Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 375, Issue 6, pp 377–382

Variability in PXR-mediated induction of CYP3A4 by commercial preparations and dry extracts of St. John’s wort

  • Ute Gödtel-Armbrust
  • Annegret Metzger
  • Ulrike Kroll
  • Olaf Kelber
  • Leszek Wojnowski
Original Article

DOI: 10.1007/s00210-007-0172-8

Cite this article as:
Gödtel-Armbrust, U., Metzger, A., Kroll, U. et al. Naunyn-Schmied Arch Pharmacol (2007) 375: 377. doi:10.1007/s00210-007-0172-8

Abstract

St. John’s wort (SJW, Hypericum perforatum) is a well-tolerated herbal medicine widely used for the treatment of mild and moderate depressions. In the last 5 years, SJW has been implicated in drug interactions, which are largely mediated by the induction of the drug metabolizing enzymes, especially CYP3A4. There is still some controversy regarding the exact mechanism of induction and the identity of the SJW constituents involved. We investigated in LS174T cells the induction of CYP3A4 by ten SJW extracts, six commercial preparations, and the purified SJW constituent hyperforin. The content of hyperforin among the commercial preparations of SJW varied 62-fold (range 0.49–30.57 mg/dose). The CYP3A4 induction was mediated by PXR, but not by CAR. The magnitude of the induction correlated statistically significantly with the content of hyperforin in commercial SJW preparations (R = 0.87, p = 0.004) and in dry extracts (R = 0.65, p = 0.03), but not with their content of flavonoids or hypericin. Most of the CYP3A4 induction response occurred in the hyperforin range encountered in the blood of patients treated with SJW preparations. A temperature-induced decrease in the hyperforin content of a selected dry SJW extract abolished the induction of CYP3A4. In conclusion, commercial SJW preparations still exhibit an enormous variability in CYP3A4 induction, which is mediated by hyperforin and PXR. SJW preparations with lower hyperforin content should reduce the frequency of clinical interactions involving this herbal drug.

Keywords

St. John’s wortHyperforinInductionCYP3A4CYP3APXRCARDrug interactions

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Ute Gödtel-Armbrust
    • 1
  • Annegret Metzger
    • 1
  • Ulrike Kroll
    • 2
  • Olaf Kelber
    • 2
  • Leszek Wojnowski
    • 1
  1. 1.Institut für PharmakologieJohannes Gutenberg UniversitätMainzGermany
  2. 2.Wissenschaftliche AbteilungSteigerwald Arzneimittelwerk GmbHDarmstadtGermany