Orofacial anti-hypernociceptive effect of citral in acute and persistent inflammatory models in rats

Author(s)

Santos, Bruna M. ; Santos, Wanderson S. ; Solon, Isabelly G. ; Garcia, Felipe S. ; Emilio-Silva, Maycon T. ; Jesus, Aline A. ; Hiruma-Lima, Clelia A. ; Nascimento, Glauce C. ; Carnio, Evelin C. ; Branco, Luiz G. S.

• Document type: Journal article
• Source: ARCHIVES OF ORAL BIOLOGY; v. 152, p. 7-pg., 2023-05-25.

Abstract

Orofacial pain has significant psychological and physiological effects. Citral (3,7-dimethyl-2,6-octadienal) is the main component of Cymbopogon citratus (DC) Stapf, an herb with analgesic properties. Although citral has been considered a potent analgesic, its putative effects on orofacial pain are still unknown.Objective: The objective of this study is to test the hypothesis that citral modulates orofacial pain using two experimental models: formalin-induced hyperalgesia in the vibrissae area and during persistent temporoman-dibular hypernociception using Complete Freund's Adjuvant -CFA test.Methods: For the formalin test, citral (100 and 300 mg/kg, oral gavage) or its vehicle (Tween 80, 1 %) were given 1 h before the formalin injection subcutaneously (sc) into the vibrissae area. For the CFA model, we analyzed the prophylactic (100 mg/kg of citral by oral gavage, 1 h before CFA injection) and the chronic therapeutic (citral treatment 1-hour post-CFA injection and daily post-CFA injection) effect of citral or its vehicle in animals treated with CFA for 8 days. Results: Citral caused a decrease in formalin-induced local inflammation and the time spent performing noci-ceptive behavior in a dose-dependent fashion. Similarly, prophylactic and therapeutic citral treatment decreased the CFA-induced persistent mechanical hypernociception in the temporomandibular area.Conclusion: Our data strengthen the notion that citral plays a powerful antinociceptive role by decreasing oro-facial hypernociception in formalin and CFA models. (AU)

• FAPESP's process: 16/09364-3 - Role of endogenous preoptic hydrogen sulfide modulating LPS tolerance.
• Grantee: Bruna Maitan Santos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/17681-9 - Pathophysiological changes during systemic inflammation
• Grantee: Luiz Guilherme de Siqueira Branco
• Support Opportunities: Research Projects - Thematic Grants