Protective effects of green tea polyphenols administered by oral intubation against chemical carcinogen-induced forestomach and pulmonary neoplasia in A/J mice.
Our studies and others have shown the cancer chemopreventive effects of chronic administration of green tea in several animal tumor models. In this study, the administration of a polyphenolic fraction isolated from green tea (GTP) by oral intubation at a dose of 5 mg in 0.2 ml water 30 min prior to challenge with carcinogen, afforded significant protection against both diethylnitrosamine (DEN)- and benzo(a)pyrene (BP)-induced forestomach and lung tumorigenesis in A/J mice. The protective effects were evident by a decrease in numbers of tumors/mouse in GTP-fed groups compared to non GTP-fed controls. In the forestomach tumorigenesis protocol, GTP afforded 71 and 66% protection against, respectively DEN- and BP-induced tumor multiplicity. In the case of lung tumorigenesis protocol, however, the protective effects of GTP were 41 and 39%, respectively. Histological examination of forestomach tumors showed significantly lesser number of squamous cell carcinoma formation in GTP-fed groups of mice compared to carcinogen alone-treated controls. When pulmonary tumors were examined histologically, no adenocarcinomas were observed in GTP-fed groups compared to 15% mice with adenocarcinomas in DEN and BP alone-treated controls. The results of this study suggest that limited doses of GTP administration by gavage 30 min prior to carcinogen challenge may afford protection against carcinogen-induced tumorigenesis in internal body organs.
Katiyar
S K
SK
Department of Dermatology, University Hospitals of Cleveland, Case Western Reserve University, OH 44106.
Agarwal
R
R
Mukhtar
H
H
D000284:Administration, Oral; D000818:Animals; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D001564:Benzo(a)pyrene; D004052:Diethylnitrosamine; D005260:Female; D005419:Flavonoids; D008175:Lung Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D051379:Mice; D008805:Mice, Inbred A; D010636:Phenols / Q000627:therapeutic use*; D010936:Plant Extracts / Q000627:therapeutic use*; D011108:Polymers / Q000627:therapeutic use*; D059808:Polyphenols; D013274:Stomach Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D013662:Tea
D016588:Anticarcinogenic Agents; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D011108:Polymers; D059808:Polyphenols; D013662:Tea; D001564:Benzo(a)pyrene; D004052:Diethylnitrosamine