Goitrin — a nitrosatable constituent of plant foodstuffs

Summary

N-nitrosamides are known as direct-acting carcinogens at the site of their formation; they do not need any metabolic activation in vivo. The conditions leading to their formation in the stomach, and also their genotoxicity, have been thoroughly studied with some model compounds^{1, 2}. Several reports link this type of compound to the induction of gastric cancer in human^{3, 4}. However, only limited data are presently available about possible precursors of N-nitrosamides in foods. In the present study we found that goitrin — a naturally occurring compound in cruciferous vegetables and rape—could be easily nitrosated by treatment with nitrite under stomach conditions, yielding with loss of sulfur the N-nitroso-oxazolidone4 (fig.). This product has a mutagenicity pattern and potency similar to that of N-nitroso-N-methyl-N′-nitroguanidine (MNNG) in the Ames Salmonella/mammalian microsome test.