Investigação da atividade antibacteriana da própolis vermelha e substâncias isoladas frente a bactérias multirresistentes

• Ano de defesa: 2020
• Autor(a) principal: Silva, Thayná de Souza
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade de Franca; Brasil; Pós-Graduação; Programa de Mestrado em Ciências; UNIFRAN
• Palavras-chave em Português: Química - Produtos naturais; Bactérias multirresistentes; Própolis vermelha; Atividade antibacteriana; Atividade antivirulência; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://repositorio.cruzeirodosul.edu.br/handle/123456789/3066

Resistance to antibacterials is also linked to the existence of genes contained in the microorganism that encode different biochemical mechanisms that impede the action of drugs. Infections caused by these multi-resistant microorganisms are an emerging problem worldwide, and in recent years a considerable number are developing resistance to conventional antibacterials. The global result of the emergence of human pathogens exhibiting multi-drug resistance has been the search for new antimicrobial substances from other sources, including plants. Propolis has been used as a popular medicine since 300 BC, in the literature numerous biological properties have been reported. The composition of propolis varies, depending on the region and time of collection. In view of this biological potential shown by propolis, the scarcity of new antibacterials and the constant increase in multiresistant bacteria, the aim of this study was to evaluate the antibacterial, antibiofilm, synergistic and antivirulence activities of red propolis (crude extract, fractions - dichloromethane, acetate, hexane, nbutanol, and isolated substances – gutiferone E and oblongifolin) against multiresistant bacteria. For the evaluation of antimicrobial activity, the minimum inhibitory concentration (MIC), minimum bactericidal concentration (CBM), inhibition of biofilm formation (CIMB50), fractional inhibitory concentration index (ICIF) and antivirulence against multiresistant strain of S. aureus (ATCC 43300). The results showed a promising antibacterial activity (MIC and CBM of 31.25 and 62.5 μg/mL) for the crude extract of red propolis, against multiresistant strains of Staphylococcus spp. For the isolated substances, promising results were also found where the MIC was 12.5 μg/mL for Staphylococcus spp. The red propolis fractions did not show antibacterial activity against the panel of multiresistant bacteria evaluated. In evaluating the inhibition of biofilm formation against multiresistant bacteria, the substances gutiferone E and oblongifolin inhibited biofilms by more than 50% at concentrations between 1.56 and 6.25 μg/mL for Staphylococcus spp. In the ICIF determination assay, the isolated substances - gutiferone E and oblongifolin - combined with vancomycin, showed only an indifferent effect in these combinations against the evaluated bacteria. In the determination of antivirulence, only the substance gutiferone E (12.5 μg/mL) was able to inhibit catalase, one of the virulence factors of S. aureus (ATCC 43300) evaluated. Therefore, we can conclude that the results of this study evidenced the promising antibacterial potential of the substances gutiferone E and oblongifolin, which can be used in the development of new therapeutic strategies to combat multiresistant strains. Keywords: Multi-resistant bacteria; natural products; red propolis; antibacterial activity; antivirulence activity.