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 x 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 ED(50) 67.92 mg x kg(-1). The essential oil in doses (mg x 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 ED(50) of 29.41 mg x 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 x 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.