Reactions of 1-methyl-2-phenylindole with malondialdehyde and 4-hydroxyalkenals. Analytical applications to a colorimetric assay of lipid peroxidation.
Under acidic and mild-temperature conditions, 1-methyl-2-phenylindole was found to react with malondialdehyde (MDA) and 4-hydroxyalkenals to yield a stable chromophore with intense maximal absorbance at 586 nm. The use of methanesulfonic acid results in optimal yields of chromophore produced from MDA as well as from 4-hydroxynonenal. By contrast, the use of hydrochloric acid results in an optimal yield of chromophore produced from MDA and a negligible reaction of 4-hydroxynonenal. Taking advantage of such chromogenic reactions, we developed a new colorimetric assay of lipid peroxidation. Using a methanesulfonic acid-based medium, MDA and 4-hydroxyalkenals can be measured at the 586 nm wavelength. However, the presence of endogenous inhibitors of the reaction with 4-hydroxyalkenals is common, and this means that the latter may be underestimated in some biological samples. The assay performed in a hydrochloric acid-based medium enables the specific measurement of MDA in the presence of 4-hydroxyalkenals. Upon hydrolysis of Schiff bases in hydrochloric acid (pH 1.5), either assay can be used to specifically measure the amount of total MDA in biological samples because 4-hydroxyalkenals undergo an irreversible cyclization reaction under the hydrochloric acid-based conditions of hydrolysis. The two assays were applied to the determination of the amount of MDA alone and of MDA and 4-hydroxyalkenals in an in vitro model of lipid peroxidation. This methodology was also used to clarify complex patterns of tissue-specific MDA production in vivo, following hydrolysis of Schiff bases, in rodents treated with doxorubicin.
Gérard-Monnier
D
D
Centre de Recherche Oxis International S.A., 94385 Bonneuil sur Marne, France.
Erdelmeier
I
I
Régnard
K
K
Moze-Henry
N
N
Yadan
J C
JC
Chaudière
J
J
D000447:Aldehydes / Q000378:metabolism*; D000818:Animals; D002863:Chromogenic Compounds / Q000378:metabolism; D003124:Colorimetry; D005260:Female; D006801:Humans; D007211:Indoles / Q000378:metabolism; D015227:Lipid Peroxidation; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity
D000447:Aldehydes; D002863:Chromogenic Compounds; D007211:Indoles; D008315:Malondialdehyde; C520322:1-methyl-2-phenylindole; C027576:4-hydroxy-2-nonenal