A Combination of Tea (Camellia senensis) Catechins Is Required for Optimal Inhibition of Induced CYP1A Expression by Green Tea Extract
- 19 September 2003
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of Agricultural and Food Chemistry
- Vol. 51 (22), 6627-6634
- https://doi.org/10.1021/jf030181z
Abstract
It was previously demonstrated that the commercial green tea extract Polyphenon 100 (P100), and to a lesser extent (-)-epigallocatechin-3-gallate (EGCG), partially antagonizes 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced transcription of human CYP1A1 (Williams, S. N.; Shih, H.; Guenette, D. K.; Brackney, W.; Denison, M. S.; Pickwell, G. V.; Quattrochi, L. C. Chem.-Biol. Interact. 2000, 128, 211-229). Here, P100 is compared to a reconstituted mixture of the four major tea catechins (referred to as P100R) to determine whether inhibition was due to additional polyphenols in the extract or from synergistic interactions among the tea catechins. It was found that cotreatment of cells with TCDD and either P100 or P100R inhibited TCDD-induced CYP1A promoter-driven luciferase reporter activity (HepG2 cells) and CYP1A expression (HepG2 and primary human hepatocytes), similarly. These results indicate that modulation of human CYP1A expression by P100 can be attributed entirely to the combination of the four tea catechins. These findings may be important in the evaluation of future chemoprevention strategies using green tea and single catechin agents.This publication has 13 references indexed in Scilit:
- Human hepatocyte culture systems for the in vitro evaluation of cytochrome P450 expression and regulationEuropean Journal of Pharmaceutical Sciences, 2001
- Aflatoxin and liver cancerBest Practice & Research Clinical Gastroenterology, 1999
- Effects of chemoprotective agents on the metabolic activation of the carcinogenic arylamines PhIP and 4‐aminobiphenyl in human and rat liver microsomesNutrition and Cancer, 1999
- Green tea and cancer in humans: A review of the literatureNutrition and Cancer, 1998
- The Kinetics of Aflatoxin B1Oxidation by Human cDNA-Expressed and Human Liver Microsomal Cytochromes P450 1A2 and 3A4Toxicology and Applied Pharmacology, 1996
- Tea polyphenols as inhibitors of mutagenicity of major classes of carcinogensMutation Research/Genetic Toxicology, 1996
- Role of Human Cytochromes P450 in the Metabolic Activation of Chemical Carcinogens and ToxinsDrug Metabolism Reviews, 1994
- Response of Human CYP1-Luciferase Plasmids to 2,3,7,8-Tetrachlorodibenzo-p-dioxin and Polycyclic Aromatic HydrocarbonsToxicology and Applied Pharmacology, 1993
- Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extractionAnalytical Biochemistry, 1987
- Rapid colorimetric assay for cellular growth and survival: Application to proliferation and cytotoxicity assaysJournal of Immunological Methods, 1983