Atividade antifúngica contra Aspergillus e caracterização toxicológica da amida sintética 2- cloro-N-fenilacetamida

• Ano de defesa: 2021
• Autor(a) principal: Ferreira, Elba dos Santos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Farmacologia; Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos; UFPB
• Palavras-chave em Português: Aspergillus; Antifúngico; Acetamidas; Ergosterol; Toxicidade; Antifungal; Acetamides; Toxicity; CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/123456789/22826

The Aspergillus genus comprises a group of saprophytic fungi that cause opportunistic infections that mainly affect immunocompromised individuals. The species A. flavus and A. niger are, respectively, the second and third major causes of aspergillosis documented in the literature. Knowing that Aspergillus spp resistance to current therapies has been growing and reducing the possibilities of treatment with available antifungal agents, and that the synthetic amide 2-chloro-N-phenylacetamide has shown antifungal potential against this genus, the aim of this study was to evaluate the effect of synthetic amide 2-chloro-N-phenylacetamide on Aspergillus and to determine its toxicological profile. Therefore, the minimum inhibitory concentration, minimum fungicidal concentration, conidia germination, associations with antifungal agents, elucidation of the probable mechanism of action by assays involving fungal cell wall and membrane, as well as molecular prediction by docking, were evaluated. The pharmacokinetic and toxicological profile was evaluated from in silico assays using Swiss ADMET and OSIRIS software. In addition, cytotoxicity was evaluated in vitro through the hemolysis test, the protective capacity through the osmotic fragility test and the ex vivo genotoxic effects on cells of the oral mucosa. It was observed that 2-chloro-N-phenylacetamide showed antifungal activity against A. flavus strains with minimal inhibitory concentrations between 16 and 256 μg/mL and minimal fungicidal concentrations ranging from 32 to 512 μg/mL. The evaluated compound showed antifungal activity against A. niger strains with MICs and CFMs ranging, respectively, from 32 and 256 μg/mL, and 64 to 1024 μg/mL, thus exhibiting fungicidal activity for all strains used. For both species, 2-chloro-N-phenylacetamide promoted inhibition of conidia germination at all concentrations used, and the association with amphotericin B or voriconazole was antagonistic. Ergosterol binding in the fungal plasma membrane is the likely mechanism of action, together with the possible inhibition of DNA synthesis through inhibition of thymidylate synthase. In the evaluation of the in silico pharmacokinetic and in vitro and ex vivo toxicological profile, it was observed that 2-chloro-N-phenylacetamide presents favorable physicochemical parameters according to Lipinski's rule, presenting good oral bioavailability, absorption through the tract gastrointestinal, ability to cross the bloodbrain barrier, inhibition of CYP1A2 and mutagenic, tumorigenic, and reproductiverelated damage effects. 2-chloro-N-phenylacetamide, has low hemolytic capacity at concentrations of 50, 100 and 500 µg/mL, medium toxicity at a concentration of 1000 µg/mL and shows a protective effect of red blood cells of blood types A and O. The compound promotes few genotoxic changes, including karyolysis and karyorrhexis in cells of the oral mucosa, but at a lower frequency than that observed for the positive control hydrogen peroxide. Therefore, it can be concluded that 2-chloro-Nphenylacetamide has promising antifungal potential with a favorable pharmacokinetic profile for oral administration, and low cytotoxic and genotoxic potential, being a promising candidate for in vivo toxicity studies.