Chemical Composition and In Vitro Antibiofilm Action of Varronia curassavica Jacq. (Boraginaceae) Essential Oil: A Promising Natural Agent Against Bacterial Infections.

Antimicrobial resistance is an increasing threat to public health, with alarming estimates of mortality rates. In this context, the clinical properties of Varronia curassavica Jacq. are highlighted due to its biological and pharmacological activities. This study aims to analyze the phytochemical composition of the essential oil from V. curassavica (EOVC) and its antibiofilm activity against Gram-positive and Gram-negative strains. The essential oil was extracted from the leaves using hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), phytochemical analysis of EOVC identified 97.36% of the total composition, predominantly composed of monoterpenes (α-pinene at 44.46%) and sesquiterpenes (β-caryophyllene at 21.82%). Antibiofilm tests were performed on five bacterial strains (both Gram-positive and Gram-negative) to evaluate the ability to inhibit and eradicate biofilms, with statistical analysis of the results. Antibiofilm formation tests demonstrated that EOVC exhibited efficacy against Staphylococcus aureus and Staphylococcus epidermidis, with minimum inhibitory concentrations (MIC) of 1.024 and 10.240 µg/mL, respectively, values comparable to those observed for the reference antibiotic. In addition, at high concentrations (10 × MIC), EOVC inhibited biofilm development by Streptococcus mutans and Enterococcus faecalis, achieving performance similar to that of gentamicin. In biofilm eradication assays, EOVC showed effective activity against E. faecalis, S. epidermidis, and S. aureus at concentrations of 10.240 µg/mL, equivalent to gentamicin. However, resistance was found in strains of Pseudomonas aeruginosa and S. mutans, with P. aeruginosa showing the highest level of resistance to EOVC.