Peroxyl Radical-trapping Capacity Research Articles

Simultaneous effect of nitrogen, trifluoromethyl and dimethyl amino group on the radical trapping capacity of diphenylamine: a quantum chemical study

In order to maximize the peroxyl radical trapping capacity of diphenynlamines, the substituents such as N, NMe2, and CF3 are suggested to add to their phenolic rings. The reasonable combination of these substituents at right position can reduce the bond strength of the N-H bond, but still keep the derivatives stable in air.

A Modified Method for Studying Behavioral Paradox of Antioxidants and Their Disproportionate Competitive Kinetic Effect to Scavenge the Peroxyl Radical Formation

We have described a modified method for evaluating inhibitor of peroxyl radicals, a well-recognized and -documented radical involved in cancer initiation and promotion as well as diseases related to oxidative stress and ageing. We are reporting hydrophilic and lipophilic as well as natural and synthetic forms of antioxidants revealing a diversified behaviour to peroxyl radical in a dose-dependent manner (1 nM–10 μM). A simple kinetic model for the competitive oxidation of an indicator molecule (ABTS) and a various antioxidant by a radical (ROO•) is described. The influences of both the concentration of antioxidant and duration of reaction (70 min) on the inhibition of the radical cation absorption are taken into account while determining the activity. The induction time of the reaction was also proposed as a parameter enabling determination of antioxidant content by optimizing and introducing other kinetic parameters in 96-well plate assays. The test evidently improves the original PRTC (peroxyl radical trapping capacity) assay in terms of the amount of chemical used, simultaneous tracking, that is, the generation of the radical taking place continually and the kinetic reduction technique (area under curve, peak value, slope, and V max).

Efficiency and capacity of antioxidant rich foods in trapping peroxyl radicals: A full evaluation of radical scavenging activity

For the first time a variety of foods, characterized by high antioxidant activity, have been tested for the reactivity by which the system of antioxidants present in these foods competes for peroxyl radicals with poly-unsaturated fatty acids. The oxygraphic method we have used, on the basis of a rigorous kinetic model, permits to obtain the reactivity that is the Peroxyl Radical Trapping Efficiency (PRTE), beyond the Peroxyl Radical Trapping Capacity (PRTC) and to assign to each food characteristic values of these parameters, so facilitating their inter-comparison. In the analyzed foods the PRTE/PRTC ratio spans more than one order of magnitude, so reflecting the quality of antioxidants present in foods. According to the PRTE values and on the basis of the serving size the ranking of antioxidant food efficiency in trapping peroxyl radicals was blueberry>red chicory>coffee>pineapple≈red wine≥orange≈dark chocolate≈apple≥tea>pomegranate.

Hyperuricemia, Oxidative Stress, and Carotid Artery Tone in Experimental Renal Insufficiency

Hyperuricemia may play a role in the pathogenesis of cardiovascular disease, but uric acid is also a significant antioxidant. We investigated the effects of oxonic acid-induced hyperuricemia on carotid artery tone in experimental renal insufficiency. Three weeks after 5/6 nephrectomy (NX) or Sham operation, male Sprague-Dawley rats were allocated to 2.0% oxonic acid or control diet for 9 weeks. Blood pressure was monitored using tail cuff, isolated arterial rings were examined using myographs, and blood and urine samples were taken, as appropriate. Oxidative stress and antioxidant status were evaluated by measuring urinary 8-isoprostaglandin F(2 alpha) (8-iso-PGF(2 alpha)) excretion and plasma total peroxyl radical-trapping capacity (TRAP), respectively. Plasma creatinine was elevated twofold in NX rats, but neither NX nor oxonic acid diet influenced blood pressure. Urinary 8-iso-PGF(2 alpha) excretion was increased over 2.5-fold in NX rats on control diet. Oxonic acid diet increased plasma uric acid 2-3-fold, TRAP 1.5-fold, and reduced urinary 8-iso-PGF(2 alpha) excretion by 60-90%. Carotid vasorelaxation to acetylcholine in vitro, which could be abolished by nitric oxide (NO) synthase inhibition, was reduced following NX, whereas maximal response to acetylcholine was augmented in hyperuricemic NX rats. Vasorelaxation to nitroprusside was impaired in NX rats, whereas oxonic acid diet increased sensitivity also to nitroprusside in NX rats. Oxonic acid-induced hyperuricemia reduced oxidative stress in vivo, as evaluated using urinary 8-iso-PGF(2 alpha) excretion, increased plasma TRAP, and improved NO-mediated vasorelaxation in the carotid artery in experimental renal insufficiency.

Evaluation of bioprocesses to improve the antioxidant properties of chickpeas

Abstract Chickpea seeds ( Cicer arietinum cv. Blanco lechoso ) were submitted to different bioprocesses; i) germination of seeds for 2 and 3 days, ii) natural fermentation of flour or cracked seeds, and iii) induced fermentation of flour or cracked seeds with Lactobacillus plantarum , in order to improve the antioxidant properties. Determination of vitamins C and E, reduced glutathione (GSH) and total phenolic compounds (TPC) were carried out. Antioxidant capacity was measured by SOD-like activity, peroxyl radical-trapping capacity (PRTC), lipid peroxidation inhibition (LPI) and trolox equivalent antioxidant capacity (TEAC). Vitamin C and E increased after germination, whilst fermentation caused a decrease in vitamin E. Both bioprocesses caused an increment in TPC content while GSH decreased. Germination increased SOD-like activity (47–41%), PRTC (16–55%) and TEAC (12–23%) and a slight inhibition of LPI was observed. After fermentation, SOD-like activity suffer a drastic reduction. The LPI decreased between 11.3 and 21.3%, while an increase of TEAC (29–57%) and PRTC (27–44%) was observed, except in flour natural fermented seeds where decreased the PRTC. TPC contributed highly to total antioxidant capacity (TEAC). Results indicated that with the bioprocesses studied the antioxidant properties of chickpea flours are enhanced and they can be used as desired ingredients for new functional food formulations.

Total phenolics and antioxidant capacity of heat-treated peanut skins

Total phenolics and antioxidant capacities of heat-treated skins from Runner, Virginia and Spanish peanut types were evaluated. Peanut skin extracts were evaluated for total phenolics (TP), Trolox equivalent antioxidant capacity (TEAC) and peroxyl-radical trapping capacity (PRTC) assay. Factors studied were temperature (90, 112, 135, 158 and 180 °C), time (5, 15 and 25 min) and peanut types. Runners significantly ( P < 0.05) contained more total phenolics and had higher TEAC and PRTC values than Virginia and Spanish types. Maximum values for total phenolics (280 mgGAE/g), TEAC value (2.56 mM TEAC/g) and PRTC value (31 μM Trolox/g) were obtained with Runners heated at 135 °C for 5 min. Regression analysis showed that temperature and time were not related to total phenolics in all three peanut types. TEAC values could be predicted by temperature and time for Runner, Virginia and Spanish, but PRTC values could be predicted for Runner and Virginia samples only. Generally, only mild heat treatments (<135 °C, 15 min) could further enhance the antioxidant capacity of peanut skins.

Antioxidant capacity and polyphenolic content of high-protein lupin products

In order to produce high protein lupin products, α-galactoside extraction from Lupinus angustifolius cv. Troll and cv. Emir and Lupinus albus cv. Multolupa, and protein isolation from L. albus cv. Multolupa were carried out. Trolox equivalent antioxidant capacity (TEAC), DPPH radical-scavenging activity (DPPH-RSA), peroxyl radical-trapping capacity (PRTC), superoxide dismutase-like activity (SOD-like activity), total phenolic compounds (TPC) and total flavonoids were determined in lupin products. In L. angustifolius cv. Troll, L. angustifolius cv. Emir and L. albus cv. Multolupa α-galactoside-low flours, the TEAC and DPPH-RSA decreased (43%, 38%; 73%, 82%; 77%, 38%, respectively). PRTC decreased in L. angustifolius cv. Troll and L. albus cv. Multolupa α-galactoside-low flours (13% and 98%, respectively), while in those of L. angustifolius cv. Emir, PRTC increased (25%). SOD-like activity and TPC were also affected by α-galactoside extraction and reductions of 30–52% and 38–56%, respectively, were observed. The protein isolate of L. albus cv. Multolupa presented lower TEAC (24%), a similar level of PRTC and twice higher level of DPPH-RSA than did α-galactoside-low Multolupa flour. Moreover, the SOD-like activity of lupin protein isolate was sharply reduced but the TPC content was 24% higher. The technological procedures, α-galactoside extraction and protein isolation, provide high protein lupin products but with lower antioxidant capacity and total phenolic compounds than the raw seeds, although the levels of antioxidant capacity of these lupin products resemble those of cereals.

Determination of the Relative Contribution of Quercetin and Its Glucosides to the Antioxidant Capacity of Onion by Cyclic Voltammetry and Spectrophotometric Methods

This paper describes the use of cyclic voltammetry (CV), spectrophotometric methods [Trolox equivalent antioxidant capacity (TEAC), peroxyl radical trapping capacity (PRTC), DPPH radical scavenging activity (RSA), and Folin-Ciocalteu reagent (FCR) reducing capacity], and photochemiluminescence (PCL) for the measurement of the antioxidant capacity of onion var. Sochaczewska and var. Szalotka. The antioxidant and reducing activity of the dominant onion flavonoids quercetin (Q), quercetin-3- O-beta-glucoside (Q3G), quercetin-4'- O-beta-glucoside (Q4'G), and quercetin-3,4'-di- O-beta-glucoside (Q3,4'G) were determined by spectrophotometric (TEAC and PRTC) and CV methods, respectively. The contribution of quercetin and its glucosides to the antioxidant capacity of onion was calculated in consequence of the qualitative and quantitative analysis of onion flavonoids by high-performance liquid chromatography-ultraviolet-mass spectrometry. The dominant forms of quercetin in the onion var. Sochaczewska and Szalotka included Q4'G (61 and 54%), Q3,4'G (37 and 44%), Q3G (1.4 and 1.1%), and free quercetin (1.1 and 0.7%), respectively. The CV experiment showed the highest reducing activity of Q while Q3G, Q4'G, and Q3,4'G exhibited about 68, 51, and 30% of the reducing power noted for Q. The order of the reducing activity of onion flavonoids was confirmed by their free radical scavenging activity and evaluated by TEAC and PRTC assays as follows: Q > Q3G > Q4'G > Q3,4'G. The Q4'G and Q3,4'G showed poor antioxidant activity under both applied spectrophotometric assays but still exhibited reducing activity based on CV experiments. The reducing capacity of onions determined by CV method was twice higher than the antioxidant capacity formed by water-soluble compounds (ACW) evaluated by PCL, and it was about 50% higher than PRTC and DPPH RSA results and the converted FCR reducing capacity. In contrast, the reducing capacity of onions determined by the CV method was 3-fold and about four times lower when compared to the antioxidant capacity evaluated by the TEAC method and that formed by lipid-soluble compounds (ACL) provided by PCL, respectively. The highest antioxidant capacity of onion was found under cumulative consideration of PCL (ACW + ACL) and TEAC assays. The relative contribution of Q and its glucosides to the antioxidant capacity of onions showed a low contribution of Q, Q3G, and Q3,4'G derived from CV, TEAC, and PRTC assays while the highest contribution to the antioxidant capacity of onions was provided by Q4'G.

Fast and Simple Method for the Simultaneous Evaluation of the Capacity and Efficiency of Food Antioxidants in Trapping Peroxyl Radicals in an Intestinal Model System

A simple oxygraphic method, for which the theoretical and experimental bases have been recently revised, has been successfully applied to evaluate the peroxyl radical chain-breaking characteristics of some typical food antioxidants in micelle systems, among which is a system that reproduces conditions present in the upper part of the digestive tract, where the absorption and digestion of lipids occur. This method permits one to obtain from a single experimental run the peroxyl radical trapping capacity (PRTC, that is, the number of moles of peroxyl radicals trapped by a given amount of food), the peroxyl radical trapping efficiency (PRTE, that is, the reciprocal of the amount of food that reduces to half the steady-state concentration of peroxyl radicals), and the half-life of the antioxidant ( t(1/2)) when only a small fraction of peroxyl radicals reacts with the antioxidants present in foods. Examples of application of the method to various types of foodstuffs have been reported, assessing the general validity of the method in the simple and fast evaluation of the above-reported fundamental antioxidant characteristics of foods.

Kinetic study of the antioxidant compounds and antioxidant capacity during germination of Vigna radiata cv. emmerald, Glycinemax cv. jutro and Glycine max cv. merit

The purpose of this study was to determine the antioxidant capacity and the content of antioxidant compounds in raw mung bean seeds and sprouts ( Vigna radiata cv. emmerald) germinated for 2, 3, 4, 5 and 7 days and of soybean seeds of Glycine max cv. jutro germinated for 2, 3 and 4 days and of Glycine max cv. merit germinated for 2, 3, 4, 5 and 6 days. Antioxidant compounds, such as vitamin C and E, total phenolic compounds and reduced glutathione (GSH) were studied. Antioxidant capacity was measured by superoxide dismutase-like activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), trolox equivalent antioxidant capacity (TEAC) and inhibition of lipid peroxidation in unilamellar liposomes of egg yolk phosphatidylcholine (PC). The results indicated that changes in the contents of vitamin C, vitamin E and GSH depended on the type of legume and germination conditions. Sprouts of mung bean and soybeans provided more total phenolic compounds than did raw seeds. The SOD-like activity increased after germination of mung bean seeds for 7 days, by 308%, while no change was observed in sprouts of Glycine max cv. jutro and an increase was observed after 5 and 6 days of germination (∼20%) in Glycine max cv. merit. PRTC and TEAC increased during the germination process and retentions of 28–70% and 11–14%, respectively, for soybean, and 248% and 61%, respectively, for mung bean were observed at the end of germination. The inhibition of lipid peroxidation increased by 389% in 5–7 days’ germination of Vigna radiata cv. emmerald sprouts, and 66% in Glycine max cv. merit sprouts whilst, in Glycine max cv. jutro, germination did not cause changes in lipid peroxidation inhibition. According to the results obtained in this study, germination of mung bean and soybean seeds is a good process for obtaining functional flours with greater antioxidant capacity and more antioxidant compounds than the raw legumes.

Effect of fermentation conditions on the antioxidant compounds and antioxidant capacity of Lupinus angustifolius cv. zapaton

To study the effect of fermentation on the antioxidant compounds and antioxidant capacity of Lupinus angustifolious cv. zapaton, two different types of fermentation processes were performed. Solid-state fermentations in cracked seeds carried out by Aspergillus oryzae, Rhizopus oryzae and Bacillus subtilis and liquid state fermentations in flour and cracked seeds carried out by the microbial population present in the seed (natural fermentation) or by L. plantarum inocula. Antioxidant compounds that were quantified included vitamin C by micellar electrokinetic capillary electrophoresis, vitamin E isomers by high performance liquid chromatography, total phenolic compounds (TPC) by spectrophotometry and reduced glutathione (GSH) by spectrofluorimetry. The antioxidant capacity was analysed by determining the superoxide dismutase-like activity (SOD-like activity), Peroxyl Radical-Trapping Capacity (PRTC) and Trolox Equivalent Antioxidant Capacity (TEAC) and by in vitro methods using unilamellar liposomes of egg yolk phosphatidylcholine (PC). In general, fermentation process produced a reduction in vitamin C, vitamin E activity, GSH and SOD-like activity, however TPC, PRTC, TEAC and inhibition of PC peroxidation increased under most of the fermentation conditions. Optimal results to obtain functional lupin products were achieved in cracked seeds fermented with B. subtilis where increases in TPC content, PRTC, inhibition of PC peroxidation and TEAC content of 490, 669, 492 and 224%, respectively, were found. Also, fermentation carried out with L. plantarum in lupin flours and naturally in cracked seeds caused smaller, although significant (P ≤ 0.05) increases in TPC, PRTC, inhibition of PC and TEAC (80–148, 50–90, 23 and 45–65%, respectively).

Fermentation as a Bio-Process To Obtain Functional Soybean Flours

The effect of fermentation on the antioxidant compounds [vitamins C and E, total phenolic compounds (TPC), and reduced glutathione (GSH)], and antioxidant capacity [superoxide anion scavenging activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), inhibition of phosphatidylcholine (PC) peroxidation, and Trolox equivalent antioxidant capacity (TEAC)] of soybean (Glycine max cv. Merit) was studied. Fermentation was carried out in solid state in cracked seeds inoculated with Aspergillus oryzae, Rhizopus oryzae, Bacillus subtilis, and Lactobacillus plantarum and in liquid state either in cracked seeds or milled soybean flours fermented naturally by only the microorganisms present in the seeds or by inoculation with L. plantarum. Vitamin C was not detected in the studied samples. Fermentation caused a decrease in vitamin E activity, except when cracked seed was fermented with A. oryzae, R. oryzae, or B. subtilis that increased 31, 30, and 89%, respectively. Fermentation produced an increase in TPC content and did not affect or reduce the GSH content. Fermentation decreased SOD-like activity drastically, while PRTC increased except when it was carried out naturally in cracked seed. TEAC values rose sharply when soybeans were fermented with B. subtilis. Processed soybean extracts inhibited PC peroxidation in comparison with the control assay. On the basis of the results obtained, the relative contributions of vitamin E, TPC, and GSH to antioxidant capacity were calculated and results showed a very high TPC contribution and a low contribution of GSH and vitamin E activity. Optimum results for functional soybean flours were achieved when fermentation was carried out with B. subtilis inoculum.

A method to evaluate capacity and efficiency of water soluble antioxidants as peroxyl radical scavengers

In this paper, we report on a method to evaluate the activity of water soluble and H-atom donor antioxidants as peroxyl radical scavengers in a micelle system reproducing the conditions occurring in the upper small intestine in humans, during digestion and absorption of lipids. This method, which overcomes some of the problems of the total radical trapping antioxidant parameter (TRAP) assays, measures the peroxyl radical trapping capacity ( n) and the peroxyl radical trapping efficiency IC 50 − 1 of antioxidants, that is the number “ n” of peroxyl radicals trapped by one molecule of the studied antioxidant and the reciprocal of the antioxidant concentration that halves the steady-state concentration of peroxyl radicals, respectively. These two fundamental parameters characterizing the radical chain breaking of many water soluble antioxidants, among which dietary polyphenols, can be obtained with relatively good precision from a single experiment, on the basis of a rigorous treatment of the kinetic data.

Germination as a process to improve the antioxidant capacity of Lupinus angustifolius L. var. Zapaton

Antioxidant capacity, measured by glutathione (GSH), superoxide dismutase-like activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), trolox equivalent antioxidant capacity (TEAC) and inhibition of lipid peroxidation in unilamellar liposomes of egg yolk phosphatidylcholine (PC) has been evaluated in raw and germinated lupin seeds (Lupinus angustifolius L. var. Zapaton) for 2, 3, 4, 5, 6 and 9 days. The content of antioxidant vitamins E and C has been also studied. The tripeptide GSH kept invariable for the first 5 days of germination and suffered a decrease of 20 and 78% after 6 and 9 days, respectively. During lupin germination, SOD-like activity increased slightly whilst PRTC doubled the amount after 9 days. TEAC values changed slightly up to 5 days of germination but after 6 and 9 days a significant increase (25 and 28%, respectively) was found. The oxidation of PC was inhibited by germinated lupin extracts and 9-day germination seeds provided the highest inhibition. Furthermore, germinated lupins provided more vitamin C, vitamin E activity and polyphenols than raw seeds, and the largest amounts of these bioactive compounds were found after 6 days of germination. Therefore, germination of lupin seeds (Lupinus angustifolius L. var. Zapaton) seems to be a good process to enhance their antioxidant capacity.

Antioxidant activity of ethanolic and aqueous extracts of Uncaria tomentosa (Willd.) DC.

The antioxidant properties of aqueous and ethanolic extracts of the Uncaria tomentosa bark were evaluated. The analysis included trolox equivalent antioxidant capacity (TEAC), peroxyl radical-trapping capacity (PRTC), superoxide radical scavenging activity (SOD) and quantitation of total tannins (TT) and total phenolic compounds (TPC). The obtained results indicate high antioxidant capacity of the studied materials in comparison to the other extracts of fruits, vegetables, cereals and medicinal plants. Higher antioxidant activity and total phenolic compounds of the alcoholic preparations – TEAC=0.57mmol of Trolox/g, PRTC=0.52mmol of Trolox/g and SOD=0.39U/mg than of the aqueous preparation – TEAC=0.34mmol of Trolox/g, PRTC=0.19mmol of Trolox/g and SOD=0.10U/mg were observed. These results might suggest higher medical suitability of alcoholic extracts. However, the highly elevated level of tannins in alcoholic extracts may cause undesirable gastric effects.

Red chicories as potent scavengers of highly reactive radicals: a study on their phenolic composition and peroxyl radical trapping capacity and efficiency.

Eight varieties of Cichorium genus vegetables (five heavily red colored, one red spotted, and two fully green) were investigated for their phenolic content (by HPLC and UV-vis spectrophotometry) and for their antioxidant activity. In particular, the capacity (that is, the amount of trapped peroxyl radicals) and the efficiency (that is, the amount of antioxidant necessary to halve the steady-state concentration of peroxyl radicals) were measured. All of the studied chicories are characterized by the presence of a large amount of hydroxybenzoic and hydroxycinnamic acids, whereas the red color is due to cyanidin glycosides. The presence of these phenolics in red chicories confers to them an exceptionally high peroxyl radical scavenging activity in terms of both capacity and efficiency, particularly in their early stage of growth, and makes this popular and low-cost foods comparable or superior to many foods having well-known antioxidant properties such as red wine, blueberry, and tomato.

Antioxidant status in different regions of heroin addicts’ brain

Heroin is an illicit narcotic abused by millions of people worldwide. In the present work, we estimated peroxyl radical-trapping capacity (PRTC), oxidative stress markers – malondialdehyde and protein carbonyl groups, as well as antioxidant enzymes – superoxide dismutase and catalase, in different regions of brain. Studies conducted on nine brains from heroin abusers and eight from control subjects revealed a decrease in PRTC in each part of heroin intoxicated brains and an increase in lipid peroxidation in brain cortex, brain stem and white matter but not in hippocampus. Protein oxidation was increased in hippocampus and in brain stem, but it was unchanged in gray and white matters. Superoxide dismutase and catalase activities were unchanged in heroin addicts. We conclude that heroin intoxication changes the antioxidant status in human brain by increasing the amount of organic rather then inorganic peroxides. The most severe condition of oxidative stress occur in brain stem.

Effect of Processing on the Antioxidant Vitamins and Antioxidant Capacity ofVigna sinensisVar. Carilla

Cowpea (Vigna sinensis L. var. Carilla) flours obtained by fermentation with inoculum Lactobacillus plantarum (PF) or with the natural microorganisms present in the flour (NF) and subsequent heat treatment in an autoclave were prepared to study the effect of fermentation on the antioxidant vitamin content and on the antioxidant capacity. Bacterial counts and pH values, vitamins C and E, carotenoids, glutathione (GSH), superoxide dismutase-like activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), lipid peroxidation in unilamillar liposomes, and Trolox equivalent antioxidant capacity (TEAC) were evaluated in raw and processed cowpea flours. gamma-Tocopherol and delta-tocopherol were found in raw cowpea, whereas vitamin C and carotenoids were not detected. An increase in the vitamin E activity was observed in PF, whereas vitamin C and carotenoids were not detected in fermented cowpea flours. Fermentation or heat treatment in an autoclave after fermentation produced processed cowpea flours with lower PRTC, glutathione content, and SOD-like activity than those of the raw seeds. However, those processes increased the capacity to inhibit the lipid peroxidation in unilamellar lipoposomes and TEAC. According to the results obtained in this study, the fermentation of cowpeas (naturally or with L. plantarum) and fermentation and subsequent heat treatment in an autoclave are good processes to obtain functional cowpea flours having higher antioxidant capacity than the raw legume.

Stable free radicals and peroxyl radical trapping capacity in red wines.

Thirty-two experimental red wines, obtained from eight cultivars and aged in bottles for 2 and 7 years, were examined for the presence of stable free radicals (SFR), for the peroxyl radical trapping capacity (PRTC), and for the concentrations of some important polyphenol families. Aging significantly increases SFR, polyphenol polymers with n > or = 5 (HMWP), and PRTC and is accompanied by a strong decrease of free anthocyanins. Multivariate regression analyses show that HMWP and SFR are independently associated with PRTC while HMWP and anthocyanins are independently associated with the formation of SFR. These results indicate that polymeric polyphenols generated from anthocyanins and proanthocyanidins during wine aging are able to convert highly reactive free radicals into nonreactive radicals through electron delocalization. The strict correlation between SFR and antioxidant activity that we found suggests that these characteristics are related to the functional properties of food.

Elevated exhalation of hydrogen peroxide and thiobarbituric acid reactive substances in patients with community acquired pneumonia

Background: Bacterial pneumonia involves influx of activated phagocytes into distal airways. These cells release oxidants including H 2O 2, that may be exhaled or induce peroxidative damage to lung tissues with formation of thiobarbituric reactive substances (TBARs). Study objectives: To determine whether concentrations of H 2O 2 and TBARs in exhaled breath condensate (EBC) is elevated and correlate with systemic response to pneumonia during 10 days of hospital treatment. Design: The concentration of H 2O 2 and TBARs was measured in EBC of 43 inpatients with community acquired pneumonia (CAP) and 20 healthy never smoked subjects over 10 days and were accompanied by monitoring of WBC count, serum concentration of C-reactive protein (CRP) and peroxyl radical-trapping capacity. Results: Patients with CAP exhaled 4.6-, 3.7-, 3.9-, 3.3-times more H 2O 2 than healthy controls at 1st, 3rd, 5th and 10th day of treatment ( P<0.05), respectively. EBC concentrations of TBARs were elevated at 1st and 3rd day. H 2O 2 and TBARs levels decreased along with treatment course. Correlation ( P<0.05) was found between H 2O 2 levels and CRP and WBC count ( r=0.31) at 1st day and between TBARs and CRP at 5th ( r=0.34) and 10th day ( r=0.46). The mean H 2O 2 exhalation estimated over ten days of treatment correlated with pneumonic chest X-ray score ( r=0.42), CRP levels ( r=0.46) and WBC count ( r=0.33) at admission ( P<0.05). Conclusions: Pneumonia is accompanied by oxidative stress in airways that moderately correlates with intensity of systemic inflammatory response. Determination of H 2O 2 in EBC may be helpful for non-invasive monitoring of oxidants production during lower respiratory tract infection.