Seasonal Variation in Content and Chemical Composition of Essential Oils from Leaves of Mentha longifolia Huds. (Lamiaceae)

Abstract

Essential oil content and composition from Mentha longifolia leaves were assessed across harvesting seasons per European Pharmacopoeia 4th Ed. using gas chromatography-mass spectrometry. Highest oil content occurred during flowering (1.9%). Main constituents throughout phenophases were oxygenated monoterpenes piperitone oxide (1.9-63.6%) and 1,8-cineole (5-12%), plus sesquiterpenes trans-caryophyllene (3-9.3%) and germacrene D (0.16-10%). Piperitone oxide served as stable chemotype marker for taxonomy.