DS44170716 is an inhibitor of Ca2+-induced mitochondrial permeability transition. It has a different mechanism of action from cyclosporin A that is not dependent on PPIF, a peptidyl-prolyl cis-trans isomerase associated with the mitochondrial permeability transition pore (MPTP). Instead DS44170716 blocks Ca2+ flux into the mitochondria by decreasing mitochondrial membrane potential and inhibits enzyme activities of mitochondrial respiratory chain complex III, IV and V. It showed a similar potent protective effect against Ca2+-induced death in human liver cells as Cyclosporin A.