Synthesis, characterization and antibiofilm/antimicrobial activity of nanoemulsions containing Tetragastris catuaba (Burseraceae) essential oil against disease-causing pathogens

Essential oils are natural compounds that have been widely studied in the control of various microbial diseases. In this context, Listeria monocytogenes and Enterococcus faecalis are disease-causing human pathogens that can lead to important health complications. This work aimed to evaluate effect of the essential oil (EO) of Tetragastris catuaba leaves, as well as its main compound in free and nanoemulsion-encapsulated forms, on the biofilm formation and planktonic growth of E. faecalis and L. monocytogenes. The chemical composition of the EO was identified using GC-MS, and the formulated nanoemulsions were evaluated for their physicochemical characteristics. The essential oil comprised 54 compounds, with beta-caryophyllene being the major component (25.6%). The average size of nanoemulsions were 40.7 +/- 0.07 nm for EO nanoemulsion and 41.7 +/- 0.41 nm for beta-car-yophyllene nanoemulsion. The biological activities were observed mainly for the free EO and its nanoemulsion, with a significant reduction in biofilm formation and planktonic growth for both bacteria. While for beta-car-yophyllene, activity was observed only against E. faecalis, showing no activity against L. monocytogenes. These results indicate that T. catuaba EO may have promising applications in the prevention and control of contamination by bacterial biofilms. Furthermore, the formulated nanoemulsions proved to be an effective drug delivery system due to their stability and solubility in aqueous media.

Automated summary

This study found that the essential oil of Tetragastris catuaba leaves, as well as its nanoemulsion form, can significantly reduce biofilm formation and planktonic growth of Enterococcus faecalis and Listeria monocytogenes, suggesting their potential applications in preventing and controlling bacterial biofilm contamination.