INHIBITORY EFFECTS OF ANTIOXIDANTS ON FORMATION OF HETEROCYCLIC AMINES

It is important to search for effective antioxidants to suppress forma tion of mutagenic and carcinogenic heterocyclic amines (HCAs), like 2- amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-meth yl-6-phenylimidazo[4,5-b]pyridine (PhIP), because these HCAs are consi dered to be probable human carcinogens. The effects of various food-de rived antioxidants on MeIQx formation were examined by their addition (0.2 mmol each) to mixtures of creatine (0.4 mmol), glycine (0.4 mmol) and glucose (0.2 mmol), and heating at 128 degrees C for 2 h. Glycine was replaced by L-phenylalanine in the case of PhIP formation. Among the 14 kinds of antioxidants tested, green tea catechins and the major component [(-)-epigallocatechin gallate], two flavonoids (luteolin an d quercetin) and caffeic acid were found to clearly suppress the forma tion of both MeIQx and PhIP, being 3.2-75% of the level of the control s. These phenolic antioxidants also reduced the total mutagenicity of the heated mixtures. The results suggest that foodstuffs containing ca techins, flavonoids and caffeic acid may suppress the formation of HCA s in cooked foods. (C) 1998 Elsevier Science B.V. All rights reserved.