Purpose: The purpose of the study was to evaluate the activity of 50 % hydroalcohol flower extract of Nerium oleander Linn. on the central nervous system (CNS) of mice.

Methods: The effect of the 50 % hydroalcohol extract of N. oleander flowers at dosage levels of 100 and 200 mg/kg p.o. on the locomotor activity of mice was measured with an actophotometer while muscle relaxant activity was evaluated on rotarod apparatus. Also, the anticonvulsant activity of the extract in mice (following maximal electroshock and pentyleneterazol-induced convulsion) as well as the potentiation of pentobarbital-induced sleep were determined using standard procedures. Diazepam was used as the reference standard.

Result: The extract (at doses of 100 and 200 mg/kg) significantly reduced (p < 0.01) spontaneous locomotor activity and also potentiated pentobarbital-induced sleep. At the higher dose (200 mg/kg) the extract showed 66 % protection against electroshock-induced convulsions while the lower dose (100 mg/kg) produced a significant reduction (p < 0.01) in pentylenetetrazol (PTZ)-induced convulsions.

Conclusion: The ethanol extract of Nerium oleander flowers has anticonvulsant activity in an experimental animal model.

Keywords: Nerium oleander extract, CNS depression, Locomotor activity, Anticonvulsant activity.