The mechanism of the rearrangement of linoleate hydroperoxides

Chan, Henry; Levett, Gordon; Matthew, Jennifer A.

doi:10.1016/0009-3084(79)90072-0

Cited by 3 publications

(5 citation statements)

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“…The reversibility of oxygen addition has been established by oxygen scrambling in studies on hydroperoxide rearrangements with isotopically labeled hydroperoxides or molecular oxygen and has led to the conclusion that the rearrangement of conjugated diene hydroperoxides proceeds via -fragmentation (Chan et al 1978(Chan et al , 1979Porter et al 1980). As in the autoxidation of methyl oleate, the rate of the -fragmentation depends on the geometry of the pentadienyl radical generated in the process.…”

Section: Figure 10mentioning

confidence: 99%

“…The peroxidation reaction is reversible, based on oxygen scrambling studies with methyl linoleate hydroperoxides by Chan et al (1978Chan et al ( , 1979. In Fig.…”

Section: Figure 16mentioning

confidence: 99%

“…The regioselectivity and reversibility of oxygen addition to pentadienyl radicals has been established by kinetic and ESR studies by Chan et al (1978Chan et al ( , 1979 and Porter and Wujek (1984). Oxygen addition to unsymmetrical pentadienyl radicals, such as 2A, occurs faster at the transoid end than at the cisoid end.…”

Section: Isomeric Distribution (Ii Iii)mentioning

confidence: 99%

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Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α‐Tocopherol: The Hydroperoxide Pathway

Pajunen

Johansson

Hase

et al. 2008

Lipids

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The autoxidation of conjugated linoleic acid (CLA) is poorly understood in spite of increasing interest in the beneficial biological properties of CLA and growing consumption of CLA-rich foods. In this thesis, the autoxidation reactions of the two major CLA isomers, 9-cis,11-transoctadecadienoic acid and 10-trans,12-cis-octadecadienoic acid, are investigated. The results contribute to an understanding of the early stages of the autoxidation of CLA methyl ester, and provide for the first time a means of producing and separating intact CLA methyl ester hydroperoxides as well as basic knowledge on lipid hydroperoxides and their hydroxy derivatives.Conjugated diene allylic monohydroperoxides were discovered as primary autoxidation products formed during autoxidation of CLA methyl esters in the presence and absence oftocopherol. This established that one of the autoxidation pathways of CLA methyl ester is the hydroperoxide pathway.Hydroperoxides were produced from the two major CLA methyl esters by taking advantage of the effect of -tocopherol to promote hydroperoxide formation. The hydroperoxides were analysed and separated first as methyl hydroxyoctadecadienoates and then as intact hydroperoxides by HPLC. The isolated products were characterized by UV, GC-MS, and NMR techniques. In the presence of a high amount of -tocopherol, the autoxidation of CLA methyl ester yields six kinetically-controlled conjugated diene monohydroperoxides and is diastereoselective in favour of one particular geometric isomer as a pair of enantiomers. The primary autoxidation products produced from the two major CLA isomers include new positional isomers of conjugated diene monohydroperoxides, the 8-, 10-, 12-, and 14-hydroperoxyoctadecadienoates. Furthermore, two of these new positional isomers have an unusual structure for a cis,trans lipid hydroperoxide where the allylic methine carbon is adjacent to the cis instead of the usual trans double bond.The 1 H and 13 C NMR spectra of nine isomeric methyl hydroxyoctadecadienoates and of ten isomeric methyl hydroperoxyoctadecadienoates including the unusual cis,trans hydroperoxides, i.e. Me 8-OOH-9c,11t and Me 14-OOH-10t,12c, were fully assigned with the aid of 2D NMR spectroscopy. The assigned NMR data enabled determination of the effects of the hydroxyl and hydroperoxyl groups on the carbon chemical shifts of CLA isomers, identification of diagnostic signals, and determination of chemical shift differences of the olefinic resonances that may help with the assignment of structure to as yet unknown lipid hydroperoxides either as hydroxy derivatives or as intact hydroperoxides.A mechanism for the hydroperoxide pathway of CLA autoxidation in the presence of a high amount of -tocopherol was proposed based on the characterized primary products, their relative distribution, and theoretical calculations. This is an important step forward in CLA research, where exact mechanisms for the autoxidation of CLA have not been presented before. Knowledge of these hydroperoxide formation steps is of cr...

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Section: Figure 10mentioning

confidence: 99%

“…The peroxidation reaction is reversible, based on oxygen scrambling studies with methyl linoleate hydroperoxides by Chan et al (1978Chan et al ( , 1979. In Fig.…”

Section: Figure 16mentioning

confidence: 99%

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Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α‐Tocopherol: The Hydroperoxide Pathway

Pajunen

Johansson

Hase

et al. 2008

Lipids

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“…13-HPETrE accumulated, whereas 13-HPETE was converted to 15R-HPETE by Mn-LO. This presumably implies that Mn III -LO can transform 13-HPETE (but not 13-HPETrE) to a peroxyl radical at C-13, part of which will undergo rapid b-fragmentation and isomerization to a peroxyl radical at C-15 and form 15R-HETE (19,50). It should be possible to determine the structural basis for this difference between 13-HPETE and 13-HPETrE, as positional isomers of 20:4n-6 and 20:3n-3 are available.…”

Section: Discussionmentioning

confidence: 99%

On the singular, dual, and multiple positional specificity of manganese lipoxygenase and its G316A mutant

Cristea

Oliw

2007

Journal of Lipid Research

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manganese lipoxygenase (Mn-LO) oxygenates 18:3n-3 and 18:2n-6 to bis-allylic 11S-hydroperoxy fatty acids, which are converted to 13R-hydroperoxy fatty acids. Other unsaturated C 16 -C 22 fatty acids, except 17:3n-3, are poor substrates, possibly because of ineffective enzyme activation (Mn II YMn III ) by the produced hydroperoxides. Our aim was to determine whether unsaturated C 16 -C 22 fatty acids were oxidized by Mn III -LO. Mn

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“…Several hypotheses have been raised to explain these results (Miyamoto et al 2003b). The most plausible ones were the oxygen exchange mechanism between labeled peroxyl radicals and molecular oxygen (Chan et al 1979) (Fig. 1.3 Besides labeled singlet oxygen detection, labeled alcohol and ketone products ( Fig.…”

Section: ð1:3þmentioning

confidence: 96%

Lipid Hydroperoxides as a Source of Singlet Molecular Oxygen

Miyamoto

Mascio

2013

Lipid Hydroperoxide-Derived Modification of Biomolecules

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Lipid hydroperoxides (LOOH) are formed in biological system by enzymatic and non-enzymatic pathways. These hydroperoxides exerts multiple damaging effects on cellular macromolecules and are also important regulators of cellular processes. Several classes of hydroperoxides including fatty acid, phospholipid, cholesterol and cholesteryl ester hydroperoxides have been detected and characterized both in vitro and in vivo. Although cells are normally endowed with enzymatic defenses capable to reduce LOOH to less reactive hydroxides, LOOH may accumulate in several pathological conditions and attention has been focused on elucidating their pathophysiological role. In the last years we have demonstrated the generation of singlet molecular oxygen (O2 (1)Δg or (1)O2) in several reactions involving LOOH. The generation of (1)O2 was directly evidenced by spectroscopic detection and characterization of its light emission at 1,270 nm. Moreover, using 18-oxygen labeled hydroperoxides (L(18)O(18)OH) we could detect the formation of (18)O-labeled (1)O2 by chemical trapping with anthracene derivatives followed by detection of the corresponding labeled endoperoxides by HPLC coupled to tandem mass spectrometry. The experimental evidences indicate that (1)O2 is generated at a yield close to 10 % by the Russell mechanism from LOOH, either free or in membranes, in the presence of biologically relevant oxidants, such as metal ions, peroxynitrite, HOCl and cytochrome c.

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The mechanism of the rearrangement of linoleate hydroperoxides

Cited by 3 publications

References 0 publications

Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α‐Tocopherol: The Hydroperoxide Pathway

Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α‐Tocopherol: The Hydroperoxide Pathway

On the singular, dual, and multiple positional specificity of manganese lipoxygenase and its G316A mutant

Lipid Hydroperoxides as a Source of Singlet Molecular Oxygen

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