Kaempferol 3 o rutinoside

All reagents and chemicals used in this study were of HPLC grade except for sodium chloride (NaCl) and potassium hydroxide (KOH), which were analytical grade and procured from Beijing Chemical Reagent, Co. (Beijing, China). Methanol, formic acid, methyl tert-butyl ether (MTBE), hexane and ether were purchased from Fisher (Fair, United States). Trifluoroacetic acid (TFA), butylhydroxytoluene (BHT) and standards, such as cyanidin 3,5-O-diglucoside, pelargonidin 3,5-O-diglucoside, quercetin 3-O-glucoside, kaempferol 3-O-rutinoside, kaempferol 3-O-glucoside, kaempferol, and β-carotene were procured from Sigma-Aldrich (St. Louis, MO, United States). Remaining standards, including violaxanthin, antheraxanthin, and zeaxanthin were purchased from CaroteNature (Ostermundigen, Switzerland). HPLC grade deionized water was produced with a Pall Cascada LS Ultra Pure Water system (18.2 MΩ cm, East Hills, NY, United States).

All of the solvents were purchased from Carlo Erba in Val de Reuil, France, and were at least HPLC grade. From Penta (Prague, Czech Republic), we obtained gallic acid; phosphate buffer; anhydrous sodium carbonate; 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,4,6-tri-2-pyridinyl-1,3,5-triazine (TPTZ); and Folin–Ciocalteu reagent. From Sigma-Aldrich (Taufkirchen, Germany), phenolics (i.e., chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, rutin, quercetin 3-O-galactoside, and kaempferol 3-O-rutinoside), aluminum chloride, iron (III) chloride, hydrochloric acid, ascorbic acid, and trichloroacetic acid were purchased as chemical standards. All of the experiments that were performed used deionized water.

Catechin hydrate (>98%), trans-resveratrol (>99%), quercetin 3-O-glucuronide (≥95%), cyanin chloride (≥90%), ferulic acid (99%), kaempferol, p-coumaric acid, kaempferol 3-O-rutinoside (98%), myricetin, isorhamnetin and rutin (quercetin 3-O-rutinoside) hydrate (>94%) were obtained from Sigma-Aldrich (Darmstadt, Germany). Sodium carbonate anhydrous (99%), Folin–Ciocalteu reagent, and glycerol anhydrous (99%) were purchased from Penta (Praha, Czechia). Formic acid (99%), L-ascorbic acid and citric acid (≥99.5%) were from Carlo Erba (Milan, Italy). All solvents used for chromatography were of appropriate (HPLC) grade. The radical probe 2,2-diphenyl-1-picrylhydrazyl (DPPH), quercetin hydrate (97%) and caffeic acid (99%) were from Alfa Aesar (Karlsruhe, Germany). Iron chloride hexahydrate (FeCl₃ • 6H₂O) was purchased from Merck (Darmstadt, Germany). 2,4,6-Tris(2-pyridyl)-s-triazine (TPTZ) was from Fluka (Steinheim, Germany).

Reagents of Mass Spectrometry grade, including acetonitrile, methanol, water, and formic acid, were purchased from Sigma Chemical Co. (St. Louis, MO, USA). Also, Folin–Ciocalteu’s phenol reagent was obtained from Sigma Chemical Co. Analyzed phenols included protocatechuic acid, m-hydroxybenzoic acid, chlorogenic acid, salicylic acid, caffeic acid, syringic acid, sinapic acid, ferulic acid, p-coumaric acid, m-coumaric acid, o-coumaric acid, gallic acid, o-hydroxybenzoic acid, 3,4-dihydroxyphenylacetic acid, trans-cinnamic acid, vanillic acid, benzoic acid, ellagic acid, vitexin, rutin, (+)-catechin, apigenin, kaempferol, orientin, naringenin, myricetin, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside, kaempferol-3-O-rutinoside, quercetin, and its derivativeswere purchased from Sigma Chemical Co. (St. Louis, MO, USA). Folin–Ciocalteu’s phenol reagent, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH), and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) were obtained from Sigma Chemical Co. (St. Louis, MO, USA).

ACS-grade methanol for extraction, LC-MS Optima^TMacetonitrile, and UHPLC-MS/MS Optima^TM grade solvents (water, acetonitrile, methanol) were from Fisher (Thermo Fisher Scientific, Nepean, ON, Canada). SupraPur^TM formic acid (98%–100%) and ACS grade isopropyl alcohol were from VWR (VWR International LLC, Mississauga, ON, Canada). Commercially available analytical standards were sourced from Extrasynthese (Genay, Cedex, FR) (quercetin-3-O-glucoside ≥ 99%; kaempferol-3-O-rutinoside ≥ 98%; quercetin-3-O-rhamnoside ≥ 98.5%) or Sigma-Aldrich (St. Louis, MO, USA) (quercetin-3-O-rutinoside ≥ 95%; kaempferol-3-O-glucoside ≥ 97%; xanthohumol ≥ 96%; quercetin-3-O-(6’’-O-malonyl)-glucoside ≥ 85%). International Calibration Extract 3 (ICE-3), an alpha & beta acid standardized mixture, was sourced from Labor Veritas (AG, Zurich, CZ). Deuterated solvent (DMSO-d₆) was from CIL (Cambridge Isotope Laboratories Inc., Tewksbury, MA, USA). Pyridine, o-tolyl isothiocyanate, L-cysteine methyl ester, D-glucose, L-glucose, D-galactose, L-galactose were purchased from Sigma-Aldrich.

The Folin-Ciocalteu phenol reagent (FCR), gallic acid, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid (Trolox), ferrozine, caffeic acid, quercetin, p-coumaric acid, ferulic acid, rutin, and kaempferol-3-O-rutinoside were obtained from Sigma-Aldrich (St. Louis, MO, USA). Methanol, acetonitrile, sodium carbonate, ferric chloride, ferrous chloride, ferrous sulfate, and potassium persulfate were acquired from Avantor Performance Materials (Gliwice, Poland). The ACL kit was purchased from Analytik Jena (Jena, Germany).