Résumé:
This thesis deals with a comparative study of the microbial activity of Rosmarinus officinalis L and Mentha spicata essential oils. The essential oil was extracted using the hydro-distillation method. Antimicrobial activity was tested against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Citrobacter freundii and Candida albicans. The disc diffusion method revealed that Mint inhibited E. coli with an inhibition diameter of 11 mm and S. aureus with diameters of up to 20 mm. Rosemary, although less effective against E. coli (0 to 9 mm), showed strong activity against S. aureus with inhibition diameters of 11 to 24 mm. For P. aeruginosa, both oils showed an inhibition of 9 mm, and for Ci. freundii, Mint varied from 6 to 11 mm, while Rosemary showed a constant inhibition of 9 mm. None of the oils showed any inhibitory activity against Candida albicans.
Minimum inhibitory concentrations (MICs) were determined for each oil against the bacteria tested. For Rosemary oil, E. coli showed sensitivity from 1.25 mg/ml, S. aureus was sensitive at all concentrations tested, and Ci. freundii became sensitive from 2.5 mg/ml. For Mint oil, E. coli became sensitive from 10 mg/ml, while S. aureus and Ci. freundii showed complete sensitivity at all the concentrations tested. These observations reinforce the potential of essential oils as natural alternatives to conventional antibiotics.
