Ethanolic extract of anise (Pimpinella anisum L.) attenuates morphine physical dependence in mice

Introduction: Previous studies revealed that anise (Pimpinella anisum L.) has several pharmacological effects including analgesic, antidepressant, anxiolytic, anti-inflammatory and antispasmodic activities. This study aimed to evaluate its effect on morphine physical dependence in mice.Methods: In this experimental study, ۴۰ male NMRI mice (۲۵-۳۰ g) were randomly divided into ۵ groups of ۸. Control group received morphine and normal saline (۱۰ mL/kg, i.p.) and other groups received diazepam (۵ mg/kg) plus one of three doses of P. anisum (۵۰,۱۰۰ or ۲۰۰ mg/kg, i.p.). Dependence was induced by administration of increasing doses (۵۰-۷۵ mg/kg, i.p.) of morphine. A time of ۳۰ minutes after naloxone injection was considered for the critical period of the withdrawal syndrome. The number of jumps and scores of ۰ to ۳ were given for incidences of wet dog shakes, teeth chattering, climbing, writing, diarrhea, grooming, and rearing during a ۳۰-minute period.Results: All doses of P. anisum (P < ۰.۰۱) reduced the number of jumps. Additionally, all doses of the extract reduced the behaviors of grooming (P < ۰.۰۵, P < ۰.۰۱ and P < ۰.۰۱, respectively) and writhing (P < ۰.۰۵, P < ۰.۰۰۱and P < ۰.۰۰۱, respectively). None doses of the extract could reduce diarrhea (P > ۰.۰۵). Climbing, rearing and wet dog shakes reduced only by the high dose of the extract (P < ۰.۰۵). Teeth chattering reduced by ۱۰۰ and ۲۰۰ mg/kg of the extract (P < ۰.۰۵).Conclusion: These results obviously show that P. anisum ethanolic extract is effective in suppression of morphine physical dependence and further studies are needed to find out the responsible constituents and also the exact mechanisms of actions.