POSSIBLE MECHANISMS OF ANTIMUTAGENIC EFFECT OF MAILLARD REACTION-PRODUCTS PREPARED FROM XYLOSE AND LYSINE

Possible mechanisms of antimutagenicity of Maillard reaction products (MRPs) prepared by heating xylose and lysine (molar ratio 1:2) at pH 9.0 and 100 degrees C for 1 h were investigated using a Salmonella/ microsome assay. The mutagenicity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) was markedly reduced by the addition of xylose-lysine MRPs toward Salmonella typhimurium TA98 and TA100, whereas the mutagenicity of 4-nitroquinoline N-oxide was not inhibited. The xylose-lysine MRPs exhibited no inhibitory activity to IQ on the bioantimutagenic assay; this result indicated that the antimutagenic effect of xylose-lysine MRPs is a desmutagenic action, not by modification of DNA repair processes in the bacterium cell. According to further study to elucidate the antimutagenic mechanisms of action, xylose-lysine MRPs reduced the mutagenicity of IQ by interaction with proximate metabolites of IQ, not by direct-inhibition of hepatic microsomal activation. The mutagenicity of IQ was decreased by increasing reaction periods between xylose-lysine MRPs and IQ metabolites, but with neither S9 mixture, intact IQ, or DNA. In conclusion, the antimutagenic effects of xylose-lysine MRPs to IQ might be due to interaction with proximate metabolites of IQ to form inactive adducts.