Reactive Carbonyl-Scavenging Ability of 2-Aminoimidazoles: 2-Amino-1-methylbenzimidazole and 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)

The carbonyl-scavenging ability of 2-amino-1-methylbenzimidazole (AMBI) and the heterocyclic aromatic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was investigated in an attempt to identify new routes that can modify the carbonyl content of foods. The reaction of both AMBI and PhIP with 2-alkenals, 2,4-alkadienals, 4-oxo-2-alkenals, 4,5-epoxy-2-alkenals, and 4-hydroxy-2-nonenal produced fluorescent adducts, whose structure was determined for the adduct produced between AMBI and 2-pentenal. This adduct was isolated and identified by one- and two-dimensional nuclear magnetic resonance and high-resolution mass spectrometry as 2,10-dihydro-2-ethyl-10-methylpyrimido[1,2-a]benzimidazole. The formation of these adducts was parallel to the elimination of AMBI and PhIP. The Ea of the reaction between PhIP and 4-oxo-2-nonenal was 27.4 kJ/mol. All these results suggest that 2-aminoimidazoles can be employed to modify the carbonyl content of foods. At the same time and because the reaction produces the disappearance of the amino compound, lipid-derived carbonyl compounds can be employed to eliminate 2-aminoimidazoles, which suggests a new strategy for the elimination of heterocyclic aromatic amines in foods.