Spearmint (Mentha spicata L.) is one of the best known aromatic and medicinal plants. The characterization of essential oil variation is of commercial importance as well as helpful for appropriate use of M. spicata. Thirteen strains of cultivated or spontaneous mints were collected from 10 Moroccan regions and acclimatized for two years in Meknes. Their leaves collected at full flowering were dried for hydrodistillation. Essential oil yields were found to vary from 1.32 % to 5.83 %. Analysis of these oils by GC/MS indicated a large variation in chemical composition among the studied strains of Moroccan M. spicata (9 to 51 compounds). The highest yields characterize the cultivated strains of Agadir (5.83 %), S2 of Larache (4.84 %) and the spontaneous strain S3 of Ifrane (4.17%). The richest strain in number of compounds is S3 of Ifrane with 51 compounds whereas uncultivated S2 from the same region has only 9 compounds. Some strains are rich in carvone such as the cultivated strain of Ouarzazate (65.94%) and the spontaneous S2 of Ifrane (72.3 %). Others are rich in eucalyptol, pulegone or 3-Cyclopenten-1-one, 2-hydroxy-3-(3-methyl-2-butenyl) such as those of Marrakech (21.1 %), Agadir (30.7 %) and S1 of Larache (22.1 %), respectively. The strains of Settat and Ifrane (S1) have high levels of limonene (17.8-18.1%).
Keywords: Mentha spicata, Essential oils, Carvone, Eucalyptol, Cluster analysis, GC/MS