Galangin

The standard compounds and reagents (all of analytical grade): MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), DMSO (dimethyl sulfoxide), gallic acid, Na₂CO₃, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), Folin-Ciocalteu’s reagent, resazurin, tetracycline, chloramphenicol, kanamycin, acetonitrile (LC-MS grade, gradient grade), formic acid, 4-methoxybenzoic acid, 4-hydroxy-3-methoxycinnamaldehyde, caffeic acid, quercetin, luteolin and pinostrobin PBS were purchased from Merck (Darmstadt, Germany). The standards of 4-hydroxybenzoic acid, p-coumaric acid, ferulic, isoferulic acid, pinobanksin, chrysin, sakuranetin, naringenin, apigenin, kaempferol, isorhamnetin, acacetin and pinocembrin were obtained from Extrasynthese (Genay, France) and galangin from Alfa Aesar, (Haverhill, MA, USA). The antibiotics: ampicillin, oxacillin, teicoplanin, gentamicin, amikacin, fusidic acid, erythromycin, mupirocin, rifampicin, levofloxacin, norfloxacin, linezolid, bacitracin were purchased from Argenda (Poland). Methanol, ethanol, vanillin, benzoic acid, cinnamic acid were purchased from (POCH, Gliwice, Poland). Ultrapure H₂O (18.0 MΩ) was obtained with a Milli-Q Advantage A10 system (Millipore, Billerica, MA, USA). The absorbance of the reaction mixture in Folin-Ciocalteu, DPPH assays were measured using a Genesys 20 spectrophotometer (Thermo Scientific, Waltham, MA, USA).

All standards and reagents were LC-MS grade and were used without any further treatments. Authentic standards of 2,5-Dihydroxybenzoic acid (gentisic acid), 3,4-dihydroxybenzoic acid (protocatechuic acid), 4-hydroxybenzoic acid, cinnamic acid, epicatechin, eriodictyol, ferulic acid, gallic acid, myricetin, p-coumaric acid, pinoresinol, quercetin, resveratrol, rosmarinic acid, salicylic acid, syringic acid, taxifolin, and vanillic acid were purchased from Sigma-Aldrich (Stenheim, Germany). Apigenin, caffeic acid, catechin, ethyl vanillin (internal standard, IS), galangin, genistein, naringenin, tyrosol, and vanillin were acquired from Alfa Aesar (Karlsruche, Germany), whereas hydroxytyrosol and luteolin were obtained from Santa Cruz Biotechnology (Santa Cruz, CA, USA).
2-Propanol (LC–MS grade) and methanol (MeOH) (LC–MS grade) were purchased from Fisher Scientific (Geel, Belgium) and Merck (Darmstadt, Germany), respectively. Formic acid 99%, ammonium acetate and sodium hydroxide monohydrate for trace analysis ≥ 99.9995% were all obtained from Fluka (Buchs, Switzerland). Ultrapure water (18.2 MΩ resistivity) was provided by a Millipore Direct-Q UV purification System (Millipore, Bedford, MA, USA). The wine samples were filtered using regenerated cellulose syringe filters (RC filters, pore size 0.2 μm, diameter 15 mm) purchased from Phenomenex (Torrance, CA, USA).