Síntese, caracterização e avaliação antitubercular e antileishmanial de complexos de prata(I) com sulfas e bases de Schiff

Abstract

Tuberculosis is an airborne infectious disease that primarily affects the lungs. Despite advances in treatment and control, it remains a serious global public health issue, particularly in resource-limited regions. Similarly, leishmaniasis is endemic in many parts of the world, especially in tropical and subtropical regions, and despite available treatments, it also poses a global problem. Therefore, studying new drugs that are more effective with fewer side effects and lower toxicity against tuberculosis and leishmaniasis is of great importance. In this work, eight Schiff bases were synthesized and characterized using the sulfonamides sulfapyridine, sulfadiazine, sulfacetamide, and sulfamerazine, and the aldehydes o-vanillin and salicylaldehyde. The crystal structures of four of these Schiff bases were determined by X-ray diffraction of polycrystals. Eight silver(I) complexes were obtained from these Schiff bases. Additionally, new silver(I) complexes were synthesized from free sulfonamides (sulfapyridine, sulfamerazine, and sulfanilamide), and their crystal structures were determined by X-ray diffraction of polycrystals. Biological tests were conducted against L. amazonensis, in both promastigote and amastigote forms, with the Schiff bases and their respective silver(I) complexes. Some compounds showed activity, though it was lower compared to that of reference drugs. In addition to these tests, assays against M. tuberculosis were performed using silver(I) complexes with sulfapyridine and sulfamerazine. The results showed that the complex with sulfamerazine, compared to silver sulfadiazine, exhibited good selectivity, with a MIC90 value of 1.61 µmol/L and a selectivity index of 3.67, supporting future studies as a promising new antimycobacterial agent.