Inhibitory Effects of (−)-Epigallocatechin Gallate on the Mutation, DNA Strand Cleavage, and DNA Adduct Formation by Heterocyclic Amines

• Published in: Journal of agricultural and food chemistry Vol. 51; no. 17; pp. 5150 - 5153
• Main Authors: Arimoto-Kobayashi, Sakae, Inada, Naomi, Sato, Yasuko, Sugiyama, Chitose, Okamoto, Keinosuke, Hayatsu, Hikoya, Negishi, Tomoe
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 13.08.2003
• Subjects: Animals; Camellia sinensis - chemistry; Catechin - analogs & derivatives; Catechin - pharmacology; chemoprevention; circular DNA; DNA Adducts - metabolism; DNA damage; DNA Damage - drug effects; Drosophila; Drosophila - genetics; genotoxicity; green tea; heterocyclic amines; Heterocyclic Compounds - pharmacology; Hot Temperature; Imidazoles - pharmacology; Mutagenesis; mutagenicity; Mutagens - pharmacology; mutation; Plant Extracts - chemistry; Plant Leaves - chemistry; Quinolines - pharmacology
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0302761

Green tea is known to be a potential chemopreventive agent against cancer. In this study, we investigated the inhibitory activities of tea extracts, and in particular the polyphenolic component (−)-epigallocatechin gallate (EGCG), against heterocyclic amine-induced genotoxicity. The tea extracts displayed inhibition of 2-hydroxyamino-6-methyldipyrido[1,2-a,3‘,2‘-d]imidazole (Glu-P-1(NHOH))-induced mutagenicity. This inhibition can be accounted for by the presence of EGCG in the extracts. The mutagenic effect of Glu-P-1(NHOH), which induces single-strand cleavage in supercoiled circular DNA under neutral conditions, was inhibited by EGCG. Using the Drosophila repair test, a test for gross DNA damage, and DNA adduct detection by 32P-postlabeling, we showed that EGCG prevented 2-amino-3,8-dimethylimidazo[4,5-f]quinoline-induced DNA damage and adduct formation in insect DNA. EGCG was found to accelerate the degradation of Glu-P-1(NHOH) in vitro. This observation suggested that the inhibition by EGCG is associated with an accelerated degradation of metabolically activated heterocyclic amines. Keywords: Green tea; epigallocatechin gallate; heterocyclic amines; DNA strand break; antimutagenicity; DNA adduct; Drosophila