Tetrahydrophthalazinone Inhibitor Of Phosphodiesterase With In Vitro Activity Against Intracellular Trypanosomatids

The phosphodiesterase inhibitor tetrahydrophthalazinone NPD-008 was explored by phenotypic in vitro screening, target validation, and ultrastructural approaches against Trypanosoma cruzi. NPD-008 displayed activity against different forms and strains of T. cruzi (50% effective concentration (EC50), 6.6 to 39.5 mu M). NPD-008 increased cAMP levels of T. cruzi and its combination with benznidazole gave synergistic interaction. It was also moderately active against intracellular amastigotes of Leishmania amazonensis and Leishmania infantum, confirming a potential activity profile as an antitrypanosomatid drug candidate.