Myrciaria pilosa is a tree species of the Brazilian Caatinga biome. This paper is the first report on the chemical composition and the antimicrobial and antivirulence activities of essential oil extracted from its leaves. The oil was extracted by hydrodistillation. Chemical composition determined by GC-MS and CG-FID revealed 63 compounds; the sesquiterpenes guaiol (13.17%) and (E)-β-caryophyllene (11.26%) dominated. Antimicrobial activity against strains of Staphylococcus aureus was evaluated by the broth microdilution method. It showed minimum inhibitory concentrations (MIC) of 5 μg/mL against evaluated strains and minimum bactericidal concentrations (MBC) ranging from 10 to 20 μg/mL. Evaluation of antivirulence activity showed reductions of 92.0% and 47.2%, respectively, in haemolytic action and production of staphyloxanthin. These findings show that the essential oil of M. pilosa has potential as an antimicrobial drug to control infection by multi-resistant strains of S. aureus.
Keywords: Myrciaria pilosa; Myrtaceae; S. aureus; antimicrobial activity; caatinga; sesquiterpenes.