title: Ginkgo biloba does not alter clearance of flurbiprofen, a cytochrome P450-2C9 substrate.
abstract: The effect of Ginkgo biloba on the activity of CYP2C9, the isoform responsible for S-warfarin clearance, was assessed in 11 healthy volunteers who received single 100-mg doses of flurbiprofen, a probe substrate for CYP2C9. Subjects also received either a standardized G biloba leaf preparation (Ginkgold, 3 doses of 120 mg) or matching placebo in a randomized, double-blind, 2-way crossover study. Mean kinetic variables for flurbiprofen with either placebo or G biloba were elimination half-life, 3.9 versus 3.5 hours; total AUC, 57 versus 55 microg/mL h; and oral clearance, 32.9 versus 31.6 mL/min. None of these differences was significant. Based on highperformance liquid chromatography analysis, each 60-mg Ginkgold tablet contained 6.6 mug of amentoflavone and 61.2 microg of quercetin, both previously identified as CYP2C9 inhibitors. These amounts were apparently too low to inhibit CYP2C9 function in vivo. The results confirm previous controlled clinical studies showing no effect of ginkgo on the kinetics or dynamics of warfarin.
authors.affiliation: Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Greenblatt
authors.forename: Lisa L
authors.initials: LL
authors.lastname: von Moltke
authors.forename: Yan
authors.initials: Y
authors.lastname: Luo
authors.forename: Elke S
authors.initials: ES
authors.lastname: Perloff
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Horan
authors.forename: Allison
authors.initials: A
authors.lastname: Bruce
authors.forename: Robyn C
authors.initials: RC
authors.lastname: Reynolds
authors.forename: Jerold S
authors.initials: JS
authors.lastname: Harmatz
authors.forename: Bharathi
authors.initials: B
authors.lastname: Avula
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
authors.forename: Peter
authors.initials: P
authors.lastname: Goldman
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics*; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D065729:Cytochrome P-450 CYP2C9; D004347:Drug Interactions; D005260:Female; D005480:Flurbiprofen / Q000493:pharmacokinetics*; D020441:Ginkgo biloba / Q000737:chemistry*; D006801:Humans; D008297:Male; D010641:Phenotype; D010936:Plant Extracts / Q000494:pharmacology; D013050:Spectrometry, Fluorescence
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D010936:Plant Extracts; D005480:Flurbiprofen; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases