Relaxation Effects of Essential Oils Are Explained
by Their Interactions with Human Brain Neurotransmitter
Receptors and Electroencephalography Rhythms
posted on 2021-12-17, 13:33authored byMinoli Aponso, Milton T. W. Hearn, Antonio F. Patti, Louise E. Bennett
Inhaled
essential oils (EOs) are bioavailable to the brain and
are consistently reported to promote relaxation effects. Their mechanisms
of action are however not well understood. The aim of this investigation
was to assess the neuroactivity of EOs based on their (i) binding
interactions to neurotransmitter receptors and (ii) bioelectrical
activities in the brain as measured by electroencephalography (EEG).
These EO properties were compared to those of reference pharmaceutical
compounds with effects also measured by EEG. Relative receptor binding
efficacies of 10 reference compounds, 180 EOs, and 9 EO extracts with
7 different neurotransmitter receptors were calculated using in silico molecular docking procedures. Changes in brain
EEG rhythms, as standardized changes in absolute power, were determined
for the reference compounds and selected EOs and compared to receptor
binding efficacy results. The reference compounds had diverse receptor
binding patterns, with EEG responses dominated by EEG-delta wave frequencies.
In contrast, the receptor binding pattern of the EOs was remarkably
consistent and replicated a subclinical affinity pattern corresponding
to the inhibitory glycine-α-GLRA3 and dopamine-D2 receptors,
producing responses dominated by EEG-alpha wave frequencies. The results
support the hypothesis that EOs stimulate neuroactivity by modulating
patterns of neurotransmission affecting alpha wave EEG responses.