Co-mutagenic effect of norharman with N-nitrosamine derivatives.

The mutagenicities of 14 nitrosamine compounds were tested on Salmonella typhimurium TA98 and TA100 in the presence of the co-mutagen norharman. N-Nitrosophenyl compounds, such as N,N-diphenylnitrosamine, N-methyl-N-phenylnitrosamine, N-ethyl-N-phenylnitrosamine and N-phenyl-N-benzylnitrosamine, were mutagenic when norharman was added to the incubation mixture, but not mutagenic in its absence. Norharman did not enhance the mutagenic activities of N-nitrosoaliphatic compounds.