Nicotiflorin

Reference standards of apigenin, daidzein, daidzin, formononetin, genistein and genistin were obtained from Sigma-Aldrich Co. (St Louis, MO, USA); astragalin, calendoflavoside, cosmosiin, cynaroside, glycitin, hyperoside, isoquercitrin, isorhamnetin 3-O-glucoside, luteolin, narcissin, nicotiflorin and rutin as well as 6-methoxyluteolin and 6-methoxyflavone as internal standards were purchased from Extrasynthese (Genay, France); 6-O-malonyldaidzin and 6-O-malonylgenistin from Synthose Inc. (Ontario, Canada); kaempferol 3-O-gentiobioside, quercetin 3-O-gentiobioside and quercetin 3-O-sophoroside from PhytoLab GmbH & Co. (Vestenbergsgreuth, Germany); Cacticin and trifolin from MedChemExpress (Monmouth Junction, USA). LC–MS grade methanol, acetonitrile and water were supplied from Thermo Fisher Scientific Inc. (Waltham, MA, USA). Besides, formic acid (Junsei Chemical, Tokyo, Japan) was used as eluent additive in extraction and chromatographic separation of flavonoid derivatives.

The following chemicals were used: methylglyoxal (40% in water), 2,2–diphenyl–1–picrylhydrazyl,2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid, trolox, metformin hydrochloride, 98–100% formic acid, methanol (HPLC grade), acetonitrile (HPLC gradient grade and LC–MS grade), and water (LC–MS grade) were purchased from Merck–Sigma–Aldrich (Sigma–Aldrich Sp. z o.o., Poznań, Poland); NaCl, KCl, Na₂HPO₄ and KH₂PO₄ (reagent grade) were obtained from Chempur (Piekary Śląskie, Poland); quercetin, quercitrin, astragalin, hyperoside, rutin, nicotiflorin, narcissin, taxifolin, gallic acid, p-coumaric acid, ferulic acid, caffeic acid, and chlorogenic acid were from Extrasynthese (Genay Cedex, France); galegine sulfate was purchased from SelectLab (Münster, Germany). Water was glass-distilled and deionized.
The stock solutions of standards (1 mg/mL) were prepared by dissolving 5 mg of a reference compound in 5 mL of methanol. Working standard solutions in the range of 10–400 μg/mL were made by mixing with 50% aq. (aqueous) methanol (v/v), filtered through hydrophilic Millex Syringe Filters (Durapore 0.22 μm; Millipore, Burlington, MA, USA) and stored at −20 °C.

All chemicals and reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA) unless stated otherwise. Narcissin and nicotiflorin were purchase from Extrasynthese (Genay, France). Solvents for HPLC experiments were purchased from Burdick & Jackson (Morristown, NJ, USA). All cell culture reagents were purchased from Gibco (Grand Island, NY, USA) unless stated otherwise. The Lyophilized powder of dried OFI fruits was purchased from Jeju Cactus Town (Hallim, Jeju-do, Korea) and a representative sample (150101MC) has been deposited at the Herbarium of the College of Science, Sookmyung Women’s University, Seoul, Republic of Korea. The composition of the OFI fruit extract has been analyzed using HPLC-diode array detector (DAD) as described previously [12 (link),13 (link)] (Figure S1A and Table S3). Stock solutions of chemicals or OFI powder were prepared in dimethyl sulfoxide (DMSO) or olive oil and a solution of the lyophilized powder of OFI fruits was defined as OFIE in this study. The enzyme-hydrolyzed (hdl) OFIE sample was prepared as described previously [13 (link)]. The composition of the hdl OFIE has been presented in Figure S1B and Table S3. Human liver microsomal fraction (UltraPool^TM HLM150; Catalog No. 452117) was purchased from Corning (San Jose, CA, USA).