Antinociceptive and anti-inflammatory effects of the aerial parts of Artemisia dracunculus in mice

Context: Tarragon (Artemisia dracunculus L., Asteraceae) is an ancient herb, which is widely used as a medicine, flavoring, or fragrance. Objective: To determine the antinociceptive and anti-inflammatory effects of aerial parts of tarragon, we investigated the effects of ethanolic extract of the plant in adult male Balb/c mice. Materials and methods: Antinociceptive activity was determined using formalin, hot-plate, and writhing tests. The effect of the ethanolic extract on acute inflammation was evaluated by xylene-induced ear edema in mice. The ethanolic extract was administered at doses of 5, 10, 50, and 100mg/kg, i.p. The control group received saline as vehicle of ethanolic extract. Results: Our results showed that the ethanolic extract (50 and 100mg/kg) decreased both phases of pain in the formalin test (ED50=109.66 and 87.13mg/kg, respectively). In the hot-plate test, the extract (50 and 100mg/kg) increased pain threshold during 60min (ED50=81.03mg/kg). The extract (50 and 100mg/kg) exhibited antinociceptive activity against acetic acid-induced writhing (ED50=66.99mg/kg). The extract (50 and 100mg/kg) showed significant activity in the xylene ear edema test (ED50=78.20mg/kg). Pretreatment of the animals with naloxone decreased the analgesia induced by the extract in hot-plate and formalin tests; therefore, opioid receptors may be involved, at least partly, in the analgesic effect of tarragon extract. Discussion and conclusion: The results suggested that tarragon have significant analgesic and anti-inflammatory effects in mice, and, therefore, further studies are required to evaluate these effects and additional potential of the plant.