antinociceptive and anti-inflammatory effects of pistacia vera leaf extract in mice

pistacia vera l., a member of anacardiaceae family, has been used for sedation and analgesia in traditional medicine. in this study, the antinociceptive and anti-inflammatory effects as well as acute toxicity of the aqueous and ethanolic extracts of p. vera leaves were investigated in mice. the antinociceptive activity was studied using hot plate and writhing tests. the effect of the extracts against acute inflammation was determined using xylene-induced ear edema and the activity of the extracts, against chronic inflammation, was assessed using the cotton pellet test. the ld50 values of the infusion and maceration extracts were 0.8 g/kg and 0.79 g/kg, respectively. the aqueous and ethanolic maceration extracts of the p. vera leaves at the doses of 0.4 g/kg and 0.5 g/kg (ip), respectively, showed antinociceptive effects. the pretreatment of naloxone (2 mg/kg, sc) inhibited the activities of extracts in hot plate test, but naloxone at the same dose could not inhibit the antinociceptive activity in writhing test. the extracts also showed anti-inflammatory effects in acute and chronic anti-inflammatory tests. the ethanolic extract was as effective as diclofenac in both inflammatory tests. the aqueous and ethanolic extracts of p. vera leaves demonstrated central and peripheral antinociceptive activities dose-dependently and the central effect may be mediated by opioid system. the extracts also demonstrated anti-inflammatory effects against acute and chronic inflammation.