Diphenyl diselenide

Silver nitrate (>99%) and diphenyl diselenide (98%) were used as received by Sigma-Aldrich (St. Louis, MO) and TCI America (Portland, OR). Toluene was used as received by EMD Millipore (Hayward, CA). 18.2 MΩ deionized water was supplied by Millipore (Billerica, MA). Glass scintillation vials and Thermo-Fast™ 96-Well Full-Skirted Plates were purchased from Thomas Scientific (24-400). Plastic conical 1.5 ml tubes were purchased from Thomas Scientific. Dichloromethane (99.6%) was used as received by Acros Organics. DMSO (99.7%) was used as received by Cambridge Isotope Labs Incorporated. Ethyl acetate (<99.5%) was used as received by Fisher Scientific. Cyclohexane (≥99%) was used as received by Avantor.

The Se compounds tested in this study included a naturally-derived organic molecule, selenomethionine (Cayman Chemical Company^®—Ann Arbor, MI, USA), inorganic molecules sodium selenate (Sigma-Aldrich^®—USA) and sodium selenite (Sigma-Aldrich^®—USA), and synthetic organoselenium molecules, ebselen (Sigma-Aldrich^®—USA) and diphenyl diselenide (Sigma-Aldrich^®—USA) (Figure 1). selenomethionine, sodium selenate, and sodium selenite were prepared in phosphate-buffered saline (PBS) (Sigma-Aldrich^®—USA). ebselen and diphenyl diselenide were prepared in dimethyl sulfoxide (DMSO) (Êxodo Cientifica^®—Sumaré, Brazil).