The relaxing effects of lavender based on its scent are not a myth. This study, presented in the journal Frontiers in Behavioral Neuroscience, even shows that the active compound in lavender involved in this process, linalool, could be used medically to treat anxiety.
In traditional medicine, it has long been believed that fragrant compounds derived from plant extracts can relieve anxiety, says one of the researchers, Hideki Kashiwadani, from Kagoshima University (Japan). Lavender is one of these extracts, and is now “everywhere” in hygiene and care products, fabric softeners and other household products. “But why not in our hospitals, to relieve stress and preoperative anxiety disorders? ask these Japanese researchers. They indeed reveal a bit of the science behind the magic of the fragrant plant.
Research shows for the first time that linalool, a compound in lavender, must be “smelled” and not absorbed by the lungs, to exert its calming effects. Many researchers have assumed that absorption into the blood via the respiratory tract has direct effects on the receptors of certain brain cells, such as "GABAAR" (γ-aminobutyric acid type A receptor), also targets of benzodiazepines .
Relaxation is triggered by olfactory signals caused by the smell of linalool: the researchers checked on mice whether the stimulation of olfactory neurons (sensitive to odors) in the nose was indeed the cause of the triggering of relaxation. In particular, they observed the behavior of mice exposed to linalool vapor to assess the anxiolytic effects and found that it was indeed the smell of linalool that caused this anxiolytic effect in normal mice. An effect that does not burden their motor skills, "which contrasts with benzodiazepines and linalool injections, whose effects on movements are similar to those of alcohol", specify the authors.
Conversely, no anxiolytic effect is observed in anosmic mice, whose olfactory neurons have been eliminated.
Finally, the anxiolytic effect observed in normal mice disappears when they have been pretreated with flumazenil, a drug that blocks the GABAA receptors sensitive to benzodiazepines.
Towards use in clinical practice: this deciphering of the true mechanism of the relaxing effects of linalool is a key step in the transition to clinical use in humans. Because taken together, these results suggest that linalool does not act directly on GABAA receptors, unlike benzodiazepines, but will activate them via olfactory neurons in the nose to produce these relaxing and anxiolytic effects. Further research is therefore needed to establish the targets, safety and efficacy of linalool administered by different routes, before moving to clinical trials in humans.
However, the clinical use of linalool to relieve anxiety already seems promising with multiple possible indications such as alleviating preoperative stress and placing patients under general anesthesia more easily. Vaporized linalool could also be a safe alternative for patients who have difficulty administering anxiolytics by mouth or suppository.
Modern medicine seems to have overlooked these fragrant compounds derived from plant extracts, despite the need for safer alternatives to current anti-anxiety drugs.