H. arenarium inflorescences were kindly provided by the specialized market for dried plant material (Natural Loti, Slovenia). Sample was ground in the electric blender for 1 min, sieved, and kept in a dark place before analysis.
Choline chloride (≥98%), lactic acid (85%), 1,2-propanediol (99%), D-(-)-fructose (≥99%), urea (99–101%), potassium persulfate (K2S2O8, ≥99.5%), iron (III) chloride hexahydrate (FeCl3 × 6H2O, ≥99%), sodium acetate (CH3COONa, p.a.), 2,4,6-tri(2-pyridyl)-s-triazine reagent (TPTZ, ≥99%), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS reagent), (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox, 97%) as well as the analytical standards: chlorogenic acid (>98.0%) and naringenin (≥98.0%) were acquired from Sigma-Aldrich (St. Louis, MO, USA). The HPLC standard for isosalipurposide (phlorizin) (99.9%) was obtained from ChromaDex (Los Angeles, CA, USA). Folin Ciocalteu’s reagent (FCR), glacial acetic acid (99.8%), anhydrous sodium carbonate (Na2CO3, >99.5%), iron (II) sulfate heptahydrate (FeSO4 × 7H2O, ≥99.5%) as well as gallic acid standard (99%) were supplied by Merck (Darmstadt, Germany). HPLC-grade methanol (MeOH) and ethanol (EtOH, 96%) were supplied by Honeywell (Germany) and Kefo (Slovenia), respectively. Ultrapure water was treated in the laboratory on a daily basis.
Choline chloride (≥98%), lactic acid (85%), 1,2-propanediol (99%), D-(-)-fructose (≥99%), urea (99–101%), potassium persulfate (K2S2O8, ≥99.5%), iron (III) chloride hexahydrate (FeCl3 × 6H2O, ≥99%), sodium acetate (CH3COONa, p.a.), 2,4,6-tri(2-pyridyl)-s-triazine reagent (TPTZ, ≥99%), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS reagent), (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox, 97%) as well as the analytical standards: chlorogenic acid (>98.0%) and naringenin (≥98.0%) were acquired from Sigma-Aldrich (St. Louis, MO, USA). The HPLC standard for isosalipurposide (phlorizin) (99.9%) was obtained from ChromaDex (Los Angeles, CA, USA). Folin Ciocalteu’s reagent (FCR), glacial acetic acid (99.8%), anhydrous sodium carbonate (Na2CO3, >99.5%), iron (II) sulfate heptahydrate (FeSO4 × 7H2O, ≥99.5%) as well as gallic acid standard (99%) were supplied by Merck (Darmstadt, Germany). HPLC-grade methanol (MeOH) and ethanol (EtOH, 96%) were supplied by Honeywell (Germany) and Kefo (Slovenia), respectively. Ultrapure water was treated in the laboratory on a daily basis.