Inhibitory effect of nelumbo nucifera leaf extracts on the formation of heterocyclic amines and mutagenicity during cooking beef steak

Heterocyclic amines (HCAs) are food mutagens and carcinogens that are found in cooked fish, meat, and protein-rich foods. This study examined the inhibitory effect of marinades containing a Nelumbo nucifera leaf fraction on HCA formation in cooked beef steak. As a result of the Ames assay, cooked beef marinated with the N. nucifera leaf butanol fraction (2.0 g) cooked at 190oC showed a 61.5% reduction in overall mutagenicity. However, these data revealed no significant difference in mutagenicity in the ethanol, ethyl acetate, or water fractions. Formation of MeIQx (2-amino-3,8 dimethylimidazo[ 4,5-f]-quinoxalin) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine) was inhibited 60.7-63.5%. Cooked beef marinated with the water fraction of the N. nucifera leaf significantly (p<0.05) reduced the formation of MeIQx, PhIP, and DiMeIQx (2-amino-3,4,8 trimethylimidazo[4,5-f]-quinoxaline) by 65.3, 67.6, and 73.9%, respectively. These results show that marinades containing the N. nucifera leaf fraction could be an alternative method for reducing HCA formation in cooked beef steak.