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Original Article

Korean J Pain 2019; 32(2): 79-86

Published online April 1, 2019 https://doi.org/10.3344/kjp.2019.32.2.79

Copyright © The Korean Pain Society.

Analgesic effects of eucalyptus essential oil in mice

Ganggeun Lee1, Junbum Park1, Min Sun Kim2, Geun Hee Seol3, and Sun Seek Min2

1Department of Anesthesiology and Pain Medicine, Eulji University Hospital, Daejeon, 2Department of Physiology and Biophysics, Eulji University School of Medicine, Daejeon, 3Department of Basic Nursing Science, Korea University School of Nursing, Seoul, Korea

Correspondence to:Sun Seek Min, Department of Physiology and Biophysics, Eulji University School of Medicine, 77 Gyeryong-ro 771beon-gil, Jung-gu, Daejeon 34824, Korea, Tel: +82-42-259-1633, Fax: +82-42-259-1639, E-mail: ssmin@eulji.ac.kr, ORCID: https://orcid.org/0000-0001-7144-1987

Received: October 15, 2018; Revised: January 18, 2019; Accepted: January 21, 2019

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background: The use of aroma oils dates back to at least 3000 B.C., where it was applied to mummify corpses and treat the wounds of soldiers. Since the 1920s, the term “aromatherapy” has been used for fragrance therapy with essential oils. The purpose of this study was to determine whether the essential oil of Eucalyptus (EOE) affects pain pathways in various pain conditions and motor coordination.
Methods: Mice were subjected to inhalation or intraperitoneal injection of EOE, and its analgesic effects were assessed by conducting formalin, thermal plantar, and acetic acid tests; the effects of EOE on motor coordination were evaluated using a rotarod test. To determine the analgesic mechanism, 5’-guanidinonaltrindole (κ-opioid antagonist, 0.3 mg/kg), naltrindole (δ-opioid antagonist, 5 mg/kg), glibenclamide (δ-opioid antagonist, 2 mg/kg), and naloxone (δ-opioid antagonist, 4, 8, 12 mg/kg) were injected intraperitoneally.
Results: EOE showed an analgesic effect against visceral pain caused by acetic acid (EOE, 45 mg/kg); however, no analgesic effect was observed against thermal nociceptive pain. Moreover, it was demonstrated that EOE did not have an effect on motor coordination. In addition, an anti-inflammatory effect was observed during the formalin test.
Conclusions: EOE, which is associated with the µ-opioid pain pathway, showed potential effects against somatic, inflammatory, and visceral pain and could be a potential therapeutic agent for pain.

Keywords: Acetic acid, Analgesics, Aromatherapy, Eucalyptus, Formaldehyde, Glyburide, Intraperitoneal injections, Mice, Naloxone, Naltrindole, Rotarod performance test, Opioid antagonists.