AVALIAÇÃO DO POTENCIAL CITOPROTETOR DE Stryphnodendron rotundifolium Mart., CONTRA EFEITO TÓXICO DO CLORETO DE MERCÚRIO

Os metais pesados são potentes poluentes ambientais que podem causar sérios danos a aos seres vivos quando em contato prolongado. O mercúrio, metal com elevada capacidade de bioacumulação no solo e em ambientes aquáticos, pode atingir uma cadeia biológica e bioacumular-se, representando um alto risco aos organismos vivos. O Stryphnodendron rotundifolium Mart., popularmente conhecido como “barbatimão” bastante citado quanto ao seu uso popular em virtude das propriedades antimicrobianas e de suas funções biológicas referente à atividade antioxidante, pode ser uma alternativa para a proteção ambiental contra metais pesados. O presente estudo objetiva avaliar o efeito citoprotetor Stryphnodendron rotundifolium Mart., contra cloreto de mercúrio (HgCl2) em modelos microbianos (bactérias e fungos). Para tanto, realizou-se a determinação da Concentração Inibitória Mínima (CIM) e, a partir desta, a avaliação do potencial tóxico do HgCl2 por meio do uso de placas estéreis de microdiluição. O extrato foi utilizado nas concentrações subinibitórias de 32 e 64 µg/mL para bactérias e de 128 e 256 µg/mL para fungos e o HgCl2 na concentração inicial de 1mM. Observou-se que o extrato em questão apresentou leve efeito citoprotetor em modelos bacterianos e não apresentou tal efeito em cepas fúngicas. Vale ressaltar ainda que, nesse último, extrato potencializou o efeito tóxico, promovendo a morte dos fungos em concentrações menores do metal. Acredita-se que tal fato possa ser explicado pelos efeitos antimicrobianos atribuídos ao Stryphnodendron rotundifolium, devido ao seu elevado conteúdo de taninos, o que requer estudos mais aprofundados para maiores conclusões.

Evaluación de la actividad antibacteriana y moduladora del extracto etanólico de Calotropis procera (Aiton) W.T. Aiton contra cepas bacterianas multirresistentes

El objetivo de este estudio fue evaluar la actividad antibacteriana y moduladora del extracto etanólico de Calotropis procera (Aiton) W.T. Aiton contra cepas multirresistentes de bacterias. Por el método de microdilución, fueron definidas la concentración inhibidora mínima (MIC) del extracto y la modulación con la concentración inhibidora CIM / 8 del extracto con norfloxacina, gentamicina e imipenem contra Staphylococcus aureus, Escherichia coli y Pseudomonas aeruginosa. Se obtuvo 512 μg/mL para g/mL para Pseudomonas aeruginosa. Se descubrió sinergismo en el caso de Staphylococcus aureus, en la modulación con norfloxacina y gentamicina, mientras que con imipenem frente a Pseudomonas aeruginosa y con gentamicina para Escherichia coli. Con base en estos resultados, se necesitan más estudios para probar la actividad antibacteriana del extracto.The objective of this study was to evaluate the antibacterial and modulatory activities of ethanolic extract of Calotropis procera (Aiton) W.T. Aiton against resistant species. By microdilution method, the minimum inhibitory concentration (MIC) of the extract and modulation of the subinhibitory concentration MIC/8 to norfloxacine, gentamicin and imipenem against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. There was obtained 512 μg/mL para g/mL to Pseudomonas aeruginosa. To Staphylococcus aureus, modulation showed synergism to norfloxacin and gentamicin, with imipenem against Pseudomonas aeruginosa and gentamicin against Escherichia coli. Based on these results, more studies are needed to test the antibacterial activity of the extract

Effect of α-Bisabolol and Its β-Cyclodextrin Complex as TetK and NorA Efflux Pump Inhibitors in Staphylococcus aureus Strains

Efflux pumps are proteins present in the plasma membrane of bacteria, which transport antibiotics and other compounds into the extracellular medium, conferring resistance. The discovery of natural efflux pump inhibitors is a promising alternative. α-Bisabolol is a sesquiterpene isolated from several plants such as Matricaria chamomilla L. and has important properties such as antibacterial and anti-inflammatory activity. Currently, the formation of inclusion complexes with β-Cyclodextrin has been used for improving the physicochemical characteristics of the host molecule. This study evaluated the effect of α-Bisabolol, in isolation and in complexation with β-Cyclodextrin, as TetK and NorA efflux pump inhibitors in Staphylococcus aureus strains. The minimum inhibitory concentration (MIC) was determined. Subsequently, inhibitory activity over the pumps was observed by an MIC reduction for the antibiotics, by using subinhibitory concentrations (MIC/8) in combination with tetracycline and norfloxacin. The MIC of the compounds was ≥1024 μg/mL. α-Bisabolol potentiated the action of tetracycline and reduced the MIC of norfloxacin to a clinically relevant concentration. The complexed substance showed synergism however, the effect of the isolated α-Bisabolol was superior to the complex. These results indicate α-Bisabolol is a potential substance to be used as an efflux pump inhibitor

Physico-chemical characterization and antibacterial activity of inclusion complexes of Hyptis martiusii Benth essential oil in β-cyclodextrin

Bezerra, Daniel Pereira. Fundação Gonçalo Moniz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil. a Pharmacy Department, Federal University of Sergipe, Sergipe, Brazil b Department of Biological Chemistry, Regional University of Cariri, Crato, Ceará, Brazil c Physiology Department, Federal University of Sergipe, Sergipe, Brazil d Gonçalo Muniz Research Center, Oswaldo Cruz Foundation, Bahia, Brazil e Department of Mineralogy and Geotectonics, Institute of Geosciences, University of SãoPaulo-SP, BrazilSubmitted by Ana Maria Fiscina Sampaio ([email protected]) on 2018-04-23T13:36:40Z No. of bitstreams: 1 Andrade TA Physico-chemical....pdf: 3585852 bytes, checksum: 8a7e1bcbe17cb62a62c347459f8804ba (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2018-04-23T13:48:34Z (GMT) No. of bitstreams: 1 Andrade TA Physico-chemical....pdf: 3585852 bytes, checksum: 8a7e1bcbe17cb62a62c347459f8804ba (MD5)Made available in DSpace on 2018-04-23T13:48:34Z (GMT). No. of bitstreams: 1 Andrade TA Physico-chemical....pdf: 3585852 bytes, checksum: 8a7e1bcbe17cb62a62c347459f8804ba (MD5) Previous issue date: 2017Conselho Nacional de Desenvolvimento Científico e Tecnológico/CNPq/Brazil and Fundação de Amparo à Pesquisa do Estado de Sergipe/FAPITEC-SE.Múltipla – ver em NotasCyclodextrins (CDs) have been used as important pharmaceutical excipients for improve the physicochemical properties of the drugs of low solubility as the essential oil of Hyptis martiusii. This oil is important therapeutically, but the low solubility and bioavailability compromises your use. Therein, the aim of this study was to obtain and to characterize physico-chemically the samples obtained by physical mixture (PM), paste complexation (PC) and slurry complexation (SC) of the essential oil Hyptis martiusii (EOHM) in β-CD, and to compare the antibacterial and modulatory-antibiotic activity of products obtained and oil free. The physicochemical characterization was performed by differential scanning calorimetry (DSC), thermogravimetry/derivative thermogravimetry (TG/DTG), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Karl Fischer titration. Additionally, the antibacterial tests were performed by microdilution technique. Thus, it was observed that the PM method showed low complexing capacity, unlike PC and SC in which it was observed the formation of inclusion complexes. In addition, the second stage of the TG/DTG curves showed that SC was the best method inclusion with mass loss of 6.9% over the PC that was 6.0%. The XRD results corroborate with the results above suggesting the formation of new solid phase and the SEM photomicrographs showed the porous surface of the samples PC and SC. The essential oil alone demonstrated an antibacterial and modulatory effect against the S. aureus and the Gram negative strain, respectively. However, the β-CD and the inclusion complex did not demonstrate any biological activity in the performed antibacterial assays