Title:Rational Basis for the Use of Bergamot Essential Oil in Complementary Medicine to Treat Chronic Pain
VOLUME: 16 ISSUE: 9
Author(s):L. Rombolà, D. Amantea, R. Russo, A. Adornetto, L. Berliocchi, L. Tridico, MT Corasaniti, S. Sakurada, T. Sakurada, G Bagetta and L.A. Morrone
Affiliation:Department of Pharmacy, Health Science and Nutrition and University Consortium for Adaptive Disorders and Head Pain (UCADH), Section of Neuropharmacology of Normal and Pathological Neuronal Plasticity, University of Calabria, 87036 Rende (CS), Italy
Keywords:Bergamot essential oil, complementary medicine, neuropathic pain, nociceptive pain.
Abstract:In complementary medicine, aromatherapy uses essential oils to improve agitation and
aggression observed in dementia, mood, depression, anxiety and chronic pain. Preclinical research
studies have reported that the essential oil obtained from bergamot (BEO) fruit (Citrus bergamia, Risso) modifies normal
and pathological synaptic plasticity implicated, for instance, in nociceptive and neuropathic pain. Interestingly, recent
results indicated that BEO modulates sensitive perception of pain in different models of nociceptive, inflammatory and
neuropathic pain modulating endogenous systems. Thus, local administration of BEO inhibited the nociceptive behavioral
effect induced by intraplantar injection of capsaicin or formalin in mice. Similar effects were observed with linalool and
linalyl acetate, major volatile components of the phytocomplex, Pharmacological studies showed that the latter effects are
reversed by local or systemic pretreatment with the opioid antagonist naloxone hydrochloride alike with naloxone
methiodide, high affinity peripheral μ-opioid receptor antagonist. These results and the synergistic effect observed
following systemic or intrathecal injection of an inactive dose of morphine with BEO or linalool indicated an activation of
peripheral opioid system. Recently, in neuropathic pain models systemic or local administration of BEO or linalool
induced antiallodynic effects. In particular, in partial sciatic nerve ligation (PSNL) model, intraplantar injection of the
phytocomplex or linalool in the ipsilateral hindpaw, but not in the contralateral, reduced PSNL-induced extracellularsignal-
regulated kinase (ERK) activation and mechanical allodynia. In neuropathic pain high doses of morphine are
needed to reduce pain. Interestingly, combination of inactive doses of BEO or linalool with a low dose of morphine
induced antiallodynic effects in mice. Peripheral cannabinoid and opioid systems appear to be involved in the
antinociception produced by intraplantar injection of β -caryophyllene, present in different essential oils including BEO.
The data gathered so far indicate that the essential oil of bergamot is endowed with antinociceptive and antiallodynic
effects and contribute to form the rational basis for rigorous testing of its efficacy in complementary medicine.
