Anticarcinogenic effect of black tea on pulmonary tumors in Swiss albino mice.

The widespread consumption of tea as beverage throughout the world has stimulated interest in the possibility of its use in chemoprevention of cancer. The present set of investigation was carried out to evaluate the anticarcinogenic activity of black tea using lung tumorigenesis model in Swiss albino mice. Diethylnitrosoamine (DEN), a known inducer of pulmonary tumors was given at the multiple (total eight) doses of 20mg/kg body weight through oral intubation to Swiss albino mice. Simultaneously, three different groups of animals received 1, 2 and 4% aqueous black tea extracts (ATE) as a sole source of drinking solution. The positive control group received DEN treatment only. The animals were sacrificed after 28 weeks of the first dose of DEN. They were identified for different histological types of alveologenic pulmonary tumors. In the positive DEN treated group, higher incidences of pulmonary tumors were observed, while in ATE treated groups, a lower incidence of DEN induced lung tumorigenicity was recorded. The percentage of mice having lung tumors was decreased following ATE administration. Besides this, significant decrease in the number of tumors/mouse was observed in 2 and 4% ATE supplemented groups. The histological examination revealed a significant decrease in pulmonary adenomas at all doses of ATE. The number of animals showing pulmonary adenocarcinomas induced by DEN was found to be inhibited significantly by 4% ATE. In addition, splenomegaly was found to be protected by ATE administration.