Antinociceptive, anti-inflammatory and acute toxicity effects of Zhumeria majdae extracts in mice and rats.

Antinociceptive and anti-inflammatory effects and acute toxicity of aqueous infusion and ethanolic maceration extracts of the aerial parts of Zhumeria majdae were studied in mice and rats. Antinociceptive activity was determined using hot-plate and writhing tests. The effect of the extracts against acute inflammation was studied by acetic acid increased vascular permeability and xylene-induced ear edema in mice. The activity of the extracts against chronic inflammation was assessed using the cotton pellet test in rats. LD50 values of the infusion and maceration extracts were 3.09 g/kg body wt., and 3.94 g/kg body wt., respectively. Phytochemical screening of the extracts indicated the presence of flavonoids and tannins. In the hot-plate test, the intraperitoneal injection of both extracts showed significant and dose-dependent antinociceptive activity in mice. Naloxone, an opioid antagonist, on pretreatment inhibited the antinociceptive activity of the extracts. The extracts exhibited antinociceptive activity against acetic acid-induced writhing, which was partially blocked by naloxone. Both extracts showed significant effect against acute inflammation induced by acetic acid in mice. In the chronic inflammation test, efficacy of the extracts was similar to that of baclofen and dexamethasone in rats. It is concluded that the aqueous infusion and ethanolic maceration extract of the aerial parts of Zhumeria majdae have antinociceptive effects and this may be mediated by opioid receptors. The extracts also showed anti-inflammatory effects against acute and chronic inflammation.