Avaliação in vitro da atividade anti-leishmania induzida por complexos metálicos a base de prata

Abstract

Leishmaniasis is an infectious disease - parasitic caused by a parasite of the genus Leishmania and transmitted by the bite of infected female sandfly. Human infections caused by Leishmania can manifest in different ways, depending on the causal species, such as cutaneous leishmaniasis (CL) or visceral leishmaniasis (VL). The therapeutic arsenal against LT is still very restricted. The pentavalent antimony remain the drugs of choice for the treatment and, despite its efficacy, have side effects with prolonged treatment time. Medicinal Chemistry Inorganic have offered new possibilities for research, and metals, especially transition, offer some advantages over drugs, including the variety of oxidation states, enabling their participation in redox biological processes. In the present work we studied the in vitro effect of two metal complexes silver base (Ag1 and Ag2), against promastigotes and amastigotes of Leishmania. (Leishmania) amazonensis and Leishmania. (Viannia) guyanensis in periods of 24, 48 and 72 hours. The metal complexes were synthesized by the team of "Istituto per l'Energetica and le Interfasi" IENI, Padua, Italy (CNR, National Research Council, IT) and sent to biological testing at the National Institute for Amazonian Research (INPA). Results of bioassays with L. (L.) amazonensis showed that Ag2 substance showed higher anti-leishmania activity in the concentration of 160μM/ml, from 72h, EC50 14.53 uM/ml in the manual counting method, and by the MTT method at 24 hours period with EC50 11.35 uM/mL. In cons tests the amastigote form, there was little infection of macrophages by Ag1 complex, 25% infected, compared with 61% without infection amastigotes. Results with L. (V.) guyanensis, the manual counting method, Ag1 did not show satisfactory values, with EC50> 60 uM / ml, Ag2 showed moderate activity in the period of 24h and 48h, EC50 43.22 uM / ml and 57, 64 uM / ml. For the MTT the two substances had EC50 values> 60 uM / ml. Against amastigote forms, with Ag1 complex was cell death of the macrophages. Ag2 showed 38% infection rate, with 47% of uninfected macrophages. Thus, the two metal complexes did not perform well when tested across the promastigote and amastigote forms of L. (V.) guyanensis. Against forms L. (L.) amazonensis, both complexes showed satisfactory results, and the Ag2 complex, with better results in promastigote and amastigote forms