Anticonvulsant activities of nutmeg oil of Myristica fragrans.

The purpose of this study was to investigate the anticonvulsant activity of the volatile oil of nutmeg, the dried seed kernel of Myristica fragrans Houtt, using well-established animal seizure models and to evaluate its potential for acute toxicity and acute neurotoxicity. The volatile oil of nutmeg (nutmeg oil) was tested for its effects in maximal electroshock, subcutaneous pentylenetetrazole, strychnine and bicuculline seizure tests. All the experiments were performed at the time of peak effect of nutmeg oil. Nutmeg oil showed a rapid onset of action and short duration of anticonvulsant effect. It was found to possess significant anticonvulsant activity against electroshock-induced hind limb tonic extension. It exhibited dose dependent anticonvulsant activity against pentylenetetrazole-induced tonic seizures. It delayed the onset of hind limb tonic extensor jerks induced by strychnine. It was anticonvulsant at lower doses, whereas weak proconvulsant at a higher dose against pentylenetetrazole and bicuculline induced clonic seizures. Nutmeg oil was found to possess wide therapeutic margin, as it did not induce motor impairment when tested up to 600 microL/kg in the inverted screen acute neurotoxicity test. Furthermore, the LD(50) (2150 microL/kg) value was much higher than its anticonvulsant doses (50-300 microL/kg). The results indicate that nutmeg oil may be effective against grand mal and partial seizures, as it prevents seizure spread in a set of established animal models. Slight potentiation of clonic seizure activity limits its use for the treatment of myoclonic and absence seizures.