Use of 4-(nitrobenzyl)pyridine (4-NBP) to test mutagenic potential of slow-reacting epoxides, their corresponding olefins, and other alkylating agents.

Olefins and their corresponding epoxide derivatives are extensively used in industrial processes. Many epoxides are used as intermediates in organic synthesis as well as in surfactants, fumigants, industrial sterilants, cosmetics, and pharmaceuticals. These compounds pose potential hazards for biological systems where 1,2-epoxides are able to cause adverse biological effects through genetic interactions Although there are some reports that aliphatic epoxides are mutagenic agents, sufficient evidence of carcinogenicity is still lacking. However, most of bacterial mutagenicity tests have shown that aliphatic epoxides are mutagenic. Trials showing possible carcinogenicity for ethylene oxide, propylene oxide, styrene oxide, 1,2-epoxybutane have been described Studies on the mutagenicity of styrene oxide and styrene have been controversial. However, the mutagenicity of styrene oxide was found to be positive in bacteria (Sugiura and Goto 1981). Epoxy butane was shown to be mutagenic (Hardin et al 1983; Voogd et al 1981), but there exists some disagreement concerning its carcinogenicity and mutagenicity. Eugene et al (1963) first used a 4-NBP (4-(4-Nitrobenzyl)pyridine) to determine the presence of alkylating agents. Later Hammock et al (1974) and Agarwal et al (1979) studied chemical reactivity of epoxide derivatives, demonstrating that the aliphatic epoxides showed strong reactivity to 4-NBP. Nelis et al (1982) have used a standard in vitro procedure for comparing alkylating agents of bionucleophUes based on their reaction with 4-NBP. An understanding of the biochemistry of genotoxins has led to the preliminary development of a modified NBP test system (Archer and Eng 1981). However, this test system depended on the use of gaseous oxygen which made it difficult and time consuming to employ. A modified chemical activation system (CAS) employing hydrogen peroxide in place of oxygen and designed to mimic the mammalian mixed oxidase enzymes, was developed and tested in this laboratory (Mauro 1982). A mixture of hydrogen peroxide, ascorbic acid, ferrous ion, EDTA, and hydrazine in phosphate buffer was found to activate Send reprint requests to John J. Thomas at the above address.