Comparing the Antileishmanial Activity of Gold(I) and Gold(III) Compounds in L. amazonensis and L. braziliensis in Vitro

Abstract: A series of mononuclear coordination or organometallic Au(I)/Au(III) complexes (1–9) have been comparatively studied in vitro for their antileishmanial activity against promastigotes and amastigotes, the clinically relevant parasite form, of Leishmania amazonensis and Leishmania braziliensis. One of the cationic Au(I) bis‐N‐heterocyclic carbenes (3) has low EC(50) values (ca. 4 μM) in promastigotes cells and no toxicity in host macrophages. Together with two other Au(III) complexes (6 and 7), the compound is also extremely effective in intracellular amastigotes from L. amazonensis. Initial mechanistic studies include an evaluation of the gold complexes′ effect on L. amazonensis’ plasma membrane integrity.