Methylglyoxal in food and living organisms

Abstract

Methylglyoxal (MG) is a highly reactive alpha-oxoaldehyde formed endogenously in numerous enzymatic and nonenzymatic reactions. It modifies arginine and lysine residues in proteins forming advanced glycation end-products such as N(delta)-(5-methyl-4-imidazolon-2-yl)-L-ornithine (MG-H1), 2-amino-5-(2-amino-5-hydro-5-methyl-4-imidazolon-1-yl)pentanoic acid (MG-H2), 2-amino-5-(2-amino-4-hydro-4-methyl-5-imidazolon-1-yl)pentanoic acid (MG-H3), argpyrimidine, N(delta)-(4-carboxy-4,6-dimethyl-5,6-dihydroxy-1,4,5,6-tetrahydropyrimidine-2-yl)-L-ornithine (THP), N(epsilon)-(1-carboxyethyl)lysine (CEL), MG-derived lysine dimer (MOLD), and 2-ammonio-6-({2-[4-ammonio-5-oxido-5-oxopently)amino]-4-methyl-4,5-dihydro-1H-imidazol-5-ylidene}amino)hexanoate (MODIC), which have been identified in vivo and are associated with complications of diabetes and some neurodegenerative diseases. In foodstuffs and beverages, MG is formed during processing, cooking, and prolonged storage. Fasting and metabolic disorders and/or defects in MG detoxification processes cause accumulation of this reactive dicarbonyl in vivo. In addition, the intake of low doses of MG over a prolonged period of time can cause degenerative changes in different tissues, and can also exert anticancer activity. MG in biological samples can be quantified by HPLC or GC methods with preliminary derivatization into more stable chromophores and/or fluorophores, or derivatives suitable for determination by MS by use of diamino derivatives of benzene and naphthalene, 6-hydroxy-2,4,5-triaminopyrimidine, cysteamine, and o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine. The methods include three basic steps: deproteinization, incubation with derivatization agent, and chromatographic analysis with or without preliminary extraction of the formed products.

Dietary Advanced Glycation End Products and Their Role in Health and Disease

“…The main difficulties include the high reactivity and ubiquitous character of these compounds, their low concentrations, the possible polymerization or formation of adducts with sample components, and de novo generation during sample handling. The chemical complexity of the samples (biological fluids, clinical samples, and food) and the risk of sample contamination from reagents, air, and water should also be noted (74)(75)(76). It is clear from the above considerations that the conditions applied at procedural stages before and during derivatization should be as mild as possible, avoiding drastic changes in chemical conditions and prolonged heating.…”

Phytochemicals from berries and grapes inhibited the formation of advanced glycation end‐products by scavenging reactive carbonyls

“…Methylglyoxal and glyoxal are found in foods that contain large amounts of carbohydrates or in foods that are processed at high temperatures (Nemet, Varga-Defterdarovic, & Turk, 2006). Typical examples include baked meats, soy sauces, and carbonated soft drinks (Tan, Wang, Lo, Sang, & Ho, 2008).…”

CE: A useful analytical tool for the characterization of Maillard reaction products in foods

“…Quantitative data on most reported specific food MRP were furosine [14][15][16][17][18][19][20][21] hydroxymethylfurfural (HMF), furfural [22][23][24][25][26][27] and acrylamide [28][29][30][31]. Additionally, methylglyoxal (MG) is one of the key dicarbonyls leading to AGE formation that has been determined in foods such as wines, beer, dairy products, and honey [32]. Melanoidins are widely distributed in foods such as bread crust, coffee, cocoa, roasted malt, honey, and tomato sauce [1,[33][34][35].…”