928 resultados para phosphite antioxidants
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Turmeric oleoresin is a colorant prepared by solvent extraction of turmeric (Curcuma longa L.). Curcumin, the major pigment present in turmeric, has been described as a potent antioxidant, anti-inflammatory and anticarcinogenic agent. Turmeric pigments are lipid soluble and water insoluble and are sensitive to light, heat, oxygen and pH, which can be overcome by microencapsulation of turmeric oleoresin. The aim of this work was to investigate microencapsulation of turmeric oleoresin by complex coacervation using gelatin and gum Arabic as encapsulants and freeze-drying as the drying method. The coacervation process was studied by varying the concentration of biopolymer solution (2.5, 5.0 and 7.5%) and the core material: total encapsulant ratio (25, 50, 75 and 100%). Microcapsules were evaluated for encapsulation efficiency, morphology, solubility and stability to light. Encapsulation efficiency ranged from 49 to 73% and samples produced with 2.5% of wall material and 100% core: encapsulant ratio showed better stability to light. © 2012 Wiley Periodicals, Inc.
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Scope. To elucidate the morphological and biochemical in vitro effects exerted by caffeine, taurine, and guarana, alone or in combination, since they are major components in energy drinks (EDs). Methods and Results. On human neuronal SH-SY5Y cells, caffeine (0.125-2 mg/mL), taurine (1-16 mg/mL), and guarana (3.125-50 mg/mL) showed concentration-dependent nonenzymatic antioxidant potential, decreased the basal levels of free radical generation, and reduced both superoxide dismutase (SOD) and catalase (CAT) activities, especially when combined together. However, guarana-treated cells developed signs of neurite degeneration in the form of swellings at various segments in a beaded or pearl chain-like appearance and fragmentation of such neurites at concentrations ranging from 12.5 to 50 mg/mL. Swellings, but not neuritic fragmentation, were detected when cells were treated with 0.5 mg/mL (or higher doses) of caffeine, concentrations that are present in EDs. Cells treated with guarana also showed qualitative signs of apoptosis, including membrane blebbing, cell shrinkage, and cleaved caspase-3 positivity. Flow cytometric analysis confirmed that cells treated with 12.5-50 mg/mL of guarana and its combinations with caffeine and/or taurine underwent apoptosis. Conclusion. Excessive removal of intracellular reactive oxygen species, to nonphysiological levels (or antioxidative stress), could be a cause of in vitro toxicity induced by these drugs. © 2013 Fares Zeidán-Chuliá et al.
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Several mushroom species have been pointed out as sources of antioxidant compounds, in addition to their important nutritional value. Agaricus blazei and Lentinus edodes are among the most studied species all over the world, but those studies focused on their fruiting bodies instead of other presentations, such as powdered preparations, used as supplements. In the present work the chemical composition (nutrients and bioactive compounds) and antioxidant activity (free radical scavenging activity, reducing power and lipid peroxidation inhibition) of dried powder formulations of the mentioned mushroom species (APF and LPF, respectively) were evaluated. Powder formulations of both species revealed the presence of essential nutrients, such as proteins, carbohydrates and unsaturated fatty acids. Furthermore, they present a low fat content (<2 g/100 g) and can be used in low-calorie diets, just like the mushrooms fruiting bodies. APF showed higher antioxidant activity and higher content of tocopherols and phenolic compounds (124 and 770 μg/100 g, respectively) than LPF (32 and 690 μg/100 g). Both formulations could be used as antioxidant sources to prevent diseases related to oxidative stress. © 2012 Elsevier Ltd. All rights reserved.
Antioxidant activity of basil and oregano extracts added to soybean oil for accelerated storage test
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The objective of this research was to evaluate the antioxidant activity of extract of basil and oregano, and its synergistic effect when added to soybean oil and subjected to accelerated storage test. Extracts of basil, oregano and mixtures of both were applied to soybean oil at a concentration of 2.000mg/kg, then the extracts were heated in an oven at 60C for a period of 10 days. Samples were taken every 2 days and analyzed for concentrations of peroxides and conjugated dienes. Synthetic antioxidant tert-butylhydroquinone (TBHQ) at a concentration of 50mg/kg and soybean oil free antioxidant (control) subject to the same conditions were used as benchmarks. The results showed that the antioxidant effect decreases according to oil heating for all treatments. However, the synthetic antioxidant showed superior protection to the soybean oil during the formation of primary oxidation compounds, followed by the natural extracts, which showed no synergism. © 2012 Wiley Periodicals, Inc.
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Naringenin and quercetin are considered antioxidant compounds with promising activity against oxidative damage in human cells. However, no reports have described their effects on reactive oxygen species (ROS) production by phagocytes during microbicidal activity. Thus, the present study evaluated the effects of naringenin and quercetin on ROS production, specifically hypochlorous acid (HOCl), and their involvement in the microbicidal activity of neutrophils. Naringenin and quercetin inhibited HOCl production through different systems, but this inhibition was more pronounced for quercetin, even in the cell-free systems. With regard to the microbicidal activity of neutrophils, both naringenin and quercetin completely inhibited the killing of Staphylococcus aureus. Altogether, these data indicate that the decrease in the oxidant activity of neutrophils induced by these compounds directly impaired the microbicidal activity of neutrophils. Naringenin and quercetin exerted their effects by controlling the effector mechanisms of ROS production, with both positive and negative effects of these antioxidant agents in oxidative stress conditions and on ROS in the microbicidal activity of phagocytes. The present results challenge the traditional view of antioxidants as improvers of pathological conditions. © 2013 Francielli de Cássia Yukari Nishimura et al.
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The aim of the present study was to test the hypothesis that oxidative stress and alteration of oxidative metabolism and apoptosis of neutrophils in dogs vary with the stage of leishmaniasis and to determine the contribution of uremia to such alterations. Dogs with leishmaniasis were classified into two stages: moderate (Leish II, n = 20) or very severe (i.e. with concurrent uremia; Leish IV, n = 20) according to the LeishVet Consensus. The two leishmaniasis groups were compared with uremic dogs without leishmaniasis (Uremic, n = 10) and to healthy dogs (Control, n = 30). To determine oxidative stress, total antioxidant/oxidant capacity, lipid peroxidation, total glutathione and the plasma antioxidants albumin, uric acid and bilirubin were quantified. Superoxide production was determined using the hydroethidine probe and viability and apoptosis were measured using annexin V-PE by capillary flow cytometry. Oxidative stress was present in both uremia and leishmaniasis with reduced total antioxidant capacity and was associated with increased induced production of superoxide and apoptosis. The greatest amount of oxidants was observed in animals with moderate disease only. Neutrophils from uremic dogs with and without leishmaniasis had decreased viability and an increased apoptosis rate in addition to increased lipid peroxidation. In conclusion, oxidative stress occurs in both stages of leishmaniasis with differences in intensity and levels of plasma markers; however, uremia does contribute to the decreased spontaneous viability of neutrophils in dogs in the final stage of the disease. © 2013 Elsevier Ltd. All rights reserved.
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This paper aimed at evaluating fatty acids profile and the total alteration of lemon seeds extract added to soybean oil under thermoxidation, verifying the isolated and synergistic effect of these antioxidants. Therefore, Control treatments, LSE (2,400 mg/kg Lemon Seeds Extract), TBHQ (mg/kg), Mixture 1 (LSE + 50 mg/kg TBHQ) and Mixture 2 (LSE + 25 mg/kg TBHQ) were subjected to 180 C for 20 h. Samples were taken at 0, 5, 10, 15 and 20 h intervals and analyzed as for fatty acid profile and total polar compounds. Results were subjected to variance analyses and Tukey tests at a 5% significance level. An increase in the percentage of saturated fatty acids and mono-unsaturated, and decrease in polyunsaturated fatty acids was observed, regardless of the treatments studied. For total polar compounds, it was verified that Mixtures 1 and 2 presented values lower than 25% with 20 h of heating, not surpassing the limits established in many countries for disposal of oils and fats under high temperatures, thus proving the synergistic effect of antioxidants. © 2011 Association of Food Scientists & Technologists (India).
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The physiological control to support the absence of O2 for long periods of diving, and oxidative damage impact caused by the whole process of hypoxia/reperfusion in freshwater turtles is well known. However, effects of contaminants may act as co-varying stressors and cause biological damage, disrupting the hypoxia/reperfusion oxidative damage control. In order to investigate the action of environmental stressors present in domestic or industrial wastewater effluent, we performed a biochemical analysis of biotransformation enzymes, oxidative stress, as well as neuromuscular, physiological and morphological parameters in Phrynops geoffroanus, an hypoxic-tolerant freshwater turtle endemic of South America, using animals sampled in urban area, contaminated by sewage and industrial effluents and animals sampled in control area. Here we demonstrate the physiological and biochemical impact caused by pollution, and the effect that these changes cause in antioxidant activity. Animals from the urban area exhibited higher EROD (ethoxyresorufin-O-deethylase, CYP1A1), GST (glutathione S-transferase), G6PDH (glucose-6-phosphate deshydrogenase), AChE (acetilcholinesterase) activities and also TEAC (trolox-equivalent antioxidant capacity) and TBARS (thiobarbituric acid reactive substances) values. We examined whether two morphometric indices (K - condition factor and HIS - hepatosomatic index) which help in assessing the general condition and possible liver disease, respectively, were modified. The K of the urban animals was significantly decreased compared to the control animals, but the HIS value was increased in animals from the urban area, supporting the idea of an impact in physiology and life quality in the urban freshwater turtles. We propose that this freshwater turtle specie have the ability to enhance its antioxidants defenses in order to protect from tissue damage caused by hypoxia and reperfusion, but also that caused by environmental contamination and that the oxidative damage control in hypoxic conditions has resulted in an adaptive condition in hypoxic-tolerant freshwater turtle species, in order to better tolerate the release of contaminated effluents resulting from human activity. © 2013 Elsevier Inc.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Agronomia (Agricultura) - FCA
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Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Aquicultura - FCAV
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)