Document Detail

Green tea (Camellia sinensis) extract does not alter cytochrome p450 3A4 or 2D6 activity in healthy volunteers.
MedLine Citation:
PMID:  15319329     Owner:  NLM     Status:  MEDLINE    
Green tea extract is a widely used dietary supplement. The objective of this study was to assess the influence of a decaffeinated green tea (DGT; Camellia sinensis) extract on the activity of the drug-metabolizing enzymes cytochrome P-450 2D6 and 3A4. Probe drugs dextromethorphan (30 mg, CYP2D6 activity) and alprazolam (ALPZ; 2 mg, CYP3A4 activity) were administered orally to healthy volunteers (n = 11) at baseline, and again after treatment with four DGT capsules/day for 14 days. Each DGT capsule contained 211 +/- 25 mg of green tea catechins and <1 mg of caffeine. Dextromethorphan metabolic ratios (DMRs) and alprazolam pharmacokinetics were determined at baseline and after DGT treatment. There were no significant differences in ALPZ pharmacokinetics at baseline and after DGT treatment (all P values >/= 0.05; maximum concentration in plasma, 33 +/- 8 versus 34 +/- 13 ng/ml; time to reach maximum concentration in plasma, 1.4 +/- 1.2 versus 1.4 +/- 1.2 h; area under the plasma concentration versus time curve, 480 +/- 119 versus 510 +/- 107 h. ng. ml(-1); half-life of elimination, 12.3 +/- 1.7 versus 13.1 +/- 3.4 h). The DMR was 0.053 +/- 0.045 at baseline and 0.041 +/- 0.032 after DGT supplementation (P > 0.05). The plasma concentration of the green tea flavonoid, (-)-epigallocatechin gallate, reached 1.3 +/- 1.8 microM 2 h after DGT treatment. Our results indicate that DGT is unlikely to alter the disposition of medications primarily dependent on the CYP2D6 or CYP3A4 pathways of metabolism.
Jennifer L Donovan; Kenneth D Chavin; C Lindsay Devane; Robin M Taylor; Jun-Sheng Wang; Ying Ruan; John S Markowitz
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Drug metabolism and disposition: the biological fate of chemicals     Volume:  32     ISSN:  0090-9556     ISO Abbreviation:  Drug Metab. Dispos.     Publication Date:  2004 Sep 
Date Detail:
Created Date:  2004-08-20     Completed Date:  2005-06-23     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9421550     Medline TA:  Drug Metab Dispos     Country:  United States    
Other Details:
Languages:  eng     Pagination:  906-8     Citation Subset:  IM    
Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston 29425, USA.
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MeSH Terms
Administration, Oral
Alprazolam / administration & dosage,  blood,  pharmacokinetics
Camellia sinensis / chemistry*
Catechin / analogs & derivatives*,  blood,  chemistry,  pharmacology*
Cytochrome P-450 CYP2D6 / physiology*
Cytochrome P-450 CYP3A
Cytochrome P-450 Enzyme System / physiology*
Dextromethorphan / administration & dosage,  blood,  pharmacokinetics
Dietary Supplements / analysis
Drug Administration Schedule
Plant Extracts / chemistry,  metabolism,  pharmacology*
Plant Leaves / chemistry
Time Factors
Grant Support
Reg. No./Substance:
0/Capsules; 0/Plant Extracts; 125-71-3/Dextromethorphan; 154-23-4/Catechin; 28981-97-7/Alprazolam; 9035-51-2/Cytochrome P-450 Enzyme System; 989-51-5/epigallocatechin gallate; EC protein, human; EC protein, human; EC P-450 CYP2D6; EC P-450 CYP3A
Erratum In:
Drug Metab Dispos. 2004 Nov;32(11):1331

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