Core aldehydes

The elution factors in normal-phase TLC and RP-HPLC, using a fixed set of chromatographic parameters, were determined for a series of saturated triacylglycerides with TCN from C30 to Ceo, serving as reference compounds and various oxidation derivatives of analogous unsaturated triglycerides, including hydroperoxides, peroxides, epoxides, core aldehydes and their DNP derivatives. From these measurements, a series of incremental... 

The ozonides of choline and ethanolamine phosphatides subjected to reduction with PhsP yield the corresponding core aldehydes. After hydrolysis with phospholipase C to eliminate the polar group and silylation with trimethylsilyl chloride, the core aldehydes can be determined by GLC-FID using temperature programming to high temperatures . ... 

The ozonides of choline and ethanolamine phosphatides and triglycerides can be subjected to reduction with triphenylphosphine to yield the corresponding core aldehydes, and further derivatized to the 2,4-dinitrophenylhydrazones (DNP). The core aldehydes and their DNP derivatives can be separated by HPLC and characterized by various techniques, including EI-MS and TS-MS of positive and negative ions . See also Section VHI.E. 

Dinitrophenylhydrazones (DNP) aldehyde determination, 670 core aldehydes, 689 malondialdehyde determination, 669 ozonide reduction, 726... 

X PV +AV) being a better index of oxidation than either PV or AV alone. Volatile products can be removed from oils by deodorization, but aldehydes attached to the carboxyl end of the chain remain part of the triacylglycerol (sometimes called core aldehydes) and are indicators of previous oxidative damage. 

Ahmed, Z. et al. Apohpoprotein A-1 promotes the formation of phosphatidylcholine core aldehydes that are hydrolyzed hy paraoxonase (PON-1) during high density hpoprotein oxidation with a peroxynitrite donor, J. Biol. Chem., 276, 24473, 2001. 

Polyunsaturated fatty acids and especially arachidonic acid are highly susceptible to lipid peroxidation, which leads to the generation of lipid hydroperoxides, which then undergo carbon-carbon bond cleavage giving rise to the formation of short chain, unesterified aldehydes and aldehydes still esterified to the parent lipid, termed core-aldehydes (Esterbauer et al. 1987). Considerable progress has been made in recent years in dissecting the molecular structures of OxPL, which consequently allowed for the experimental use of defined compounds rather than complex lipoproteins and lipid mixtures. 

Both LC-MS and MS/MS have permitted greatly improved analyses of various lipid oxidation products in the form of the intact neutral and polar lipid molecules or their partial degradation products, which was not possible by chromatographic methods alone. Thus, the hydroperoxides, epoxides, hydroxides, isoprostanes, and the core aldehydes and acids generated during nonenzymatic peroxidation have been identified in plasma lipoproteins and atheroma samples and have provided a new basis for hypotheses about the origin and progression of vascular disease. 

Kuksis A, Kamido H, and Ravandi A (2003) Glyceropho-spholipid core aldehydes Mechanism of formation, methods of detection, natural occurrence, and biological significance. In Kamal-Eldin A (ed.) Lipid Oxidation Pathways, pp. 138-189. Champaign AOCS Press. 

Sevanian et al. (1994) applied GLC and LC/TS/MS for the analysis of plasma cholesterol-7-hydroperoxides and 7-ketocholesterol. Analysis of human and rabbit plasma identified the commonly occurring oxidation products, yet dramatic increases in 7-ketocholesterol and cholesterol-5p, 6P-epoxide were observed. The study failed to reveal the presence of choles-terol-7-hydroperoxides, which were either too unstable for isolation, metabolized or further decomposed. The principal ions of cholesterol oxides monitored by LC/TS/MS were m/z 438 (cholestane triol) m/z 401 (cholesterol-7-hydroperoxide) m/z 401 (7-ketocholesterol) m/z 367 (7a-hydroxycholesterol) m/z 399 (cholesta-3,5-dien-7-one) and m/z 385 (choles-terol-5a,6a-epoxide). The major ions were supported by minor ions consistent with the steroid structure. Kamido et al. (1992a, b) synthesized the cholesteryl 5-oxovaleroyl and 9-oxononanoyl esters as stable secondary oxidation products of cholesteryl arachidonate and linoleate, respectively. These compounds were identified as the 3,5-dinitrophenylhydrazone (DNPH) derivatives by reversed-phase LC/NICI/MS. These standards were used to identify cholesteryl and 7-ketocholesteryl 5-oxovaleroyl and 9-oxononanoyl esters as major components of the cholesteryl ester core aldehydes generated by copper-catalysed peroxidation of low-density lipoprotein (LDL). In addition to 9-oxoalkanoate (major product), minor amounts of the 8, 9, 10, 11 and 12 oxo-alkanoates were also identified among the peroxidation products of cholesteryl linoleate. Peroxidation of cholesteryl arachidonate yielded the 4, 6, 7, 8, 9 and 10 oxo-alkanoates of cholesterol as minor products. The oxysterols resulting from the peroxidation of the steroid ring were mainly 7-keto, 7a-hydroxy and 7P-... 

Kuksis et al. (1993), Sjovall et al. (1995) and Sjovall and Kuksis (1995) have reported the direct identification of the hydroperoxides and core aldehydes of selected synthetic and natural TGs. Mixed hydroperoxide and core aldehyde derivatives were obtained following treatment with tert-butyl hydroperoxide and Fe ions. The oxidation products were identified by... 

Kamido, H., Kuksis, A., Marai, L. and Myher, J. J. (1993) Identification of core aldehydes among in vitro peroxidation products of cholesteryl esters. Lipids, 28, 331-6. 

Kamido, H., Nonaka, K., Yamana, K. et al. (1997) Cholesteryl ester core aldehydes (components of extensively oxidized low density lipoproteins) exist in human atherosclerotic lesions and are cytotoxic to cultured human endothelial cells. Arteriosclerosis and Thrombosis, submitted. 

Ravandi, A., Kuksis, A., Myher, J. J. and Marai, L. (1995b) Determination of lipid ester ozonides and core aldehydes by high performance liquid chromatography with on-line mass spectrometry. J. Biochem. Biophys. Methods, 30, 271-85. 

Ravandi, A., Kuksis, A., Shaikh, N. A. and Jackowski, G. (1997) Schiff base formation between amino glycerophospholipids, amino acids and polypeptides and the core aldehydes of phosphatidylcholine. Lipids (in press). 

Sjovall, O. and Kuksis, A. (1995) Detection and quantitation of lipid ester core aldehydes in edible oils using HPLC and LC/MS with electrospray, in Abstracts, 21st World Congress and Exhibition of the Intenational Society for Fat Research (ISF), 1-6 October, The Hague, Netherlands, International Society for Fat Research, pp. 52-53. 

Sjovall, O. and Kuksis, A. (1997b) Analysis of oxidized triacyl ycerols by LC/MS with electrospray ionization. II. Core aldehydes. Lipids, submitted. 

For Plavix core, aldehyde 104 was converted to an epoxide 105 using chloroiodomethane and n-BuLi, followed by its treatment with potassium thiocyanate to give vinyl thiirane 106. Ring expansion of 106 was achieved by heating with 5 mol% Cu(hfacac)2 in benzene, to afford dihydrothiophene core 107, which can be transformed to Plavix by a previously reported procedure (Scheme 11.63). ... 

The ESI technique was applied to the analyses of synthetic isomers of triacylglycerol hydroperoxides of eicosapentaenoic acid, and other oxidation products, including hydroxides, epoxides and triglyceride core aldehydes... 

Sjovall, O., Kuskis, A. and Kalho, H. Tentative identification and quantification of TAG core aldehydes as dinitrophenylhydrazones in autoxidized sunflowerseed oil using reversed-phase HPLC with electrospray ionization MS. Lipids 38,1179-1190 (2003). 

Thermal oxidation of unsaturated fats is accompanied by considerable isomerization of double bonds, leading to products containing trans double bonds and conjugated double bond systems. Non-volatile decomposition products are formed by thermal oxidation, hydrolysis and cyclization. A large number of hydroxy, alkoxy-substituted, epoxy and keto compounds are produced by oxidation, free fatty acids and mono- and diacylglycerols by hydrolysis, and cyclic monomers by cyclization of polyunsaturated fatty acids in heated fats. Aldehydo glycerides (also referred to as core aldehydes ) and keto glycerides... 

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