Objective: To study the anticonvulsant activity of alcoholic extract of bark of Pinus roxburghii Sarg. (AEPR) used in Indian traditional medicine system in treating convulsion.

Methods: Anticonvulsant activity was evaluated by maximal electroshock (MES) and pentylenetetrazole (PTZ)-induced seizures in Wistar albino rats. In the MES model, 150 mA current for 0.2 s was given through ear electrodes to induce convulsions in rats. The duration of tonic extension of hind limb was used as the end point, namely, prevention or decrease in the duration of hind limb extension was considered as a protective action. In the PTZ model, the anticonvulsant property of AEPR was assessed by its ability to delay the onset of myoclonic spasm and clonic convulsions produced by intraperitoneal administration of PTZ.

Results: In the MES-induced seizure model, AEPR in doses of 300 and 500 mg/kg body weight reduced all the phases of convulsion significantly (P＜0.01). Standard drug phenytoin at a dose of 25 mg/kg significantly reduced flexion phase (P＜0.01) and abolished all phases of convulsion. In the PTZ-induced seizure model, the administration of the extract at doses of 300 and 500 mg/kg 30 min prior to injection of PTZ significantly delayed the onset of clonic seizure (P＜0.01). AEPR at the dose of 100 mg/kg body weight could not exert any significant protective effect on PTZ-induced convulsions. Standard drug diazepam at a dose of 4 mg/kg showed much delayed onset of clonic seizure.

Conclusion: The study suggests that AEPR would be effective against generalized tonic-clonic and partial seizures. Thus AEPR possesses anticonvulsant property against MES- and PTZ-induced seizures in Wistar rats. However, further research is in progress to isolate the compound responsible for its activity.

Key words: Pinus, plant extracts, anticonvulsants, electroshock, pentylenetetrazole, rats