Hyperoside

UPLC-grade acetonitrile and methanol were purchased from Fisher Scientific (Pittsburgh, PA, USA). All other reagents were of analytical purity. Ultrapure water was prepared by w Milli-Q system (Millipore, Bedford, MA, USA) water purification system. The reference compounds required for the experiment were all purchased from ChromaDex Inc. (Santa Ana, CA, USA), including eleutheroside B, eleutheroside E, protocatechuate, hyperoside, oleanolic acid, kaempferol, isofraxidin, syringci acid, vanillic acid, salicylic acid, cinnamic acid, gallic acid, ferulic acid, cholorogenic acid, caffeic acid, p-hydroxycinnamic acid, p-coumaric acid, petunidin, luteolin, apigenin, naringenin, genistein, quercetin-3-O-rhamnoside, quercetin, myricitrin and catechin. The purities of these standards were higher than 98%.

HPLC-grade water, MeOH, and MeCN were purchased from Avantor Performance Materials Inc. (Center Valley, PA, USA). Formic acid and leucine enkephalin were purchased from Sigma–Aldrich (St. Louis, MO, USA). Reference standards for the identification of LC-MS/MS peaks were purchased as follows: neochlorogenic acid (2) from Interpharm (Koyang, Korea), scopoletin (12) from Sigma Aldrich, chlorogenic acid (6), hyperoside (16), luteolin-7-O-glucoside (18), and isorhamnetin-3-O-β-d-glucoside (24) from Chromadex (Irvine, CA, USA).

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).