Evaluation of Antioxidant Capacity and Synergistic Associations of Quinonemethide Triterpenes and Phenolic Substances from Maytenus ilicifolia (Celastraceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of phenolic compounds and evaluation of antioxidant capacity of Campomanesia adamantium leaves

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of the cultivation system in the aroma of the volatile compounds and total antioxidant activity of passion fruit

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Lipid peroxidation and antioxidant capacity of G6PD-deficient patients with A-(202G>A) mutation

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an enzymopathy in which reduced NADPH concentrations are not maintained, resulting in oxidative damage. We evaluated G6PD activity, oxidative stress levels and Trolox equivalent antioxidant capacity in individuals with the A-(202G>A) mutation for G6PD deficiency. Five hundred and forty-four peripheral blood samples were screened for G6PD deficiency; we also analyzed lipid peroxidation products measured as thiobarbituric acid reactive species and Trolox equivalent antioxidant capacity. Men with the A-(202G>A) mutation had lower G6PD activity than women with the same mutation. Individuals with the A-(202G>A) mutation also differed in mean Trolox equivalent antioxidant capacity values but not for thiobarbituric acid reactive species values. We concluded that A-(202G>A) mutation is associated with reduced G6PD activity and increased Trolox equivalent antioxidant capacity. ©FUNPEC-RP.

Influence of beta(S) allele in the lipid peroxidation and antioxidant capacity parameters

Introduction: The oxidative process plays a fundamental role in the pathophysiology of sickle cell anemia (SCA), and population and environmental characteristics may influence redox balance. The aim of this study was to evaluate lipid peroxidation and antioxidant capacity in Brazilian Hb S carriers undergoing different therapies.MethodsBlood samples from 270 individuals were analyzed (Hb SS, n=68; Hb AS, n=53, and Hb AA, n=149). Hemoglobin genotypes were assessed through cytological, electrophoretic, chromatographic, and molecular methods. Plasma lipid peroxidation and antioxidant capacity were measured by spectrophotometric methods.ResultsPatients with SCA who used iron-chelating drugs combined with hydroxyurea, associated with regular transfusions, showed lower levels of TBARS (P <= 0.05), higher levels of TEAC (P <= 0.01), and lower TBARS/TEAC ratio (R=255.8). The redox profile of Hb AS subjects was not statistically different (P>0.05) from that of Hb AA subjects.ConclusionThe data suggest that oxidative stress is lower in the patients with SCA who received regular blood transfusions associated with the combined use of HU and iron chelators than the group received only HU. The redox system of the Hb AS carriers is compatible with the control group.

A magnetically drivable nanovehicle for curcumin with antioxidant capacity and MRI relaxation properties

Curcumin possesses wide-ranging anti-inflammatory and anti-cancer properties and its biological activity can be linked to its potent antioxidant capacity. Superparamagnetic maghemite (gamma-Fe2O3), called surface-active maghemite nanoparticles (SAMNs) were surface-modified with curcumin molecules, due to the presence of under-coordinated Fe-III atoms on the nanoparticle surface. The so-obtained curcumin-modified SAMNs (SAMN@curcumin) had a mean size of 13 +/- 4 nm. SAMN@curcumin was characterized by transmission and scanning electron microscopy, UV/Vis, FTIR, and Mossbauer spectroscopy, X-ray powder diffraction, bulk susceptibility (SQUID), and relaxometry measurements (MRI imaging). The high negative contrast proclivity of SAMN@curcumin to act as potential contrast agent in MRI screenings was also tested. Moreover, the redox properties of bound curcumin were probed by electrochemistry. SAMN@curcumin was studied in the presence of different electroactive molecules, namely hydroquinone, NADH and ferrocyanide, to assess its redox behavior. Finally, SAMN@curcumin was electrochemically probed in the presence of hydrogen peroxide, demonstrating the stability and reactivity of bound curcumin.

Método de quantificação da capacidade antioxidante total sérica: padronização e validação para espécie ovina

Pós-graduação em Ciência Animal - FMVA

Isoflurane and propofol contribute to increasing the antioxidant status of patients during minor elective surgery: a randomized clinical study

Isoflurane is a volatile halogenated anesthetic used especially for anesthesia maintenance whereas propofol is a venous anesthetic utilized for anesthesia induction and maintenance, and reportedly an antioxidant. However, there are still controversies related to isoflurane-induced oxidative stress and it remains unanswered whether the antioxidant effects occur in patients under propofol anesthesia.Taking into account the importance of better understanding the role of anesthetics on oxidative stress in anesthetized patients, the present study was designed to evaluate general anesthesia maintained with isoflurane or propofol on antioxidant status in patients who underwent minimally invasive surgeries.We conducted a prospective randomized trial in 30 adult patients without comorbidities who underwent elective minor surgery (septoplasty) lasting at least 2 h admitted to a Brazilian tertiary hospital.The patients were randomly allocated into 2 groups, according to anesthesia maintenance (isoflurane, n = 15 or propofol, n = 15). Peripheral blood samples were drawn before anesthesia (baseline) and 2-h after anesthesia induction.The primary outcomes were to investigate the effect of either isoflurane or propofol anesthesia on aqueous plasma oxidizability and total antioxidant performance (TAP) by fluorometry as well as several individual antioxidants by high-performance liquid chromatography. As secondary outcome, oxidized genetic damage (7,8-dihydro-8-oxoguanine, known as 8-oxo-Gua) was investigated by the comet assay.Both anesthesia techniques (isoflurane or propofol) for a 2-h period resulted in a significant decrease of plasma α-tocopherol, but not other antioxidants including uric acid, carotenoids, and retinol (P > 0.05). Propofol, in contrast to isoflurane anesthesia, significantly increased (P < 0.001) anti-inflammatory/antioxidant plasma γ-tocopherol concentration in patients. Both anesthesia types significantly enhanced hydrophilic antioxidant capacity and TAP, with no significant difference between them, and 8-oxo-Gua remained unchanged during anesthesia in both groups. In addition, both anesthetics showed antioxidant capacity in vitro.This study shows that anesthesia maintained with either propofol or isoflurane increase both hydrophilic and total antioxidant capacity in plasma, but only propofol anesthesia increases plasma γ-tocopherol concentration. Additionally, both types of anesthetics do not lead to oxidative DNA damage in patients without comorbidities undergoing minimally invasive surgery.

Antioxidant capacity and environmentally friendly synthesis of dihydropyrimidin-(2H)-ones promoted by naturally occurring organic acids

The Biginelli reaction is a multicomponent reaction involving the condensation between an aldehyde, a beta-ketoester, and urea or thiourea, in the presence of an acid catalyst, producing dihydropyrimidinones (DHPMs). Owing to their important pharmacological properties, the DHPMs have been studied by many authors. However, most of the methodologies used for the synthesis of these compounds require drastic reaction conditions. In the current study, we report an efficient and clean procedure for preparing DHPMs by the use of citric acid or tartaric acid as a promoter of the Biginelli synthesis in ethanol as solvent. In addition, we have evaluated the antioxidant capacity of the compounds synthesized by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay and the thiobarbituric acid-reactive species test. Two compounds presented antioxidant activity and also reduced lipid peroxidation at concentrations of 200 and 300 mu M. In summary, we report an environmentally friendly procedure for the preparation of DHPMs and demonstrate the antioxidant capacity of some of the compounds. (C) 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:155161, 2012; View this article online at . DOI 10.1002/jbt.20424

Effects of acute creatine supplementation on iron homeostasis and uric acid-based antioxidant capacity of plasma after wingate test

Background: Dietary creatine has been largely used as an ergogenic aid to improve strength and athletic performance, especially in short-term and high energy-demanding anaerobic exercise. Recent findings have also suggested a possible antioxidant role for creatine in muscle tissues during exercise. Here we evaluate the effects of a 1-week regimen of 20 g/day creatine supplementation on the plasma antioxidant capacity, free and heme iron content, and uric acid and lipid peroxidation levels of young subjects (23.1 +/- 5.8 years old) immediately before and 5 and 60 min after the exhaustive Wingate test. Results: Maximum anaerobic power was improved by acute creatine supplementation (10.5 %), but it was accompanied by a 2.4-fold increase in pro-oxidant free iron ions in the plasma. However, potential iron-driven oxidative insult was adequately counterbalanced by proportional increases in antioxidant ferric-reducing activity in plasma (FRAP), leading to unaltered lipid peroxidation levels. Interestingly, the FRAP index, found to be highly dependent on uric acid levels in the placebo group, also had an additional contribution from other circulating metabolites in creatine-fed subjects. Conclusions: Our data suggest that acute creatine supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since creatine-induced iron overload was efficiently circumvented by acquired FRAP capacity attributed to: overproduction of uric acid in energy-depleted muscles (as an end-product of purine metabolism and a powerful iron chelating agent) and inherent antioxidant activity of creatine.

Quali-quantitative study of the phenolic and polyphenolic compounds and their antioxidant capacity in vegetal matrix processed with different technologies

Food technologies today mean reducing agricultural food waste, improvement of food security, enhancement of food sensory properties, enlargement of food market and food economies. Food technologists must be high-skilled technicians with good scientific knowledge of food hygiene, food chemistry, industrial technologies and food engineering, sensory evaluation experience and analytical chemistry. Their role is to apply the modern vision of science in the field of human nutrition, rising up knowledge in food science. The present PhD project starts with the aim of studying and improving frozen fruits quality. Freezing process in very powerful in preserve initial raw material characteristics, but pre-treatment before the freezing process are necessary to improve quality, in particular to improve texture and enzymatic activity of frozen foods. Osmotic Dehydration (OD) and Vacuum Impregnation (VI), are useful techniques to modify fruits and vegetables composition and prepare them to freezing process. These techniques permit to introduce cryo-protective agent into the food matrices, without significant changes of the original structure, but cause a slight leaching of important intrinsic compounds. Phenolic and polyphenolic compounds for example in apples and nectarines treated with hypertonic solutions are slightly decreased, but the effect of concentration due to water removal driven out from the osmotic gradient, cause a final content of phenolic compounds similar to that of the raw material. In many experiment, a very important change in fruit composition regard the aroma profile. This occur in strawberries osmo-dehydrated under vacuum condition or under atmospheric pressure condition. The increment of some volatiles, probably due to fermentative metabolism induced by the osmotic stress of hypertonic treatment, induce a sensory profile modification of frozen fruits, that in some way result in a better acceptability of consumer, that prefer treated frozen fruits to untreated frozen fruits. Among different processes used, a very interesting result was obtained with the application of a osmotic pre-treatment driven out at refrigerated temperature for long time. The final quality of frozen strawberries was very high and a peculiar increment of phenolic profile was detected. This interesting phenomenon was probably due to induction of phenolic biological synthesis (for example as reaction to osmotic stress), or to hydrolysis of polymeric phenolic compounds. Aside this investigation in the cryo-stabilization and dehydrofreezing of fruits, deeper investigation in VI techniques were carried out, as studies of changes in vacuum impregnated prickly pear texture, and in use of VI and ultrasound (US) in aroma enrichment of fruit pieces. Moreover, to develop sensory evaluation tools and analytical chemistry determination (of volatiles and phenolic compounds), some researches were bring off and published in these fields. Specifically dealing with off-flavour development during storage of boiled potato, and capillary zonal electrophoresis (CZE) and high performance liquid chromatography (HPLC) determination of phenolic compounds.

Cyclosporine A induced changes to plasma and erythrocyte antioxidant defences

Organ transplant recipients develop pronounced cardiovascular disease, and decreased antioxidant capacity in plasma and erythrocytes is associated with the pathogenesis of this disease. These experiments tested the hypothesis that the immunosuppressant cyclosporine A (CsA) alters erythrocyte redox balance and reduces plasma antioxidant capacity. Female Sprague-Dawley rats were randomly assigned to a control or CsA treated group. Treatment animals received 25 mg/kg/day of CsA via intraperitoneal injection for 18 days. Control rats were injected with the same volume of the vehicle. Three hours after the final CsA injection, rats were exsanguinated and plasma analysed for total antioxidant status (TAS), alpha-tocopherol, malondialdehyde (MDA), and creatinine. Erythrocytes were analysed for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glucose-6-phosphate dehydrogenase (G6PD) activities, alpha-tocopherol, and MDA. CsA administration resulted in a significant (P < 0.05) decrease in plasma TAS and significant increases (P < 0.05) in plasma creatinine and MDA. Erythrocyte CAT was significantly (P < 0.05) increased in CsA treated rats compared to controls. There were no significant differences (P > 0.05) in erythrocyte SOD, GPX, G6PD, alpha-tocopherol or MDA between groups. In summary, CsA alters erythrocyte antioxidant defence and decreases plasma total antioxidant capacity.

alpha-tocopherol and alpha-lipoic acid enhance the erythrocyte antioxidant defence in cyclosporine A-treated rats

The aim of this study was to determine the effects of dietary antioxidant supplementation with alpha-tocopherol and alpha-lipoic acid on cyclosporine A (cyclosporine)-induced alterations to erythrocyte and plasma redox balance. Rats were randomly assigned to either control, antioxidant (alpha-tocopherol 1000 IU/kg diet and alpha-lipoic acid 1.6 g/kg diet), cyclosporine (25 mg/kg/day), or cyclosporine + antioxidant treatments. Cyclosporine was administered for 7 days after an 8 week feeding period. Plasma was analysed for alpha-tocopherol, total antioxidant capacity, malondialdehyde, and creatinine. Erythrocytes were analysed for glutathione, methaemoglobin, superoxide dismutase, catalase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, alpha-tocopherol and malondialdehye. Cyclosporine administration caused a significant decrease in superoxide dismutase activity (P < 0.05 control versus cyclosporine) and this was improved by antioxidant supplementation (P < 0.05 cyclosporine versus cyclosporine + antioxidant; P < 0.05 control versus cyclosporine + antioxidant). Animals receiving cyclosporine and antioxidants showed significantly increased (P < 0.05) catalase activity compared to both groups not receiving cyclosporine. Cyclosporine administration induced significant increases in plasma malondialdehyde and creatinine concentration (P < 0.05 control versus cyclosporine). Antioxidant supplementation prevented the cyclosporine induced increase in plasma creatinine (P < 0.05 cyclosporine versus cyclosporine + antioxidant; P > 0.05 control versus cyclosporine + antioxidant), however, supplementation did not alter the cyclosporine induced increase in plasma malondialdehyde concentration (P > 0.05 cyclosporine versus cyclosporine + antioxidant). Antioxidant supplementation resulted in significant increases (P < 0.05) in plasma and erythrocyte alpha-tocopherol in both of the supplemented groups compared to non-supplemented groups. In conclusion, dietary supplementation with alpha-tocopherol and alpha-lipoic acid enhanced the erythrocyte antioxidant defence and reduced nephrotoxicity in cyclosporine treated animals.