Antinociceptive effect of the essential oil of tarragon (Artemisia dracunculus)

Context: Tarragon [Artemisia dracunculus L. (Asteraceae)] is used as a commercial flavoring and in perfumery. In traditional folk medicine, tarragon has been used for treatment of pain and gastrointestinal disturbances. Objective: This study investigated the antinociceptive effect of the essential oil of A. dracunculus (EOAD) in various experimental models. Materials and methods: The median lethal dose (LD50) of EOAD was estimated using the method of Lorke. The antinociceptive effect was assessed using chemical (formalin and acetic acid) and thermal (hot-plate) nociceptive tests in rats and mice. In all experiments, EOAD was administered intraperitoneally at the doses of 10, 30, 100 and 300 mg/kg. Results: In the acute toxicity test, the value of estimated LD50 for EOAD was 1250 mg/kg. EOAD (100 and 300 mg/kg) significantly reduced (p<0.001) the pain response in the first (59.5 and 91.4%) and second (52.5 and 86.3%) phases of the formalin test, respectively. Central involvement in analgesic profile was confirmed by the hot-plate test, in which the EOAD showed a significant analgesic activity by increasing latency time. EOAD (10, 30, 100 and 300 mg/kg) significantly (p<0.001) inhibited (89, 95, 97 and 97%) the nociception produced by acetic acid. Naloxone failed to antagonize the antinociceptive effect of the essential oil in the acetic acid-induced writhing test. It seems that mechanism(s) other than opioid receptors is (are) involved in the analgesic effect of EOAD. Conclusions: This study reported the peripheral and central antinociceptive activity of the EOAD and rationalized the traditional use of the plant in the treatment of different painful conditions.