Method for attaining rosemary essential oil with differential composition from dried or fresh material.

Rosemary (Rosemarinus officinalis L.) is a well-known medicinal and essential oil plant, utilized by humankind since ancient times. The objective was to determine the effect of steam distillation time (DT) and material (dry or fresh biomass) on essential oil yield, composition, and bioactivity; and to develop regression models that can predict oil yield and composition at specific DT.