Antinociceptive, anti-inflammatory and acute toxicity effects of Zataria multiflora Boiss extracts in mice and rats

Antinociceptive,anti-inflammatory and acute toxicity of the aqueous infusio n and ethanolic maceration extracts of the aerial parts of Zataria multiflo ra Boiss were studied in mice and rats. Antinociceptive activity was done u sing hot-plate and writhing tests. The effect of the extracts against acute inflammation was studied by vascular permeability increased by acetic acid and xylene induced ear edema in mice. The activity of the extracts against chronic inflammation was assessed by the cotton pellet test in rats. LD50 of the infusion and maceration extract was 3.85 and 3.47 g/kg, respectively . Intraperitoneal injection of both extracts in mice showed significant and dose-dependent antinociceptive activity. Naloxone, an opioid antagonist, p retreatment inhibited the antinociceptive activity of the extracts. The ext racts exhibited antinociceptive activity against acetic acid induced writhi ng which was partially blocked by naloxone. Both extracts did not show rema rkable activity against acute inflammation induced by acetic acid in mice. In the xylene ear edema, Z. multiflora Boiss extracts showed significant ac tivity in mice. In the chronic inflammation the efficacy of the extracts wa s more than in acute inflammation. It is concluded that aqueous infusion an d maceration of the aerial parts of Z. multiflora Boiss have antinociceptiv e effect and this may be mediated by opioid receptors. The extracts showed also anti-inflammatory effect against acute and chronic inflammation. (C) 2 000 Elsevier Science Ireland Ltd. All rights reserved.