Structure-based design, optimization of lead, synthesis, and biological evaluation of compounds active against Trypanosoma cruzi.

Chagas' disease affects approximately eight million people throughout the world, especially the poorest individuals. The protozoan that causes this disease-Trypanosoma cruzi-has the enzyme cruzipain, which is the main therapeutic target. As no available medications have satisfactory effectiveness and safety, it is of fundamental importance to design and synthesize novel analogues that are more active and selective. In the present study, molecular docking and the in silico prediction of ADMET properties were used as strategies to optimize the trypanocidal activity of the pyrimidine compound ZN3F based on interactions with the target site in cruzipain. From the computational results, eight 4-amino-5-carbonitrile-pyrimidine analogues were proposed, synthesized (5a-f and 7g-h) and, tested in vitro on the trypomastigote form of the Tulahuen strain of T. cruzi. The in silico study showed that the designed analogues bond favorably to important amino acid residues of the active site in cruzipain. An in vitro evaluation of cytotoxicity was performed on L929 mammal cell lines. All derivatives inhibited the Tulahuen strain of T. cruzi and also exhibited lower toxicity to L929 cells. The 5e product, in particular, proved to be a potent, selective (IC50 = 2.79 ± 0.00 µM, selectivity index = 31.3) inhibitor of T. cruzi. The present results indicated the effectiveness of drugs based on the structure of the receptor, revealing the potential trypanocidal of pyrimidines. This study also provides information on molecular aspects for the inhibition of cruzipain.

Synthesis, antimicrobial evaluation and in silico studies of the (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles

In recent years, investigations in the field of oxadiazoles have been intensified due to their numerous therapeutic uses. Oxadiazoles are a class of compounds that exhibit several biological applications, citing antimicrobial, anti-inflammatory, anti-diabetic, anthelmintic, anti-tumor, among others. Encouraged by the biological potential of oxadiazoles, were carried out synthesis, antimicrobial evaluation and in silica studies of five (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles. In this way, (Z)-aryl-N'-hydroxybenzimidamides and ethyl (E)-cinnamate were synthesized, which were subjected to an O-acylamidoxime reaction after by dehydration using microwave irradiation to form the oxadiazole nucleus. The compounds were characterized by spectroscopic techniques, while in vitro antimicrobial activity was evaluated against S. aureus, E. faecalis, E. coli, P. aeruginosa, and against the fungus C. utilis using the microplate microdilution method. Thus, (Z)-aryl-N'-hydroxybenzimidamides, ethyl (E)-cinnamate, and (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles were synthesized with yields ranging from moderate to good. The (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles exhibited a reduced spectrum of action, which were active against the bacterium P. aeruginosa and for the fungus C. utilis.