Quercetin action on pain modulation/ Ação da quercetina sobre a modulação da dor

Abstract

Background: Quercetin is a flavonoid widely found in plant kingdom and target of studies in pharmacological area due to its potent antinociceptive effect compared to analgesics used in conventional therapies. The aim was to evaluate its antinociceptive activity and antinociception mechanism. Methods: For this, 40 Norvegicus Wistar rats were used, divided into 4 groups: Q50 (treated with quercetin 50 mg/Kg), Q100 (treated with quercetin 100 mg/Kg), Q500 (treated with quercetin 500 mg/Kg) and Positive control (PC) without quercetin treatment), who were submitted through the pain induction methods by tail immersion and formalin in the first step to assess antinociceptive action and in the second step, tail immersion method receiving antagonists from opioid, cholinergic and nitric oxide - L-arginine to evaluate the action mechanism. Results: Quercetin antinociceptive activity was verified at the dose of 50 mg/kg and 100 mg/kg in tail immersion test after formalin injection, with better performance at the dose of 50 mg/kg. There were no statistically significant results in paw opening and capsaicin tests. Quercetin demonstrated a possible influence on opioid and cholinergic pathway, which was not observed on the nitric acid - L-arginine pathway in view of parameters tested. Conclusion: Quercetin performed the best antinociceptive activity at a dose 50 mg/kg and there was a possible influence on opioid and cholinergic pathways.