Antibacterial activity of essential oils and hydrosols extracted from some Moroccan Mentha species (L.)

Nadia Zekri, Hanane Elazzouzi, Aziz Drioiche, Touria Zair, Mohammed Alaoui El Belghiti

Faculty of Sciences, Mohammed V University, Rabat, Morocco

ABSTRACT

Hydrosols (HYDs) have attracted a great interest this last decade by the scientific community. Although, studies about HYDs remain limited compared to those dealt with essential oils (EOs). These magic waters have found a huge interest in the cosmetic, food and phytotherapeutic industries. Their biological activities have not yet been assessed. The aim of this present work was to evaluate the antibacterial activity of three HYDs and to compare this activity to that of EOs from Mentha species facing some bacteria strains that caused various human diseases and infections. M. pulegium, M. suaveolens and M. spicata were collected from Azrou (Moroccan Middle-Atlas). Their EOs and HYDs were tested on six bacteria strains: S. aureus, E. coli BLSE, E. coli (wild-type), Ps. aeruginosa, Ps. putida, and P. mirabilis, using the micro-dilution and agar diffusion methods. The chemical compositions of three HYDs were different from the EOs; they were rich in hydrophilic and oxygenated compounds and lack in hydrocarbon constituents. The qualitative evaluation of the antimicrobial activity showed strong power for all the tested EOs by highlighting zones of inhibition with diameters exceeding 20 mm, thus showing significant sensitivity of the treated bacteria. These results were confirmed by quantifying this activity by MIC and MBC values, thus demonstrating their antibacterial power. As for HYDs, they have also shown their inhibitory efficacy against certain strains. Consequently, these promising results could serve as a basis to confirm the efficacy of these natural products and their ability to serve as alternative antimicrobial agents.

Keywords:

Mentha, Essential oil, Hydrosol, Bacteria, Antibacterial activity