Notes: Thioredoxin reductase 1 inhibitor 1 (TRi-1) is an irreversible inhibitor of thioredoxin reductase 1 (TrxR1; IC50 = 0.012 µM).{55379} It inhibits TrxR1-induced reduction of Trx1 in a cell-free assay (IC50 = 4.3 µM). TRi-1 (10 µM) reduces the mitochondrial oxygen consumption rate in HCT116 colorectal cancer cells. It increases the intracellular levels of hydrogen peroxide in FaDu head and neck squamous cell carcinoma (HNSCC) cells in a time- and concentration-dependent manner. TRi-1 decreases the viability of FaDu cells (IC50 = 0.72 µM). In vivo, TRi-1 (10 mg/kg twice per day) decreases tumor growth in a FaDu HNSCC mouse xenograft model. It induces intratumoral apoptosis in a FaDu HNSCC mouse xenograft model when administered at a dose of 5 mg/kg daily. TRi-7 also is toxic to S. mansoni adult worms (LD50 = 10.07 µM).{67537}