Pentaclethra macroloba tannins fractions active against methicillin-resistant staphylococcal and Gram-negative strains showing selective toxicity
AUTOR(ES)
Leal, Ivana Correa Ramos, I. Júnior, Ivaldo, Pereira, Eliezer M., Laport, Marinella da S., Kuster, Ricardo M., Santos, Kátia Regina Netto dos
FONTE
Revista Brasileira de Farmacognosia
DATA DE PUBLICAÇÃO
05/08/2011
RESUMO
The ethanol extract of the vegetal species Pentaclethra macroloba (Willd.) Kuntze, Fabaceae, was fractioned and the antibacterial activity was determined. The active ethyl acetate (ea) fraction showed activity against Gram-positive (Staphylococcus spp. and Enterococcus spp.) and Gram-negative (Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella pneumoniae) multiresistant bacteria. Gallic acid derivatives were identified as the main compounds in inactive subfractions from the ea fraction, while the active one afforded ellagic acid as the major constituent when submitted to acid hydrolysis reaction, which suggests the presence of hydrolysable tannins. The minimum bactericidal concentration analysis showed a bactericide mechanism of action for the tannin subfraction found. The antibacterial mechanism of action of the active tannin subfraction against S. aureus reference strains (ATCC 29213 e 33591) was proposed adopting an in vitro assay of protein synthesis inhibition. For this, bacterial cells were labeled with [35S] methionine in the presence of the subfraction. The protein synthesis inhibition was observed at 256 µg/mL of this subfraction. At this concentration it did not present cytotoxicity in eukaryotic cells by the neutral red technique, suggesting selective toxicity. The present study is the first in vitro investigation of the antibacterial properties of tannin fractions obtained from a polar extract of P. macroloba.
Documentos Relacionados
- Bactericidal activity of ciprofloxacin against amikacin- and cefotaxime-resistant gram-negative bacilli and methicillin-resistant staphylococci.
- Sensitization of Complement-Resistant Smooth Gram-Negative Bacterial Strains
- Local Variants of Staphylococcal Cassette Chromosome mec in Sporadic Methicillin-Resistant Staphylococcus aureus and Methicillin-Resistant Coagulase-Negative Staphylococci: Evidence of Horizontal Gene Transfer?
- Postantibiotic Leukocyte Enhancement of Meropenem against Gram-Positive and Gram-Negative Strains
- Amifloxacin activity against well-defined gentamicin-resistant, gram-negative bacteria.