Exploring Pharmacological Mechanisms of Essential Oils on the Central Nervous System

Abstract

Essential oils (EOs) have been traditionally used as ancient remedies to treat many health disorders due to their enormous biological activities. As mainstream allopathic medication currently used for CNS disorders is associated with adverse effects, the search to obtain safer alternatives as compared to the currently marketed therapies is of tremendous significance. Research conducted suggests that concurrent utilization of allopathic medicines and EOs is synergistically beneficial. Due to their inability to show untoward effects, various scientists have tried to elucidate the pharmacological mechanisms by which these oils exert beneficial effects on the CNS. In this regard, our review aims to improve the understanding of EOs' biological activity on the CNS and to highlight the significance of the utilization of EOs in neuronal disorders, thereby improving patient acceptability of EOs as therapeutic agents. Through data compilation from library searches and electronic databases such as PubMed, Google Scholar, etc., recent preclinical and clinical data, routes of administration, and the required or maximal dosage for the observation of beneficial effects are addressed. We have also highlighted the challenges that require attention for further improving patient compliance, research gaps, and the development of EO-based nanomedicine for targeted therapy and pharmacotherapy.

Keywords: Alzheimer’s disease; CNS; aromatherapy; essential oils; nanomedicine.

Figure 1

Biological effects of essential oils on the CNS through activation of various components of the brain. Created using Biorender.com. (Last accessed on 14 December 2021).

Figure 2

Flow chart presenting the selection protocol followed for the inclusion of published data into the present paper.

Figure 3

Chemical structures of bio-active constituents present in EOs acting on the CNS. Created using ChemDraw 20.1.0. URL: https://perkinelmerinformatics.com/products/research/chemdraw/ (accessed on 14 December 2021).

Figure 4

Ability of lavender oil to inhibit the degradation of FAAH and MAGL, thereby increasing levels of AEA and AG, which assist in mood elevation and analgesic effects. Created using Biorender.com. (Last accessed on 14 December 2021).

Figure 5

Interaction of EOs with the ECS leads to the modulation of several pathways. Created using Biorender.com. (Last accessed on 14 December 2021).

Figure 6

Ability of EOs to inhibit acetylcholinesterase (AChE), thereby increasing levels and duration of acetylcholine in the brain and assisting with memory retention. Created using Biorender.com. (Last accessed on 14 December 2021).