Chinese tea inhibits the occurrence of oesophageal tumours induced by N-nitrosomethylbenzylamine and blocks its formation in rats.

Chinese tea can inhibit the occurrence of oesophageal tumours not only by blocking the formation of N-nitrosomethylbenzylamine (NMBzA) in vivo, but also by inhibiting the carcinogenesis of preformed NMBzA. The incidence of oesophageal tumours in rats intubated with preformed NMBzA (5 mg/kg bw per week) and with the precursors of NMBzA (methylbenzylamine, 1 mM/kg bw; nitrite, 0.5 mM/kg bw) without Chinese tea was higher than in tea-treated groups; the same tendency was found with regard to the severity of the oesophageal lesions. The anticarcinogenic effects of five varieties of Chinese tea were different from one another.