Bioavailability of Echinacea Constituents: Caco-2 Monolayers and Pharmacokinetics of the Alkylamides and Caffeic Acid Conjugates

Matthias, Anita, Penman, Kerry G., Matovic, Nick J., Bone, Kerry M., De Voss, James J. and Lehmann, Reg P. (2005) Bioavailability of Echinacea Constituents: Caco-2 Monolayers and Pharmacokinetics of the Alkylamides and Caffeic Acid Conjugates. Molecules, 10 10: 1242-1251. doi:10.3390/10101242


Author Matthias, Anita
Penman, Kerry G.
Matovic, Nick J.
Bone, Kerry M.
De Voss, James J.
Lehmann, Reg P.
Title Bioavailability of Echinacea Constituents: Caco-2 Monolayers and Pharmacokinetics of the Alkylamides and Caffeic Acid Conjugates
Journal name Molecules   Check publisher's open access policy
ISSN 1420-3049
Publication date 2005-10
Sub-type Letter to editor, brief commentary or brief communication
DOI 10.3390/10101242
Open Access Status DOI
Volume 10
Issue 10
Start page 1242
End page 1251
Total pages 10
Place of publication Basel, Switzerland
Publisher Molecules/Molecular Diversity Preservation International
Collection year 2005
Language eng
Subject C1
250302 Biological and Medical Chemistry
780103 Chemical sciences
Abstract Many studies have been done over the years to assess the effectiveness of Echinacea as an immunomodulator. We have assessed the potential bioavailability of alkylamides and caffeic acid conjugates using Caco-2 monolayers and compared it to their actual bioavailability in a Phase I clinical trial. The caffeic acid conjugates permeated poorly through the Caco-2 monolayers. Alkylamides were found to diffuse rapidly through Caco-2 monolayers. Differences in diffusion rates for each alkylamide correlated to structural variations, with saturation and N-terminal methylation contributing to decreases in diffusion rates. Alkylamide diffusion is not affected by the presence of other constituents and the results for a synthetic alkylamide were in line with those for alkylamides found in an ethanolic Echinacea preparation. We examined plasma from healthy volunteers for 12 hours after ingestion of Echinacea tablets manufactured from an ethanolic liquid extract. Caffeic acid conjugates could not be identified in any plasma sample at any time after tablet ingestion. Alkylamides were detected in plasma 20 minutes after tablet ingestion and for each alkylamide, pharmacokinetic profiles were devised. The data are consistent with the dosing regimen of one tablet three times daily and supports their usage as the primary markers for quality Echinacea preparations.
Keyword Chemistry, Organic
Alkylamides
Echinacea
Pharmacokinetics
Bioavailability
Caco-2
Respiratory-tract Infections
Double-blind
Trial
Q-Index Code C1

Document type: Journal Article
Sub-type: Letter to editor, brief commentary or brief communication
Collections: Excellence in Research Australia (ERA) - Collection
2006 Higher Education Research Data Collection
School of Chemistry and Molecular Biosciences
 
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Created: Wed, 15 Aug 2007, 06:35:57 EST