Avaliação in vitro da atividade da paepalantina isoladamente e em associação com antimicrobianos em bactérias multirresistentes

• Autor(a) principal: Alves, Geraldo da Silva
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/7102
• topic: Bacterial-resistance; Paepalantine; Synergism; Resistência bacteriana; Paepalantina; Sinergismo; Biotecnologia; 61

Bacterial resistance is a global threat to public health. The use of plant-derived products with antimicrobial activity in association with traditional antibacterial drugs may be viable alternatives to the production of effective new drugs against multiresistant microorganisms. Isocoumarin paepalantine (PA) and paepalantine dimer (PAD) isolated from the capitula of P. bromelioides, have stood out as a promising substance because of their biological potential. The aim of this study was to evaluate the in vitro antibacterial activity of PA and PAD alone and in association with different antimicrobials (vancomycin, oxacillin and meropenem) in multiresistant strains of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa and to evaluate by scanning electron microscopy possible morphological changes in strains exposed to inhibitory and subinhibitory concentrations of paepalantine and dimer alone and in association with antibacterial agents. In all E. faecium strains, PA and PAD alone presented a minimal inhibitory concentration (MIC) of 32 μg/mL. The association with vancomycin did not show an increase in the activity of this drug. For S. aureus, PA and PAD had good inhibitory potential when tested alone (MIC 16 and 8 μg/mL, respectively). The association between PA and oxacillin was indifferent in three of the five strains analyzed, while the association of the PAD with this drug was synergistic in all of them, with a reduction of up to 256 times in MIC. In Gram-negative microorganisms, K. pneumoniae and P. aeruginosa, PA and PAD presented weak inhibitory potential (MIC> 256 μg/mL) and the association with meropenem did not show an increase in their activity. The present study demonstrated activity of PA and PAD only in Grampositive bacteria (E. faecium and S. aureus). The association of these isocoumarin, especially PAD, with oxacillin presented a relevant synergistic effect, which provides perspective to additional studies for development of products with association of these substances. In S. aureus, after SEM analysis, it was verified that the substances do not act altering the external structure of this microorganism under the conditions used in this study.