Plasma 1,8-cineole correlates with cognitive performance following exposure to rosemary essential oil aroma
Hailed since ancient times for its medicinal properties, we still have a lot to learn about the effects of rosemary. This paper shows for the first time that blood levels of a rosemary oil component correlate with improved cognitive performance. Rosemary is one of many traditional medicinal plants that yield essential oils. But exactly how such plants affect human behavior is still unclear. The authors designed an experiment to investigate the pharmacology of one of rosemary’s main chemical components. Results indicate for the first time in human subjects that there is relation to an individual’s cognitive performance – with higher concentrations resulting in improved performance. Both speed and accuracy were improved, however the oil did not appear to improve attention or alertness. The results also suggest that compounds given off by the rosemary essential oil affect mood (subjective state) and cognitive performance through different neurochemical pathways.
Objective: The mode of influence of the aromas of plant essential oils on human behaviour is largely unclear. This study was designed to assess the potential pharmacological relationships between absorbed 1,8-cineole following exposure to rosemary aroma, cognitive performance and mood.
Methods: Twenty healthy volunteers performed serial subtraction and visual information processing tasks in a cubicle diffused with the aroma of rosemary. Mood assessments were made pre and post testing, and venous blood was sampled at the end of the session. Pearson correlations were carried out between serum levels of 1,8-cineole, cognitive performance measures and change in mood scores.
Results: Here we show for the first time that performance on cognitive tasks is significantly related to concentration of absorbed 1,8-cineole following exposure to rosemary aroma, with improved performance at higher concentrations. Furthermore, these effects were found for speed and accuracy outcomes, indicating that the relationship is not describing a speed–accuracy trade off. The relationships between 1,8-cineole levels and mood were less pronounced, but did reveal a significant negative correlation between change in contentment and plasma 1,8-cineole levels.
Conclusion: These findings suggest that compounds absorbed from rosemary aroma affect cognition and subjective state independently through different neurochemical pathways.
Moss, M., & Oliver, L. (2012). Plasma 1,8-cineole correlates with cognitive performance following exposure to rosemary essential oil aroma Therapeutic Advances in Psychopharmacology DOI: 10.1177/2045125312436573