Anticonvulsant Activity of Viola tricolor against Seizures Induced by Pentylenetetrazol and Maximal Electroshock in Mice

Recently, there has been much more interest in the use of medicinal plants in search of novel therapies for human neurodegenerative diseases such as epilepsy. In the present study, we investigated the anticonvulsant effects of Viola tricolor (V. tricolor) on seizure models induced by pentylenetetrazol (PTZ) and maximal electroshock stimulation (MES). Totally, 260 mice were divided into 26 groups (n=10). Thirty minutes after treatment with the hydroalcoholic extract of V. tricolor (VHE 100, 200, and 400 mg/kg) and its ethyl acetate (EAF 50, 100, and 200 mg/kg) and n-butanol (NBF 50, 100, and 200 mg/kg) fractions as well as diazepam (3 mg/kg), seizure was induced by PTZ (100 mg/kg) or by MES (50 Hz, 1 s and 50 mA). Analysis was performed via ANOVA with the Tukey–Kramer post-hoc test using GraphPad Prism 6.01 (La Jolla, CA). The VHE (400 mg/kg) significantly enhanced latency to the first generalized tonic-clonic seizures (GTCs) induced by PTZ in comparison to the control group (P<0.001). All 3 concentrations of the EAF (50, 100, and 200 mg/kg) significantly prolonged the latency of PTZ-induced seizures compared to the control group. Additionally, all the concentrations of the NBF (50, 100, and 200 mg/kg) made a significant increment in GTCs latency induced by PTZ in comparison to the control group. On the other hand, all the concentrations of the VHE, EAF, and NBF significantly reduced the incidence of hind-limb tonic extension (HLTE) induced by MES, when compared to the control group. The present study showed that V. tricolor and its ethyl acetate and n-butanol fractions possessed anticonvulsant effects as confirmed by the prolongation of latency to the first GTCs induced by PTZ and decrement in the incidence of HLTE induced by MES.