Trans caffeic acid

Folin‐Ciocalteu phenol reagent, 2,4,6‐tri(2‐pyridyl)1,3,5‐triazine (TPTZ), potassium chloride, sodium acetate, 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH), quercetin, gallic acid, L‐glutamine, MTT, AlCl₃, and hydrogen peroxide were purchased from Sigma‐Aldrich (St. Louis, MO). 2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS), 6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid (Trolox), potassium persulfate, sodium carbonate, sodium bicarbonate, acetic acid, FeCl₃.6H₂O, HPLC‐grade methanol, and formic acid were purchased from Merck (Darmstadt, Germany). quercetin‐3‐glucoside (99.14%), kaempferol‐3‐glucoside (99.37%), quercetin‐3‐glucuronide (95.91%), cyanidin‐3‐glucoside (99.21%), cyanidin‐3‐rutinoside (98.02%), delphinidin‐3‐glucoside (98.02%), trans‐caffeic acid (99.81%), and 3‐caffeoylquinic acid (98.95%) were from PhytoLab GmbH (Vestenbergsgreuth, Germany). Ultrapure water was obtained using a Barnsted EasyPure water filter (Thermo Scientific, Marietta, OH). Culture medium Ham F‐12, penicillin, streptomycin, and fetal bovine serum (FBS) were obtained from Invitrogen Corp. Chemicals (Grand Island, NY).

From Sigma-Aldrich (St. Louis, MO, USA): Amberlite^® XAD7HP, gallic acid, vanillic acid, salicylic acid, 5-O-caffeoylquinic acid, pinocembrin, dimethyl sulfoxide (DMSO), and acetylcholinesterase (AChE) from Electrophorus electricus (electric eel), and butyrylcholinesterase (BChE) from equine serum. From PhytoLab (Vestenbergsgreuth, Germany): p-hydroxybenzoic acid, 3-O-caffeoylquinic acid, trans-caffeic acid, 1,5-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, (+)-catechin, B-type procyanidin dimer ((epi)catechin-(epi)catechin), naringin, naringenin, luteolin-7-O-glucuronide, myricetin-3-O-glucoside, luteolin-7-O-glucoside, quercetin-3-O-glucuronide, quercetin-3-O-galactoside, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, quercetin-3-O-arabinoside, kaempferol-3-O-glucoside, isorhamnetin-3-O-rutinoside, quercetin-3-O-rhamnoside, isorhamnetin-3-O-glucoside, apigenin-7-O-glucoside, luteolin, quercetin, isorhamnetin, and pelargonidin chloride. From Merck (Darmstadt, Germany): HPLC-grade methanol, acetonitrile, formic acid, and ethanol. Ultrapure water was obtained using a Barnstead EasyPure water filter (Thermo Scientific, Waltham, MA, USA).