Atividade antimicrobiana e sinérgica das frações das folhas de Schinopsis brasiliensis Engl. frente a clones multirresistentes de Staphylococcus aureus

Abstract

RESUMO:No presente estudo objetivou-se avaliar a atividade antimicrobiana e sinérgica de 4 frações das folhas de Schinopsis brasiliensis Engl (F1', F2', F1" e F2") frente às cepas Staphylococcus aureus MRSA multirresistentes. Os métodos utilizados foram poços de difusão em ágar, concentração mínima inibitória (CMI) -diluição em ágar, e bioautografia. Nos resultados bioautográficos observou-se três halos de inibição relacionados, no mínimo, à quatro constituintes ativos; sendo dois deles isolados das folhas (galato de metila e ácido gálico). A F2" (200µg/mL) apresentou halos de inibição de 16 e 19mm frente as cepas de S. aureus multirresistente e Klebsiella pneumoniae, e CMI 100µg/mL, respectivamente. Quanto as análises das associações das frações F1" ou F2" (25 e 50µg/mL) com a tetraciclina e oxacilina, mostraram ações aditiva e sinérgica para a F2" (50µg/mL), embora não suficiente para que a CMI atingisse valores inferiores a 2 e 4µg/mL, necessário para serem classificadas como cepas sensíveis a oxacilina e tetraciclina, respectivamente. "Assim, conclui-se que a F2" das folhas de S. brasiliensis apresentou potencial antimicrobiano frente às cepas de S. aureus MRSA multirresistentes e que as associações das frações com os antibióticos testados não apresentaram benefícios não justificando o uso concomitante. Palavras-chave: Schinopsis brasiliensis, Staphylococcus aureus, Atividade antimicrobiana, Multidroga-Resistente.ABSTRACT: Antimicrobial and synergic activity of fractions from the leaves of Schinopsis brasiliensis Engl. against Staphylococcus aureus multiresistant clones. The aim of this study was to evaluate the antimicrobial and synergic activity of 4 leaf fractions of Schinopsis brasiliensis Engl (F1', F2', F1" and F2") against multidrug-resistant Staphylococcus aureus strains. The used methods were agar well diffusion, minimum inhibitory concentration (MIC) -agar dilution, and bioautography. The bioautographic results showed three inhibition zones that corresponded to at least four active compounds, two of which (methyl gallate and gallic acid) have already been isolated from leaves. The F2" (200µg/mL) fraction showed inhibition zones of 16 mm and 19 mm against S. aureus multidrug-resistant and Klebsiella pneumoniae strains and a MIC value of 100µg/mL, respectively. The analyses of associations of fraction F1" or F2" (25 and 50µg/mL) with tetracycline and oxacillin showed additive and synergistic action for F2" (50µg/mL), although it was not enough to decrease the MIC values to less than 2 and 4µg/ mL, necessary to classify the strains as susceptible to oxacillin and tetracycline, respectively. Thus, it was concluded that F2" from the leaves of S. brasiliensis showed antimicrobial potential against multidrug-resistant MRSA strains, and the associations of the fractions with the tested antibiotics showed no benefits, not justifying their concomitant use.

Plants of the Cerrado with antimicrobial effects against Staphylococcus spp. and Escherichia coli from cattle

“…In other study, low MICs have also been reported for S. brasiliensis , E. coli ATCC 9723, and multi-resistant S. aureus isolates , with values varying from 0.025 to 0.100 mg/mL, depending on the fraction of extracts [ 14 ].…”

“…With regards to alternative antibacterial agents, four medicinal plants from the Brazilian Cerrado have been shown to inhibit the growth of S. aureus [ 13 ], and the leaf extract from Schinopsis brasiliensis Engl. is effective against multidrug-resistant S. aureus [ 14 ].…”

Development of a rapid and simple HPLC-UV method for determination of gallic acid in Schinopsis brasiliensis

“…Medeiros). resistant strains for tetracycline, gentamicin and oxacillin (Saraiva et al, 2011(Saraiva et al, , 2013 and erythromycin (Silva et al, 2015).…”

Evaluation of the potential modulator of bacterial resistance, acute toxicity and chemical composition of Schinopsis brasiliensis Engl.

“…The presence of a considerable concentration of phenolic compounds such as tannins and flavonoids as well as antioxidant and antimicrobial properties has been reported (Saraiva et al, 2011(Saraiva et al, , 2013. A new alkyl phenol, methyl 6-eicosanyl-2-hydroxy-4-methoxybenzoate and an unusual steroid 5a,8a-epidioxyergosta-6,22-dien-3-b-ol have been isolated from this plant (Cardoso et al, 2005).…”

“…Extracts of S. brasiliensis showed the antimicrobial activity reported in the literature. Chaves et al (2011) when testing the hydroalcoholic extract, Saraiva et al (2011) the methanol extract and Saraiva et al (2013) different proportions of different fractions of methanolic extract showed efficacy against gram positive, gram negative and fungal strains through an agar diffusion test. However, the impossibility of measuring the amount of extract spread on the agar affects the ease of using this method to accurately determine the MIC (Hadacek and Greger, 2000).…”