Analgesic activity of the methanolic extract and total alkaloids of Glaucium paucilobum.

The species of Glaucium have been used in Iranian herbal medicine as laxative, hypnotic, narcotic, and antidiabetic agents and also in the treatment of dermatitis. The analgesic activity of the aerial parts of Glaucium Freyn (Papaveraceae), a native plant of Iran, were studied using formalin, hot plate, and writhing tests in rodents. The methanolic extract and total alkaloids of Glaucium paucilobum caused graded inhibition of both phases of formalin-induced pain. In the hot plate test, i.p. administration of G. paucilobum extract at the doses of 50-90 mg/kg and total alkaloids at the dose of 10-60 mg/kg significantly raised the pain threshold at an observation time of 30 min in comparison with control (p < 0.001). In the writhing test, the extract at the doses of 30-90 mg/kg and total alkaloids at the doses of 10-60 mg/kg produced a significant decrease in the number of writhings in comparison with the control group (p < 0.001). The methanolic extract and total alkaloids of G. paucilobum, at antinociceptive doses, did not affect the motor coordination of animals when assessed in the rotarod model. The results showed that analgesic activity of this plant may be related partly to the alkaloids.