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 carcinogenesis was investigated. A total of 129 female F344 rats were given an intrarectal instillation of 2 mg of N-methyl-N-nitrosourea 3 times a week for 2 weeks, and received a water solution of green tea extract (GTE) as drinking water throughout the experiment. Autopsies at week 35 revealed significantly lower incidence of colon carcinomas in rats ingesting 0.05%, 0.01% or 0.002% GTE solution than in controls ingesting 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 inhibitory effect on colon carcinogenesis.
Narisawa
T
T
Akita University College of Allied Medical Science.
Fukaura
Y
Y
D000818:Animals; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D004326:Drinking; D005260:Female; D005419:Flavonoids; D008770:Methylnitrosourea / Q000633:toxicity*; D010636:Phenols / Q000008:administration & dosage / Q000494:pharmacology*; D011108:Polymers / Q000008:administration & dosage / Q000494:pharmacology*; D059808:Polyphenols; D051381:Rats; D011916:Rats, Inbred F344; D013662:Tea / Q000737:chemistry*
D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D059808:Polyphenols; D013662:Tea; D008770:Methylnitrosourea