Mutagenic activity of heterocyclic amines in cooked foods.

Abstract

Mutagenic heterocyclic amines are generated in foods when they are cooked at temperatures over 1 50°C. These compounds are present from 0.1 to 50 ppb, depending on the food and cooking conditions. These heterocyclic amines are not only present in cooked red meat, fish, and chicken, but are also present at lower levels in baked and fried foods derived from grain. Mutagenicity of fried beef hamburgers cooked at 230°C is 800 ± 37 TA98 revertants per gram cooked weight. We measured 2-amino-3,8-dimethylimidazo[4,5-flquinoxaline (MelQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMelQx), and 2-amino-3-methylimidazo[4,5-flquinoline (IQ) formation at this temperature and found 3.0 ± 2.0, 1.0 ± 0.18, and 0.06 ± 0.03 ng/g, respectively. 2-amino-1-methyl--phenylimidazo[4,5-blpyridine (PhIP) was found at a higher concentration of 9.6 ng/g. In our laboratory we have shown these heterocyclic amines are capable of producing both reverse and forward mutations in Salmonella bacteria and forward mutations in Chinese hamster ovary cells (CHO). We have also been able to show a statistically significant increase in mutations in the pancreas of the "mutamouse" following PhIP exposure. The pancreas also shows relatively high DNA binding compared to other organs in the mouse. The number and type of mutations depend on the repair capacity of the cells for both Salmonella and CHO. In Salmonella the mutations are primarily 2-base deletions when the cells lack uvrB repair, but mutations are more complex (larger deletions and insertions) but lower in frequency when repair is functional. Efforts are now under way to assess specific sequence changes in the aprt gene in mutant CHO cells. -Environ Health Perspect 102 (Suppl 6):201-204 (1994)

Development and characterization of a stable epithelial cell line from Muta™Mouse lung

“…Following a two-stage activation pathway, BaP diol epoxides bind to DNA to form N 2 -dG, N 6 -dA, and N 7 -dG adducts [Jeffrey, 1985]. PhIP, an aminoimidazoazaarene formed during the cooking of meat, is a potent mutagen and animal carcinogen [Felton et al, 1994;Ito et al, 1991]. PhIP undergoes N-hydroxylation by hepatic Cyp1A2 [Boobis et al, 1994], followed by esterification to form the highly electrophilic N-acetoxy-PhIP.…”

Polymorphism in the N-acetyltransferase 1 alleles NAT1*10 and NAT1*14A and cytological gradings of exfoliated urothelial cells in benzidine-exposed Chinese workers: discussion of ethnic differences

“…Aromatic amines in combustion products containing fumes are known to induce bladder cancer in experimental animals (Shirai et al 1997). During combustion or pyrolysis of plant and animal proteins, some carcinogenic compounds can also be formed (Felton et al 1994;Vineis et al 1994). Cigarette smoking is considered as one of the major risk factors for bladder cancer.…”

Bilirubin and Related Tetrapyrroles Inhibit Food-Borne Mutagenesis: A Mechanism for Antigenotoxic Action against a Model Epoxide

“…60 It is metabolized by multiple CYPs, forming a 2-hydroxyamino intermediate, mainly provoking frame-shift and base substitution mutations. 61 …”