Antinociceptive effect of selected Mexican traditional medicinal species.

Pain is considered one of the most common complaints worldwide for which patients seek treatment. Conventional analgesic agents have played an important role in modern pain therapy, but they cause several adverse effects. Therefore, the search for new and better analgesics agents continues. The present study was designed to investigate the antinociceptive potential of six Mexican medicinal herbs commonly employed for the treatment of anti-inflammatory diseases and pain. The antinociceptive effect was tested in male mice using the writhing test. In this test intraperitoneal administration of acetic acid (0.6%) provokes abdominal contractions, movements of the body as a whole (particularly of the hind paws), twisting of dorsoabdominal muscles, and reduction in motor activity. Reduction of stretching per unit of time was considered as antinociception. Methanol-chloroform extract of the plants Exostema caribaeum, Brickellia veronicaefolia, Scaphyglottis livida, Ligusticum porteri, Gnaphalium spp, and Amphipterygium adstringens were prepared by maceration. After eliminating the solvent in vacuo, the extracts were administered orally and the antinociceptive activity determined. The results indicated that the extracts of Exostema caribaeum, Gnaphalium spp, and Amphipterygium adstringens did not produce an antinociceptive effect. However, those of Brickellia veronicaefolia, Scaphyglottis livida and Ligusticum porteri produced a significant reduction in the number of stretches in the acetic acid-induced writhing test.