Screening of antimicrobial activity of Ilex paraguariensis St. Hil. leaf extracts against carbapenemase-producing bacteria

ONETTO, AL; NOVOSAK, MG; WINNIK, DL; CORTESE, IJ; STOCKMANNS, PE; OVIEDO, PN; LACZESKI, ME

ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS.

ACAD BRASILEIRA DE CIENCIAS

Lugar: Rio de Janeiro; Año: 2023

0001-3765

Ilex paraguariensis is a south American species of agronomic interest withstudies supporting its medicinal properties. As the investigation of active ingredientswith antimicrobial effect from medicinal plants is a suitable approach to the currentantibacterial resistance problem, the aim of the present study was to determine theantibacterial activity of yerba mate ethanolic extracts against carbapenemase-producinggram-negative bacteria (reference strains and clinical isolates). Extracts showedantibacterial activity against Klebsiella pneumoniae ATCC® BAA-2342™ (KPC producing),Providencia rettgeri (NDM producing), Pseudomonas aeruginosa (MBL producing) andP. aeruginosa (VIM producing) at the concentrations tested. The Minimal-InhibitoryConcentration and Minimal-Bactericidal-Concentration values ranged between 1 and 32 mg.ml for the clinical isolates. The MBC/MIC index characterized the extracts as bactericidal. The combinations ofcommercial antibiotics and extracts showed a synergistic action on the reference strainsstudied. The lethal concentration 50 obtained using the Artemia salina toxicity assaywere higher than 1 mg.ml-1 for the reference strains, and between 0.125 and 1 mg.ml-1 for all the extracts, indicating a low toxicity. The in vitro activity and low toxicity suggest that ethanolic I. paraguariensis leaf extracts constitute an outstanding source for new antibacterial compounds, and further studies should be carried out to understand their mechanism of action. -1