Antinociceptive effect of 7-methoxyflavone isolated from Zornia brasiliensis.

In this study, we investigated the antinociceptive effect of 7-methoxyflavone (7MF) in mice using the following tests: acetic acid-induced writhing, glutamate- and formalin-induced nociception and hotplate. 7MF (30, 50, 100 and 300mol/kg, i.p.) reduced the number of writhes, with ID50=82.5 +/- 11.7mol/kg and E-max=58.4%. 7MF treatment (100mol/kg, i.p.) inhibited paw-licking time in the neurogenic phase of the formalin pain response (65.6%) and did not decrease the nociceptive response in the inflammatory phase. In addition, in glutamate-induced nociception, 7MF inhibited 26% of the nociceptive answer. On the other hand, 7MF did not increase the latency time of the animals in the hotplate test. These results suggest that 7MF has peripheral antinociceptive activity.