Comparative study of anticonvulsant activity of Valeriana officinalis, Lavandula officinalis and Melissa officinalis on pentylenetetrazole-induced seizure threshold in mice

Reza Ebrahimi Hariry1, Brett Cromer2, Davood Mahdipour Aghabagher1. 1Young Researchers Club, Islamic Azad University-Ardabil Branch, Ardabil, Iran, 22Health Innovations Research Institute, RMIT University, Melbourne, Australia

Current evidences show that many people rely on traditional treatments especially medicinal plants. However, few people know scientifically about the safety and efficacy of herbals. There are many herbs that are used traditionally in seizure and epilepsy around the world. Some such frequently used medicinal plants are Valeriana officinalis, Lavandula officinalis and Melissa officinalis. This study compared the anticonvulsant activity of the hydro-alcoholic extract of Valeriana officinalis, Lavandula officinalis and Melissa officinalis on pentylenetetrazole (PTZ)-induced seizures threshold in mice.

Albino male BALB/c mice (25–30 g, N=10 per each dose per each extract (total N=160)) were used in this study according with standard conditions (12/12 h light/dark cycle, 22 ± 2°C and free access to food and water). The roots and rhizomes of Valeriana officinalis, flowers of Lavandula officinalis and leaves and the whole plant of Melissa officinalis were used by a routine method to produce an injectable solution for administration. The initial dosage of solution of all three extracts was 100 mg/kg. Dose selection should have rational like 1/10th of lethal dose (LD50 dose). Injectable solution of all extract and normal saline (as control group) 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 extracts and comparing them with each other in mice, convulsive symptoms were divided into 3 level (scores 1-3) which were C1, C2 and C3. C1 was the onset of a general clonus which was characterized by forelimb clonus. C2 was the onset of myoclonic convulsion and C3 was the onset of the tonic-clonic convulsion. The time taken before C1, C2 and C3 and the percentage of seizure and also the mortality protection rate of all three extracts were recorded. All statistical analyses were performed with using SPSS 11.5 and One-way repeated measures analysis of variance (ANOVA) was used to determine the association of each factor and to be significant was considered at p<0.05. Statistical analyses of all treatment and control groups showed that all three extracts significantly could increase onset time of convulsive symptoms in all 3 levels of seizure in the PTZ model. Valeriana officinalis, Lavandula officinalis and Melissa officinalis at the all dose prolonged the C1, C2 and C3 symptoms of convulsion. They exhibited their protection against seizure in a dose-dependent manner. In addition, Comparative study of anticonvulsive effect of Valeriana officinalis, Lavandula officinalis and Melissa officinalis showed that there is a significant difference between anticonvulsant activities of these three extracts. Anticonvulsive effect of extracts was compared on binary method. The results showed that Valeriana officinalis is the most potent extract among the extracts. On the other hand, Lavandula officinalis also had more anticonvulsant effect in comparison with Melissa officinalis.

In brief, the present study provides evidence for anticonvulsant activity of Valeriana officinalis, Lavandula officinalis and Melissa officinalis in the seizure of PTZ model and also investigates the comparative anticonvulsant effect of them. As the protective effects of them in seizure, it seems that all extracts have anticonvulsant activity which suggests that all three herbs could be useful for treatment of seizure and epilepsy. However, comparative results showed that the Valeriana officinalis was the most potent anticonvulsant extract while Lavandula officinalis and Melissa officinalis were in the next positions.