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


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.
Department of Medicinal and Industrial Plants, Institute of Biotechnology, Urmia University , Urmia , Iran and.
Masoud
M
Maham
Hemmat
H
Moslemzadeh
Ghader
G
Jalilzadeh-Amin
D000700:Analgesics / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D019306:Artemisia / Q000737:chemistry*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D007274:Injections, Intraperitoneal; D007928:Lethal Dose 50; D008297:Male; D008519:Medicine, Traditional; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D009822:Oils, Volatile / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D010147:Pain Measurement; D051381:Rats; D017208:Rats, Wistar; D023382:Toxicity Tests, Acute
D000700:Analgesics; D009822:Oils, Volatile; D009270:Naloxone