Antinociceptive effects of Teucrium polium L. total extract and essential oil in mouse writhing test

In this study, the effect of Teucrium polium L., a wild-growing flowering plant belonging to the family Labiatae and found abundantly in Iran was studied on writhing test, a visceral pain model in mice. The total extract and essential oil were administered intraperitoneally 30 min before acetic acid 0.6% injection. Total extract in doses (mg kg(-1)) of 150 (39.13%, P < 0.001), 225 (65.44%, P < 0.001), 300 (21.41%, P < 0.01) induced reduction in writhing response as compared to control with the ED50 67.92 mg kg(-1). The essential oil in doses (mg kg(-1)) of 9.37 (35.22%, P < 0.001), 18.75 (59.63%, P < 0.001), 37.5 (86.60%, P < 0.001), 75 (90.22%, P < 0.001) and 150 (78.58%, P < 0.001) induced significant reduction in writhing response when compared to control with the ED50 Of 29.41 mg kg(-1). In order to ensure the importance of essence in production of visceral antinociception, the extract free from essential oil was prepared and injected into mice at a dose of 225 mg kg(-1) (the most effective dose of the extract) which in comparison to total extract, the antinociception, reduced from 65.44 to 49.85% (P < 0.001). It is concluded that essential oil is responsible for analgesic properties of T polium. This study confirms the antivisceral pain properties of T polium comparable to those of hyoscine and indomethacin and suggests a good place for it in antispasmodic therapies in human. The presence of flavonoids and sterols might be responsible for the anti-inflammatory activity of this plant. (C) 2003 Elsevier Science Ltd. All rights reserved.