Antimicrobial activity and chemical composition of Mentha pulegium L. essential oil

Ethnopharmacological relevance: The flowering aerial parts of Mentha pulegium L. (Labiatae) has been traditionally used for its antiseptic properties for treatment of infectious diseases. Aim of the study: In order to validate its antiseptic properties with respect to traditional uses, we have screened the antimicrobial activity of flowering aerial parts of Mentha pulegium L. essential oil against different microorganisms. Materials and methods: This oil was obtained using hydrodistillation method and analyzed by GC and GC/MS. The antimicrobial activity was achieved using disc diffusion method and microbroth dilution assay. Results: Analysis of the essential oil revealed the presence of piperitone (38.0%), piperitenone (33.0%), alpha-terpineol (4.7%), and pulegone (2.3%) as the major components. The results showed a significant activity against microorganisms especially Gram-positive bacteria with inhibition zones and minimal inhibitory concentration values in the range of 8-21 mm and 0.25-4 mu l/ml, respectively, whereas the least susceptible were Gram-negative bacteria especially Escherichia coli. Conclusions: This investigation showed that the oil of Mentha pulegium L. has a potent antimicrobial activity and the Iranian Mentha pulegium L. oil belongs to piperitone/piperitenone type. Further research is required to evaluate the practical values of therapeutic applications. (C) 2008 Elsevier Ireland Ltd. All rights reserved.