Abstract: Acrolein (ACR) is a food toxin produced during thermal processing and shows high reactivity with amino acids to form adducts. However, the toxicity of the adducts is seldom investigated until now. In this study, ACR was reacted with alanine (Ala) at various molar ratios (2:1, 1:1, 1:2, 1:3 and 1:4) in a water bath at 37 or 50 ℃ for various durations (0.5, 3, 5 and 6 h). The highest yield of adduct was attained with an ACR to Ala ratio of 1:2 at 50 ℃ for 5 h. After separation and purification by reversed-phase silica gel column chromatography, the purity of the adduct reached more than 95%, and it displayed maximum absorption at 220 nm as determined by high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry. Analysis by high-resolution mass spectrometry and nuclear magnetic resonance (NMR) showed that the relative molecular mass of the adduct was 183.082 3, which was a nitrogen-containing six-membered ring compound formed by the Michael addition between one molecule of Ala and two molecules of ACR followed by an aldol condensation. After incubating human normal gastric mucosal cells (GES-1) for 24 and 48 h, it was found that the cytotoxicity of the adduct (with half maximal inhibitory concentration (IC50) of 3.286 and 0.869 mmol/L) was significantly lower than that of its parent toxin, ACR (with IC50 of 0.058 and 0.067 mmol/L). This finding indicates that Ala may act as a potential scavenger of ACR.

Key words: acrolein; alanine; adduct; cytotoxicity