Phloridzin

Authentic phenolic standards of chlorogenic acid, catechin, epicatechin, quercetin-3-O-galactoside, rutin, quercetin-3-O-glucoside, quercetin-3-O-xyloside, quercetin-3-O-arabinoside, quercetin-3-O-rhamnoside, isorhamnetin-3-O-glucoside, quercetin, kaempferol, eriodictyol-7-O-glucoside, cyanidin-3-O-galactoside, cyanidin-3-O-arabinoside, cyanidin-3-O-rhamnoside, and phloridzin were purchased from Extrasynthese (Genay, France) or Sigma-Aldrich (St. Louis, MO, USA). Sugars (glucose, fructose, sucrose, and sorbitol) and organic acids (citric acid, malic acid, and shikimic acid) were also purchased from Sigma-Aldrich. Acetonitrile (HPLC-grade) was obtained from J.T. Baker (Phillipsburg, NJ, USA). Nanopure water used in the study was obtained from a water purification system (Milli-Q Direct 8, Merck Millipore, Billerica, MA, USA).

All solvents, reagents, and standards used were of analytical grade. Acetonitrile and acetic acid were obtained from Sigma-Aldrich GmbH (Buchs, Switzerland), ethanol was obtained from AB Stumbras (Kaunas, Lithuania), hyperoside, rutin, quercitrin, phloridzin, procyanidin B1, procyanidin B2 and chlorogenic acid standards were purchased from Extrasynthese (Genay, France), reynoutrin, (+)-catechin and (−)-epicatechin–from Sigma-Aldrich GmbH (Steinheim, Germany), and avicularin, procyanidin C1 and isoquercitrin–from Chromadex (Santa Ana, CA, USA). Purified deionized water used in the tests was prepared with the Milli-Q^® (Millipore, Bedford, MA, USA) water purification system.

All solvents, reagents, and standards used were of analytical grade. The standards used in the HPLC analysis were the following: hyperoside, rutin, quercitrin, phloridzin, procyanidin B1, procyanidin B2 and chlorogenic acid, obtained from Extrasynthese (Genay, France); reynoutrin, (+)-catechin and (–)-epicatechin, purchased from Sigma-Aldrich GmbH (Buchs, Switzerland); and avicularin and isoquercitrin, obtained from Chromadex (Santa Ana, CA, USA). The chemicals applied in the modeling of semi-solid pharmaceutical forms were glycerin, castor oil, sorbitan monolaurate (Span 20), polyethylene glycol sorbitan monolaurate (Tween 20) and sodium hydroxide (NaOH), obtained from Sigma-Aldrich Chemie GmbH (Steinheim, Germany). Carbomer 980 was obtained from Lubrizol (Wickliffe, OH, USA). The reagents used in the antioxidant activity assay were 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and sodium acetate, acquired from Scharlau (Barcelona, Spain). Iron (III) chloride hexahydrate (FeCl₃ × 6H₂O) was purchased from Vaseline-Fabrik Rhenania (Bonn, Germany) and 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ) was obtained from Carl Roth (Karlsruhe, Germany).

All solvents, reagents, and standards used were of analytical grade. Acetonitrile, acetic acid, D(+)-glucose monohydrate, hypromellose, Aerosil^TM 200, microcrystalline cellulose, silicon dioxide and starch were obtained from Sigma-Aldrich GmbH (Buchs, Switzerland), and ethanol was obtained from Stumbras AB (Kaunas, Lithuania). Hyperoside, rutin, quercitrin, phloridzin, procyanidin B1, procyanidin B2, and chlorogenic acid standards were purchased from Extrasynthese (Genay, France), reynoutrin, (+)-catechin and (−)-epicatechin were purchased from Sigma-Aldrich GmbH (Buchs, Switzerland), and avicularin, procyanidin C1, and isoquercitrin were purchased from Chromadex (Santa Ana, USA). In this study, we used deionized water produced by the Milli-Q^® (Millipore, Bedford, MA, USA) water purification system.

All the solvents, reagents, and standards used were of analytical grade. Acetonitrile and acetic acid were obtained from Sigma-Aldrich GmbH (Buchs, Switzerland) and ethanol from Stumbras AB (Kaunas, Lithuania). Hyperoside, rutin, quercitrin, phloridzin, phloretin, caffeic acid, and chlorogenic acid standards were purchased from Extrasynthese (Genay, France), (+)-catechin and (–)-epicatechin from Fluka (Buchs, Switzerland) and avicularin and isoquercitrin from Chromadex (Santa Ana, USA). 1,1-Diphenyl-2-picrylhydrazyl (DPPH^•) radical, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), potassium persulfate, sodium acetate trihydrate, iron (III) chloride hexahydrate, and 2,4,6-tripyridyl-s-triazine (TPTZ) were obtained from Sigma-Aldrich (Steinheim, Germany). Folin-Ciocalteu reagent, gallic acid monohydrate, sodium carbonate, aluminum chloride hexahydrate, and hexamethylenetetramine were purchased from Sigma-Aldrich GmbH (Buchs, Switzerland). Deionized water, produced by the Crystal E high-performance liquid chromatography (HPLC, Adrona SIA, Riga, Latvia) water purification system, was used.

Methanol, ascorbic acid, acetic acid, formic acid, and acetonitrile were purchased from Sigma-Aldrich (Germany). Quercetin, phloridzin, phloretin, catechin, epicatechin, procyanidin and phenolic acids were purchased from Extrasynthese (Genay, France). Folin-Ciocalteu’s phenol reagent, gallic acid, Trolox (Tx), rutin, and ABTS (2,2′-azino-bis(3-ethylobenzothiazoline-6-sulphonic acid)-diamonium salt) were purchased from Sigma-Aldrich (Hamburg, Germany).

All solvents, reagents, and standards used were of analytical grade. Acetonitrile and acetic acid were obtained from Sigma-Aldrich GmbH (Buchs, Switzerland) and ethanol from AB Stumbras (Kaunas, Lithuania). Hyperoside, rutin, quercitrin, phloridzin, procyanidin B1, procyanidin B2, and chlorogenic acid standards were purchased from Extrasynthese (Genay, France); reynoutrin, (+)-catechin, and (−)-epicatechin from Sigma-Aldrich GmbH (Steinheim, Germany); and avicularin, procyanidin C1, and isoquercitrin from Chromadex (Santa Ana, CA, USA). Purified deionized water used in the tests was prepared with the Milli-Q^® (Millipore, Bedford, MA, USA) water purification system.
The reagents used in antioxidant activity assays—6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and sodium acetate—were obtained from Scharlau (Barcelona, Spain), 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ) was obtained from Carl Roth (Karlsruhe, Germany), and iron (III) chloride hexahydrate (FeCl₃·6H₂O) from Vaseline-Fabrik Rhenania (Bonn, Germany).