title: Development and Validation of an in vitro Experimental GastroIntestinal Dialysis Model with Colon Phase to Study the Availability and Colonic Metabolisation of Polyphenolic Compounds.
abstract: The biological effects of polyphenols depend on their mechanism of action in the body. This is affected by bioconversion by colon microbiota and absorption of colonic metabolites. We developed and validated an in vitro continuous flow dialysis model with colon phase (GastroIntestinal dialysis model with colon phase) to study the gastrointestinal metabolism and absorption of phenolic food constituents. Chlorogenic acid was used as model compound. The physiological conditions during gastrointestinal digestion were mimicked. A continuous flow dialysis system simulated the one-way absorption by passive diffusion from lumen to mucosa. The colon phase was developed using pooled faecal suspensions. Several methodological aspects including implementation of an anaerobic environment, adapted Wilkins Chalgren broth medium, 1.10(8) CFU/mL bacteria suspension as inoculum, pH adaptation to 5.8 and implementation of the dialysis system were conducted. Validation of the GastroIntestinal dialysis model with colon phase system showed a good recovery and precision (CV < 16 %). Availability of chlorogenic acid in the small intestinal phase (37 ± 3 %) of the GastroIntestinal dialysis model with colon phase is comparable with in vivo studies on ileostomy patients. In the colon phase, the human faecal microbiota deconjugated chlorogenic acid to caffeic acid, 3,4-dihydroxyphenyl propionic acid, 4-hydroxybenzoic acid, 3- or 4-hydroxyphenyl acetic acid, 2-methoxy-4-methylphenol and 3-phenylpropionic acid. The GastroIntestinal dialysis model with colon phase is a new, reliable gastrointestinal simulation system. It permits a fast and easy way to predict the availability of complex secondary metabolites, and to detect metabolites in an early stage after digestion. Isolation and identification of these metabolites may be used as references for in vivo bioavailability experiments and for investigating their bioactivity in in vitro experiments.
authors.affiliation: NatuRA - Laboratory of Nutrition and Functional Food Science, Department of Pharmaceutical Sciences, University of Antwerp, Belgium.
authors.forename: Annelies
authors.initials: A
authors.lastname: Breynaert
authors.affiliation: NatuRA - Laboratory of Nutrition and Functional Food Science, Department of Pharmaceutical Sciences, University of Antwerp, Belgium.
authors.forename: Douwina
authors.initials: D
authors.lastname: Bosscher
authors.affiliation: Laboratory of Bio-Organic Mass Spectrometry, Department of Pharmaceutical Sciences, University of Antwerp, Belgium.
authors.forename: Ariane
authors.initials: A
authors.lastname: Kahnt
authors.affiliation: Laboratory of Bio-Organic Mass Spectrometry, Department of Pharmaceutical Sciences, University of Antwerp, Belgium.
authors.forename: Magda
authors.initials: M
authors.lastname: Claeys
authors.affiliation: Laboratory of Microbiology, Parasitology and Hygiene, Department of Pharmaceutical Sciences, University of Antwerp, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Cos
authors.affiliation: NatuRA - Laboratory of Pharmacognosy and Pharmaceutical Analysis, Department of Pharmaceutical Sciences, University of Antwerp, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Pieters
authors.affiliation: NatuRA - Laboratory of Nutrition and Functional Food Science, Department of Pharmaceutical Sciences, University of Antwerp, Belgium.
authors.forename: Nina
authors.initials: N
authors.lastname: Hermans
mesh_terms: D001682:Biological Availability; D002109:Caffeic Acids / Q000378:metabolism; D002726:Chlorogenic Acid / Q000378:metabolism*; D003106:Colon / Q000502:physiology*; D003408:Cresols / Q000378:metabolism; D003956:Dialysis; D004063:Digestion; D005243:Feces / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000502:physiology; D006801:Humans; D007081:Ileostomy; D064307:Microbiota / Q000502:physiology*; D008954:Models, Biological; D010226:Parabens / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D010666:Phenylpropionates / Q000378:metabolism; D059808:Polyphenols / Q000378:metabolism*
chemical_list: D002109:Caffeic Acids; D003408:Cresols; D010226:Parabens; D010636:Phenols; D010666:Phenylpropionates; D059808:Polyphenols; D002726:Chlorogenic Acid; C035253:3-phenylpropionic acid; C038193:4-hydroxybenzoic acid; C040048:caffeic acid; C025390:creosol