Tagetes lucida Cav. essential oil and the mixture of its main compounds are antibacterial and modulate antibiotic resistance in multi-resistant pathogenic bacteria

We evaluated an essential oil (EO) of Tagetes lucida Cav. and the mixture of its main compounds against multi-drug resistant bacteria. We found that EO and the partially reconstituted blend of its main components have antibacterial activity and inhibit antibiotic resistance (ampicillin, chloramphenicol, nalidixic acid, vancomycin and imipenem) in strains of Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa HIM-MR01. The T. lucida EO alone or added to the antibiotics showed antimicrobial activity against S. aureus and P. aeruginosa. The EO main bioactive compounds were methyl eugenol (relative abundance in EO: 46 center dot 15%), estragole (32 center dot 93%), linalool (2 center dot 48%) and geraniol (0 center dot 33%). The mixture (PREO) of those compounds at those proportions inhibited the growth of P. aeruginosa in 45% at 683 center dot 62 mu g ml(-1) and that of S. aureus in 51 center dot 7% at 39 center dot 04 mu g ml(-1). The PREO had higher antibacterial and modulatory activities than the original EO. In conclusion, we overcame the unpredictability of EO activity (due to their natural variability) by determining which EO components inhibited bacteria and then producing a PREO to generate a reproducible mixture with predictable antibacterial and modulation of resistance activities. Thus, the PREO, and its components, show potential as alternatives to manage multidrug-resistant pathogens.

Automated summary

We evaluated the activity of Tagetes lucida essential oil (EO) and its main compound mixture against multi-drug resistant bacteria. The EO and its partially reconstituted blend showed antibacterial activity and inhibition of antibiotic resistance in Staphylococcus aureus and Pseudomonas aeruginosa strains. The EO consisted mainly of methyl eugenol, estragole, linalool, and geraniol. The mixture of these compounds at specific proportions exhibited higher antibacterial and modulation of resistance activities than the original EO. This study suggests that the EO and its components have the potential to be alternative options for managing multidrug-resistant pathogens.