Estudo da atividade antinociceptiva e anti-inflamatória do extrato etanólico bruto de Sargassum polyceratium Montagne

Abstract

The marine natural products have been the target of important researches in the last decades; in that period, the quantity of isolated products that presented therapeutic activity has increased exponentially. However, due to the vast biological arsenal that the marine environment presents, it is still little explored. The algae represent one of the resources most biologically active in nature and due to that, it has aroused the interest of research community for being producers of chemical substances with high chances of having therapeutic activity. Sargassum polyceratium is a benthic macroalgae ecologically important for the marine environment. Previous studies isolated and identified four substances from brute ethanolic extract of Sargassum polyceratium (SpEE) and reveal confirmed antinociceptive activity of this extract, although it is known nothing about its action mechanism. In the present study, it was studied the possible action mechanism of SpEE using pharmacological antagonists and having the formalin test as experimental protocol. The antinociception produced by SpEE was significantly blocked in animals pre-treated with caffeine (10 mg/kg, s. c.), indicating the involvement of the adenosinergic system. However, the antinociceptive effect of SpEE was not reversed by nexalone (non-selective opioid antagonist, 5 mg/kg, s. c.), glibenclamide (K+ATP channel blockers, 10 mg/kg, i.p.), sulpiride (antagonist of dopaminergic receptors type D2, 20 mg/kg, s.c.), neither by yohimbine (selective antagonist of receptors α2-adrenergic, 015 mg/kg, i.p.), suggesting that SpEE does not act directly by these mechanisms. In the peritonitis model induced by carrageenan, the treatment with SpEE reduced the flow of leukocytes to the inflamed site. Thus, these results show that SPEE promotes antinociceptive activity with possible participation of adenosinergic system, in addition to having anti-inflammatory activity.