Malondialdehyde belong to the class of β-dicarbonyls. A colorless liquid, malondialdehyde is a highly reactive compound that occurs as the enol.[2] It is a physiological metabolite, and a marker for oxidative stress.
Malondialdehyde mainly exists as its enol, hydroxyacrolein:[2]
CH2(CHO)2 → HOC(H)=CH-CHO
In organic solvents, the cis-isomer is favored, whereas in water the trans-isomer predominates. The equilibrium is rapid and is inconsequential for many purposes.
In the laboratory it can be generated in situ by hydrolysis of its acetal 1,1,3,3-tetramethoxypropane, which is commercially available and shelf-stable, unlike malondialdehyde.[2] Malondialdehyde is easily deprotonated to give the sodium salt of the enolate (m.p. 245 °C).
Reactive oxygen species degrade polyunsaturated lipids, forming malondialdehyde.[5] This compound is a reactive aldehyde and is one of the many reactive electrophile species that cause toxic stress in cells and form covalent protein adducts referred to as "advanced lipoxidation end-products" (ALE), in analogy to advanced glycation end-products (AGE).[6] The production of this aldehyde is used as a biomarker to measure the level of oxidative stress in an organism.[7][8]
Malondialdehyde reacts with deoxyadenosine and deoxyguanosine in DNA, forming DNA adducts, the primary one being M1G, which is mutagenic.[9] The guanidine group of arginine residues condense with malondialdehyde to give 2-aminopyrimidines.
Human ALDH1A1 aldehyde dehydrogenase is capable of oxidizing malondialdehyde.
Malondialdehyde and other thiobarbituric reactive substances (TBARS) condense with two equivalents of thiobarbituric acid to give a fluorescent red derivative that can be assayed spectrophotometrically.[2][10] 1-Methyl-2-phenylindole is an alternative more selective reagent.[2]
Levels of malondialdehyde can be also considered (as a marker of lipid peroxidation) to assess the membrane damage in spermatozoa; this is crucial because oxidative stress affects sperm function by altering membrane fluidity, permeability and impairing sperm functional competence.[15]
^ abcdeV. Nair, C. L. O'Neil, P. G. Wang "Malondialdehyde", Encyclopedia of Reagents for Organic Synthesis, 2008, John Wiley & Sons, New York. doi:10.1002/047084289X.rm013.pub2 Article Online Posting Date: March 14, 2008
^Rouzer, Carol A.; Marnett, Lawrence J. (2003). "Mechanism of Free Radical Oxygenation of Polyunsaturated Fatty Acids by Cyclooxygenases". Chemical Reviews. 103 (6): 2239–2304. doi:10.1021/cr000068x. PMID12797830.
^Pryor WA, Stanley JP (1975). "Letter: A suggested mechanism for the production of malondialdehyde during the autoxidation of polyunsaturated fatty acids. Nonenzymatic production of prostaglandin endoperoxides during autoxidation". J. Org. Chem. 40 (24): 3615–7. doi:10.1021/jo00912a038. PMID1185332.
^Del Rio D, Stewart AJ, Pellegrini N (2005). "A review of recent studies on malondialdehyde as toxic molecule and biological marker of oxidative stress". Nutr Metab Cardiovasc Dis. 15 (4): 316–28. doi:10.1016/j.numecd.2005.05.003. PMID16054557.
^Hartman PE, Putative mutagens and carcinogens in foods. IV. Malonaldehyde (malondialdehyde) Environ Mutagen. 1983;5(4):603-7
^Dourerdjou, P.; Koner, B. C. (2008), Effect of Different Cooking Vessels on Heat-Induced Lipid Peroxidation of Different Edible Oils" Journal of Food Biochemistry, 32: 740–751. doi:10.1111/j.1745-4514.2008.00195.x
