Journal of Medicinal Plants Research Vol. 6(29), pp. 4522-4525,1 August, 2012 Available online at http://www.academicjournals.org/JMPR DOI: 10.5897/JMPR11.933 ISSN 1996-0875 ©2012 Academic Journals Full Length Research Paper Essential oil content and composition of Mentha longifolia (L.) Hudson grown wild in Iran Zarir Saeidi 1 , Hadi babaahmadi 2 *, Keramat Allah Saeidi 3 , Amin Salehi 4 , Ramin Saleh Jouneghani 3 , Hosain Amirshekari 5 and Abdallah Taghipour 2 1 Agricultural and Natural Resources Research Center, Chaharmahal va Bakhtiari, Iran. 2 Jahad Daneshgahi Center, Charmahal and Bakhtiari, Iran. 3 Department of Horticulture Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. 4 Department of Agronomy, Faculty of Agriculture, Yasuj Universiy, Iran. 5 Department of Agronomy, Faculty of Agriculture, Shahed Universiy, Iran. Accepted 29 August, 2011 Essential oil content and composition of Mentha longifolia (L.) Huds. collected from five regions in south-west of Iran were determined. The essential oil isolated by hydro-distillation for 3 h using a Clevenjer-type apparatus and the oil was analyzed by GC and GC-MS. Essential oil content was varying from 1.39 to 4.05%. From 23 identified compounds, the major compounds were; Piperitenone oxide (7.41 to 59.67%), Pulegone (3.61 to 49.43%), 1,8–Cineole (7.25 to 24.66%), α-Terpineol (2 to 6%) and β- pinene (1.32 to 4.19%). Key words: Mentha longifolia, essential oil, Pulegone, Piperitenone oxide, Iran. INTRODUCTION Iran is considered as one of the major centers of plant biodiversity in the word. Iran’s natural environment is very diverse, ranging from tropical to cold temperate. This ecological diversity has contributed not only to a high genetic diversity, but also allowed the successful introduction and cultivation of a great number of plant taxa. Menthe longifolia, a perennial essential oil bearing plant that belonging to the Lamiaceae family, grows as wild in various regions of Iran (Omidbaigi, 2005; Mozaffarian, 1996). M. longifolia (L.) Huds. is used in Iranian traditional medicine as a stomach pain-relieving agent, antispasmodic, digestive and carminative (Zargari, 1990). Aerial part of the M. longifolia containing essential oils that has medicinal effects. The essential oil of Mentha species was reported to have fungicidal, anti- inflammatory, antimicrobial and antioxidant activities (Mimica-Dukic et al., 2003; Gulluce et al., 2007; Mkaddem et al., 2009). The essential oil content of this medicinal plant, depending on the climatic and geographical factors (Hajlaoue et al., 2008), is varied between 0.9 to 1.8% (Younis and Beshir, 2004). Main identified compounds of the M. longifolia oil were: *Corresponding author. E-mail: hadi_babaahmadi@yahoo.com Dihydrocarvone (23.64%), Piperitone (17.33%) and Cis- dihydrocarvone (15.68%) (Dzamic et al., 2010). Ciscarveol (53 to 78%) was reported as the major constitute of Iranian samples (Zenali et al., 2005), whereas, the main compounds in the collected samples from Sudan and India were Carvone (67.3 to 78.9%) and Piperitenone oxide (54.23%) (Younis and Beshir, 2004; Singh et al., 2008). Hafedh et al. (2010) reported that the most important components of essential oil from M. longifolia were: Menthol (32.51%), Menthone (20.71%) and Pulegone (17.76%). Lawrence (1998) and Pino et al. (1990) showed that Pulegone was the main constituent of M. longifolia essential oil, and its percentage ranged from 25 to 92%. Maffei (1998) reported that essential oil of a new chemotype of M. longifolia, growing wild in the Piedmont valley (Italy), was rich in Piperitenone oxide (77.43%). The aim of the present investigation was to study essential oil content and its composition in M. longifolia grown wild in different regions of south-west in Iran. MATERIALS AND METHODS Collection of samples Aerial parts of M. longifolia were collected at the full flowering stage