Antibacterial activity of nanoemulsion of essential oil from Brazilian pepper tree (Schinus terebinthifolia Raddi) against sensitive and multidrug-resistant strains

Abstract

Abstract Schinus terebinthifolia, a species of the Anacardiaceae family, is known for its medicinal properties and high yield of essential oil with significant biological activities, particularly antibacterial. Nanoemulsions enhance the bioavailability and efficacy of these compounds. This study evaluated the antibacterial activity of different concentrations of nanoemulsion of essential oil extracted from S. terebinthifolia fruits. Tests were conducted on sensitive strains (Escherichia coli 25922, Pseudomonas aeruginosa, Staphylococcus aureus, and Proteus mirabilis) and multidrug-resistant bacterial isolates. Formulations were characterized for their physicochemical properties, and antibacterial activity was determined using the microdilution method to assess minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The nanoemulsion exhibited superior antibacterial activity compared to pure essential oil. The best results were observed against sensitive strains of E. coli (MIC and MBC of 0.005 mg/mL) and S. aureus (MIC of 0.39 mg/mL and MBC of 0.78 mg/mL). Among multidrug-resistant isolates, the nanoemulsion was most effective against MCR-2 producing E. coli (MIC of 0.19 mg/mL). The nanoemulsion outperformed the pure essential oil, likely due to increased particle number and longer contact time with microbial cell surfaces. Nanoemulsions of S. terebinthifolia essential oil significantly enhance antibacterial activity and have potential applications in medicinal and cosmetic products. This study supports the development of nanoformulations to improve the bioavailability and efficacy of essential oils.

Keywords

• Anacardiaceae
• gas-chromatography
• secondary metabolites
• nanotechnology