Effect and mechanism of senkyunolide I as an anti-migraine compound from Ligusticum chuanxiong.

OBJECTIVE: To evaluate the analgesic and anti-migraine activities of senkyunolide I from Ligusticum chuanxiong. METHODS: Mice were orally administered various doses of senkyunolide I, and their pain levels were assessed in a hot-plate test and by application of acetic acid. The levels of 5-hydroxytryptamine (5-HT), 5-hydroxytryptophan (5-HTP), 5-hydroxyindoleacetic acid (5-HIAA), norepinephrine (NE) and dopamine (DA) in plasma and brain were assessed, and the monoamine turnover rates (5-HT/5-HTP, 5-HIAA/5-HT and NE/DA) were also calculated. RESULTS: Mice given senkyunolide I at 16 and 32 mg/kg had significantly elevated pain thresholds in the hot-plate test, and a dose of 32 mg/kg also reduced the number of abdominal writhing responses caused by acetic acid. Significant improvements were observed in the neurotransmitter levels of the drug-treated rats compared with the saline-administered controls. Compared to the rats with nitroglycerin-induced migraines, the levels of nitric oxide in the plasma and whole brain of rats given senkyunolide I were lower. CONCLUSIONS: The present study suggests that senkyunolide I may be an active component of L. chuanxiong, traditionally used to treat migraine. The mechanism of pain relief in migraine model rats may be through adjusting the levels of monoamine neurotransmitters and their turnover rates, as well as decreasing nitric oxide levels in the blood and brain. Therefore, senkyunolide I may be developed as a potential treatment for migraine pain.