Inhibition of 1,2-dimethylhydrazine-induced oxidative DNA damage in rat colon mucosa by black tea complex polyphenols

• Published in: Food and chemical toxicology Vol. 38; no. 12; pp. 1085 - 1088
• Main Authors: Lodovici, M, Casalini, C, De Filippo, C, Copeland, E, Xu, X, Clifford, M, Dolara, P
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2000; New York, NY Elsevier Science
• Subjects: 1,2-Dimethylhydrazine - toxicity; 2-dimethylhydrazine; 8-hydroxy-2′-deoxyguanosine; Alkylating Agents - toxicity; Animals; Antioxidants - pharmacology; Biological and medical sciences; black tea; Carcinogenesis, carcinogens and anticarcinogens; Carcinogens - toxicity; Catechin - analogs & derivatives; Catechin - pharmacology; Chromatography, High Pressure Liquid; Colonic Neoplasms - chemically induced; Colonic Neoplasms - prevention & control; Deoxyguanosine - analogs & derivatives; Deoxyguanosine - analysis; DNA Damage - drug effects; Flavonoids; Foods and miscellaneous; Intestinal Mucosa - drug effects; Male; Medical sciences; oxidative DNA damage; oxygen radicals; Phenols - pharmacology; Phytotherapy; Polymers - pharmacology; Polyphenols; Rats; Rats, Inbred F344; Tea - chemistry; Tea - therapeutic use; theafulvin; thearubigin; Tumors; polyphenols; 2-dimethylhydrazine; TFu; oxidative DNA damage; 8-hydroxy-2′-deoxyguanosine; oxygen radicals; 1; 2dG; theafulvin; thearubigin; DMH; TR; 8-OHdG; Rat; Rodentia; Malignant tumor; Anticarcinogen; Antioxidant; Biological activity; Colonic disease; Tea; Vertebrata; Polyphenol; Mammalia; Animal; DNA; Plant origin; Digestive diseases; Intestinal disease; Colon; Mechanism of action
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/S0278-6915(00)00109-5

The effect of black tea polyphenols on 1,2-dimethylhydrazine (DMH)-induced oxidative DNA damage in rat colon mucosa has been investigated. Fischer 344 rats were treated orally with thearubigin (TR) or theafulvin (TFu) for 10 days (40 mg/kg), injected ip with DMH (20 mg/kg) or saline and sacrificed 24 hr after DMH administration. The levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG) were measured in colonic mucosa DNA and expressed as a ratio relative to 2′-deoxyguanosine (2dG). Control rat mucosa had 8-OHdG values of 1.12 ± 0.14/10 5 dG (mean ± SEM, n=11), whereas DMH-treated rats significantly higher values (1.52 ± 0.14/10 5 dG, n=26, P<0.05). Pretreatment of rats with TR had significantly inhibited DMH-induced oxidative DNA damage 0.99 ± 0.09/10 5 dG, n=10, P<0.05) and a similar, although less marked, effect was observed with TFu (1.15 ± 0.19/10 5, n=9, P=0.06). These findings confirm that DMH causes oxidative DNA damage in the colon mucosa of rats and demonstrate that this effect is prevented by the consumption of complex polyphenols from black tea.