4-Methoxyindole derivatives as nitrosable precursors of mutagens in Chinese cabbage

Two indole compounds isolated from fresh Chinese cabbage wereshown to be mutagen precursors that yielded direct-acting mutagenson treatment with nitrite. They were identified as 4-methoxyindole-3-acetonitrileand 4-methoxy-indole-3-aldehyde. When these compounds were treatedwith 50 mM nitrite at pH 3.0 for 1 h at 37°C, 4-methoxyindole-3-acetonitrileinduced 31 800 and 10 000 revertants of Salmonella typhimuriumTA100 and TA98, respectively, per mg of mutagen precursor inthe absence of S9 mix, and 4-meth-oxyindole-3-aldehyde induced156 900 revertants of TA100 and 26 800 revertants of TA98 permg in the absence of S9 mix.