European Journal of Clinical Pharmacology

, Volume 74, Issue 9, pp 1189–1190 | Cite as

Response: Similar effect of quercetin on CYP2E1 and CYP2C9 activities in humans?

  • Satish Kumar BedadaEmail author
  • Prasad Neerati
Letter to the Editor

Dear Editor,

We thank Shingen Misaka and Kenju Shimomura for their interest in our recent article [1]. We recognize their comments and would like to answer in the following way.

The published study results suggest that treatment with quercetin 500 mg twice daily for 10 days significantly enhanced the exposure of chlorzoxazone, a CYP2E1 substrate, in healthy subjects [1]. We had used the same study design in another study with different subjects reported from our lab [2]. In this study, quercetin treatment significantly enhanced the exposure of diclofenac, a CYP2C9 substrate, in heathy volunteers. Although the study design is identical in two studies, the obtained plasma concentrations and pharmacokinetic parameters of chlorzoxazone are different when compared with that of diclofenac. Moreover, our results are consistent with previously published healthy volunteer studies [3, 4, 5, 6]. Further, the results obtained from two studies with different subjects indicate that quercetin...


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Drug Metabolism and Pharmacokinetics Division, University College of Pharmaceutical SciencesKakatiya UniversityWarangalIndia

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