| Interaction of epicatechins derived from green tea with rat hepatic cytochrome P-450. | |
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MedLine Citation:
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PMID: 2894963 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Green tea has been used for generations in China and Asia as an antipyretic and diuretic. Prior studies have shown that extracts of green tea inhibit the mutagenicity of polycyclic aromatic hydrocarbons and aflatoxin B1. In this study, we investigated the interaction of certain flavonoid components of green tea epicatechin derivatives including (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin-3-gallate (ECG), and (-)-epigallocatechin-3-gallate (EGCG) with rat hepatic microsomal cytochrome P-450 (P-450). The addition of EC, EGC, ECG, and EGCG to hepatic microsomes prepared from phenobarbital (PB)-treated rats resulted in spectral changes characterized by absorbance maxima at 420 nm and minima at 380 nm, typical of modified Type II (reverse Type I) binding. Of the epicatechin derivatives, EGCG and ECG showed greater spectral change with oxidized P-450 and time- and concentration-dependent inhibition of the binding of carbon monoxide to dithionite-reduced cytochrome P-450. The addition of EC, EGC, ECG, and EGCG to microsomes prepared from control, PB- or 3-methylcholanthrene-treated rats resulted in a dose-dependent inhibition of cytochrome P-450-dependent aryl hydrocarbon hydroxylase, 7-ethoxycoumarin O-deethylase, and 7-ethoxyresorufin O-deethylase activities. EGCG was the most potent in this regard. Green tea polyphenols and epicatechin derivatives also significantly inhibited NADPH-cytochrome c reductase activity. An examination of the structure activity relationship of epicatechin derivatives suggests that the inhibitory effect on the microsomal enzyme system may be due to the galloyl groups or hydroxyl groups on the molecule. Our data indicate that these extracts of green tea may have potential as anticarcinogens. |
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Authors:
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Z Y Wang; M Das; D R Bickers; H Mukhtar |
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Publication Detail:
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Type: In Vitro; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Drug metabolism and disposition: the biological fate of chemicals Volume: 16 ISSN: 0090-9556 ISO Abbreviation: Drug Metab. Dispos. Publication Date: 1988 Jan-Feb |
Date Detail:
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Created Date: 1988-04-27 Completed Date: 1988-04-27 Revised Date: 2009-11-19 |
Medline Journal Info:
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Nlm Unique ID: 9421550 Medline TA: Drug Metab Dispos Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 98-103 Citation Subset: IM |
Affiliation:
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Department Dermatology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Binding, Competitive Carbon Monoxide / metabolism Catechin / pharmacology* Cytochrome P-450 Enzyme System / metabolism* Epoxide Hydrolases / metabolism Guanosine Triphosphate / metabolism Liver / enzymology* Male Microsomes, Liver / metabolism NADPH-Ferrihemoprotein Reductase / metabolism Rats Rats, Inbred Strains Tea / analysis* |
| Grant Support | |
ID/Acronym/Agency:
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AM34368/AM/NIADDK NIH HHS; CA-38028/CA/NCI NIH HHS; ES-1900/ES/NIEHS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Tea; 154-23-4/Catechin; 630-08-0/Carbon Monoxide; 86-01-1/Guanosine Triphosphate; 9035-51-2/Cytochrome P-450 Enzyme System; EC 1.6.2.4/NADPH-Ferrihemoprotein Reductase; EC 3.3.2.-/Epoxide Hydrolases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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