Uvaol

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.

β-Amyrin, α-amyrin, lupeol, erythrodiol, uvaol, oleanolic acid, ursolic acid, and asiatic acid were purchased from Extrasynthese (Genay, France). Betulin and MeJA were purchased from Sigma-Aldrich (St. Louis, MO, USA). Betulinic acid was purchased from Tokyo Chemical Industry (Tokyo, Japan). Soyasapogenol B and soyasapogenol A were purchased from Tokiwa Phytochemical (Chiba, Japan). Sophoradiol, 24-hydroxy-β-Amyrin, and soyasapogenol E were kindly provided by Dr. Kiyoshi Ohyama (Tokyo Institute of Technology, Japan).

All triterpenoid standards (uvaol, β-amyrin, erythrodiol, oleanolic acid, and maslinic acid) were purchased from Extrasynthese (Genay, France).