Suppression of genotoxicity of carcinogens by (-)-epigallocatechin gallate.
Epidemiological evidence shows that green tea may be a factor in lowering cancer risk. We have investigated the possibility that (-)-epigallocatechin gallate (EGCG), a major polyphenol in green tea, might be an antimutagenic substance. In the Ames Salmonella test, EGCG suppressed the direct-acting mutagenicity of 3-hydroxyamino-1-methyl-5H-pyrido-[4,3-b]indole (Trp-P-2(NHOH)) and 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1(NHOH)), the activated forms of food-derived carcinogens 3-amino-1-methyl-5H-pyrido[4,3-b]indole and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole. EGCG was also effective in reducing the mutagenicity of Trp-P-2(NHOH) in mouse FM3A cells in culture. Furthermore, EGCG demonstrated a suppressive effect in the in vivo Drosophila mutation assays, i.e., the wing spot test, and the DNA repair test, on several carcinogens. EGCG was also effective in inhibiting DNA single-strand breaks in vitro caused by Glu-P-1(NHOH). We conclude that the mechanism of inhibition may not have resulted from direct interaction between EGCG and the mutagens, but rather from indirect interception of mutagen action by EGCG.
Hayatsu
H
H
Faculty of Pharmaceutical Sciences, Okayama University, Japan.
Inada
N
N
Kakutani
T
T
Arimoto
S
S
Negishi
T
T
Mori
K
K
Okuda
T
T
Sakata
I
I
D000818:Animals; D016587:Antimutagenic Agents / Q000032:analysis / Q000494:pharmacology*; D015197:Carcinogenicity Tests; D002392:Catechin / Q000031:analogs & derivatives* / Q000032:analysis / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects*; D005419:Flavonoids; D051379:Mice; D010636:Phenols / Q000032:analysis; D011108:Polymers / Q000032:analysis; D013662:Tea / Q000737:chemistry
D016587:Antimutagenic Agents; D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate