using the cupric reducing antioxidant capacity (CUPRAC) methodology (TACc) with bathocuproinedisulfonic acid disodium salt as chelating agent, evaluating also possible variations due to the use of two different automated analyzers. The method is based on the reduction of Cu2+ into Cu1+ by the action of the non-enzymatic antioxidants that are present in the sample.ResultsImprecision was low in both apparatus utilized, and the results were linear across serial Trolox and canine serum samples dilutions. Lipids did not interfere with the assay; however, hemolysis increased the TACc concentrations. When TACc concentrations were determined in ten healthy (control) dogs and in twelve dogs with inflammatory bowel disease (IBD), dogs with IBD had lower TACc concentrations when compared with the healthy dogs.ConclusionsThe method validated in this paper is precise, simple, and fast and can be easily adapted to automated analyzers.

Spectroscopic determination of the dissociation constants of 2,4- and 2,5-dihydroxybenzaldehydes and relationships to their antioxidant activities

UV–visible spectra of 2,4- and 2,5-dihydroxy-benzaldehydes (2,4DHB and 2,5DHB) are recorded in a wide range of pH. The dissociation p K values obtained from these measurements were 6.94 ± 0.03 and 9.28 ± 0.03 for 2,4DHB and 8.42 ± 0.03 and 10.93 ± 0.03 for 2,5DHB. The results indicate that the pH at which the assays for antioxidant capacity measurements are made is very important in light of the hydroxyl group dissociation, because of the different dissociation constants of the different isomers. The percentage of dissociation of each group is essential, the positions of these groups in the ring appearing as a secondary factor.

A high-throughput screening method for identifying lycopene-overproducing E. coli strain based on an antioxidant capacity assay

A straightforward, high-throughput screening method for identifying recombinant Escherichia coli strains that yield high levels of lycopene was developed based on the antioxidative properties of lycopene. Twenty-four recombinant E. coli strains were constructed using plasmids with various orderings of lycopene biosynthesis genes, Shine-Dalgarno regions, and aligned spacing regions. The high-throughput screening was based on antioxidant capacity measurements; we assessed the 2,2-diphenyl-1-picrylhydrazyl method, reducing activity method, and hydroxyl free radical scavenging method; the hydroxyl free radical scavenging method was determined to be the most suitable for use with our lycopene-overproducing system. The accuracy of this method was comparable to that of assay by high-performance liquid chromatography. The strain E. coli IEB11, which had the strongest antioxidant capacity and the highest lycopene-accumulating capacity, was selected and investigated for its ability to produce lycopene at different temperatures, glycerol concentrations, and fermentation times. In the optimal conditions in a 5-L fermenter, lycopene content of 1288mg/L and a mean productivity of 53.7mg/L/h were obtained after 24h.

A Comparison Of Oxidative Stress Markers In Active Vs. Sedentary College Age Students

PURPOSE: To determine the effects of activity level, aerobic capacity and body mass index (BMI) on markers of oxidative stress in college age females. METHODS: 17 female collegiate cross-country athletes (19.1 ± 0.86 years old) and 17 female sedentary college students (21.5 ± 1.8 years old) were examined. Measures of oxidative stress (d-ROMs) and antioxidant capacity (PAT) were obtained using the FRAS-4 Evolvo Analytical System. Height, weight and BMI were recorded for each subject. For the sedentary group, a subjects’ maximum aerobic capacity (VO2 max) was estimated via a submaximal 1-mile walk/jog test. For the cross-country athletes, VO2 max was directly measured using a Parvo Medics TrueOne metabolic cart during an incremental treadmill test to volitional exhaustion. A t-test was used to compare differences between groups. A Pearson correlation was used to determine if a linear relationship existed between any of the test variables. RESULTS: Sedentary subjects demonstrated significantly (p<0.01) higher d-ROMs values (547 ± 172) compared to athletes (385 ± 156). There was no difference in PAT values between the two groups (Sedentary 2287 ± 329, Athletes 2295 ± 518.) Cross-Country athletes had a significantly lower body mass index (20.68 ± 1.64, 26.11 ± 5.11) and a higher VO2 max (50.6 ± 4.70, 36.45 ± 3.29) compared to the sedentary group. There was a strong positive correlation between BMI and d-ROMs (r=0.53, p<0.001) and a strong negative correlation between d-ROMs and VO2max (r=-0.56, p<0.001). CONCLUSION: Elevated BMI, reduced aerobic capacity and a sedentary lifestyle may be associated with increased oxidative stress in college age individuals. Given the established association between oxidative stress and medical conditions such as cardiovascular disease, diabetes and certain types of cancer, this may place these individuals at a greater risk for medical co-morbidities. Supported by Quinnipiac University, School of Health Sciences

Multi-radical (ORACMR5) antioxidant capacity of selected berries and effects of food processing

BACKGROUND: Fruits and berries are known to contain relatively high amounts of antioxidant/bioactive compounds. Several methods have been used for measurement of antioxidant capacity (AC), but not all methods have direct relevance to in vivo antioxidant status. OBJECTIVE: Determine AC in berry/fruit samples, processed berry products, and purified compounds by utilizing 5 different biologically relevant free radical/oxidant sources. METHODS: Samples were assayed for AC capacity using 5 different free radical/oxidant sources: peroxyl radical (ORAC), hydroxyl radical (HORAC), peroxynitrite (NORAC), superoxide anion (SORAC) and singlet oxygen (SOAC)]. Total AC (sum of AC with 5 individual radicals) was expressed as Oxygen Radical Absorption Capacity using Multiple Radicals (ORACMR5). RESULTS: SOAC contributed more than 60% of ORACMR5 in blackberries, sweet and tart cherries; and no detectable levels of SOAC were found in strawberries, black currants and raspberries. Whole fruit purees of mango, wild blueberry and cherry contained 95, 85 and 67% respectively of total ORACMR5 from SOAC. However, freeze dried wild blueberry powder from same production season had only 28% as SOAC and 42 and 22% as ORAC and HORAC. Blueberry/Pomegranate and Mango/Pineapple smoothies had 67% and 77% of ORACMR5 as SOAC. CONCLUSIONS: The antioxidant quenching potential using 5 different radical/oxidant sources of different berries and fruits varied widely and understanding this variation may be helpful in understanding health benefits of different berries and foods.

Evaluation of the antioxidant capacity of a milk protein matrix in vitro and in vivo in women aged 50–70 years

Bovine milk proteins have emerged as a novel, dairy-based source of dietary antioxidants and a component of a nutritional strategy to maintain muscle mass during ageing. The aim of this study was to characterise the in vitro antioxidant capacity (AOC) of a milk-based protein matrix (MPM) before and after simulated gastrointestinal digestion (SGID) and determine whether plasma AOC was similarly modified in vivo following acute ingestion of the MPM in healthy 50–70 years old women. To achieve this, the AOC of the MPM was measured by the oxygen radical absorbance capacity (ORAC) assay prior to and following SGID. In parallel, plasma obtained from women prior to and for 3 h following ingestion of the MPM was analysed ex vivo for change in AOC to evaluate the translation in vivo. SGID of the MPM increased AOC by ∼35% (27,365 ± 2152 versus 42,592 ± 2299 μmol TE/100 g dw; p < 0.05). Sampled ex vivo, ingestion of the MPM increased fasting plasma AOC by ∼23% (10,952 ± 751 to 13,519 ± 800 μmol TE/L; p < 0.05). These data provide preliminary evidence of an association between the change in the ORAC-based measurement of AOC of an MPM subjected to simulated digest in vitro and the change in plasma AOC following ingestion of the MPM sampled ex vivo from healthy elderly women.

Measurement of Antioxidant Capacity by Electron Spin Resonance Spectroscopy Based on Copper(II) Reduction.

A new method is proposed for measuring the antioxidant capacity by electron spin resonance spectroscopy based on the loss of electron spin resonance signal after Cu(2+) is reduced to Cu(+) with antioxidant. Cu(+) was removed by precipitation in the presence of SCN(-). The remaining Cu(2+) was coordinated with diethyldithiocarbamate, extracted into n-butanol and determined by electron spin resonance spectrometry. Eight standards widely used in antioxidant capacity determination, including Trolox, ascorbic acid, ferulic acid, rutin, caffeic acid, quercetin, chlorogenic acid, and gallic acid were investigated. The standard curves for determining the eight standards were plotted, and results showed that the linear regression correlation coefficients were all high enough (r > 0.99). Trolox equivalent antioxidant capacity values for the antioxidant standards were calculated, and a good correlation (r > 0.94) between the values obtained by the present method and cupric reducing antioxidant capacity method was observed. The present method was applied to the analysis of real fruit samples and the evaluation of the antioxidant capacity of these fruits.

Determination of total antioxidant capacity of humic acids using CUPRAC, Folin–Ciocalteu, noble metal nanoparticle- and solid–liquid extraction-based methods

Total antioxidant capacity (TAC) of humic acid (HA) samples was determined using CUPRAC (CUPric Reducing Antioxidant Capacity), FC (Folin–Ciocalteu), QUENCHER-CUPRAC, QUENCHER-FC, Ag-NP (Silver nanoparticle)‒ and Au-NP (Gold nanoparticle)‒based methods. Conventional FC and modified FC (MFC) methods were applied to solid samples. Because of decreased solubility of Folin–Ciocalteu's phenol reagent in organic solvents, solvent effect on TAC measurement was investigated using QUENCHER-CUPRAC assay by using ethanol:distilled water and dimethyl sulfoxide:distilled water with varying ratios. To see the combined effect of solubilization (leaching) and TAC measurement of humic acids simultaneously, QUENCHER experiments were performed at 25°C and 50°C; QUENCHER-CUPRAC and QUENCHER-FC methods agreed well and had similar precision in F-statistics. Although the Gibbs free energy change (ΔG°) of the oxidation of HA dihydroxy phenols with the test reagents were negative, the ΔG° was positive only for the reaction of CUPRAC reagent with isolated monohydric phenols, showing CUPRAC selectivity toward polyphenolic antioxidants. This is the first work on the antioxidant capacity measurement of HA having a sparingly soluble matrix where enhanced solubilization of bound phenolics is achieved with coupled oxidation by TAC reagents.

Increased oxidative stress in pemphigus vulgaris is related to disease activity and HLA-association

Pemphigus vulgaris (PV) is a rare blistering skin disorder characterized by the disadhesion of keratinocytes due to autoantibody attack against epidermal targets including desmoglein (Dsg) 3, Dsg 1 and possibly other adhesion and non-adhesion molecules. The mechanisms leading to immune-mediated pathology in PV are multifactorial and not fully understood. Recently, oxidative stress (antioxidant/oxidant disequilibrium) has been proposed as a contributory mechanism of autoimmune skin diseases, including PV. In this study, we directly assessed oxidative stress via measurement of total antioxidant capacity (TAC) using ELISA in 47 PV patients, 25 healthy controls and 18 bullous pemphigoid (BP) patients. We also performed microarray gene expression analysis on a separate set of 21 PV patients and 10 healthy controls to evaluate transcriptional dysregulation in oxidative stress-related pathways. Our data indicate that there is a significant reduction in TAC levels in PV patients compared with healthy controls, as well as BP patients. Furthermore, PV patients with active disease have significantly lower TAC levels than PV patients in remission. We also find that HLA allele status has a significant influence on oxidative stress. These findings are corroborated by microarray analysis showing differentially expressed genes involved in oxidative stress between the aforementioned groups. Collectively, our findings provide support for a role of oxidative stress in PV. Whether increased oxidative stress leads to disease manifestation and/or activity, or if disease activity leads to increased oxidative stress remains unknown. Future longitudinal studies may help to further elucidate the relationship between PV and oxidative stress.

Assessment of salivary total antioxidant capacity in patients with primary untreated head and neck squamous cell carcinoma with ORAC.

Oxidative DNA damage leads to abnormalities in endogenous cellular processes and constitutes a direct link between free radicals, antioxidants and squamous cell carcinoma (SCC). Oxygen radical absorbance capacity (ORAC) method is used to measure antioxidant capacity versus oxygen free radicals. There is no report on the application of ORAC to evaluate salivary antioxidant capacity in patients with head and neck SCC. This study investigated the relation between total antioxidant capacity of saliva, measured with ORAC method, and the incidence, location, size and histopathological grading of SCC. Salivary antioxidant capacity was assessed in 30 male and female patients with histopathologically confirmed oral and laryngeal SCC. Histopathological grading of SCC was based on WHO classification. Mean ORAC in patients with SCC was higher than the mean value in the control group. Statistically significant difference was observed in the study group versus the control group. No significant differences were observed for ORAC values in relation to histopathological grading, tumour size and spread to lymph nodes. The obtained results can advocate local compensatory mechanism in saliva in response to increased oxidative stress associated with primary tumour. ORAC can become an additional factor in head and neck SCC prognosis, but further investigation is required.