Naringin

1,1-Diphenyl-2-picrylhydrazyl radical (DPPH); 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox); 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), dimethyl sulfoxide (DMSO), FeCl₃, acetonitrile, formic acid, sweroside (S), and secologanin (SLo) were acquired from Sigma-Aldrich (Steinheim, Germany). Acetic acid was obtained from Chempur (Piekary Śląskie, Poland). acetonitrile for LC–MS was purchased from POCh (Gliwice, Poland). Cyanidin 3-O-glucoside (Cy 3-glc) and p-coumaric acid (p-CuA), caffeic acid (CA), ferulic acid (FA), quercetin 3-O-glucoside, luteolin 7-O-glucoside (Lglc), luteolin 7-O-rutinoside, diosmin, hesperidin, naringin, rutin, (+)-catechin, (−)-epicatechin, procyanidin B1, loganic acid (LA), and loganin (Lo) were purchased from Extrasynthese (Lyon Nord, France). 5-O-caffeoylquinic acid (5-CQA, chlorogenic acid), 3-O-caffeoylquinic acid (3-CQA, neochlorogenic acid), and 4-O-caffeoylquinic acid (4-CQA, cryptochlorogenic acid) were purchased from TRANS MIT GmbH (Giessen, Germany). All reagents were of analytical grade.

Methanol of analytical grade purity was from Lab-Scan (Lisbon, Portugal). The culture media Brain Heart Infusion Agar (BHIA), Mueller Hinton Broth (MHB), Mueller Hinton Agar (MHA), and all the antibiotics were obtained from Oxoid (Hampshire, UK). The saline solution was prepared with NaCl from Merck (Darmstadt, Germany). The dye resazurin and crystal violet were purchased from Sigma-Aldrich (St Louis, Mosby, USA). All the organic solvents were HPLC grade. Ultrapure water from purified system (Isopad Isomantle, Gemini BV, Pr Beatrixlaan 301, 7312 DG Apeldoorn, Netherlands) was used. External standards caffeic acid, catechin, chlorogenic acid, ferulic acid, gallic acid, (-)-epicatechin, naringin, p-hydroxybenzoic acid, quercitrin, and rutin were purchased from Extrasynthese (Lyon Nord, Genay Cedex, France). Dulbecco's Modified Eagle Medium (DMEM), fetal bovine serum (FBS), non-essential amino acids, penicillin, streptomycin, and trypsin–EDTA were obtained from Invitrogen Corporation (Life Technologies, SA, Madrid, Spain).

Methanol and ethanol of analytical grade (Fisher Chemical, Loughborough, UK) were used as extraction solvents. Folin-Ciocalteu, gallic acid, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), 2,2-diphenyl-1-picrylhydrazyl (DPPH), sodium carbonate, potassium persulfate, 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), acetic acid, hydrochloric acid, ferric chloride, acetonitrile, and trifluoroacetic acid (TFA) were purchased from Sigma-Aldrich (St. Louise, MO, USA). All the organic solvents were HPLC grade. Ultrapure water from a purified system (Isopad Isomantle, Gemini BV, Pr. Beatrixlaan 301, 7312 DG Apeldoorn, The Netherlands) was used. External standards (purity ≥ 99%) caffeic acid, catechin, chlorogenic acid, diosmetin, ferulic acid, glycitin, isorhamnetin, (-)-epicatechin, luteolin-7-O-glucoside, luteolin-4′-O-glucoside, myricetin, naringin, p-hydroxybenzoic acid, quercetin, and rutin were purchased from Extrasynthese (Lyon Nord, Genay Cedex, France). Hispidin (purity ≥ 98%) was purchased from Sigma-Aldrich.