The cascade mechanism to explain ozone toxicity: The role of lipid ozonation products

Pryor, William A.; Squadrito, G; Friedman, Mitchell

doi:10.1016/0891-5849(95)02033-7

Cited by 298 publications

(210 citation statements)

References 28 publications

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“…1 The determination of molecular structure of ozonized fatty acids is one of aim of scientists which work with ozonized vegetable oils and ozone therapy. 2 Many studies have been carried out to develop new analytical techniques that, with very little or any manipulation of the sample, can afford the identification of the vegetable oil and lipids. 3,4 Specifically, one spectroscopic technique with a high potential in this field is High-Resolution Nuclear Magnetic Resonance Spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Characterization by NMR of Ozonized methyl linoleate

Díaz

Gavín²

2007

J. Braz. Chem. Soc.

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No presente estudo o linoleato de metila ozonizado com índice de peróxidos de 1.800 mmol-equiv. kg -1 foi caracterizado quimicamente. Os efeitos do ozônio sobre o linoleato de metila produz hidroperóxidos, ozonideos e aldeídos, os quais foram identificados por técnicas de ressonância magnética nuclear de 1 H e 13 C, mono-e bidimensional. O linoleato de metila padrão e o linoleato de metila ozonizado mostram espectros muito similares, excetuando os valores de ressonância (δ 9,7 e δ 9,6) que correspondem aos hidrogênios aldeídicos (δ 5,7 e δ 5,5) e olefínicos de hidroperóxidos (δ 5,2). Outras atribuições estão baseadas nas conectividades fornecidas pelas constantes de acoplamento. Estes resultados indicam que a espectrometria de RMN pode oferecer informação valiosa a respeito da quantidade de compostos oxigenados formados à partir do linoleato de metila ozonizado para o uso em ozonoterapia e na química de óleos vegetais ozonizados.In the present study ozonized methyl linoleate with peroxide index of 1,800 mmol-equiv kg -1 was chemically characterized. Ozonation of methyl linoleate produced hydroperoxides, ozonides and aldehydes which were identified by 1 H and 13 C NMR two-dimensional. The standard methyl linoleate and ozonized methyl linoleate shown very similar 1 H NMR spectra except for the signals at δ 9.7 and δ 9.6 that correspond to aldehydic hydrogen, δ 5.7 and δ 5.5 (olefinic signals from hydroperoxides) and δ 5.2 ppm (multiplet from ozonides methynic hydrogen). Other resonance assignments are based on the connectivities provided by the hydrogen scalar coupling constants. These results indicate that NMR spectroscopy can provide valuable information about the amount of formed oxygenated compounds in the ozonized methyl linoleate in order to use it to follow up ozone therapy and chemistry of ozonized vegetable oil. 5,6 However, data on the spectra of ozonized fatty acids is scarce in the literature. KeywordsThe reaction of ozone with vegetable oil and lipids occurs almost exclusively with the carbon-carbon double bonds present in unsaturated fatty acids. Different kinds of oxygenated products are formed (hydroperoxides, ozonides and aldehydes) that probably are responsible for the biological activity of ozonized fatty acids.7-9 The mechanism of this reaction is well known (Criegee mechanism, Figure 1), as well as the conditions necessary to enhance the preferential formation of any of these oxygenated compounds. 10,11 Of all the natural fatty acids, linoleic acid is one of the most widely distributed and is present in practically all lipids. For this reason, methyl linoleate was chosen as a model compound to be ozonized and chemically Experimental General ozonization procedureA mixture of 1.6 mL (0.0048 mol L -1 ) of methyl linoleate (99%) and 0.16 mL of water were introduced into a bubbling reactor where ozone reaction took place at room temperature. 7,8 The reaction was continued during 7.25 minutes and one sample was taken at applied ozone doses 245 mg g -1 . The samples were stored at -80 °C until NMR ...

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Section: Introductionmentioning

confidence: 99%

Characterization by NMR of Ozonized methyl linoleate

Díaz

Gavín²

2007

J. Braz. Chem. Soc.

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“…3 This reaction produces several oxygenated compounds such as hydroperoxides, ozonides, aldehydes, peroxides, diperoxides and polyperoxides. [3][4][5][6][7] These oxygenated compounds could be also responsible for the wide biological activity of ozonized vegetable oils. The yield of oxygenated compounds from unsaturated oils depends on reaction conditions necessary, as the type of medium where the reaction takes place, the presence of additives, the reaction temperature, the type of reactor, the agitation of the reaction mixture, the applied ozone doses, etc.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of ozonized olive oil and ozonized sunflower oil

Díaz¹,

Hernández²,

Martínez³

et al. 2006

J. Braz. Chem. Soc.

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“…Because biosurfaces are universally protected by interfacial fluids containing antioxidants such as ascorbic acid (AH 2 ), reduced glutathione (GSH), and uric acid (UA) in mM concentrations, which intercept and prevent gaseous O 3 from reaching the underlying tissues, a rational approach to unraveling the mechanism of synergic oxidative stress would involve the characterization of chemical events that impair or disable this natural line of defense. The high reactivity of O 3 implies that oxidative aggression is transduced across epithelial lining fluids (ELF) by deleterious secondary oxidants generated in the rapid ozonolysis of sacrificial antioxidants (9)(10)(11)(12). These secondary oxidants need only last the few microseconds required for diffusing through typical Ϸ0.1-m-thick ELF layers (13).…”

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confidence: 99%

Acidity enhances the formation of a persistent ozonide at aqueous ascorbate/ozone gas interfaces

Enami

Hoffmann

Colussi

2008

Proc. Natl. Acad. Sci. U.S.A.

100

164

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The pulmonary epithelium, like most aerial biosurfaces, is naturally protected against atmospheric ozone (O3) by fluid films that contain ascorbic acid (AH 2) and related scavengers. This mechanism of protection will fail, however, if specific copollutants redirect AH2 and O3(g) to produce species that can transduce oxidative damage to underlying tissues. Here, the possibility that the synergistic adverse health effects of atmospheric O 3(g) and acidic particulate matter revealed by epidemiological studies could be mediated by hitherto unidentified species is investigated by electrospray mass spectrometry of aqueous AH 2 droplets exposed to O3(g). The products of AH2 ozonolysis at the relevant air-water interface shift from the innocuous dehydroascorbic acid at biological pH to a C 4-hydroxy acid plus a previously unreported ascorbate ozonide (m/z ‫؍‬ 223) below pH Ϸ5. The structure of this ozonide is confirmed by tandem mass spectrometry and its mechanism of formation delineated by kinetic studies. Present results imply enhanced production of a persistent ozonide in airway-lining fluids acidified by preexisting pathologies or inhaled particulate matter. Ozonides are known to generate cytotoxic free radicals in vivo and can, therefore, transduce oxidative damage.ascorbic acid ͉ oxidative damage ͉ particulate matter ͉ lung ͉ biosurfaces

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The cascade mechanism to explain ozone toxicity: The role of lipid ozonation products

Cited by 298 publications

References 28 publications

Characterization by NMR of Ozonized methyl linoleate

Characterization by NMR of Ozonized methyl linoleate

Comparative study of ozonized olive oil and ozonized sunflower oil

Acidity enhances the formation of a persistent ozonide at aqueous ascorbate/ozone gas interfaces

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