Anticonvulsant effects of hydroalcoholic extract of Melissa officinalis on pentylenetetrazole (PTZ) model of convulsion in mice

Extracts of Melissa officinalis (Lemon Balm) are extensively used in traditional medicines. This study examined the anticonvulsant activity of the hydroalcoholic extract of M. officinalis on pentylenetetrazole (PTZ)-induced seizures threshold in mice. The fresh leaves and the whole plant of M. officinalis were used by a routine method to produce an injectable solution for administration. M. officinalis and normal Saline were injected intraperitoneally (IP) at the doses 100, 300, 600 and 900 and 1200 mg/kg, i.p and 10 ml/kg i.p, respectively, 30 min before the administration of PTZ (90 mg/kg, i.p). For measurement of anticonvulsant activity of animals, convulsive symptoms were divided into 3 level (scores 1-3) which were C-1, C-2 and C-3. The time taken before C-1, C-2 and C-3 and the percentage of seizure and mortality protection rate were recorded. Statistical analyses of all treatment and control groups show that M. officinalis significantly can increases onset time of convulsive symptoms in all 3 levels of seizure in the PTZ model. On the other hand, onset time of convulsive symptoms increases by doses increasing which may indicate the dose-dependent effect of M. officinalis. It seems that it can be useful for treatment of seizure.