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Evidence-Based Complementary and Alternative Medicine
Volume 2014 (2014), Article ID 150351, 5 pages
Research Article

Inhibition of Human Cytochrome P450 Enzymes by Allergen Removed Rhus verniciflua Stoke Standardized Extract and Constituents

Department of Medical Consilience, Graduate School, Dankook University, 152, Jukjeon-ro, Suji-gu, Yongin-si, Gyeonggi-do 448-701, Republic of Korea

Received 22 April 2014; Accepted 9 June 2014; Published 30 June 2014

Academic Editor: Mohamed Eddouks

Copyright © 2014 Hyunsik Jung and Sanghun Lee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. Potential interactions between herbal extracts and the cytochrome P450 (CYP) system lead to serious adverse events or decreased drug efficacy. Rhus verniciflua stoke (RVS) and its constituents have been reported to have various pharmacological properties. We evaluated the inhibitory potential of RVS and its constituents on the major CYP isoforms. Methods. The effects of allergen removed RVS (aRVS) standardized extract and major components, fustin and fisetin isolated from aRVS, were evaluated on CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 isoenzyme activity by a luminescent CYP recombinant human enzyme assay. Results. The aRVS extract showed relative potent inhibitory effects on the CYP2C9 (IC50, <0.001 μg/mL), CYP2C19 (IC50, 9.68 μg/mL), and CYP1A2 (IC50, 10.0 μg/mL). However, it showed weak inhibition on CYP3A4 and CYP2D6. Fustin showed moderate inhibitory effects on the CYP2C19 (IC50, 64.3 μg/mL) and weak inhibition of the other CYP isoforms similar to aRVS. Fisetin showed potent inhibitory effects on CYP2C9, CYP2C19, and CYP1A2. Fisetin showed moderate inhibition of CYP2D6 and weak inhibition of CYP3A4. Conclusions. These results indicate that aRVS, a clinically available herbal medicine, could contribute to herb-drug interactions when orally coadministered with drugs metabolized by CYP2C9, CYP2C19, and CYP1A2.