Oral Administration of Ethanol Extract of Myristica fragrans Elicited Hyperactivity, Anxiety and Reduced Dopamine Level in Rats

Objective: Myristica fragrans, a common kitchen spice, is reported to have psychoactive properties, producing hallucinations and fear. The psychoactive action is attributed to the presence of myristicin. This study aimed to assess the effects of ethanol seed extract of Myristica fragrans (ESMF) on anxiety-like behaviour and dopamine levels in rats. Materials and Methods: Thirty-six male Wistar rats were divided into six groups of six rats each. Groups I (control, received 2 ml/kg distilled water); Group II (received 2 ml/kg of tween 80 Oil); Groups III, IV and V received ESMF (500 mg/kg; 1000 mg/kg and 1500 mg/kg, respectively) and group VI received methylphenidate (1 mg/kg) as standard stimulant. All administration was done orally for 28 days. The rats were subjected to neurobehavioral tests: an open field test to assess hyperactivity and an elevated plus maze to assess anxiety-like behaviour. Brain samples were harvested and homogenized for neurochemical analysis of dopamine using a dopamine kit. Results: Hyperactivity was observed as increased line crossing and total distance travelled in the ESMF (500mg/kg)-treated group when compared with the control group and reduced anxiety-like behaviour by reduced frequent close arm entry and duration. Dopamine levels were reduced in the 1500 mg/kg ESMF-treated group compared to the control. Conclusion: Exposure to ethanol seed extract of Myristica fragrans elicited anxiety-like behaviour. ESMF at a dose of 500mg/kg possesses anxiolytic properties, while at a dose of 1500 mg/kg; elicits anxiety by a reduction in dopamine levels in rats.