Ursolic acid

The following substances and solvents were used in the study: procyanidins B1, B2, C1, A1, A2, A4, (+)-catechin, (–)-epicatechin, quercetin, quercitrin (quercetin-3-O-rhamnoside), isoquercitrin (quercetin-3-O-glucoside), avicularin (quercetin-3-O-arabinofuranoside), guaiaverin (quercetin-3-O-arabinopyranoside), rutin (quercetin-3-O-rutinose), reynoutrin (quercetin-3-O-xyloside), kaempferol, nicotiflorin (kaempferol-3-O-rutinoside), afzelin (kaempferol-3-O-rhamnoside), astragalin (kaempferol-3-O-glucoside), chlorogenic acid (3-O-caffeoylquinic acid), neochlorogenic acid (5-O-caffeoylquinic acid), cryptochlorogenic acid (4-O-caffeoylquinic acid), p-coumaric acid, arbutin, hydroquinone, α-amyrin, β-amyrin, β-sitosterol, lupeol, erythrodiol, maslinic acid, oleanolic acid, acetonitrile, acetone, and methanol, which were purchased from Sigma–Aldrich (Steinheim, Germany); hyperoside (quercetin-3-O-galactoside), procyanidin B3, uvaol, friedelin, 6″-O-acetylisoquercitrin (quercetin-3-O-(6″-acetylglucoside)), betulin, and betulinic and corosolic acids from Extrasynthese (Genay, France); ursolic acid from Carl Roth (Karlsruhe, Germany); and trifluoroacetic acid from Merck (Darmstadt, Germany). All used chemicals were of HPLC grade. Ultrapure water used in this study was prepared with Milli–Q^® 180 (Millipore, Bedford, MA, USA) water purification system.

Analytical- and chromatographic-grade chemicals and solvents were used for this study: acetonitrile, methanol, glacial acetic acid, erythrodiol, maslinic, oleanolic acids from Sigma-Aldrich (GmbH, Karlsruhe, Germany); uvaol, betulin, corosolic acids, ursolic acid from Carl Roth (Karlsruhe, Germany); polyphenols (gallic acid, ellagic acid, neochlorogenic acid, chlorogenic acid, oenothein B, rutin, hyperoside, isoquercitrin, quercitrin, quercetin, guaijaverin, afzelin) were purchased from ChromaDex (Santa Ana, CA, USA), Sigma-Aldrich (Saint Louis, MO, USA), and Hwi Analytik (Rülzheim, Germany); all solvents used were of HPLC grade. Water was obtained using a Mili-Q purification system (Millipore, Burlington, MA, USA). Also, other reagents were used, such as sodium carbonate (Sigma-Aldrich, Scnelldorf, Germany), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), aluminium chloride, hexaethylenetetraamine, acetic acid obtained from Sigma-Aldrich (Buchs, Switzerland); potassium persulfate from Alfa Aesar (Karlsruhe, Germany); Trolox (98%) was received from Fluka Chemika (Buchs, Switzerland).

Analytical and chromatographic grade chemicals and solvents were used for this study: acetonitrile, methanol, tetrahydrofuran, acetic acid, α-amyrin, β-amyrin, β-sitosterol, lupeol, erythrodiol, maslinic and oleanolic acids from Sigma-Aldrich (Steinheim, Germany); uvaol, friedelin, betulin, betulinic and corosolic acids from Extrasynthese (Genay, France); and ursolic acid from Carl Roth (Karlsruhe, Germany). Ultrapure water was supplied by a Milli-Q water purification system from Millipore (Bedford, MA, USA).