Pain neuromodulation exerted by Ruta graveolens aqueous extract in experimental models of nociception/ Neuromodulação da dor exercida pela Ruta graveolens extrato aquoso em modelos experimentais de nocicepção

Abstract

Introduction: The use of medicinal plants for therapeutic purposes has been common practice since antiquity. Ruta graveolens L., commonly known as rue, has been shown to have antiparasitic, antioxidant, antibacterial and allelopathic activity. Objective: The objective was to investigate the antinociceptive effect of rue, as well as the mechanisms behind this effect. Materials and Methods: The sample consisted of 40 male Norvegicus (Wistar) rats, randomly divided into a positive control and three treatment groups administered Ruta graveolens L. aqueous extract at the following doses: 50 mg/kg, 100 mg/kg or 500 mg/kg, p.o. The experimental models of nociception used in this study to assess effectiveness of the treatments were the formalin and capsaicin tests. Five days prior to nociceptive challenges, the tail immersion assay was conducted to determine baseline pain threshold. Results: Antinociceptive activity was observed at Ruta graveolens L. aqueous extract concentrations of 50 mg/kg and 100mg/kg. 500 mg/kg induced pro-nociceptive activity with activation of the L-arginine-oxide-nitric system. Conclusion: These results suggest Ruta graveolens L. aqueous extract antinociceptive activity, and possible antagonism towards receptors