Avaliação do efeito analgésico e anti-inflamatório do ácido cóstico em modelos de dor e hiperalgesia em ratos

Abstract

Introduction: Medicinal plants are crucial sources for discovering new active ingredients used to treat various diseases. An example of herbal medicine is costic acid, a sesquiterpene present in several plants, such as Dittrichia viscosa. Published results indicate an anti-inflammatory effect of this extract in a model of chronic inflammation. Thus, hyperalgesia that results in increased pain sensitivity is a crucial component in the inflammatory response, being the main motivator for the search for anti-inflammatory treatments. Objectives: Evaluate the analgesic or antihyperalgesic potential of costic acid. Methods: The analgesic potential of the molecule was evaluated through the capsaicin test on rat paws and the anti-inflammatory and antihyperalgesic potential was investigated using the inflammation model induced by the injection of carrageenan into the rat paw, by measuring the mechanical sensitivity threshold (electronic von Frey) and evaluating the paw volume using the plethysmometer. Furthermore, the possible effect of costic acid on neuronal membrane potential in primary cultures of rat dorsal root ganglia neurons was examined using a voltage-sensitive fluorescent (DiBAC4(3)). Results: Costic acid, at the dosage tested, had no impact on capsaicin-induced nociception. However, it demonstrated the ability to decrease hyperalgesia, suggesting an anti-inflammatory effect. Furthermore, in primary cultures of rat dorsal root ganglion, costic acid caused a low intensity neuronal depolarization, only when administered at the highest concentration tested. However, this depolarization does not seem to have significant effects in vivo, considering the effect of costic acid on nociception. Conclusion: Costic acid showed anti-inflammatory properties, but did not demonstrate an analgesic effect.