Ascorbic acid

All reagents used are HPLC grade. Ultrapure deionized water, with resistivity of 18.2 megaohm-cm was obtained from a Milli-Q^® Integral water purification system with Q-pod (Millipore, Bedford, MA, USA). Formic acid was purchased from Carlo Erba (Milan, Italy). Ethanol, acetonitrile and mEthanol from Merck (Darmstadt, Germany). Ammonium acetate, acetone and 2-propanol were purchased from Carlo Erba (Milan, Italy). The SPE cartridges Waters Oasis HLB (200 mg) from Waters S.p.A. (Milan, Italy). Standard solutions of gallic acid, ascorbic acid, vanillic acid, caffeic acid, chlorogenic acid, catechin, epicatechin, vanillic acid, coumaric acid and hydroxybenzoic acid were purchased from Extrasynthese (Genay Cedex, France); quercetin, rutin, apigenin, luteolin, ferulic acid, kaempferol, palmitic acid, stearic acid, oleic acid, linoleic acid, glucose, N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA), trimethylchlorosilane (TMCS) and pyridine were acquired from Sigma-Aldrich S.r.l. (Milan, Italy).

Chemicals, reagents, and consumables were purchased from the following manufacturers: delphinidin chloride (Extrasynthese, Genay, France); DMSO, ascorbic acid, formic acid, gallic acid, gelatin solution (type B, 2% in H₂O), endothelial cell growth supplement, sodium pyruvate, HEPES solution, 0.5% trypsin/EDTA (1X), iron(lll) chloride (FeCl₃), 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), and ferrous sulfate heptahydrate (FeSO₄·7H₂O) (Sigma-Aldrich, Poole, Dorset, UK); basal medium M199 (+Earle's, +L-glutamine, and +phenol red) and basal medium M199 (+Earle's, +L-glutamine, −phenol red, and +bicarbonate) (Invitrogen, Paisley, UK); pyrogallol, methanol, acetonitrile, ethanol, acetone, Coomassie (Bradford) reagent kit, sodium acetate, and hydrochloric acid (Thermo Fisher Scientific Ltd., Loughborough, UK); Tempone-H hydrochloride and ROS-ID® Total ROS/Superoxide detection kit (ENZO Life Sciences Ltd., Exeter, UK); PBS (without Ca and Mg), foetal bovine serum, penicilin/streptomycin (100X), and bovine serum albumin (PAA Laboratories GmbH, Pasching, Austria); HUVECs (Cell Applications Inc., San Diego, CA, USA); heparin sodium (Wockhardt Ltd., Wrexham, UK); GSH, catalase, and SOD assay (Cayman Chemical Company, Ann Arbor, MI, USA); and filter vials (Thomson single StEP standard filter vials) (Thomson Instrument Company, Oceanside, CA, USA).

LC and LC–MS grade
chemicals were purchased from VWR International Oy (Espoo, Finland).
Ethanol (≥99.7%) was purchased from Altia Oyj (Helsinki, Finland).
The standards of ethyl acetate, acetaldehyde, butan-1-ol, and acetic
acid were obtained from Sigma-Aldrich (St. Louis, MO, United States).
The standards of myo-inositol, xylose, fructose, glucose, sorbitol,
sucrose, tartaric acid, malic acid, succinic acid, citric acid, quinic
acid, and ascorbic acid were purchased from Extrasynthese (Genay,
France). (−)-Epicatechin, (+)-catechin, arbutin, 3-O-caffeoylquinic acid, 5-O-caffeoylquinic
acid, p-coumaric acid, gallic acid-4-O-glucoside, and caffeic acid were provided by Sigma-Aldrich Co. (St.
Louis, MO, United States). Quercetin-3-O-glucose,
kaempferol-3-O-glucose, and procyanidin B2 were obtained
from Extrasynthese (Genay, France).