Department of Food Science and Technology, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000-00200, Nairobi, Kenya.
Free Radic Biol Med. 2010 Nov 30;49(10):1594-600. doi: 10.1016/j.freeradbiomed.2010.08.012. Epub 2010 Aug 17.
Malondialdehyde (MDA) is a mutagenic compound that has been widely used as a biomarker of oxidative stress. However, the nonenzymatic mechanisms of its formation are not well understood. Some lipid oxidation products were previously suggested to be MDA precursors and found to afford MDA heterolytically under acidic conditions. We predict that some of these compounds are not important MDA sources under the autoxidative conditions under which the bulk of MDA should be formed in vivo and that others require further oxidative modifications to generate MDA homolytically. Thus, we outline the likely important pathways of MDA formation in vivo. All these pathways are intense aldehyde producers, generating two other aldehydic products for every MDA molecule formed. Some of the predicted aldehydes are new and may merit further analytical and biological studies. Peracids derived from the aldehydes are proposed to participate in the formation of isofurans (which at high oxygen tensions are excellent markers of oxidative stress) as well as important bioactive epoxides such as leukotoxins. This generates interest in the biological relevance of lipid aldehyde-derived peracids. The suitability of tissue MDA determination methods is discussed based on their likelihood of involving acid-catalyzed artifactual MDA formation.
丙二醛（MDA）是一种诱变化合物，已被广泛用作氧化应激的生物标志物。然而，其形成的非酶机制尚不清楚。先前有一些脂质氧化产物被认为是 MDA 的前体，并在酸性条件下通过异裂方式生成 MDA。我们预测，在体内形成大部分 MDA 的自动氧化条件下，其中一些化合物不是重要的 MDA 来源，而其他化合物则需要进一步的氧化修饰才能通过均裂方式生成 MDA。因此，我们概述了体内 MDA 形成的可能重要途径。所有这些途径都是强烈的醛类产生物，每形成一个 MDA 分子就会产生另外两个醛类产物。一些预测的醛类是新的，可能值得进一步的分析和生物学研究。提议从醛类衍生的过酸参与异呋喃（在高氧张力下是氧化应激的极好标志物）以及重要的生物活性环氧化物（如白细胞毒素）的形成。这引发了人们对脂质醛衍生过酸的生物学相关性的兴趣。根据它们是否涉及酸催化的人为 MDA 形成，讨论了组织 MDA 测定方法的适用性。
