Ruthenium Polypyridyl Complexes: Synthesis, Characterization and Biological Activity on Leishmania (L) Mexicana

Tris-polypyridine ruthenium complexes were synthesized by the reaction methods reported. These compounds were characterized by FAB-mass, Elemental Analysis, 1H/31P NMR, UV-Vis and IR spectroscopies. Absorption and viscometric studies, carried out by the interaction of the complexes [Ru(bipy)2phendiamine] (PF6)2 (1) and [Ru(phen)2Phendione](PF6)2 (2) with calf thymus DNA, suggested that the complex 2 binded by intercalation, whilst the complex 1 did by a nonintercalative way, likely by the groove binding mode. The biological activity of the complexes was tested in vitro on Leishmania (L) mexicana promastigotes. The growth inhibition of 36% and 49% by 1 and 2 respectively, after 48 hours of treatment with 10 μM concentration, was associated with high proportion of parasite fission forms, motility loss and abundant vacuolization. These findings suggest that the leishmanistatic activity could be related to complexes-DNA parasite interactions as possible mechanism of action, constituting new promising chemotherapeutic alternatives in the fight against cutaneous leishmaniasis.