4 5 dicaffeoylquinic acid 4 5 dicqa

5-caffeoylquinic acid (5-CQA) was purchased from Phytolab (Vestenbergsgreuth, Germany).
Acetonitrile and methanol (HPLC grade) were purchased from Sigma -Aldrich S.r.l. (Milano, Italy) while formic acid was obtained from CARLO ERBA Reagents S.r.l. (Cornaredo, Italy). Standards not commercially available (p-coumaroylquinic acids) were synthetized according to the literature (Gutiérrez Ortiz et al., 2017) and their identity was confirmed by 1 H and 13 C NMR spectroscopy. 3,4 dicaffeoylquinic acid (3,4-diCQA), 3,5-dicaffeoylquinic acid (3,5-diCQA), 4,5-dicaffeoylquinic acid (4,5-diCQA) were purchased from Phytolab, feruoylquinic acids (FQAs) were obtained from the division of organic chemistry and biochemistry at Ruđer Bošković Institute (Zagreb, Croatia) (Dokli, Navarini, & Hameršak, 2013) . Water was treated in a Milli-Q water purification system (Millipore Academic).

Caffeic acid, ferulic acid, sinapic acid, 5-O-caffeoylquinic acid (5-CQA), caffeine, human saliva α-amylase (300-1500 U/mg protein), pepsin (674 U/mg), pancreatin (4 x UPS) and bile salts were purchased from Sigma-Aldrich (Steinheim, Germany). 4,5-Dicaffeoylquinic acid (4,5-DiCQA) was obtained from Phytolab (Vestenbergsgreuth, Germany) and dihydroCaffeic acid and dihydroferulic acid from Alfa Aeser (Heysham, UK). Culture flasks, Transwell fitted with polycarbonate membranes were acquired from Corning® Costar® Transwell (Sigma Aldrich, St. Louis, US). Dulbecco's modified Eagle's medium (DMEM) was purchased from Gibco Invitrogen (Paisley, UK). The Caco-2 cell line PD7 clone was kindly provided by Dr. Edith Brot-Laroche (Paris, France). All chemicals and reagents used were of analytical grade from Panreac (Barcelona, Spain), Fisher Scientific (Loughborough, UK), and Sigma Aldrich (Steinheim, Germany).