title: Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction.
abstract: Here we describe a liquid chromatography/mass spectrometry (LC/MS) method with automated online extraction (LC/LC/MS) to simultaneously determine the in vitro inhibitory potency of herbal extracts on six major human drug-metabolising cytochrome P450 enzymes. Substrates were incubated with a commercially available mixture of CYP1A2/2C8/2C9/2C19/2D6 and 3A4 from baculovirus-infected insect cells and the resulting metabolites were quantified with LC/LC/MS using electrospray ionisation in the selected ion monitoring mode. Consistent inhibitory activities were obtained for known inhibitors and plant extracts using the enzyme/substrate cocktail and the individual enzymes/substrates. Popular herbal remedies including devil's claw root (Harpagophytum procumbens), feverfew herb (Tanacetum parthenium), fo-ti root (Polygonum multiflorum), kava-kava root (Piper methysticum), peppermint oil (Mentha piperita), eucalyptus oil (Eucalyptus globulus), red clover blossom (Trifolium pratense) and grapefruit juice (GJ; Citrus paradisi) could be identified as inhibitors of the applied CYP enzymes with IC(50) values between 20 and 1000 microg/mL.
authors.affiliation: Institute of Pharmacy and Food Chemistry, Julius Maximilians-University Würzburg, 97074 Würzburg, Germany. m.unger@pzlc.uni-wuerzburg.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Unger
authors.forename: Andreas
authors.initials: A
authors.lastname: Frank
mesh_terms: D005591:Chemical Fractionation / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods*; D045424:Complex Mixtures / Q000032:analysis / Q000737:chemistry; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004365:Drugs, Chinese Herbal / Q000737:chemistry; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D008832:Microchemistry / Q000379:methods; D009862:Online Systems; D010936:Plant Extracts / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry*; D025941:Protein Interaction Mapping / Q000379:methods*; D015203:Reproducibility of Results; D012371:Robotics / Q000379:methods; D012680:Sensitivity and Specificity; D013379:Substrate Specificity
chemical_list: D045424:Complex Mixtures; D065607:Cytochrome P-450 Enzyme Inhibitors; D004365:Drugs, Chinese Herbal; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D003577:Cytochrome P-450 Enzyme System