Efeitos dos extratos etanólico e hidroalcoólico de Caesalpinia ferrea (Jucá) na inibição de biofilme de Staphylococcus aureus e em conjugação de plasmídeos de resistência em Escherichia coli

Abstract

Caesalpinia ferrea Mart. (Caesalpinoideae), known as jucá or pau - ferro, is traditionally used in folk medicine due to its antifungal, antibacterial, antiulcerogenic, anti - inflammatory and analgesic activities. The objective of this study was to investigate the antibacterial effects subinhibitory concentrations of ethanolic and hydroalcoholic extracts from the bark of Caesalpinia ferrea Mart., on, on the biofilm production in Staphylococcus aureus and on the conjugation rate of plasmid conferring antimicrobial resistance in Escherichia coli. The ethanolic and hydroalcoholic extracts were extracted by means of three techniques, two cold (maceration and turbolise) and one hot (soxhlet). Inhibition of biofilm production was determined in vitro using the 96-well microtiter plate. The effect of Caesalpinia ferrea Mart. on the conjugation rate of plasmids was performed using the strains Escherichia coli h2332 and Escherichia coli J62 as donor and recipient, respectively. In general, lower MIC values were observed for Gram-positive than Gram-negative bacteria. The ethanol and hydroalcoholic extracts had a significant effect (p <0.05) on the inhibition of biofilm formation in Staphylococcus aureus, at concentrations of 1,16 mg / mL, 0.582 mg / mL, 0.388 mg / mL and 0.291 mg / mL (25% MIC). The plasmideal transfer rate was affected by both extracts (EEMC and EHMC), and for the EEMC extract a reduction (p <0.05) of -4.24 in the conjugation rate was observed for the concentrations 2.34 and 1, 17 mg / mL (25% and 12.5% of MIC). In relation to the EHMC extract, a reduction of -3.47 (p <0.05) was observed in the conjugation rate at the concentration of 2.34 mg / mL. The ethanolic and hydroalcoholic extracts presented low toxicity in Artemia larvae, with a 50% lethal dose of 304,068 μg / ml and 493,549 μg / ml respectively. The results showed that subinhibitory concentrations of ethanolic and hydroalcoholic extracts, obtained from Caesalpinia ferrea Mart bark, reduced the production of biofilm in Staphylococcus aureus and the conjugation rate of plasmids conferring antimicrobial resistance among E. coli.