Essential oil from pink pepper (Schinus terebinthifolius Raddi): Chemical composition, antibacterial activity and mechanism of action

Essential oils confer protection to plants, and due to their natural origin, there is great interest in their use as antimicrobials. This work aimed to determine the chemical composition, antimicrobial activity and mechanism of action of essential oil from pink pepper (PPEO), against foodborne pathogens. Eighteen compounds (4 monoterpenes and 14 sesquiterpenes) were detected by chromatographic analysis, of which beta-myrcene (41%), beta-cuvebene (12%) and limonene (9%) were the major compounds. In regards to antimicrobial activity by diffusion in agar and broth, action was verified against two Gram-positive bacteria. Staphylococcus aureus and Listeria monocytogenes presented minimum inhibitory concentration (MIC) of 0.68 and 1.36 mg/mL, respectively. The minimum bactericidal concentration (MBC) was 2.72 mg/mL for both bacteria. The micro-atmosphere diffusion assay demonstrated that the PPEO reduced the development of Escherichia colt and Salmonella Typhimurium, by up to 16 and 15%, respectively. The contact time required for MBC to act effectively on Gram-positive bacteria was less than 12 h, and Gram-negative bacteria were not inhibited, but their growth was significantly reduced by PPEO action. In addition, changes in the permeability and integrity of the cell membrane of all evaluated bacteria were observed, indicating that cell wall damage is one of their mechanisms of action.