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1. Phytother Res. 2012 Feb 8. doi: 10.1002/ptr.4619. [Epub ahead of print]

In vitro Inhibition of CYP3A4 by the Multiherbal Commercial Product Sambucus
Force and its Main Constituents Echinacea purpurea and Sambucus nigra.

Schrøder-Aasen T, Molden G, Nilsen OG.

Department of Cancer Research and Molecular Medicine, Faculty of Medicine,
Norwegian University of Science and Technology (NTNU), Norway.
torsth@alumni.ntnu.no.

The multiherbal product Sambucus Force contains Echinacea purpurea and Sambucus
nigra as its main constituents. The aims of this study were to evaluate Sambucus
Force's inhibition potential and inhibition mechanisms towards CYP3A4, and to
evaluate the inhibitory co-contribution of E. purpurea and S. nigra. Metabolic
studies were performed with recombinant human CYP3A4, with testosterone as
substrate. Sambucus Force inhibited CYP3A4 activity with a mean (95% confidence
interval) half maximal inhibitory concentration (IC(50) ) value of 1192
(1091-1302) µg/mL. The inhibitory potency seems exclusively to be exerted by E.
purpurea, implicating an insignificant inhibition by S. nigra. The inhibition by
E. purpurea as a single herb was in agreement with mechanism-based inhibition
with heterotropic positive cooperative effects. Echinacea purpurea acted
differently in the multiherbal product, which showed a dual inhibition profile
with both an uncompetitive (substrate-dependent) inhibition and a time-dependent
(substrate-independent) inhibitory mechanism. These mechanistic differences are
suggested to be caused by herb-herb interactions in the multiherbal product. The
CYP3A4 inhibition of Sambucus Force in vitro is considered relatively weak, but
recommended high herbal dosages might enhance the potential for clinical
interactions. Copyright © 2012 John Wiley & Sons, Ltd.

Copyright © 2012 John Wiley & Sons, Ltd.

PMID: 22319006 [PubMed - as supplied by publisher]