In Vitro Antimicrobial Activity of Selected Essential Oils Against Endometritis-Causing Microorganisms in Mares

This study aimed to evaluate the in vitro antimicrobial activity of essential oils (EO) from Ocimum basilicum (basil), Rosmarinus officinalis (rosemary), and Cymbopogon citratus (lemongrass) on endometritis-causing microorganisms in mares. Serial concentrations of the EO from 30.00 mg/mL to 0.47 mg/mL were tested. The major compounds of O. basilicum EO were linalyl acetate (33.32 wt.%) and citronellal (25.06 wt.%); of R. officinalis EO were borneol (26.48 wt.%), trans-β-ocimene (16.76 wt.%), camphene (12.45 wt.%), and α-phellandrene (11.08 wt.%); and of C. citratus EO were geranial (45.96 wt.%) and neral (32.62 wt.%). Regarding antimicrobial activity, C. citratus EO has had the highest inhibition percentage (73.9%), followed by O. basilicum (67.2%) and R. officinalis (58.7%). P. aeruginosa was the only pathogen unable to establish the minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) values for the studied EO. The EOs were effective against all other microorganisms (S. equi, S. aureus, K. pneumoniae, E. coli, and C. Albicans). In conclusion, the EOs of O. basilicum, R. officinalis, and C. citratus have presented in vitro antimicrobial activity against microorganisms causing endometritis in mares.