Effects of Repeated Green Tea Catechin Administration on Human Cytochrome P450 Activity
| Autor: | James A. Crowell, Min-Jian Xu, David S. Alberts, H-H. Sherry Chow, Chiu Hsieh Hsu, Donna R. Vining, Wade M. Chew, James Ranger-Moore, Iman A. Hakim, Catherine A. Cordova |
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| Rok vydání: | 2006 |
| Předmět: |
Adult
Male Epidemiology Metabolite Administration Oral Pharmacology Epigallocatechin gallate complex mixtures Camellia sinensis Catechin chemistry.chemical_compound Cytochrome P-450 Enzyme System Cytochrome P-450 CYP3A Cytochrome P-450 Enzyme Inhibitors Humans Medicine CYP2C9 Aged Tea CYP3A4 business.industry CYP1A2 food and beverages Middle Aged Bioavailability Cytochrome P-450 CYP2D6 Oncology chemistry Female business Caffeine |
| Zdroj: | Cancer Epidemiology, Biomarkers & Prevention. 15:2473-2476 |
| ISSN: | 1538-7755 1055-9965 |
| Popis: | Purpose: Preclinical studies suggested that green tea or green tea catechins can modulate the activities of drug-metabolizing enzymes. We conducted this clinical study to determine the effect of repeated green tea catechin administration on human cytochrome P450 (CYP) enzyme activities. Methods: Forty-two healthy volunteers underwent a 4-week washout period by refraining from tea or tea-related products. At the end of the washout period, study participants received a cocktail of CYP metabolic probe drugs, including caffeine, dextromethorphan, losartan, and buspirone for assessing the activity of CYP1A2, CYP2D6, CYP2C9, and CYP3A4, respectively. Blood and urine samples before and 8 h after probe drug administration were collected to determine parent drug and metabolite concentrations for measurements of baseline CYP enzyme activities. Following the baseline evaluation, study participants underwent 4 weeks of green tea catechin intervention at a dose that contains 800 mg epigallocatechin gallate (EGCG) daily. The green tea catechin product was taken on an empty stomach to optimize the p.o. bioavailability of EGCG. The EGCG dose given in this study exceeded the amounts provided by average green tea consumption. Upon completion of the green tea catechin intervention, the postintervention CYP enzyme activities were evaluated as described above. Results: There are large between-subject variations in CYP enzyme activities in healthy individuals. Four weeks of green tea catechin intervention did not alter the phenotypic indices of CYP1A2, CYP12D6, and CYP12C9, but resulted in a 20% increase (P = 0.01) in the area under the plasma buspirone concentration-time profile, suggesting a small reduction in CYP3A4 activity. Conclusions: We conclude that repeated green tea catechin administration is not likely to result in clinically significant effects on the disposition of drugs metabolized by CYP enzymes. (Cancer Epidemiol Biomarkers Prev 2006;15(12):2473–6) |
| Databáze: | OpenAIRE |
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