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Effect of tea beverages on aldehyde oxidase activity
Yoshitaka Tayama1, Kazumi Sugihara, Seigo Sanoh
1Faculty of Pharmaceutical Science, Hiroshima International University, Hiroshima, Japan. y-tayama@ps.hirokoku-u.ac.jp
Drug Metabolism and Pharmacokinetics
|November 19, 2010
Summary
Green tea beverages significantly inhibit aldehyde oxidase (AO) activity, primarily due to catechins. This suggests tea consumption may affect the metabolism and clearance of drugs processed by AO.
Area of Science:
- Pharmacology
- Biochemistry
- Drug Metabolism
Background:
- Aldehyde oxidase (AO) is crucial for metabolizing drugs like methotrexate, cyclophosphamide, and acyclovir.
- Green tea and its catechins are known modulators of cytochrome P450 enzymes, but their impact on AO remains uninvestigated.
Purpose of the Study:
- To assess the effect of green tea beverages and catechins on aldehyde oxidase (AO) activity in rat and human liver cytosol.
- To understand the potential implications for drug metabolism and clearance.
Main Methods:
- AO activity was measured by quantifying the oxidation of N-1-methylnicotinamide.
- Incubation of rat and human liver cytosol with varying concentrations of bottled green tea beverages and specific catechins.
- Comparison with mineral water as a control.
Main Results:
- Bottled green tea beverages potently inhibited AO activity, with reductions ranging from 73.9% to 93.5% depending on concentration.
- Green tea II and III demonstrated significant inhibition (24.3% and 38.8%) at 0.1% concentration.
- Epicatechin and epicatechin gallate were identified as potent AO inhibitors, indicating catechins are the primary drivers of inhibition.
- Mineral water showed no effect on AO activity.
Conclusions:
- The inhibitory effect of green tea beverages on AO activity is mainly attributed to its catechin content.
- Consumption of green tea may lead to decreased AO activity, potentially altering the metabolic clearance of drugs that are AO substrates.
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