Antibacterial and antifungal activity of Mentha cervina essential oils and their main components
Mentha cervina L. is an aromatic plant traditionally used in Portugal to flavour food and for its medicinal properties. Native of the Iberian Peninsula and North Africa, it can be found in river banks, damp and wet places, being representative of the priority habitat Natura 3170. In this work, the chemical composition of the essential oil (EO) of M. cervina, grown in Portugal, was characterized by GC and GC-MS, and its antimicrobial activity assessed against 23 bacteria including Gram-positive and Gram-negative multiresistant strains and the yeast Candida albicans. The main aromatic constituents of the EO were pulegone, menthone and isomenthone, which occurred in different relative amounts depending on the origin of the population studied. To understand the importance of the chemical composition of the EO, these as well as pure standards of pulegone, menthone and isomenthone, were also tested for antimicrobial activity. The minimum inhibitory concentration (MIC) ranged from 2 to 63mg/mL for almost all microorganisms tested including the multiresistant strains. The most effective was expressed by the EO, and not by any of the components alone. These results support the view that the EO bioactivity is a function of the synergistic effect of the different oil constituents.
Acknowledgements: L. Rodrigues is grateful to the FCT for the grant SFRH/BD/38143/2008.
References: 1. Rodrigues L., Monteiro P., Póvoa O., Teixeira G., Moldão M., Figueiredo A. & Monteiro A. (2008) Morphology of secretory structures and essential oil composition in Mentha cervina L. from Portugal. Flavour Fragr. J. 23: 340–347.