Malonaldehyde, formation

Figure 4. Periodate uptake (10f) and malonaldehyde formation (MA) during the oxidation of (1 d)-1,2,5/3,4-cyclohexanepentol with sodium metaperiodate...

Dowell et al. reported an increase in the osmotic fragility of alveolar macrophage preparations obtained horn rabbits acutely exposed to ozone at 10 ppm for 3 h or intermittently exposed to ozone at 2 ppm for 8 h/day for 7 days. Similar intermittent exposure to ozone at 0.5 ppm was without effect. A test for malonaldehyde formation was negative, but this lipid peroxide breakdown product may have been lost during the preparatory procedure. 

Matsufuji H, Shibamoto T (2004) The role of EDTA in malonaldehyde formation from DNA oxidized by Fenton reagent systems. J Agric Food Chem 52 3136-3140 Matsunga T, Hieda K, Nikaido O (1991) Wavelength dependent formation of thymine dimers and (6-4)photoproducts in DNA by monochromatic ultraviolet light ranging from 150 to 365 nm. Photochem Photobiol 54 403-410... 

The antioxidant activity of a compound depends upon which free radical or oxidant is used in the assay (Halliwell and Gutteridge, 1995), and a different order of antioxidant activity is therefore to be expected when analyses are performed using different methods. This has been demonstrated by Tsuda et al. (1994) in their study of antioxidative activity of an anthocyanin (cyanidin-3-O-p-D-glucosidc) and an anthocyanidin (cyanidin) in four different lipophilic assay systems. Both compounds had antioxidative activity in all four systems, but the relative activity between them and their activity, compared with Trolox, varied with the method used. Fukumoto and Mazza (2000) reported that antioxidant activity of compounds with similar structures gave the same trends, although not always the same results, when measured by P-carotene bleaching, DPPH and HPLC detection of malonaldehyde formation in linoleic acid emulsion. 

Strauss, R. G. 1981. Malonaldehyde formation is not a suitable screening test to detect oxidation in human neutrophils, J Clin Pathol 34, 800-802. 

Lipid peroxidation, measured by Fontecave et al. (1990) by malonaldehyde formation is induced... 

The addition of phenylisocyanate to aldehyde-derived enamines resulted in the formation of aminobutyrolactams (438,439). As aminal derivatives these produets can be hydrolyzed to the linear aldehyde amides and thus furnish a route to derivatives of the synthetically valuable malonaldehyde-acid system. With this class of reactions, a second acylation on nitrogen becomes possible and the six-membered cyclization products have been reported (440). Closely related to the reactions of enamines with isocyanates is the condensation of cyclohexanone with urea in base (441). 

Two different pathways have been proposed to explain the over-oxidation reaction of malonaldehyde. Huebner and his collaborators (32) based their conclusion on the observed behavior of digitoxose and suggested that malonaldehyde (7) was oxidized by three molar equivalents of periodate with the concomitant formation of three molar equivalents of formic acid ... 

Interaction of lipid oxidation products and amino compounds. Amino acids and primary amines may be involved in other reactions which could lead to the formation of compounds having the potential to undergo N-nitrosation. Malonaldehyde, produced as a result of oxidation of lipids, particularly polyunsaturated fatty acids, has been shown to react with amino acids to produce... 

Studies of the reaction of ozone with simplified lipid systems have shown that malonaldehyde can be produced by direct ozonolysis. The use of malonaldehyde assay as an index of lipid peroxidation is therefore invalid in ozone studies. Liposomes formed from egg lecithin and prepared in aqueous media were quite resistant to ozone, but the contribution of polyconcentric spheres to this resistance has not been fully assessed. However, the bilayer configuration, with the susceptible unsaturated fatty acids shielded from ozone by the hydrophilic areas of the molecule, may be resistant. In hexane, where the fatty acid moieties are exposed, ozone reacts stoichiometrically with the double bonds. The experiments with aqueous suspensions of phosphatidylcholine gave no evidence of the formation of lipid peroxides,nor did experiments with films of fatty acids exposed to ozone. ... 

Chemical Basis of Toxicity There is only one comprehensive theory for the action of ozone on biologic organisms—the theory of Chow and Tappel that the initial event is the formation of lipid peroxide and that successive events are an attempt to detoxify this product. The theory was developed from experiments with animals that showed that exposure to ozone increases malonaldehyde, gluthathione peroxidase, glutathione reductase, and G-6-PD ... 

Miyake, T., and T. Shibamoto. Inhibition of malonaldehyde and acetaldehyde formation from blood plasma HV092 oxidation by naturally occurring anti-... 

Tarladgis, B.G., Pearson, A.M., and Dugan, L.R. Jr. 1964. Chemistry of the 2-thiobarbituric acid test for determination of oxidative rancidity in foods. II.-Formation of the TBA-malonaldehyde complex without acid-heat treatment. J. Sci. Food Agric. 15 602-607. 

The autoxidation of polyunsaturated fatty acids (cf. Porter et al. 1981) is usually monitored by the formation of malonaldehyde using the 2-thiobarbituric acid essay. This is carried out under rather severe conditions which decomposes its precursor. This malonaldehyde-like product is obviously formed via a cycliza-tion reaction of a peroxyl radical, followed by other processes such as further cyclization and hydroperoxide formation [reactions (21)-(23)]. The resulting hydroperoxides may eliminate malonaldehyde upon a homolytic cleavage of the endoperoxidic intermediate (Pryor and Stanley 1975). 

Fig. 12.11. y-lrradiation of DNA (1 x 10 3 mol dm-3) in aqueous N20/02-saturated solution. Formation of free malonaldehyde (open triangles) and total TBA-active material (filled circles, malonalde-hyde plus DNA bound, in malonaldehyde equivalents as regards optical absorption) according to Rashid et al. (1999, with permission)... 

Toeg 1982 Krushinskaya 1983 Kapp and Smith 1970 Ullrich and Hagen 1971 Janicek et al. 1985 Rashid et al. 1999). Nearly all the TBA-activity attributable to low-molecular-weight (DNA-free) material is due to malonaldehyde (Rashid et al. 1999), and there is no indication for the formation of base propenals which dominate the products of the BLM reaction (Sect. 12.9). Moreover, at low doses the major fraction is due to TBA-active material bound to DNA (Fig. 12.11). 

Mechanistically, the formation of malonaldehyde and TBA-active DNA-bound material is not yet fully understood. While free malonaldehyde increases linearly with dose (G = 0.1 x 10 7 mol J 1 = 1.7% of OH), the efficiency of forming TBA-active DNA-bound material markedly decreases with increasing dose, that is when the integrity of the DNA is getting lost upon damage accumulation. At one stage, 02- seems to play a role, since the yield of total TBA-active material is G = 0.3 x 10"7 mol J-1 in N20/02-saturated and 0.2 x 10"7 mol J 1 in ( -saturated solution (at 100 Gy). As compared to N20/02, the OH yield is about half in 02-saturated solutions, but the 02 yield is markedly enhanced (Chap. 2.2). This could point to hydroperoxides as precursors of the TBA-active material, but details remain open. Yet, a G value of 0.2 x 10"7 mol J 1 (02-saturated) indicates that this type of lesion is not an unimportant one, about 7% of OH. 

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