Quercetin 3 xyloside

Gallic acid, rutin, Folin Ciocalteu reagent, ascorbic acid, and sodium carbonate (Na₂CO₃) were purchased from Sigma-Aldrich (St. Petersburg), ABTS [2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] was from HIMEDIA, tannic acid, and potassium iodate was from Scharlau. Standard compounds (phenolic acid standards: Gallic acid; protocatechuic; gallocatechin; catechin; cholorgenic acid; syringic acid; ellagic acid; cyanidin-3-glucoside; quercetin-3-xyloside; rutin; quercetin-3-galactoside; quercetin-3-glucoside; cyanidin-3,5-diglucoside; cyanidin-3-arabinoside; and Gallic acid) were obtained from Sigma-Aldrich (St. Petersburg) and from Extrasynthese (Genay, France), and the water was distilled and filtered through a Milli-Qapparatus filter.

Formic acid (LC-MS grade) was obtained from Merck KGaA (Darmstadt, Germany). Acetonitrile (LC-MS grade) and methanol (LC-MS grade) were purchased from VWR International Srl (Milan, Italy). Liquid nitrogen was purchased from Rivoira (Milan, Italy). Sodium fluoride, phosphoric acid, glacial acetic acid, TPTZ, ABTS, iron (III) chloride hexahydrate, Trolox, potassium chloride, (+)-catechin, sodium carbonate, F-C reagent, quercetin-3-xyloside, 3,4-dihydroxybenzoic acid, naringenin-7-glucoside, and phloridzin were purchased from Sigma–Aldrich (St. Louis, MO, USA). Quercetin-3-rutinoside and potassium peroxydisulfate were purchased from Roth (Karlsruhe, Germany). Quercetin-3-glucoside, neochlorogenic acid, cryptochlorogenic acid, cyanidin-3-galactoside chloride, and malvidin-3-glucoside chloride were purchased from Extrasynthese (Genay, France).
(−)-Epicatechin, procyanidin B1, procyanidin B2, procyanidin C1, chlorogenic acid, cyanidin-3-glucoside chloride, cyanidin-3-arabinoside chloride, phloretin, quercetin-3-arabinoside, quercetin-3-galactoside, quercetin-4’-glucoside, and quercetin-3-rhamnoside were purchased from Phytolab (Vestenbergsgreuth, Germany). Sodium acetate anhydrous was purchased from CHEMSOLUTE^® (Renningen, Germany). Hydrochloric acid from Fisher Chemical (Pittsburgh, UK). Deionized water was from MilliQ apparatus (Millipore Corp., Bedford, MA, USA).