Investigação do potencial antifúngico de compostos heterocíclicos, contendo anel 1, 2, 4 - oxadiazol, sobre fungos potencialmente patogênicos.

Abstract

In addition to the increased incidence of mycoses in recent years, another major problem is the treatment of these infections, given the increasing number of resistant microorganisms resulting from the indiscriminate use of antimicrobials. This problem is exacerbated by the countless adverse reactions that these drugs may cause. In that way, there is a constant search for new substances that present safer, more effective and potent antifungal action. In this context, heterocyclic compounds containing the 1,2,4-oxadiazole ring have been the subject of several pharmacological studies, and presented promising results. Thus, the present study aimed to investigate the antifungal potential of eight compounds of this nature against different potentially pathogenic fungi, including filamentous strains (Aspergillus flavus LM-27, Aspegillus niger LJB-01 e Rhizopus orizae LM-64) and yeast strains (Candida tropicalis HU-01, Trichosporon inkin LM-67, Geotrichum LM-03 e Rhodotorula LM-014). Therefore, microbiological screening was performed based on the solid medium diffusion technique and the Minimum Inhibitory Concentration (MIC) was determined by serial microdilution technique, the Minimum Fungicide Concentration (MFC) was also performed by sowing aliquots of 10 μL of the products present in the wells that did not show fungal growth in Sabouraud Agar Dextrose medium. As for the microbiological screening, the four yeasts tested showed resistance, and no inhibition halos were observed. Regarding to MIC, all the substances tested showed antifungal activity only against the filamentous fungus Rhizopus orizae LM-64 with MIC of 1000 μg/mL for one of the substances and 4000 μg/mL for the remaining substances. In relation to MFC, out of the eight substances tested, six presented MFC of 4000 μg/mL. The results obtained in this research allow us to conclude that there was fungal resistance to some of the compounds tested and that others had low antifungal activity, but this result contributes to the knowledge of the therapeutic potential of this class of compounds, since this is the first report on the antifungal activity of this group of heterocyclic compounds containing the 1,2,4-oxadiazolic ring.