Antinociceptive and anti-inflammatory effects of a formulation based on Alpinia zerumbet essential oil: an in vivo and in vitro approach

Abstract

Background: Current pharmacological treatments for acute orofacial pain present limitations, risks, and side effects. Thus, the search for safer alternatives is justified. The essential oil of Alpinia zerumbet (EOAz) has been used in the treatment of several medical conditions, including pain and inflammation, but scientific validation is scarce. The aim of this study was to investigate the antinociceptive and anti-inflammatory effects of EOAz in models of acute orofacial pain in rats and in inflammatory parameters in vitro. Methods: Adult male Wistar rats were subjected to intraoral incision surgery, a model of postoperative pain. The effect of the facial topical application (1 to 3 times a day for 3 days) of EOAz or a formulation based on EOAz (Fb-EOAz) was assessed on heat and mechanical hyperalgesia. The same rats were tested in the open field test (OFT) to assess the influence of the treatments on rats’ locomotion. Moreover, the effects of the treatments were evaluated on facial heat hyperalgesia induced by lipopolysaccharide (LPS), a model of myofascial pain, and in vitro, in the release of nitric oxide (NO) and interleukin-6 in macrophages stimulated by LPS. Results: EOAz and Fb-EOAz reduced postoperative heat hyperalgesia, but only Fb-EOAz reduced postoperative mechanical hyperalgesia and heat hyperalgesia induced by LPS. Fb-EOAz reduced NO and interleukin-6 release by macrophages stimulated by LPS. None of the treatments affected the rat’s locomotion. Conclusions: These data provide preclinical evidence of antinociceptive and anti-inflammatory effects of Fb-EOAz. This approach may represent an alternative or adjuvant therapy in the control of inflammatory and myofascial orofacial pain.