Evaluation of the antibacterial activity of trans-anethole against Enterococcus cloacae and Enterococcus faecalis strains of food origin.

The present study sought to evaluate the antibacterial activity of trans-anethole against food-borne strains of Enterobacter cloacae and Enterococcus faecalis. The study was performed using Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) methods, in addition, disc diffusion technique was used to evaluate the association of trans-anethole with synthetic antimicrobials. Minimum Inhibitory Concentration for Adherence (MICA) testing was also performed. The results revealed that trans-anethole presents no antibacterial activity at any of the concentrations used against the E. cloacae strains tested. However, trans-anethole presented antibacterial effect against five of the six E. faecalis bacterial strains tested, with MIC values ranging from 500 μg/mL to 1000 μg/mL. Further, when analyzing the MBC results against E. faecalis, it was observed that the compound presented values ranging from 500 μg/mL to 1000 μg/mL. As for the associations, it was observed that trans-anethole when combined with the antimicrobials ampicillin, gentamicin, ciprofloxacin, and ceftriaxone presented synergistic effect against most strains of E. faecalis. However, both trans-anethole and the control chlorhexidine (0.12%) presented no antibiofilm effects against strains of E. faecalis. In short, trans-anethole presented potential antibacterial against E. faecalis strains of food origin, and may upon further study, it may be used alone or in association with synthetic antimicrobials to combat infections caused by this bacterium.