linoleic-acid and methyl-linoleate

Two trials were conducted with duplicate groups of (first feeding) carp larvae fed artificial dry diets based on casein and dextrin over 21 or 25 days. One control diet based on yeast was also tested. Survival, growth and fatty acid profiles of larvae were studied. In trial 1, (n-3) fatty acid requirement was estimated using diets supplemented or not with methyl linolenate or cod liver oil. After 21 days, the best survival and growth were observed in larvae fed the unsupplemented diet [(n-3) fatty acid level: 0.05%]. Survival and growth were not improved by higher levels of (n-3) fatty acids. In trial 2, (n-6) fatty acid requirement was estimated using diets with graded levels of methyl linolenate or peanut oil. After 25 days, the best survival and growth were obtained with diets supplemented with 0.25% methyl linolenate (total (n-6) fatty acid level: 1%) or with 1.25% peanut oil (total (n-6) fatty acid level: 0.89%). Survival and growth were not improved by higher levels of (n-6) fatty acids. Fatty acid composition of carp reflected that of the diets and also showed that carp larvae are capable of elongating and desaturating linolenic acid and linoleic acid in longer chain fatty acids.

Topics: Aging; alpha-Linolenic Acid; Animal Feed; Animals; Carps; Cod Liver Oil; Diet; Fatty Acids, Essential; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Food, Fortified; Larva; Linoleic Acid; Linoleic Acids; Nutritional Requirements; Peanut Oil; Plant Oils

Fish lipids are comprised of considerable quantities of polyunsaturated acids and are prone to oxidation, producing reactive oxygen species and hydroperoxides. This study aimed to evaluate the biochemical and structural alterations in Caco-2 cells following exposure to 100 μg/mL methyl linoleate or fish oil, and then radiated for 24, 48 or 72 h. Electron spin resonance spectroscopy detected free radicals in the lipid membrane, Raman microscopy observed biochemical alterations and atomic force microscopy identified changes in morphology, such as the breakdown of DNA bonds. The study showed that bioimaging and biochemical techniques can be effective at detecting and diagnosing cellular injuries incurred by lipid peroxidation.

Topics: Caco-2 Cells; Cell Line, Tumor; Electron Spin Resonance Spectroscopy; Fish Oils; Free Radicals; Humans; Hydrogen Peroxide; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Membrane Lipids; Oxidation-Reduction; Reactive Oxygen Species

Reaction kinetics of betanin and its aglycone betanidin towards peroxyl radicals generated from the azo-initiated oxidation of methyl linoleate in methanol and of a heterogeneous aqueous/soybean phosphatidylcholine liposomal system were studied by monitoring formation of linoleic acid hydroperoxides and consumption of the pigments. Betanin was a weak retarder in methanol and an effective chain breaking antioxidant in the liposomal model, indicating that kinetic solvent effects and partition in lipid bilayers may affect its activity. Betanidin behaved as a chain terminating antioxidant in both models. Kinetic parameters characterizing peroxyl radical-scavenging activity showed that betanidin was more effective than betanin, in terms of both radical-scavenging rate constant and stoichiometric factor, with effectiveness of the same order as vitamin E under comparable conditions. Products identified by spectrophotometric and HPLC techniques indicated reaction of the glucose-substituted monophenol and ortho-diphenol moieties of betanin and betanidin, respectively, and suggested mechanisms of the antioxidant activity. Either betanin or betanidin incorporated in liposomes with alpha-tocopherol had additive effects, supporting partition of the pigments in the bilayer and lipoperoxyl radical reduction.

Topics: alpha-Tocopherol; Betacyanins; Chromatography, High Pressure Liquid; Drug Synergism; Free Radical Scavengers; Linoleic Acid; Linoleic Acids; Lipid Bilayers; Lipid Peroxidation; Liposomes; Methanol; Molecular Structure; Oxidation-Reduction; Phosphatidylcholines; Solutions; Solvents; Spectrophotometry; Structure-Activity Relationship; Water

The chemiluminescent response of conjugated linoleic acid isomers (CLAs), linoleic acid (LA) and methyl linoleate (LAME) against the prooxidant t-butyl hydroperoxide (tBHP) was analyzed. The c9, t11-CLA and t10, c12-CLA isomers showed significant photoemission at the highest concentration used, while photoemission was not detected at any concentration of LA and LAME analyzed. These results show that CLAs are more susceptible to peroxidation than LA and LAME. Likewise, the effect of CLA, LA and LAME on lipid peroxidation of triglycerides rich in C20:5 omega3 and C22:6 omega3 (Tg omega3-PUFAs) was investigated. For that, chemiluminescence produced by triglycerides in the presence of tBHP, previously incubated with different concentrations of CLAs, LA and LAME (from 1 to 200 mM) was registered for 60 min. Triglycerides in the presence of t-BHP produced a peak of light emission (3151+/-134 RLUs) 5 min after addition. CLAs produced significant inhibition on photoemission, t10, c12-CLA being more effective than the c9, t11-CLA isomer. LA and LAME did not have an effect on lipid peroxidation of Tg omega3-PUFAs. CLA isomers, LA and LAME were also investigated for free radical scavenging properties against the stable radical (DPPH). Both CLA isomers reacted and quenched DPPH at all tested levels (from 5 to 25 mM), while LA and LAME did not show radical quenching activity even at the highest concentration tested. These data indicate that CLAs would provide protection against free radicals, but LA and LAME cannot.

Topics: Antioxidants; Biphenyl Compounds; Esters; Hydrazines; Isomerism; Light; Linoleic Acid; Linoleic Acids; Picrates

A novel L-ascorbyl fatty acid ester, L-ascorbyl linoleate was successfully prepared by enzymatic esterification and transesterification in a non-aqueous medium using immobilized lipase as biocatalyst. Changes in enzymatic activity and product yield were studied for the following variable: the nature of the fatty acid, the fatty acid concentration and water content. The yield of synthesis for the C18 unsaturated fatty acids were higher than for the C18 saturated fatty acid. Initial enzyme concentration does not affect the equilibrium of the reaction. And the product yield (33.5%) in the transesterification was higher than that of the esterification (21.8%) at a high-substrate concentration 0.3 M. The medium water content was found to have a distinct influence on the L-ascorbyl linoleate synthesis.

Topics: Ascorbic Acid; Enzymes, Immobilized; Fungal Proteins; Linoleic Acid; Linoleic Acids; Lipase; Organic Chemicals; Solvents

A major bioactive metabolite of linoleic acid formed by the action of 15-lipoxygenase-1 is 13(S)-hydroxy-cis-9, trans-11-octadecadienoic acid (13(S)-HODE). 13(S)-HODE is an important intracellular signal agent and is involved in cell proliferation and differentiation in various biological systems. Separation and quantification of 13(S)-HODE from biological materials has previously been achieved only by using radiolabeled linoleic acid as the substrate and two serially connected or two separate HPLC columns to achieve separation of 13(S)-HODE. In the current method, separation and quantification of 13(S)-HODE was achieved by use of a normal-phase HPLC and a solvent system containing hexane/isopropanol/acetonitrile/acetic acid (800/8/30/1, v/v) using isocratic elution with detection at 235 nm. With the currently described method, good separation from unreacted interfering compounds and quantification for 13(S)-HODE were achieved within 35 min with a minimum detection limit of 0.5 ng per injection.

Topics: 2-Propanol; Acetic Acid; Acetonitriles; Animals; Chromatography, High Pressure Liquid; Hexanes; Linoleic Acid; Linoleic Acids; Liver; Lung; Rats; Rats, Sprague-Dawley

Lipid hydroperoxides are important factors in lipid oxidation due to their ability to decompose into free radicals. In oil-in-water emulsions, the physical location of lipid hydroperoxides could impact their ability to interact with prooxidants such as iron. Interfacial tension measurements show that linoleic acid, methyl linoleate, and trilinolein hydroperoxides are more surface-active than their non-peroxidized counterparts. In oil-in-water emulsion containing surfactant (Brij 76) micelles in the continuous phase, linoleic acid, methyl linoleate, and trilinolein hydroperoxides were solubilized out of the lipid droplets into the aqueous phase. Brij 76 solubilization of the different hydroperoxides was in the order of linoleic acid > trilinolein > or = methyl linoleate. Brij 76 micelles inhibited lipid oxidation of corn oil-in-water emulsions with greater inhibition of oxidation occurring in emulsions containing linoleic acid hydroperoxides. Surfactant solubilization of lipid hydroperoxides could be responsible for the ability of surfactant micelles to inhibit lipid oxidation in oil-in-water emulsions.

Topics: Alkanes; Chemical Phenomena; Chemistry, Physical; Emulsions; Kinetics; Linoleic Acid; Linoleic Acids; Lipid Bilayers; Lipid Peroxidation; Lipid Peroxides; Micelles; Surface-Active Agents; Triglycerides; Water

The mechanism by which the fatty acid (1,4)-desaturase of Calendula officinalis produces calendic acid from linoleic acid has been probed through the use of kinetic isotope effect (KIE) measurements. This was accomplished by incubating appropriate mixtures of linoleate and regiospecifically dideuterated isotopomers with a strain of Saccharomyces cerevisiae expressing a functional (1,4)-desaturase. GC-MS analysis of methyl calendate obtained in these experiments showed that the oxidation of linoleate occurs in two discrete steps since the cleavage of the C11-H bond is very sensitive to isotopic substitution (kH/kD = 5.7 +/- 1.0) while no isotope effect (kH/kD = 1.0 +/- 0.1) was observed for the C8-H bond breaking step. These data indicate that calendic acid is produced via initial H-atom abstraction at C11 of a linoleoyl substrate and supports the hypothesis that this transformation represents a regiochemical variation of the more common C12-initiated Delta12 desaturation process.

Topics: Biochemistry; Calendula; Catalysis; Deuterium; Fatty Acid Desaturases; Isotope Labeling; Linoleic Acid; Linoleic Acids; Oxidation-Reduction; Saccharomyces cerevisiae

Linoleic acid (LA) had two effects on human Kv1.5 and Kv2.1 channels expressed in Chinese hamster ovary cells: an increase in the speed of current activation process (EC(50) = 2.4 and 2.7 microM for Kv1.5 and Kv2.1, respectively) and current inhibition (IC(50) = 6.6 and 7.4 for Kv1.5 and Kv2.1, respectively). LA affected the activation kinetics via two processes: a leftward shift in the instantaneous activation curves and an increase in the rate of current rise. Current inhibition by LA was time dependent but voltage independent. Hill slopes for plots of current inhibition (3.5 and 3.9 for Kv1.5 and Kv2.1, respectively) vs. dose of LA suggested that cooperativity was involved in the mechanism of current inhibition. A similar analysis of the effects of LA on current activation did not reveal cooperative interactions. The effects of LA were mediated from the external side of the channels, since addition of 10 microM LA to the patch pipette solution was without effect. Additionally, the methyl ester of LA was effective at enhancing peak current and promoting channel activation for Kv1.5 and Kv2.1 without inducing significant current inhibition.

Topics: Animals; CHO Cells; Cricetinae; Delayed Rectifier Potassium Channels; Electrophysiology; Ion Channel Gating; Kv1.5 Potassium Channel; Linoleic Acid; Linoleic Acids; Membrane Potentials; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Voltage-Gated; Shab Potassium Channels

Selected dietary lipids may increase the atherogenic effects of environmental chemicals, such as polychlorinated biphenyls (PCBs), by cross-amplifying mechanisms leading to dysfunction of the vascular endothelium. We have shown previously that the omega-6 parent fatty acid, linoleic acid, or 3,3',4,4'-tetrachlorobiphenyl (PCB 77), an aryl hydrocarbon (Ah) receptor agonist, independently can cause disruption of endothelial barrier function. Furthermore, cellular enrichment with linoleic acid can amplify PCB-induced endothelial cell dysfunction. We hypothesize that the amplified toxicity of linoleic acid and PCBs to endothelial cells could be mediated in part by cytotoxic epoxide metabolites of linoleic acid called leukotoxins (LTX) or their diol derivatives (LTXD). Exposure to LTXD resulted in a dose-dependent increase in albumin transfer across endothelial cell monolayers, whereas this disruption of endothelial barrier function was observed only at a high concentration of LTX. Pretreatment with the cytosolic epoxide hydrolase inhibitor 1-cyclohexyl-3-dodecyl urea partially protected against the observed LTX-induced endothelial dysfunction. Endothelial cell activation mediated by LTX and/or LTXD also enhanced nuclear translocation of the transcription factor NF-kappa B and gene expression of the inflammatory cytokine IL-6. Inhibiting cytosolic epoxide hydrolase decreased the LTX-mediated induction of both NF-kappa B and the IL-6 gene, whereas the antioxidant vitamin E did not block LTX-induced endothelial cell activation. Most importantly, inhibition of cytosolic epoxide hydrolase blocked both linoleic acid-induced cytotoxicity, as well as the additive toxicity of linoleic acid plus PCB 77 to endothelial cells. Interestingly, cellular uptake and accumulation of linoleic acid was markedly enhanced in the presence of PCB 77. These data suggest that cytotoxic epoxide metabolites of linoleic acid play a critical role in linoleic acid-induced endothelial cell dysfunction. Furthermore, the severe toxicity of PCBs in the presence of linoleic acid may be due in part to the generation of epoxide and diol metabolites. These findings have implications in understanding interactive mechanisms of how dietary fats can modulate dysfunction of the vascular endothelium mediated by certain environmental contaminants.

Topics: Alcohols; Animals; Aryl Hydrocarbon Hydroxylases; Cell Nucleus; Cells, Cultured; Cytochrome P-450 Enzyme System; Electrophoresis; Endothelium, Vascular; Enzyme Inhibitors; Epoxide Hydrolases; Epoxy Compounds; Fatty Acids; Interleukin-6; Linoleic Acid; Linoleic Acids; NF-kappa B; Polychlorinated Biphenyls; Reverse Transcriptase Polymerase Chain Reaction; Steroid 16-alpha-Hydroxylase; Steroid Hydroxylases; Swine

To investigate the role of a thiol-containing biologically active compound in lipid peroxidation of membranes.. Thiyl radicals were generated from 3-(2-mercaptoethyl)quinazoline-2,4(1H,3H)-dione (MECH) using pulse radiolysis and gamma-radiolysis in aqueous and alcoholic solutions saturated with N2O. The products were analysed by 1H NMR and by HPLC.. THE thiyl radicals abstract bisallylic hydrogens from [cis-9, cis-12]-methyl linoleate, yielding a pentadienyl radical. In the absence of oxygen, a thiyl radical-induced cis/trans-isomerization leads to linoleic-type isomers. These chain-type isomerization reactions can occur with the long living pentadienyl radical, followed by a 'repair' reaction of the attached thiol, and with the thiyl radical adduct with a double bond of the fatty acid residue.. The results show that the mechanism of cis/trans-isomerization is an integral part of the thiyl radical attack on polyunsaturated fatty acids in homogeneous solutions and in bilayers.

Topics: Chromatography, High Pressure Liquid; Free Radicals; Gamma Rays; Isomerism; Linoleic Acid; Linoleic Acids; Liposomes; Magnetic Resonance Spectroscopy; Methanol; Pulse Radiolysis; Quinazolines; Sulfhydryl Compounds

Linoleic acid and oleic acid markedly increased the influx of 45Ca into isolated intestinal epithelial cells, and this increase reflected a rise in the intracellular calcium level. Methyl linoleate had no effect, while glutamic acid and somatostatin both inhibited the linoleic acid-induced influx of 45Ca. In addition, methyl linoleate had no effect, while glutamic acid inhibited linoleic acid-induced hormone-responsive pancreatic exocrine secretion.

Topics: Animals; Aspartic Acid; Calcium; Cells, Cultured; Dietary Fats; Gastrointestinal Hormones; Glutamic Acid; Intestinal Mucosa; Intestine, Small; Linoleic Acid; Linoleic Acids; Oleic Acid; Oleic Acids; Pancreas; Rats; Receptors, N-Methyl-D-Aspartate

Linoleic acid methyl ester (LME) was selected as a model to study the autoxidation of unsaturated compounds at the surfaces of inorganic excipients. From IR spectra of LME-silica adsorbates it was concluded that the interaction between LME and the silica surface is mainly due to hydrogen bonds, established between the ester carbonyl and the silica silanol groups. The autoxidation was continuously monitored by measuring the oxygen consumption of LME under UV light exposure and isobaric conditions, and, in parallel, by determining the carbonyl and peroxide values of LME. The oxidative degradation of LME is enhanced by porous and colloidal silicas as well as by colloidal aluminium oxide. From the oxygen consumption and the ratio of intermediates (carbonyls, peroxides) formed during the degradation of LME it was concluded that the prooxidative effect of the inorganic excipients can be attributed to an accelerated reaction of the peroxides of LME.

Topics: Aluminum; Aluminum Oxide; Excipients; Linoleic Acid; Linoleic Acids; Oxidation-Reduction; Silicic Acid; Silicon Dioxide; Spectrophotometry, Infrared; Ultraviolet Rays

The rates of reaction with ozone of some biological antioxidants and simple polyunsaturated fatty acids (PUFA) have been measured in water or in aqueous micellar solutions. At pH 7.0 the rate constants are ca. 10(6) M-1 sec-1 for urate, alpha-tocopherol, and PUFA, and 6 X 10(7) M-1 sec-1 for ascorbate. When ozone-containing air is breathed, ascorbate in the lung may undergo direct ozonation. However, alpha-tocopherol is probably spared direct reaction with ozone because it doesn't effectively compete with PUFA in pulmonary membranes; rather, tocopherol is used to scavenge radicals produced from the ozone-PUFA reaction.

Topics: Antioxidants; Ascorbic Acid; Chemical Phenomena; Chemistry; Fatty Acids, Unsaturated; Linoleic Acid; Linoleic Acids; Oleic Acid; Oleic Acids; Ozone; Uric Acid; Vitamin E

Topics: Animals; Aspartate Aminotransferases; Diet; Dietary Fats; Edible Grain; Fatty Acids; Linoleic Acid; Linoleic Acids; Lipids; Liver Diseases; Muscular Dystrophies; Nutrition Disorders; Research; Swine; Swine Diseases; Vitamin E

Topics: Acetates; Androgens; Androsterone; Ascorbic Acid; Barbiturates; Butyrates; Estradiol; Estriol; Estrone; Gonadal Steroid Hormones; Hexestrol; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Liver; Mitochondria; Niacin; Niacinamide; Nicotinic Acids; Pharmacology; Propionates; Pyridines; Rats; Research; Sulfonic Acids; Testosterone

Topics: Chemical Phenomena; Chemistry; Hydrocarbons; Linoleic Acid; Linoleic Acids; Methane; Plant Oils; Research; Triticum

Topics: alpha-Linolenic Acid; Chromatography; Deficiency Diseases; Dietary Fats; Fats, Unsaturated; Fatty Acids; Fatty Acids, Essential; Infrared Rays; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Liver; Ozone; Rats; Research