30 resultados para linoleic

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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Adsorption isotherms for the removal of linoleic acid from aqueous ethanol were measured using a strong anion exchange resin (Amberlyst A26 OH). The data for linoleic acid were compared with previously published results for oleic acid. The equilibrium data were correlated using the Langmuir and Freundlich isotherms. Lower average deviations between experimental and calculated results were obtained with the Langmuir model. The capacity of the resin for adsorbing linoleic acid was evaluated at different water contents in ethanol, 100 w = 0.50 to 15.27, and at 298.15 K. The water content in ethanol does not influence significantly the equilibrium behavior, and the strong anion exchange resin has a good performance in the removal of linoleic acid from the liquid phase.

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Inflammation is a crucial step for the wound healing process. The effect of linoleic and oleic acids on the inflammatory response of the skin during the healing process and on the release of pro-inflammatory cytokines by rat neutrophils in vitro was investigated. A wound in the dorsal surface of adult rats was performed and fatty acids were then topically administered. Both oleic and linoleic acids increased the wound healing tissue mass. The total protein and DNA contents of the wounds were increased by the treatment with linoleic acid. The treatments with oleic and linoleic acids did not affect vascular permeability. However, the number of neutrophils in the wounded area and air pouches was increased and the thickness of the necrotic cell layer edge around the wound was decreased. A dose-dependent increase in vascular endothelial growth factor-alpha (VEGF-alpha) and interleukin-1 beta (IL-1 beta) by neutrophils incubated in the presence of oleic and linoleic acid was observed. Oleic acid was able to stimulate also the production of cytokine-induced neutrophil chemoattractant in inflammation 2 alphalbeta (CINC-2 alpha/beta). This pro-inflammatory effect of oleic and linoleic acids may speed up the wound healing process. Copyright (c) 2007 John Wiley & Sons, Ltd.

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The high ingestion of oleic (OLA) and linoleic (LNA) acids by Western populations, the presence of inflammatory diseases in these populations, and the importance of neutrophils in the inflammatory process led us to investigate the effects of oral ingestion of unesterified OLA and LNA on rat neutrophil function. Pure OLA and LNA were administered by gavage over 10 days. The doses used (0.11, 0.22 and 0.44 g/kg of body weight) were based on the Western consumption of OLA and LNA. Neither fatty acid affected food, calorie or water intake. The fatty acids were not toxic to neutrophils as evaluated by cytometry using propidium iodide (membrane integrity and DNA fragmentation). Neutrophil migration in response to intraperitoneal injection of glycogen and in the air pouch assay, was elevated after administration of either OLA or LNA. This effect was associated with enhancement of rolling and increased release of the chemokine CINC-2 alpha beta. Both fatty acids elevated l-selectin expression, whereas no effect on beta(2)-integrin expression was observed, as evaluated by flow cytometry. LNA increased the production of proinflammatory cytokines (IL-1 beta and CINC-2 alpha beta) by neutrophils after 4 h in culture and both fatty acids decreased the release of the same cytokines after 18 h. In conclusion, OLA and LNA modulate several functions of neutrophils and can influence the inflammatory process.

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Conjugated linoleic acids (CLAs) are a group of linoleic acid isomers that are naturally found in food products originating from ruminants (meat and dairy). These acids have received special attention in recent years due to their potential human health benefits. Research efforts have been proposed to increase the CLA content in beef to improve public health. However, because there are more than 30 million beef cattle used each year by the American food industry, it will be necessary to ensure their content in a large number of samples. Therefore, it is important to have an inexpensive and rapid analytical method to measure CLA content in food products. Because gas chromatography (GC), a current popular method for measuring CLAs, is slow, this paper describes a nuclear magnetic resonance spectroscopy ((1)H NMR) method that is potentially >10 times faster than the GC method. Analyses show a correlation coefficient of 0.97, indicating the capacity of NMR to quantify the CLA content in beef samples. Furthermore, the method proposed herein is simple and does not require sophisticated sample preparation.

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Garlic contains polyphenol and sulphur compounds, which are responsible for its antioxidant activity (AA). This study aimed at evaluating the AA of fresh garlic and its commercialised products and their shelf life. Fresh garlic (FG) and its products, i.e. chopped with salt (CGS), chopped without Salt (CG), fried (FRG) and mixed garlic (FG with dehydrated garlic; MG) antioxidant activity was evaluated by three different methods: DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, beta-carotene/linoleic acid assay and Rancimat method. Amongst all the analysed products, fried garlic presented the highest antioxidant activity. The free radical-scavenging activity decreased during the shelf life of all analysed products that correlated with the decrease in the total polyphenol content. Our findings suggest that some compounds other than phenol may have contributed towards this outcome. (c) 2008 Elsevier Ltd. All rights reserved.

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Effect of processing on the antioxidant activity of amaranth grain. Amaranth has attracted increasing interest over recent decades because of its nutritional, functional and agricultural characteristics. Amaranth grain can be cooked, popped, toasted, extruded or milled for consumption. This study investigated the effect of these processes on the antioxidant activity of amaranth grain. Total phenolic content and in vitro antioxidant activity were determined according to two methods: inhibition, of lipid oxidation using the beta-carotene/linoleic acid system and the antioxidant activity index using the Rancimat (R) apparatus. The processing reduced the mean total phenolics content in amaranth grain from 31.7 to 22.0 mg of gallic acid equivalent/g of dry residue. It was observed that the ethanol extract from toasted grain was the only one that presented a lower antioxidant activity index compared with the raw grain (1.3 versus 1.7). The extrusion, toasting and popping processes did not change the capacity to inhibit amaranth lipid oxidation (55%). However, cooking increased the inhibition of lipid oxidation (79%), perhaps because of the longer time at high temperatures in this process (100 degrees C/10 min). The most common methods for processing amaranth grain caused reductions in the total phenolics content, although the antioxidant activity of popped and extruded grain, evaluated by the two methods, was similar to that of the raw grain. Both raw and processed amaranth grain presents antioxidant potential. Polyphenols, anthocyanins, flavonoids, tocopherols, vitamin C levels and Maillard reaction products may be related to the antioxidant activity of this grain.

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The purpose of this work was to evaluate the fatty acid composition of the Longissimus muscle from carcasses of Nellore steers fed diets with calcium salts of fatty acids (CSFA) and high moisture corn. Forty eight steers were fed during 70 days four diets containing dry corn (DC), high moisture corn (HM). dry corn plus CSFA (DC-CSFA) or high moisture corn plus CSFA (HM-CSFA). Fatty acid composition of the Longissimus muscle was determined by gas chromatography. Corn type had no effect on the ether extract percentage and in the content of the majority of the fatty acids, although steers fed HMC showed higher levels of polyunsaturated fatty acids and polyunsaturated/saturated ratio. Feeding CSFA increased ether extract percentage but had no effect on total of saturated, unsaturated and saturated: unsaturated ratio. Both high moisture corn and calcium salts of fatty acids increased CIA (cis9, trans11) and total CIA concentrations in intramuscular fat (C) 2008 Elsevier B.V. All rights reserved.

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Soybean oil can be deacidified by liquid-liquid extraction with ethanol. In the present paper, the liquid-liquid equilibria of systems composed of refined soybean oil, commercial linoleic acid, ethanol and water were investigated at 298.2 K. The experimental data set obtained from the present study (at 298.2 K) and the results of Mohsen-Nia et al. [1] (at 303.2 K) and Rodrigues et al. [2] (at 323.2 K) were correlated by applying the non-random two liquid (NRTL) model. The results of the present study indicated that the mutual solubility of the compounds decreased with an increase in the water content of the solvent and a decrease in the temperature of the solution. Among variables, the water content of the solvent had the strongest effect on the solubility of the components. The maximum deviation and average variance between the experimental and calculated compositions were 1.60% and 0.89%, indicating that the model could accurately predict the behavior of the compounds at different temperatures and degrees of hydration. (C) 2010 Elsevier B.V. All rights reserved.

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Liquid-liquid equilibrium experimental data for refined sunflower seed oil, artificially acidified with commercial oleic acid or commercial linoleic acid and a solvent (ethanol + water), were determined at 298.2 K. This set of experimental data and the experimental data from Cuevas et al.,(1) which were obtained from (283.2 to 333.2) K, for degummed sunflower seed oil-containing systems were correlated using NRTL and UNIQUAC models with temperature-dependent binary parameters. The deviation between experimental and calculated compositions presented average values of (1.13 and 1.41) % for NRTL and UNIQUAC equations, respectively, indicating that the models were able to correctly describe the behavior of compounds under different temperature and solvent hydration.

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BACKGROUND: Chloroform, ethyl acetate and methanol extracts of a sample of red propolis from the state of Alagoas (northeast Brazil) were analyzed by gas chromatography-mass spectrometry and high-performance liquid chromatography-diode array detection-electrospray ionization-mass spectrometry. Antimicrobial and antioxidant activities were also obtained. RESULTS: The propolis sample contained low content of narigenin-8-C-hexoside, this being the first report of a C-glycoside in propolis. The main constituent found was characterized as 3,4,2`,3`-tetrahydroxychalcone. Other important constituents were the chalcone isoliquiritigenin, the isoflavans (3S)-vestitol, (3S)-7-O-methylvestitol, the pterocarpan medicarpin, the phenylpropenes trans-anethol, methyl eugenol, elimicin, methoxyeugenol and cis-asarone, and the triterpenic alcohols lupeol and alpha- and beta- amyrins. The methanol extract exhibited high antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl and beta-carotene/linoleic acid assay methods, and antimicrobial activity toward Gram-positive and Gram-negative bacteria. CONCLUSION: Structures are suggested for new substances never before seen in any kind of propolis. This is the first report of 3,4,2`,3`-tetrahydroxychalcone and a flavone C-glycoside in a propolis sample. (C) 2011 Society of Chemical Industry

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Annona (Annonaceae) is an important source of fruits in the Brazilian Cerrado and the Amazon Rainforest. Some Annona species are widely commercialized as fresh fruit or as frozen pulp. Seeds are accustomedly discarded. Our main goal was to analyze fatty acids profile from seeds of A. crassiflora and A. coriacea from Cerrado, A. montana from Amazon Forest, and three cultivars (A. cherimola cv. Madeira, A. cherimola x A. squamosa cv. Pink`s Mammonth and A. cherimola x A. squamosa cv. Gefner). The total oil yield ranged between 20 and 42% by weight of dry mass. The A cherimola x A. squamosa cv. Gefner has significantly higher total lipid yield than all other samples. 100 g of fruit of this species present 6-8 g of seeds. Considering the fruit production of Chile (over 221 ton of fruits/year), more than 1300 ton of seed/year could be obtained, which could provide at least 200 ton of seed oil. Oleic acid was predominant for most samples, but for A. montana linoleic acid was the most abundant FA. Phenotypic variation on FAME profile was observed. These new data are an urgent requirement for supporting conservation programs, mainly for Cerrado areas in Brazil.

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Malvales is an order of flowering plants with a controversial circumscription. The relationships between taxa, particularly Malvaceae, Bombacaceae, Sterculiaceae, and Tiliaceae, are not well delineated. Several studies have reported the fatty acid compositions of Malvaceae plants but not for taxonomic purposes. In the present study, the fatty acid composition of oilseeds from seven species belonging to the Malvaceae family was determined by capillary gas chromatography/mass spectrometry (GC/MS), and the quantitative distribution of fatty acids was analyzed by a cluster analysis With Euclidean Distance and UPGMA. The oil content in the seeds was very low (8.3-11.8%). The profile of fatty acids showed that there were two distinct groups: species rich in palmitic acid (Herissantia tiubae, Sidastrum paniculatum and Sida rhombifolia) and species rich in linoleic acid (other Sida species). The fatty acid profiles found for Sida species are consistent with other reported data. Although our data support a distinction between Sida and Sidastrum, more species should be analyzed to evaluate the real taxonomic value of differences in fatty acid content for distinguishing Malvaceae. (C) 2010 Elsevier Ltd. All rights reserved.

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The reported effects of different families of fatty acids (FA; SFA, MUFA, n-3 and n-6 PUFA) on human health and the importance of macrophage respiratory burst and cytokine release to immune defence led us to examine the influence of palmitic acid (PA), oleic acid (OA), linoleic acid, arachidonic acid, EPA and DHA on macrophage function. We determined fungicidal activity, reactive oxygen species (ROS) and cytokine production after the treatment of J774 cells with non-toxic concentrations of the FA. PA had a late and discrete stimulating effect on ROS production, which may be associated with the reduced fungicidal activity of the cells after treatment with this FA. OA presented a sustained stimulatory effect on ROS production and increased fungicidal activity of the cells, suggesting that enrichment of diets with OA may be beneficial for pathogen elimination. The effects of PUFA on ROS production were time-and dose-dependently regulated, with no evident differences between n-3 and n-6 PUFA. It was worth noting that most changes induced after stimulation of the cells with lipopolysaccharide were suppressed by the FA. The present results suggest that supplementation of the diet with specific FA, not classes of FA, might enable an improvement in host defence mechanisms or a reduction in adverse immunological reactions.

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Introduction/Purpose: The effect of a triathlon competition on death of neutrophils from elite athletes was investigated. Methods: Blood was collected from 11 sedentary volunteers and 12 triathletes under rest and after a Half Ironman triathlon competition (2-km swimming, 80-km cycling, and 20-km running). Results: The triathlon competition increased DNA fragmentation, phosphatidylserine externalization, and reactive oxygen species production in neutrophils when compared to the results at rest. The proportion of neutrophils with mitochondrial transmembrane depolarization was increased in the triathletes at rest and after competition as compared with sedentary volunteers. Plasma levels of thiobarbituric acid reactive substances were increased in triathletes after competition. Expression of bcl-xL (antiapoptotic) was decreased and that of bax (proapoptotic) was increased, whereas intracellular neutral lipid content was lowered in neutrophils after the triathlon. A positive correlation was found between the proportion of neutrophils with DNA fragmentation and the plasma free fatty acid levels (r = 0.688, P < 0.05), which was elevated by threefold after competition. Plasma levels of oleic, linoleic, and stearic acids were increased in triathletes after the competition when compared with sedentary volunteers. The plasma concentration of these three fatty acids, measured after the triathlon competition, was toxic for 3-h cultured neutrophils obtained from sedentary volunteers. The maximal tolerable (nontoxic) concentration of the fatty acids by 3-h cultured neutrophils was 100 mu mol.L-1 for oleic and linoleic acids and 200 mu mol.L-1 for stearic acid. Conclusion: The triathlon competition induced neutrophil death possibly by apoptosis as indicated by DNA fragmentation and phosphatidylserine externalization. The increase in plasma levels of oleic, linoleic, and stearic acids induced by the competition may be involved in the neutrophil death observed possibly by increasing the production of reactive oxygen species and by decreasing the accumulation of intracellular neutral lipid.

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The fatty acid composition of immune cells appears to contribute to variations of cell function. The independent and combined effects of a single session of exercise (SSE) and glutamine supplementation (GS) on neutrophil fatty acid composition were investigated. Compared to control (no treatment given - i.e. neither SSE or GS), single session of exercise decreased myristic, palmitic and eicosapentaenoic (EPA) acids, and increased lauric, oleic, linoleic, arachidonic (AA) and docosahexaenoic (DHA) acids whereas glutamine supplementation combined with SSE (GS+SSE) increased oleic acid. Polyunsaturated/saturated fatty acid ratio and Unsaturation index were higher in neutrophils from the SSE and GS groups as compared with control. These findings support the proposition that SSE and GS may modulate neutrophil function through alterations in fatty acid composition.