A VERY-LOW DOSE OF GREEN TEA POLYPHENOLS IN DRINKING-WATER PREVENTS N-METHYL-N-NITROSOUREA-INDUCED COLON CARCINOGENESIS IN F344 RATS

The effect of tea polyphenols, major constituents of tea, on colon car cinogenesis was investigated. A total of 129 female F344 rats were giv en an intrarectal instillation of 2 mg of N-methyl-N-nitrosourea 3 tim es a week for 2 weeks, and received a water solution of green tea extr act (GTE) as drinking water throughout the experiment. Autopsies at we ek 35 revealed significantly lower incidence of colon carcinomas in ra ts ingesting 0.05%, 0.01% or 0.002% GTE solution than in controls inge sting 0% GTE solution: 43%, 40% and 33% vs. 67%. The data suggest that GTE, even at a very low dose (0.002% solution), has a potent inhibito ry effect on colon carcinogenesis.