BACKGROUND: Echinacea is composed of three major groups of compounds that are thought to be responsible for stimulation of the immune system--the caffeic acid conjugates, alkylamides and polysaccharides. This study has focussed on the former two classes, as these are the constituents found in ethanolic liquid extracts. OBJECTIVE: To investigate the absorption of these two groups of compounds using Caco-2 monolayers, which are a model of the intestinal epithelial barrier. RESULTS: The caffeic acid conjugates (caftaric acid, echinacoside and cichoric acid) permeated poorly through the Caco-2 monolayers although one potential metabolite, cinnamic acid, diffused readily with an apparent permeability (Papp) of 1 x 10(-4) cm/s. Alkylamides were found to diffuse through Caco-2 monolayers with Papp ranging from 3 x 10(-6) to 3 x 10(-4) cm/s. This diversity in Papp for the different alkylamides correlates to structural variations, with saturation and N-terminal methylation contributing to decreases in Papp. The transport of the alkylamides is not affected by the presence of other constituents and the results for synthetic alkylamides were in line with those for the alkylamides in the echinacea preparation. CONCLUSION: Alkylamides but not caffeic acid conjugates are likely to cross the intestinal barrier.
BACKGROUND: Echinacea is composed of three major groups of compounds that are thought to be responsible for stimulation of the immune system--the caffeic acid conjugates, alkylamides and polysaccharides. This study has focussed on the former two classes, as these are the constituents found in ethanolic liquid extracts. OBJECTIVE: To investigate the absorption of these two groups of compounds using Caco-2 monolayers, which are a model of the intestinal epithelial barrier. RESULTS: The caffeic acid conjugates (caftaric acid, echinacoside and cichoric acid) permeated poorly through the Caco-2 monolayers although one potential metabolite, cinnamic acid, diffused readily with an apparent permeability (Papp) of 1 x 10(-4) cm/s. Alkylamides were found to diffuse through Caco-2 monolayers with Papp ranging from 3 x 10(-6) to 3 x 10(-4) cm/s. This diversity in Papp for the different alkylamides correlates to structural variations, with saturation and N-terminal methylation contributing to decreases in Papp. The transport of the alkylamides is not affected by the presence of other constituents and the results for synthetic alkylamides were in line with those for the alkylamides in the echinacea preparation. CONCLUSION:Alkylamides but not caffeic acid conjugates are likely to cross the intestinal barrier.
Authors: Andrew K L Goey; Irma Meijerman; Hilde Rosing; Jacobus A Burgers; Marja Mergui-Roelvink; Marianne Keessen; Serena Marchetti; Jos H Beijnen; Jan H M Schellens Journal: Br J Clin Pharmacol Date: 2013-09 Impact factor: 4.335
Authors: A Chicca; F Pellati; B Adinolfi; A Matthias; I Massarelli; S Benvenuti; E Martinotti; A M Bianucci; K Bone; R Lehmann; P Nieri Journal: Br J Pharmacol Date: 2008-01-14 Impact factor: 8.739
Authors: Zili Zhai; Avery Solco; Lankun Wu; Eve S Wurtele; Marian L Kohut; Patricia A Murphy; Joan E Cunnick Journal: J Ethnopharmacol Date: 2008-12-07 Impact factor: 4.360
Authors: Carlie A LaLone; Kimberly D P Hammer; Lankun Wu; Jaehoon Bae; Norma Leyva; Yi Liu; Avery K S Solco; George A Kraus; Patricia A Murphy; Eve S Wurtele; Ok-Kyung Kim; Kwon Ii Seo; Mark P Widrlechner; Diane F Birt Journal: J Agric Food Chem Date: 2007-08-15 Impact factor: 5.279
Authors: Zili Zhai; Devon M Haney; Lankun Wu; Avery K Solco; Patricia A Murphy; Eve S Wurtele; Marian L Kohut; Joan E Cunnick Journal: Phytomedicine Date: 2009-03-20 Impact factor: 5.340