Evaluation of the analgesic and anxiolytic effects of Dracocephalum polychaetum

Introduction: Dracocephalum polychaetum bornum is exclusively found in a limited geographical area in the Kerman province It is used by the local people for treatment of abdominal pain, meteorism and musculoskeletal pain. No study has been performed on the effects of D. polychaetum bornum, so the aim of this work was to assess the role of the extract and essential oil of this plant on pain and anxiety assessed by formalin test and elevated plus-maze (EPM), respectively, in male rats. Methods: Analgesic effects: One hundred twelve NMRI male rats were divided into 14 groups. Aqueous extract and essential oil were administered to 8 groups at doses of 25, 50, 100 and 200 mg/kg i.p., while 2 groups were treated with normal saline, and the last 4 groups (sham positive) received ASA (300 mg/kg) and morphine (2.5 mg/kg). Anxiolytic effect: Forty-two NMRI male rats were divided into 7 groups. Four groups were injected intraperitoneally with 25, 50, 100 and 200 mg/kg of the extract of the plant and 2 groups were injected with normal saline (control group) and 1 mg/kg diazepam (positive sham). Anxiolytic effect was evaluated by EPM. Results: The results showed that the extract but not the essential oil at the dose of 200 mg/kg had a significant analgesic effect 25, 30 and 35 minutes after administration. The findings on the anxiolytic effect revealed that there was no significant difference between groups treated with different doses. Conclusion: This study showed that D. polychaetum bornum had analgesic effects.