Effect of Essential Oil of Zhumeria majdae on Morphine Tolerance and Dependence in Mice

Objective: To evaluate the effects of Zhumeria majdae essential oil (ZMEO) on morphine dependence and tolerance in mice.

Methods: ZMEO (10, 20, and 40 mg/kg) and clonidine (0.1 mg/kg) as the positive control were injected intraperitoneally (i.p.). The effect of ZMEO and clonidine on the dependence were evaluated by counting the number of jumps induced by naloxone (5 mg/kg) while the tolerance was evaluated by the tail-flick test.

Results: ZMEO at the dose of 10 mg/kg during the development period led to a significant inhibition of morphine tolerance (P<0.01), while it led to reduced morphine dependence with the doses of 20 and 40 mg/kg. ZMEO at two dose levels of 20 and 40 mg/kg indicated significant antinociceptive activity (P>0.01), and significantly reduced the withdrawal signs (number of jumps) of mice (P>0.01).

Conclusions: ZMEO had significant effects on morphine tolerance and dependence. The linalool rich essential oil of Z. majdae plays a major role in the reduction of tolerance and dependence induced by morphine.

Keywords: Zhumeria majdae; dependence; morphine; tolerance.