The influence of ascorbic acid and DL-alpha-tocopherol on the formation of nitrosamines in an in vitro gastrointestinal model system.

The nitrosation of aminopyrine (4.3 mmol/l) and dimethylamine (4.3 mmol/l) by nitrite (4.3 mmol/l) were studied over the pH range 6-8 in a system containing bile acids and lipid. Both amines were nitrosated to form N-nitrosodimethylamine. The nitrosation of aminopyrine and, to a greater extent, dimethylamine, is enhanced by bile acids. The simultaneous incorporation of ascorbic acid (8.6 mmol/l) and dl-alpha-tocopherol (4.3 mmol/l) was found to be effective in preventing the nitrosation of these two amines. dl-alpha-Tocopheryl acetate was found to be an ineffective blocking agent in this in vitro system.