*2.2. Cell Culture*

Caco-2 cells were obtained from Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures (Braunschweig, Germany) and cultured in DMEM containing 10% FCS, 1% NEAA, 2 mM Glutamin, 100 U/mL Penicillin and 100 µg/mL Streptomycin. Caco-2 cells were seeded either onto 24-well Transwell inserts (Corning, #3379) for bidirectional permeability assays or onto 96-well Transwell inserts (Corning #3391) for the screening of DME activities at a density of 160,000 cells/cm<sup>2</sup> and cultured for 3 weeks, with media change on every second day. EpiIntestinal microtissues were obtained from MatTek (Bratislav, Slovakia) and cultured according to the manufacturer's instruction (24-well format for bidirectional permeability assays and GI firstpass availability assays and 96-well format for screening of DME activities).
