The effect of hydroalcoholic extract of Achillea Millefolium on analgesic effect of Morphine in rats

Abstract

Objective: Achillea millefolium is a plant whose anti-inflammatory effects were proved by inhibition of cyclooxygenase enzyme activities. In this study, the effect of its hydroalcoholic extract on analgesic effect of morphine was investigated to lower the dose of injected morphine as much as possible. Methods: This study was performed on rats by tail flick test. At first a suitable dose of morphine that caused analgesia was selected by dose response method. Then analgesic effect of different doses of achillea millefolium extract (25, 50, 75 and 100 mg/kg) and also the effect of these doses on analgesic effect of a suitable dose of morphine (2.5 mg/kg) were investigated. Findings: According to the results and by using analytical variance method, the best dose of extract selected for improving the analgesic effect of morphine was 75 mg/kg (P<0.05). Reflex time in control group to alogenic stimulant was about 2-3 seconds and in rats, which received different doses of hydroalcoholic, extract of achillea millefolium before injection of morphine (2.5 mg/kg) in comparison to those which only received morphine showed a significant increase (P<0.05). Conclusion: All doses of hydroalcoholic extract of achillea millefolium caused an increase of analgesic effect of morphine significantly (P<0.05). Meanwhile, the strongest effect was observed at 45th minute of the trial.

Keywords

• achillea millefolium
• morphine
• pain
• rat