E piceatannol

Acetonitrile, formic acid, water, and ethanol were purchased from Merck (Darmstadt, Germany). All solvents were of HPLC grade. Ultrapure water was obtained from a Milli-Q water purification system (Millipore, Bedford, MA, USA).
Gallic, ellagic, and 4-hydroxybenzoic acid, (+)-catechin, (−)-epicatechin, (E)-resveratrol, (E)-piceatannol, quercetin-O-glucoside, and (E)-ε-viniferin were purchased from Sigma-Aldrich (St. Louis, MO, USA). Epicatechin gallate was acquired from Extrasynthèse (Genay, France). All standards were handled without exposure to light.

Acetonitrile and ethanol were purchased from Thermo Fisher Scientific (Courtaboeuf, France). A Millipore Milli-Q system (Merck Millipore, Molsheim, Germany) provided ultrapure water. Gallic acid, caffeic acid, E-Resveratrol, E-piceatannol, catechin, epicatechin, gallocatechin, E-piceid, astilbin, quercetin-3-O-glucuronide, procyanidin B1 and procyanidin B2 were obtained from Sigma-Aldrich (St. Louis, MO, USA); E-ε-viniferin and quercetin-3-O-glucoside were purchased from Extrasynthèse (Genay, France) and E-miyabenol C from Ambinter (Paris, France). Pallidol and E-δ-viniferin were graciously provided by Mary-Lorène Goddard (EA-3991, Université de Haute-Alsace, Colmar, France). Z/E-vitisin B, ampelopsin A and hopeaphenol were purified from grape canes as previously described [37 (link)]. The 2,2′-Azo-bis-(2-amidinopropane) hydrochloride (ABAP), fluorescein, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), potassium persulfate, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,4,6-Tri(2-pyridyl)-s-triazine (TPTZ), Iron(III) chloride (FeCl₃), copper(II) chloride (CuCl₂), 2,9-Dimethyl-1,10-phenanthroline (neocuproine) and 3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p′-disulfonic acid monosodium salt hydrate (ferrozine) were obtained from (Sigma-Aldrich, Saint-Quentin Fallavier, France).

Gallic acid (1), caffeic acid (2), E-resveratrol (3), E-piceatannol (4), catechin (5), epicatechin (6), gallocatechin (7), E-piceid (8), astilbin (10), quercetin-3-O-glucoside (16), and quercetin-3-O-glucuronide (23) were purchased from Sigma-Aldrich standards (St. Louis, MI, USA). Procyanidins B1 (24), B2 (25), and B3 (27) were purchased from Extrasynthèse (Genay, France). E-ε-viniferin (13), E-δ-viniferin (15), ampelopsin A (17), E-miyabenol C (32), hopeaphenol (36), isohopeaphenol (37), and Z/E-vitisin B (41) were obtained as previously described [2 (link)]. Acetonitrile, methanol, and formic acid were purchased from ThermoFisher Scientific (Courtaboeuf, France). Ultra-pure water was prepared with a Milli-Q water purification system (Merck Millipore, Molsheim, France).