title: The bioanalysis of the major Echinacea purpurea constituents dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides in human plasma using LC-MS/MS.
abstract: Alkylamides are a group of active components of the widely used herb Echinacea purpurea (E. purpurea), which have immunostimulatory and anti-inflammatory effects. For the most abundant alkylamides, dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides (DTAI), an LC-MS/MS assay has been developed and validated for quantification in human plasma. This assay will be used to support a clinical interaction study with E. purpurea. A 300 μL plasma aliquot underwent liquid-liquid extraction with diethylether-n-hexane (50:50, v/v). After evaporization and reconstitution in 100 μL of acetonitrile-water (50:50, v/v) 20 μL of sample were injected into the HPLC system. Chromatographic separation was achieved with a Polaris 3 C18-A column (50 mm × 2 mm ID, particle size 3 μm), a flow rate of 0.3 mL/min and isocratic elution with acetonitrile-water (50:50, v/v) containing 0.1% formic acid during the first 5 min. Hereafter, gradient elution was applied for 0.5 min, followed by restoration of the initial isocratic conditions. The total run time was 7.5 min. The assay was validated over a concentration range from 0.01 to 50 ng/mL for DTAI, with a lower limit of quantification of 0.01 ng/mL. Validation results show that DTAI can be accurately and precisely quantified in human plasma. DTAI also demonstrated to be chemically stable under relevant conditions. Finally, the applicability of this assay has been successfully demonstrated by measuring the plasma concentration of DTAI in patients after ingestion of a commercial extract of E. purpurea.
authors: Utrecht University, Faculty of Science, Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology & Clinical Pharmacology, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands. A.K.L.Goey@uu.nl
authors: Andrew K L
authors: AK
authors: Goey
authors: Hilde
authors: H
authors: Rosing
authors: Irma
authors: I
authors: Meijerman
authors: Rolf W
authors: RW
authors: Sparidans
authors: Jan H M
authors: JH
authors: Schellens
authors: Jos H
authors: JH
authors: Beijnen
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D020900:Echinacea / Q000737:chemistry*; D005231:Fatty Acids, Unsaturated / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D016014:Linear Models; D010936:Plant Extracts / Q000737:chemistry; D053284:Polyunsaturated Alkamides / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: C452804:2,4,8,10-dodecatetraenoic acid isobutylamide; D005231:Fatty Acids, Unsaturated; D010936:Plant Extracts; D053284:Polyunsaturated Alkamides