Potent thioredoxin reductase (TrxR) inhibitor (EC50 = 2.8 nM, IC50 = 0.03 and 0.1 μM in MCF-7 cells and HT-29 cells, respectively). Highly stable in vivo; exhibits no significant ligand exchange with albumin. Inhibits tumor proliferation in vitro and in vivo by inducing cell death. Selectively kills cancer cells. Purity 98%. MW (observed): 596.43