Robinin

Human monoamine oxidase (hMAO) isozymes, robinin, rutin, nicotiflorin, daidzin, genistin, coumestrol, daidzein, genistein, curcumin, amyloid β peptide 25–35 (Aβ_25–35), hexafluoroisopropanol (HFIP), and selegiline hydrochloride were purchased from Sigma-Aldrich (St. Louis, MO, USA). All solvents used for high pressure liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (HPLC–Q-TOF–MS) were liquid chromatography–mass spectrometry grade and purchased from Merck (Darmstadt, Germany).

The designation of antibacterial activity of 10 selected, plant-originated compounds (dioscin, aescin, glycyrrhetinic acid, ginsenoside Rg3, procyanidin A2 and C1, hypericin, robinin, amentoflavone, and zeaxanthin; all from Sigma-Aldrich, St. Louis, MO, USA) against H. pylori J99 was made by checking their minimum inhibitory concentrations (MICs) [93 (link),94 (link)]. To obtain this, bacteria in a density of 10⁷ CFU/mL were cultured in 12-well titration plates (Bionovo, Legnica, Poland) filled with 1 mL of Brain Heart Infusion broth (BHI; Oxoid, Dardilly, France) with 5% fetal calf serum (FCS; Gibco, Paisley, Scotland, UK) and a concentration gradient of the tested compounds (2–256 µg/mL). The titration plates were then followed for 3 days of microaerophilic incubation at 37 °C and 100 rpm shaking (MaxQ 6000, ThermoFisher, Waltham, MA, USA). Then, bacterial turbidity in each well of the plates was determined visually, and the lowest concentration with the lack of growth was considered as the MIC.