Structure– and dose–absorption relationships of coffee polyphenols

Abstract

Chlorogenic acids (CGAs) from coffee have biological effects related to human health. Thus, specific data on their bioavailability in the upper gastrointestinal tract are of high interest, since some molecules are absorbed here and so are not metabolized by colonic microflora. Up to now, no data on structure–absorption relationships for CGAs have been published, despite this being the most consumed group of polyphenols in the western diet. To address this gap, we performed ex vivoabsorption experiments with pig jejunal mucosa using the Ussing chamber model (a model simulating the mucosa and its luminal/apical side). The main coffee polyphenols, caffeoylquinic acid (CQA), feruloylquinic acid (FQA), caffeic acid (CA), dicaffeoylquinic acid (diCQA), and d-(?)-quinic acid (QA), were incubated in individual experiments equivalent to gut lumen physiologically achievable concentrations (0.2–3.5 mM).

3,5-diCQA; 4,5-diCQA was purchased from Biopurify Phytochemicals (Chengdu Sichuan, China).