Abstract
Objective: Describe the antimicrobial activity of Aspidosperma nitidum. Methods: The ethanolic extract (EE) was subjected to acid-base fractionation aimed at obtaining alkaloid-rich fraction (FA) and neutral fraction (FN). For checking antimicrobial activity, a screening by diffusion disc test was performed against Sthaphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Proteus mirabilis. For samples that showed an inhibition halo in the agar diffusion disk test, a microdilution test in MTT was used to determine their minimum inhibitory concentration (MIC). RESULTS: In the agar diffusion test, EE, FA, and FN inhibited S. aureus and E. coli growth. There was no growth inhibition for the other strains. In MIC determination, the EE, FA and FN presented MIC of 1000 µg/mL against E. coli. In the S. aureus strain, the EE showed a MIC of 250 µg/mL, considered moderately active, whereas the FA and FN fractions had low activity, as they presented a MIC of 500 µg/mL. Conclusion: The Greater antimicrobial activity of the extract facing S. aureus may be available with β-carbolinic alkaloids, or with a possible synergism between this class of alkaloids and indole alkaloids.