Journal of Ethnopharmacology 119 (2008) 325–327 Contents lists available at ScienceDirect Journal of Ethnopharmacology journal homepage: www.elsevier.com/locate/jethpharm Ethnopharmacological communication Antimicrobial activity and chemical composition of Mentha pulegium L. essential oil Mohaddese Mahboubi ∗ , Ghasem Haghi Research Center of Barij Essence Pharmaceutical Company, 87135-1178 Kashan, Iran article info Article history: Received 27 January 2008 Received in revised form 15 July 2008 Accepted 17 July 2008 Available online 25 July 2008 Keywords: Antimicrobial activity Mentha pulegium GC/MS Piperitone Piperitenone abstract 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%), - 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 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 activ- ity and the Iranian Mentha pulegium L. oil belongs to piperitone/piperitenone type. Further research is required to evaluate the practical values of therapeutic applications. © 2008 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Mentha, the genus of Labiatae family, includes 20 species that spread all over the world. Mentha pulegium L. is one of the Men- tha species commonly known as pennyroyal. It is native species of Europe, North Africa and in Asia Minor and near East (Chalchat et al., 2000). The flowering aerial parts of Mentha pulegium L. has been traditionally used for its antiseptic for treatment of cold, sinusi- tis, cholera, food poisoning, bronchitis and tuberculosis (Zargari, 1990), and also as antiflatulent, carminative, expectorant, diuretic, antitussive, menstruate (Newall, 1996). Some pharmacological effect of Mentha pulegium L. essential oil such as abortifacient effect in rat myometrium (Soares et al., 2005), cytotoxic activ- Abbreviations: IZ, inhibition zone; mm, millimeter; RI, retention indices; DMSO, dimethylsulfoxide; MIC, minimal inhibitory concentrations; MBC, minimal bacteri- cidal concentration; MOPS, morpholine propane sulfonilic acid; l, microliter; ml, milliliter; GC, gas chromatography; GC/MS, gas chromatography–mass spectrome- try; SDA, sabouraud dextrose agar. ∗ Corresponding author. Tel.: +98 866436 2112; fax: +98 866436 2187. E-mail addresses: Mahboubi@barijessence.com, Mohadese mahboby@yahoo.com (M. Mahboubi). ity against different human cell lines (Shirazi et al., 2004) and its antioxidant effect (El-Ghorab, 2006) were confirmed. The ingredients of Mentha pulegium L. oil have been subjected to a number of studies which have shown a difference in its con- stituents depending on the region of cultivation and there have been some variations in the constituents from different countries. It has been found Mentha pulegium L. oil from Bulgaria contains pulegone (42.9–45.4%) (Stoyanova et al., 2005); from Uruguay; pulegone (73.4%), isomenthone (12.9%) (Lorenzo et al., 2002); from Egypt; pulegone (43.5%), piperitone (12.2%) (El-Ghorab, 2006); from Tunisia, pulegone (41.8%), isomenthone (11.3%) (Mkaddem et al., 2007). These studies showed three chemotypes of Men- tha pulegium L. with the following major oil components (1) pulegone, (2) piperitenone and/or piperitone and (3) isomen- thone/neoisomenthol (Topalov and Dimitrov, 1969; Cook et al., 2007). Though the flowering aerial part of this plant commonly is used because of its antiseptic properties, heretofore there is no report that investigated the antimicrobial activity of this plant. The aim of this study was to identify the chemical composition and evaluate the antimicrobial activity of Iranian Mentha pulegium L. oil against different microorganisms in order to validate its traditionally used. 0378-8741/$ – see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2008.07.023