title: Inhibitory effect(s) of polymeric black tea polyphenols on the formation of B(a)P-derived DNA adducts in mouse skin.
abstract: The biological activities and chemopreventive properties of green tea polyphenols have been demonstrated, while similar information regarding newly formed major polymeric polyphenols in black tea are not available. Cancer chemoprevention may be achieved by the inhibition of any stage of carcinogenesis. In the present study, we investigated the anti-initiating effects of five polymeric black tea polyphenol (PBP) fractions, by determining their effects on the formation of [3H]-B(a)P-derived DNA adducts as well as the activity of cytochrome P-450 isozymes CYP 1A1 and 1A2 in vitro employing rat liver microsomes. PBP 1-3 inhibited both the microsome catalyzed [3H]-B(a)P-derived DNA adduct formation as well as the activity of CYP 1A1 and 1A2 as assessed by the decreased formation of resorufin from the respective substrates. Further investigation revealed that topical pretreatment(s) of mice with PBP 1-5 (200 mug/day x 4) resulted in a significant decrease in the levels of single topical B(a)P (1 mg/mouse) - induced DNA adducts in epidermal DNA determined by employing 32P-post labeling analysis. Overall, our results suggest that black tea-derived PBPs have one of the chemopreventive properties shown by monomeric green tea polyphenols.
authors.affiliation: Tobacco Carcinogenesis Group, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410 208, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Krishnan
authors.forename: Girish B
authors.initials: GB
authors.lastname: Maru
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D001345:Autoradiography; D001564:Benzo(a)pyrene / Q000737:chemistry; D002110:Caffeine / Q000302:isolation & purification; D028241:Camellia sinensis; D019363:Cytochrome P-450 CYP1A1 / Q000037:antagonists & inhibitors; D065609:Cytochrome P-450 CYP1A2 Inhibitors; D018736:DNA Adducts / Q000096:biosynthesis* / Q000737:chemistry; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D010636:Phenols / Q000302:isolation & purification / Q000494:pharmacology*; D010761:Phosphorus Radioisotopes; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D059808:Polyphenols; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D013662:Tea / Q000737:chemistry*; D014316:Tritium
chemical_list: D016588:Anticarcinogenic Agents; D065609:Cytochrome P-450 CYP1A2 Inhibitors; D018736:DNA Adducts; D005419:Flavonoids; D010636:Phenols; D010761:Phosphorus Radioisotopes; D010936:Plant Extracts; D059808:Polyphenols; D013662:Tea; D014316:Tritium; D001564:Benzo(a)pyrene; D002110:Caffeine; D019363:Cytochrome P-450 CYP1A1