Autoxidation of saturated fatty acids. I. The initial products of autoxidation of methyl palmitate

The radicals generated from saturated fatty acids and their derivatives by hydrogen abstraction with photochemically formed t-butoxyl radicals have been investigated. These arise from the various methylene groups in the acids. The relative rates of abstraction from the methylene groups in the a-position, the position adjacent to the terminal methyl, and the remaining chain positions are 2 : 2 : 1, respectively, at 290 K, for acids of chain length >C,.With propanoic acid, butanoic acid, and butanonitrile, hydrogen abstraction at the a-methylene group predominates. With 1lauroyl-2-myristoyl-3-palmitoyl -rac-glycerol, enhanced attack at the position adjacent to the terminal methyl was observed.

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“…The e.s.r. spectrum obtained on photolysis of a solution of butanonitrile and di-t-butyl peroxide showed the presence of radicals (5)- (7).…”

Section: Cisoid Transoidmentioning

confidence: 99%

An electron spin resonance study of fatty acids and esters. Part 2. Hydrogen abstraction from saturated acids and their derivatives

Bascetta¹,

Gunstone²,

Walton³

1984

J. Chem. Soc., Perkin Trans. 2

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“…3 The oxidative attack by free radicals may lead to oxidative stress situations in the fatty acid chains, generating relatively stable products bearing functional groups, such as hydroperoxide, hydroxyl, and truncated acyl chains with aldehyde and carboxylic groups. 4,5 These oxidized lipids affect the microscopic and macroscopic properties of the membrane, which may be associated with several inflammatory, cancer, and neurodegenerative diseases. 6−8 Lipids and proteins can diffuse laterally in the membrane, creating a random mosaic-like structure that has the fluidity of vegetable oil.…”

Section: ■ Introductionmentioning

confidence: 99%

“…These fatty acid chains can be oxidized by specific enzymes or free radicals, namely reactive oxygen and nitrogen species (RONS) . The oxidative attack by free radicals may lead to oxidative stress situations in the fatty acid chains, generating relatively stable products bearing functional groups, such as hydroperoxide, hydroxyl, and truncated acyl chains with aldehyde and carboxylic groups. , These oxidized lipids affect the microscopic and macroscopic properties of the membrane, which may be associated with several inflammatory, cancer, and neurodegenerative diseases. − …”

Section: Introductionmentioning

confidence: 99%

Lipid Oxidation: Role of Membrane Phase-Separated Domains

Oliveira

Yusupov

Bogaerts

et al. 2021

J. Chem. Inf. Model.

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Lipid oxidation is associated with several inflammatory and neurodegenerative diseases, but many questions to unravel its effects on biomembranes are still open due to the complexity of the topic. For instance, recent studies indicated that phase-separated domains can have a significant effect on membrane function. It is reported that domain interfaces are “hot spots” for pore formation, but the underlying mechanisms and the effect of oxidation-induced phase separation on membranes remain elusive. Thus, to evaluate the permeability of the membrane coexisting of liquid-ordered (Lo) and liquid-disordered (Ld) domains, we performed atomistic molecular dynamics simulations. Specifically, we studied the membrane permeability of nonoxidized or oxidized homogeneous membranes (single-phase) and at the Lo/Ld domain interfaces of heterogeneous membranes, where the Ld domain is composed of either oxidized or nonoxidized lipids. Our simulation results reveal that the addition of only 1.5% of lipid aldehyde molecules at the Lo/Ld domain interfaces of heterogeneous membranes increases the membrane permeability, whereas their addition at homogeneous membranes does not have any effect. This study is of interest for a better understanding of cancer treatment methods based on oxidative stress (causing among others lipid oxidation), such as plasma medicine and photodynamic therapy.

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“…Saturated fatty acids are considerably more stable toward oX1da-tion than are unsaturated fatty acids. However, when the temperature is raised beyond 150 0 e, saturated fatty acids are subject to oxidative as ~ The thermii _ weIl as thermal degradation (Brodnitz et al, 1968a). With unsaturated fatty acids, the predominant thermo1ytic reaction products are dimers, higher oligomers and cyclic compounds.…”

mentioning

confidence: 99%

Effects of thermal oxidation on the constitution of butterfat, butterfat fractions and certain vegetable oils

Kupranycz

Amer

Baker

1986

J Americ Oil Chem Soc

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To evaluate the thermal oxidative behavior of butterfat in comparison to selected vegetable oils, samples of winter and summer butterfat, liquid and solid butterfat fractions, and selected vegetable oils were heated at 185 C in the presence of air (30 ml/min) for 8 and 16 hr. The resultant heated fats and oils, as well as the methyl esters of their fatty acids, were examined by gel permeation chromatography. The results indicated that butterfat is much more stable to thermal oxidation than canola, sunflower and soybean oils. This was evidenced by a substantially higher content of both dimeric and higher oligomeric triglycerides in the vegetable oils than in any of the butterfat samples after both 8 and 16 hr of heating. The corn oil also exhibited a high degree of stability to thermal oxidation after 8 hr of heating. The 16 hr corn oil data, however, was less certain due to the presence of a very viscous and dark colored material which could not be removed from the oxidation flask; this was believed to contain highly polymerized oil and was not observed with any of the other samples. There were some differences in the inter‐ and intramolecular polymerization of the butterfat fractions compared with each other and with whole butterfat. With the winter butterfat samples, after 8 hr of thermal oxidation, both the solid and liquid butterfat fractions exhibited more stability toward intermolecular polymerization than did the whole butterfat. After 16 hr of heating the ratio of trimeric and higher oligomeric triglycerides to dimeric triglycerides increased with increasing degree of unsaturation of the butterfat and with increased time of heating. Similar trends were observed with regard to the degree of intramolecular polymerization.

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Autoxidation of saturated fatty acids. I. The initial products of autoxidation of methyl palmitate

Abstract: A highly purified methyl palmitate free of all detectable impurities was oxidized by aeration at 150C. Monohydroperoxide was shown by thin-layer chromatography (TLC), spot and spray test, and polarography to be the initial autoxidation product.

Cited by 25 publications

References 18 publications

An electron spin resonance study of fatty acids and esters. Part 2. Hydrogen abstraction from saturated acids and their derivatives

An electron spin resonance study of fatty acids and esters. Part 2. Hydrogen abstraction from saturated acids and their derivatives

Lipid Oxidation: Role of Membrane Phase-Separated Domains

Effects of thermal oxidation on the constitution of butterfat, butterfat fractions and certain vegetable oils

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