Guaijaverin

MEM with Earle's salts, DMEM, fetal bovine serum (FBS), trypsin‐EDTA, and antibiotics were purchased from Biochrom GmbH (Berlin, Germany). Entero‐STIM Intestinal Epithelium Differentiation Medium and MITO+ Serum Extender were purchased from Corning (Wiesbaden, Germany). Hesperetin, peltatoside, hyperoside, kaempferol, ellagic acid, isoquercitrin, quercitrin, phloretin, (−)‐epicatechin, epigallocatechin, epicatechin gallate, procyanidin B1, procyanidin B2, epigallocatechin gallate, gallocatechin, and morine were obtained from Extrasynthese (Genay Cedex, France). Phloridzin, chlorogenic acid, caffeic acid, quercetin, (+)‐catechin, gallic acid, 2‐mercaptoethanol, NaCl, MgSO₄, KCl, CaCl₂, HEPES, and xylitol were purchased from Sigma‐Aldrich (Schnelldorf, Germany). Guaijaverin and avicularin were obtained from Glentham Life Sciences (Corsham, United Kingdom). Purified and concentrated GLE (cGLE) was provided by Belan GmbH (Wels, Austria).30 Guava fruit puree for preparation of fruit extracts was obtained from Tradework BV (Rotterdam, The Netherlands), commercially available GLE and apple extract (AE) were purchased from Pfannenschmidt (Hamburg, Germany). Transwell inserts (12 mm, collagen‐treated, 0.4 μm pore size) and 12‐well plates were obtained from Corning (Wiesbaden, Germany).

Human insulin, CaCl₂, NaCl, KCl, MgSO₄, KH₂PO₄, phosphate buffered saline (PBS), Hank’s balanced salt solution (HBSS), quercetin, chlorogenic acid, neochlorogenic acid and caffeic acid were purchased from Sigma-Aldrich (Schnelldorf, Germany). Guaijaverin and avicularin were from Glentham Life Sciences (Corsham, UK). Rutin, hyperoside, isoquercitrin and quercitrin were obtained from Extrasynthese (Genay CEDEX, France). For preparation of stock solutions, the herbal compounds were dissolved in Krebs Ringer phosphate HEPES buffer (KRPH; 20 mM HEPES, 1 mM CaCl₂, 136 mM NaCl, 4.7 mM KCl, 1 mM MgSO₄ and 5 mM KH₂PO₄). A library containing 2300 water-soluble herbal extracts (PECKISH) [26 (link)] was provided by Frank Döring (Christian-Albrechts University, Kiel, Germany). NovoRapid manufactured by Novo Nordisk was a kind gift from Daniel Weghuber (Paracelsus Medical University, Salzburg, Austria). A saponin mix with 10% saponin content was provided by Delacon Biotechnik GmbH (Steyregg, Austria). Transwell inserts (8.4 mm, collagen-treated, 0.4 μm pore diameter) and 24-well plates were obtained from Greiner Bio-One (Kremsmünster, Austria).