Potencial antibacteriano de nanoemulsões bifuncionais contendo óleo essencial de murta (Blepharocalyx salicifolius) e oligonucleotídeos anti-ftsz frente a isolados de Staphylococcus aureus resistentes a meticilina

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious public health problem, requiring an urgent demand for new therapeutic agents. Thus, the objective of this work was to evaluate the antibacterial activity of the essential oil of myrtle (Blepharocalyx salicifolius) incorporated in nanoemulsion and to develop bifunctional systems aiming at the co-administration of this oil and an (ON) anti-ftsZ against clinical isolates of S. aureus methicillin resistant (MRSA). The essential oil was obtained by hydrodistillation and characterized by CG-MS. It was then incorporated into a nanoemulsion (NE-O), and later, characterized in terms of physicochemical and morphological aspects, and its determined antibacterial activity. In addition, a cationic bifunctional system was developed, containing myrtle oil and anti-ftsZ ON. The system was characterized and the association of ON and antibacterial activity against MRSA determined. All nanoemulsions showed homogeneous and nanometric droplet size distribution, with zeta potential dependent on the constitution of the formulations. NE-O showed activity higher than free essential oil (up to 65 times) against 12 clinical isolates of MRSA, with Minimum Bactericidal Concentration (MBC) equivalent to 0.19 mg / mL oil. Nanoemulsion components showed antibacterial activity when organized as ananostructure, but not when mixed together. The nanostructures and free essential oil led to a destabilization of bacterial membranes, with leakage of cytoplasmic content, as observed by transmission electron microscopy. The developed bifunctional system presented zeta potential dependent on the amount of added ON. The standardization of an electrophoresis technique allowed the quantification of the ON association rate of 33%, 58.2% and 97.2% for the nanoemulsion / ON load ratios; [+ 0.5 / -]; [+ 2.0 / -] and [+ 4.0 / -], respectively. The complexes obtained in the loading ratio [+ 4.0 / -] presented a minimum bactericidal concentration of 7.8 mg / mL, this effect probably being related to the effect of the essential oil. This paper opens up interesting prospects for the development of new therapeutic products against MRSA from myrtle essential oil.