Efeito antinociceptivo do fenilpropanóide 2-alilfenol

Abstract

2-allylphenol is a phenylpropanoid widely marketed in China under the name Yinguo. It presents structural similarity to ginkgol the isolated compound from ginkgo fruit and has fungicidal activity already reported in the literature, however its effect in painful process has not been studied yet. This work aims to investigate the antinociceptive activity of 2-allylphenol in experimental models of pain in mice. Firstly, it was carried out the determination of the lethal dose 50 (LD50), in order to establish safe doses for subsequent tests. Then methodologies were performed to evaluate the antinociceptive activity. 2-allylphenol (25, 50, 75 e 100 mg/kg, i.p.) reduced the number of writhes, when compared to the control group. In the formalin test, in the doses 75 e 100 mg/kg, 2-allylphenol reduced the licking paw time on neurogenic (0-5 min) and inflammatory phase (15-30 min). In the hot plate test, which is sensible and specific to drugs that act by supraspinal mechanisms, 2-allylphenol did not change the latency in the paw withdrawal. While the test of nociception induced by glutamate, the 100mg/kg 2-allylphenol dose reduced the licking paw time. Based on these results we propose that the antinociceptive action of 2-allylphenol may be modulating pain via both peripherally as centrally in spinal levels. In an attempt to elucidate the mechanism of action involved in the antinociceptive effect of 2-allylphenol were used pharmacological tools in the formalin test. The antinociception produced by the 2-allylphenol was significantly blocked in animals pretreated with caffeine (10 mg/kg, s.c.), only in the second phase of the test, indicating the involvement of adenosinergic system. The antinociceptive effect of the 2-allylphenol, however, was not reversed by naloxone (non-selective antagonist of opioid receptors, 5 mg/kg, s.c.) and glibenclamide (K+ ATP channel blocker, 10 mg/kg, i.p.), suggesting that 2-allylphenol does not act by these mechanisms.