Effects of tea decoctions on the mutagenicity of 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid treated with nitrite in the presence of ethanol

It was found that the mutagenicity of 1-methyl-1,2,3,4-terrahydro-beta-carboline-3-carboxylic acid (MTCCA) treated with 50 mM nitrite at pH 3, 37 degrees C for 60 min in the presence of 7.5% ethanol was strongly reduced upon adding the decoctions of green, black and oolong teas in reaction mixture with the Ames Salmonella mutagenicity test. The antimutagenicity and reducing power, which were determined of tea decoctions, gave a positive correlation, suggesting that reducing compounds, such as catechins contained in the teas, may play a significant role in the mutagenicity-reducing activity.