Biochemical activities of Iranian Mentha piperita L. and Myrtus communis L. essential oils Davod Yadegarinia a , Latif Gachkar a , Mohammad Bagher Rezaei b , Massoud Taghizadeh c , Shakiba Alipoor Astaneh c , Iraj Rasooli c, * a Department of Infectious Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran b Department of Medicinal plants, Institute for Research in Forests and Rangelands, Tehran, Iran c Department of Biology, Shahed University, Opposite Imam Khomeini’s Shrine, Tehran-Qom High way, Tehran, Iran Received 30 January 2006; received in revised form 26 April 2006 Available online 14 June 2006 Abstract GC–MS analysis of essential oils of Iranian Mentha piperita and Myrtus communis extracted by hydrodistillation lead to identification of 26 and 32 compounds, respectively. The oils had good to excellent antimicrobial activities against Escherichia coli, Staphylococcus aureus and Candida albicans with the oil of M. piperita being more active. The findings suggest feasibility of application of M. piperita oil in treatment of the infections caused by C. albicans and E. coli. D-values on exposure to M. piperita and Myrtus communis oils were (2.14 and 2.8 min), (1.4 and 12.8 min) and (4.3 and 8.6 min) for E. coli, S. aureus and C. albicans , respectively. The oils were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical scavenging and b-carotene/linoleic acid systems. M. piperirta oil exerted greater antioxidant activity than that of M. communis. Phytochemical and phytobiological char- acteristics of these oils may lead to extraction and production of active compounds in single or combined forms with useful applications. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Mentha piperita; Myrtus communis; Essential oil; E. coli; S. aureus; C. albicans; Antioxidant; Radical scavenging; Antimicrobial 1. Introduction Development of microbial resistance to antibiotics is a global concern. Isolation of microbial agents less suscepti- ble to regular antibiotics and recovery of increasing resis- tant isolates during antibacterial therapy is rising throughout the world which highlights the need for new principles. The use of essential oils as functional ingredients in foods, drinks, toiletries and cosmetics is gaining momen- tum, both for the growing interest of consumers in ingredi- ents from natural sources and also because of increasing concern about potentially harmful synthetic additives (Rei- sche et al., 1998). Within the wide range of the above-men- tioned products, a common need is availability of natural extracts with a pleasant taste or fragrance combined with a preservative action, aimed at avoiding lipid deterioration, oxidation and spoilage by microorganisms. Until recently, essential oils have been studied mostly from their flavor and fragrance viewpoints only for flavoring foods, drinks and other goods. Actually, however, essential oils and their components are gaining increasing interest because of their relatively safe status, their wide acceptance by consumers, and their exploitation for potential multi-purpose func- tional use (Ormancey et al., 2001). Many authors, in fact, have reported antimicrobial, antifungal, antioxidant and radical-scavenging properties by essential oils (Gianni et al., 2005). Lipid peroxidation is a complex process occur- ring in aerobic cells and reflects the interaction between molecular oxygen and polyunsaturated fatty acids. Radi- cals are known to take part in lipid peroxidation, which 0031-9422/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.phytochem.2006.04.025 * Corresponding author. Tel.: +98 21 55277509/66003260; fax: +98 21 55277645/66024006. E-mail address: rasooli@shahed.ac.ir (I. Rasooli). www.elsevier.com/locate/phytochem Phytochemistry 67 (2006) 1249–1255 PHYTOCHEMISTRY