Antioxidants as Blocking Agents Against Nitrosamine Formation

Abstract

N-nitroso compounds have been known since they were first synthesized in Germany in the mid-nineteenth century. They have been extensively used in organic synthesis, analytical chemistry and ₁ research for over a century. However, in 1954, Barnes and Magee found that dimethylnitrosamine (DMN) produced liver toxicity in two men in the UK. Similarly, an outbreak of acute liver toxicity in sheep in Norway was traced to the formation of DMN in fish meal preserved by nitrite.² These events prompted the early synthetic investigations of the N-nitroso compounds, particularly by groups headed by Magee in the UK and US, and Druckrey in Germany. Their work, and that of others, rapidly showed that the N-nitroso compounds, as a group, had enormous potential for carcinogenesis. This, in turn, has led to the current deep scientific interest in the analysis, formation, and occurrence of carcinogenic N-nitroso compounds in our food supply, polluted atmosphere, drinking water, beverages, cigarette smoke, cosmetics, industrial waste and by-products, and more recently to their formation in vivo.^3,4,5 It is the intention of this paper to survey several aspects of these studies and address the use of ascorbic acid and alpha-tocopherol as blocking agents to prevent the formation of these potential human carcinogens.