Mentha spicata essential oils rich in 1,8-cineole and 1,2-epoxy-P-menthane derivatives from Zakynthos (Ionian Island, W Greece)

Wild Mentha spicata plants from 3 locations on the island of Zakynthos had essential oil yields (mL /100g DW) ranging from 0.5-1.1 %. The main oil constituents were trans-piperitone oxide, piperitenone oxide and 1,8-cineole. On a whole plant basis (aerial parts) the trans-piperitone oxide content ranged from 1.4 % location (Loc 1) to 32.5 % (Loc 3) and appeared to have an inverse relationship with the 1,8-cineole content which ranged from 10.8 % (Loc 3) to 37.9 % (Loc 1). 1,8-cineole was the major oil constituent (37.9 %) of M. spicata plants from Loc 1. The major constituent of the inflorescence oils was piperitenone oxide which ranged from 32.4 % (Loc 3) to 46.3 % of the oil (Loc 1). The major constituent of the leaf oils was 1,8-cineole (40.5 %) in plants from Loc 1 and trans -piperitone oxide in plants from Loc 2 (19.8 %) and Loc 3 (33.5 %). This is the first report for wild populations in Greece of a M. spicata oil in which 1,8-cineole is the major constituent. The observed variation in essential oil composition between locations and plant organs in July would not appear to be directly related to the climatic conditions.