Maslinic

We purchased commercial lyophilizates of oleanolic, maslinic, and ursolic acids (references 42515, 68594, and 89797, respectively; Sigma-Aldrich, Barcelona, Spain), and suspended them in dimethyl sulfoxide to obtain three solutions of triterpenic acids: one with oleanolic acid (100%) (T1), one with maslinic acid (100%) (T2), and one with ursolic acid (100%) (T3).

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).