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.

Catabolism of raw and cooked green pepper ( Capsicum annuum ) (poly)phenolic compounds after simulated gastrointestinal digestion and faecal fermentation

“…An increase in caffeic acid amount was detected at the beginning of the fecal fermentation, probably due to the cleavage of quinic acids (Ludwig, de Peña, Cid, & Crozier, 2013;Rechner et al, 2004;Tomás-Barberán et al, 2014) and to the deglycosilation of caffeic acid glucosides, as illustrated in Figure 3. In agreement with Breynaert et al (2015), caffeoylquinic acids and their main metabolite, i.e. caffeic acid, were not detectable anymore after 5 h of colonic incubation, indicating a complete degradation of these compounds.…”

Flavonoids as Potent Scavengers of Hydroxyl Radicals

“…Anthocyanins are converted mainly into protocatechuic acid (56), gallic acid (57), syringic acid (58), vanillic acid (59), and phloroglucinol (60) (Crozier and others ; De Pascual‐Teresa and others ; Heinrich and others ). The similar metabolites were described also for simple organic acid (like chlorogenic acid derivatives) (Yang and others ; Breynaert and others ).…”

Evaluation of the prebiotic potential of five kiwifruit cultivars after simulated gastrointestinal digestion and fermentation with human faecal bacteria

“…This includes increases of Ruminococcaceae, along with Lachnospira (in the case of green-fleshed kiwifruit) or Akkermansia (gold-fleshed kiwifruit). Interestingly, a simulation of intestinal absorption of CGA (MW 354.31) using a 12-14 kDa dialysis membrane has showed that up to 60% of CGA is not absorbed and is therefore available to the faecal microbiota (Breynaert et al, 2015). It is increasingly realised that plant foods modulate changes in gut microbiome, not just due to the type and amount of their dietary fibre, but also due to their polyphenols (Tuohy et al, 2012;Parkar et al, 2013).…”