X3375

The following materials were used: Lutein (pharmaceutical secondary standard certified reference material; PHR1699; Sigma Aldrich, St. Louis, MO, USA); powdered marigold (Tagetes erecta L.) flower lutein extract (≥20.0% lutein content; henceforth as ‘lutein extract’; Gonmisol, Barcelona, Spain); lutein esters extract (≥20.0% lutein esters content; henceforth as ‘lutein esters extract’; Parry Nutraceuticals, Chennai, Tamil Nadu, India); PSM (59924 [Tween 80]; Sigma Aldrich); MCT oil (Miglyol 812N [F]; IOI Oleochemical Nutrition, Hamburg, Germany); Lipoid H20 (fat-free sunflower lecithin with 20% phosphatidylcholine; Lipoid, Ludwigshafen am Rhein, Germany); xylitol (≥99.0%; X3375; Sigma Aldrich); sodium benzoate (≥99.0%; 71300; Sigma Aldrich); orange concentrate (14.66.001; Presad, Mirna, Slovenia); orange aroma (02 940; Frutarom Etol, Škofja vas, Slovenia); α-tocopherol (vitamin E; ≥87.25%; Shanghai Freemen, Shanghai, China); KOH (Itrij d.o.o., Kropa, Slovenia); NaCl (≥99.5%; 71380; Fluka, Seelze, Germany); acetonitrile (HPLC grade, ≥99.9%; 34851; Honeywell, Seelze, Germany); methanol (HPLC grade, ≥99.8%; 106018; Merck, Darmstadt, Germany); ethanol (absolute; 111727; Merck); ethyl acetate (≥99.5%; 109623; Merck); and n-hexane (≥99.0%; 104367; Merck). Ultrapure water (18.2 MΩ cm, at 25 °C) was used to prepare all of the aqueous solutions, and for all of the other requirements.

Cells of 3x10⁵/well 6 well plate or 2x10⁴/well 96 well plate were seeded in triplicate in the growth medium unless specified otherwise. The following day, the medium was supplemented with ribitol (A5502 Sigma, St. Louis) or D-ribose (R7500 Sigma) or xylitol (X3375 Sigma) at a concentration of 10 mM, unless otherwise noted, and the cells were grown in the supplement for 3 days. Plates were washed with PBS and cells were processed for analysis by FACS, metabolomics, immunocytochemistry, and western blot.