title: Bioavailability and pharmacokinetics of alkamides from the roots of Echinacea angustifolia in humans.
abstract: Alkamides are suspected to contribute to the activity of Echinacea preparations. They are mainly derived from undeca- and dodecanoic acid and differ in the degree of unsaturation and the configuration of the double bonds. In total, 6 alkamides have been isolated from the roots of Echinacea angustifolia as major lipophilic constituents and have been investigated regarding their pharmacokinetics. A sensitive and specific method has been developed for the identification and quantification of these alkamides in human plasma using liquid chromatography electrospray ionization ion-trap mass spectrometry. The method was applied to analyze plasma samples obtained from a randomized, open, single-dose, crossover study after oral administration of a 60% ethanolic extract from the roots of E. angustifolia to 11 healthy subjects. The maximum concentration of dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides, the main alkamides in the roots of E. angustifolia, appeared already after 30 minutes and was 10.88 ng/mL for the 2.5-mL dose.
authors.affiliation: Institute of Pharmaceutical Sciences, Department of Pharmacognosy, Karl-Franzens-University, Graz, Austria.
authors.forename: Karin
authors.initials: K
authors.lastname: Woelkart
authors.forename: Christoph
authors.initials: C
authors.lastname: Koidl
authors.forename: Andrea
authors.initials: A
authors.lastname: Grisold
authors.forename: J David
authors.initials: JD
authors.lastname: Gangemi
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Turner
authors.forename: Egon
authors.initials: E
authors.lastname: Marth
authors.forename: Rudolf
authors.initials: R
authors.lastname: Bauer
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000577:Amides / Q000008:administration & dosage / Q000032:analysis / Q000302:isolation & purification / Q000493:pharmacokinetics*; D000893:Anti-Inflammatory Agents / Q000032:analysis / Q000493:pharmacokinetics*; D001682:Biological Availability; D020900:Echinacea; D000431:Ethanol / Q000737:chemistry; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008297:Male; D008517:Phytotherapy; D010936:Plant Extracts / Q000097:blood / Q000737:chemistry / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry*; D053284:Polyunsaturated Alkamides
chemical_list: C452804:2,4,8,10-dodecatetraenoic acid isobutylamide; D000577:Amides; D000893:Anti-Inflammatory Agents; D005231:Fatty Acids, Unsaturated; D010936:Plant Extracts; D053284:Polyunsaturated Alkamides; D000431:Ethanol