Rhamnetin

Neochlorogenic acid (3-CQA) (4), chlorogenic acid (5-CQA) (6), apigenin (30), luteolin (31), quercetin (35), isoquercitrin (49), hyperoside (50), luteolin-7-O-rutinoside (54), and rutin (55) were obtained from Extrasynthese (Genay, France). 3,4-O-diCQA (12), 3,4-O-diCQA (13), diosmetin (33), rhamnetin (37), isorhamnetin (38), luteolin-7-O-glucuronide (47), isorhamnetin-7-O-glucoside (51), and isorhamnetin-3-O-rutinoside (57) were purchased from PhytoLab (Vestenbergsgreuth, Germany).
The UHPLC-ESI/HRMS analyses were carried out on a Q Exactive Plus heated electrospray ionization (HESI-II) – high resolution mass spectrometer (HRMS) (ThermoFisher Scientific, Inc., Bremen, Germany) equipped with an ultra-high-performance liquid chromatography (UHPLC) system Dionex Ultimate 3000RSLC (ThermoFisher Scientific, Inc.) [60 (link)].

HPLC-grade acetonitrile (LC-MS grade), methanol, ethanol, petroleum ether, formic acid (>98% purity), Folin–Ciocalteu’s phenol reagent, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH^•), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS^TM), potassium persulphate, (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), gallic acid, quercetin, kaempferol, resveratrol, and rutin were supplied by Merck (Milan, Italy). De-ionized water (18.2 MΩ cm) was obtained from a Milli-Q purification system (Millipore, Bedford, MA, USA). quercetin 3-O-glucoside, kaempferol-3-O-rutinoside, kaempferol-3-O-glucoside, and hyperoside were supplied by Extrasynthese (Genay Cedex, France). Rhamnetin, isoRhamnetin, caftaric acid, and quercetin 3-O-glucuronide were from Phytolab (Vestenbergsgreuth, Germany).