Cholesterol autoxidation‐current status

Maerker, G.

doi:10.1007/bf02549301

Cited by 145 publications

(134 citation statements)

References 56 publications

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“…oxidation (Maerker, 1987). The molecule undergoes autoxidation by a free-radical mechanism leading to the formation of hydroperoxides and then to a number of o x i d a t i o n p r o d u c t s , t h e s o -c a l l e d oxysterols.…”

mentioning

confidence: 99%

Cholesterol oxidation: Health hazard and the role of antioxidants in prevention

Valenzuela

Sanhueza²,

Nieto³

2003

Biol. Res.

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BIOLOGICAL IMPORTANCE OF CHOLESTEROLSterol cholesterol (cholest-5-en-ß-ol) is an essential metabolite required for major biological functions, such as the cell membrane structure where the steroid f o r m s , t o g e t h e r w i t h p h o s p h o l i p i d molecules, the integral part of the lipid b i l a y e r ( S p e c t o r & Y o r e k , 1 9 8 5 ) . Cholesterol is inserted into membrane bilayers with its long axis perpendicular to the plane of the membrane, preventing the crystallization of fatty acyl chains by fitting b e t w e e n t h e m ( Y e a g l e , 1 9 8 5 ) a n d modifying the activity of membranebounded enzymes (Valencia et al., 1999). Cholesterol also provides the structural scaffolding for the synthesis of steroids a n d s t e r o i d h o r m o n e s , a n d f o r t h e biosynthesis of bile and bile acid salts. Sterol plays also an important role in embryonic development (Roux et al., 2000). ABSTRACTCholesterol is a molecule with a double bond in its structure and is therefore susceptible to oxidation leading to the formation of oxysterols. These oxidation products are found in many commonly-consumed foods and are formed during their manufacture and/or processing. Concern about oxysterols consumption arises from the potential cytotoxic, mutagenic, atherogenic, and possibly carcinogenic effects of some oxysterols. Eggs and egg-derived products are the main dietary sources of oxysterols. Thermally-processed milk and milk-derived products are another source of oxysterols in our diet. Foods fried in vegetable/animal oil, such as meats and French-fried potatoes, are major sources of oxysterols in the Western diet. Efforts to prevent or to reduce cholesterol oxidation are directed to the use of antioxidants of either synthetic or natural origin. Antioxidants are not only able to inhibit triglyceride oxidation, some of them can also inhibit cholesterol oxidation. Among synthetic antioxidants 2,6-ditertiarybutyl-4-methylphenol (BHT), and tertiary butylhydroquinone (TBHQ) can efficiently inhibit the thermalinduced oxidation of cholesterol. Some natural antioxidants, such as alpha-and gamma-tocopherol, rosemary oleoresin extract, and the flavonoid quercetin, show strong inhibitory action against cholesterol oxidation.

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mentioning

confidence: 99%

Cholesterol oxidation: Health hazard and the role of antioxidants in prevention

Valenzuela

Sanhueza²,

Nieto³

2003

Biol. Res.

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“…Cholesterol is known to readily oxidize in solution in the presence of air, light, free radical initiators, and/or elevated temperatures [29]; thus, it is possible that cholesterol may have been oxidized prior to analysis during storage. To test whether radicals may have been formed by pathways that do not involve laser irradiation, COP determinations were performed in solution by ES-MS. Figure 5a shows cholesterol in acetonitrile at a concentration of 155 μM.…”

Section: Solution Based Oxidationmentioning

confidence: 99%

Laser-Induced Oxidation of Cholesterol Observed During MALDI-TOF Mass Spectrometry

McAvey

Guan

Fortier

et al. 2011

J. Am. Soc. Mass Spectrom.

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Conditions for the detection of three odd-electron cholesterol oxidation peaks were determined and these peaks were shown to be artifacts of the matrix-assisted laser desorption time of flight (MALDI-TOF) process. Matrix choice, solvent, laser intensity and cholesterol concentration were systematically varied to characterize the conditions leading to the highest signals of the radical cation peaks, and it was found that initial cholesterol solution concentration and resultant density of solid cholesterol on the MALDI target were important parameters in determining signal intensities. It is proposed that hydroxyl radicals, generated as a result of laser irradiation of the employed 2, 5-dihydroxybenzoic acid (DHB) matrix, initiate cholesterol oxidation on the MALDI target. An attempt to induce the odd-electron oxidation peaks by means of adding an oxidizing agent succeeded using an acetonitrile solution of DHB, cholesterol, and cumene hydroperoxide. Moreover, addition of free radical scavengers reduced the abundances of some oxidation products under certain conditions. These results are consistent with the mechanism of oxidation proposed herein involving laser-induced hydroxyl radical production followed by attack on neutral cholesterol. Hydroxyl radical production upon irradiation of dithranol matrix may also be responsible for generation of the same radical peaks observed from cholesterol in dithranol by an analogous mechanism.

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“…Apresentam em comum a estrutura básica do núcleo ciclopentano-per-hidro-fenantreno, formado por quatro anéis condensados de hidrocarboneto (A-D), com caráter apolar e insolúvel em água, e uma cadeia lateral ramificada de hidrocarboneto unida ao carbono 17 do núcleo esteróide, também apolar e insolúvel em água. Há um grupo hidroxila no C-3, do anel A, em configuração beta, de caráter polar, que confere alguma afinidade com o meio aquoso e capacidade de esterificação com ácidos graxos, convertendo-se, neste caso, em totalmente insolú-vel (Maerker, 1987;Oliveira, Quintão, 1992;.…”

Section: óXidos De Colesterol -Oscunclassified

“…Os OsC possuem grupos funcionais álcool, cetona e epóxi, adicionais à molécula do colesterol, sobre o nú-cleo esteróide e sobre a cadeia lateral conferindo-lhes maior polaridade (Figura 1) (Maerker, 1987;. Estas diferenças estruturais e sua posição conferem aos OsC propriedades muito importantes, que definem em alguns casos, o tipo e a intensidade do efeito biológico (Crastes de Paulet et al, 1988;Peng et al, 1991).…”

Section: óXidos De Colesterol -Oscunclassified

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Óxidos de colesterol: ocorrência em alimentos, formação e efeitos biológicos

Morales-Aizpurúa¹,

Tenuta-Filho²

2002

Rev. Bras. Cienc. Farm.

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Foram revisadas questões importantes envolvendo a ocorrência de óxidos de colesterol - INTRODUÇÃOO colesterol é um composto lipídico insaturado, instável e suscetível à oxidação, sendo o processo oxidativo influenciado por muitos outros fatores, além da participação do oxigênio. Por sua vez, muitos dos óxidos de colesterol -OsC -correspondentemente formados são substâncias de interesse químico, bioquímico, farmacológico, toxicológico, tecnológico e também clínico, pela relação com processos citotóxicos, angiotóxicos, aterogênicos, mutagênicos e carcinogênicos.Por essa razão a ocorrência de OsC verificada em alimentos é de particular importância, sendo óbvio então que a oxidação do colesterol deva ser evitada. O perfil dos óxidos formados e as quantidades correspondentes também são definidos pelas características do alimento e interações entre seus componentes e produtos de decomposição, durante o processamento e/ou armazenamento.Neste trabalho de revisão foram abordadas questões relativas à oxidação do colesterol, enfocando aspectos da ocorrência de OsC em alimentos, sua formação e efeitos biológicos. ÓXIDOS DE COLESTEROL -OsCO colesterol (5-colesten-3β-ol) apresenta uma dupla ligação entre os carbonos 5 e 6 do anel B, que o torna susceptível à oxidação. Os OsC são similares ao colesterol. Apresentam em comum a estrutura básica do núcleo ciclopentano-per-hidro-fenantreno, formado por quatro anéis condensados de hidrocarboneto (A-D), com caráter apolar e insolúvel em água, e uma cadeia lateral ramificada de hidrocarboneto unida ao carbono 17 do núcleo esteróide, também apolar e insolúvel em água. Há um grupo hidroxila no C-3, do anel A, em configuração beta, de caráter polar, que confere alguma afinidade com o meio aquoso e capacidade de esterificação com ácidos graxos, convertendo-se, neste caso, em totalmente insolú-

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Cholesterol autoxidation‐current status

Cited by 145 publications

References 56 publications

Cholesterol oxidation: Health hazard and the role of antioxidants in prevention

Cholesterol oxidation: Health hazard and the role of antioxidants in prevention

Laser-Induced Oxidation of Cholesterol Observed During MALDI-TOF Mass Spectrometry

Óxidos de colesterol: ocorrência em alimentos, formação e efeitos biológicos

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