RESUMO
The effect of Tochu tea, which is an aqueous extract of Eucommia ulmoides leaves and a popular-beverage in Japan, on the urine mutagenicity before and after ingestion of raw fish and cooked beef was studied using Salmonella typhimurium YG1024. Urines were collected from seven healthy, non-smoking Japanese women before and after ingestion of raw fish and cooked beef. In experiment 1,3 were in a control group and 4 were in a Tochu tea-drinking group (2000 ml per day). The mutagenicity of urine from the Tochu tea-drinking group was much lower. In experiment 2 the 7 women switched groups; the tea-drinking group became the control group, and the control group became the Tochu tea-drinking group. Again, the mutagenicity of urine collected from the Tochu tea-drinking group was much lower. These results suggest that the decrease in the mutagenicity of the urine from the Tochu tea-drinking group was due to the intake of Tochu tea, but not to individual differences. Thus, the ingestion of Tochu tea may reduce human exposure to dietary mutagens.