Seasonal variation in essential oil yield and composition from naturalized thymus vulgaris L. in New Zealand

Abstract

AbstractThe seasonal variation in essential oil yield and composition from naturalized Thymus vulgaris L. in Central Otago, New Zealand, is reported. Essential oil yield (l/ha), from replicated, pilot‐scale distillations, was influenced by both the field production of herb and the essential oil content of the herb. The oil yield peaked at 22.8 l/ha in December, after flowering had finished. Essential oil composition also varied significantly during the 13‐month sampling period. Levels of the phenolic components, thymol and carvacrol, peaked at a total of 37% after flowering in summer (December and January). p‐Cymene was an important component of Central Otago thyme oils and ranged from 40% to 50% in winter and early spring (May to October), declining to 21% in January. To maximize yields and phenol content of the oil, naturalized thyme in Central Otago should be harvested after flowering has finished in December.