ABSTRACT
Fabaceae is the third largest family of flowering plants. Lack of essential oils in the plants of this family can be an advantage in search for safe and effective medicines. In this study the anticonvulsant effect of the leaves of Albizzia julibrissin, Acacia juliflora, Acacia nubica and aerial parts of Astragalus obtusifolius was evaluated in pentylenetetrazole [PTZ] and maximal electroshock [MES] seizure tests. The hydroalcoholic extracts of the plants were obtained by percolation. Different doses of the extracts were injected to the mice intraperitoneally [i.p.] and occurrence of clonic seizures induced by PTZ [60 mg/kg, i.p.] or tonic seizures induced by MES [50 mA, 50Hz, 1sec] were monitored up to 30 min after administration. Acute toxicity of the extracts was also assessed. The safe and effective extract was then fractionated by dichloromethane and anticonvulsant activity of the fractions was determined. Finally, the constituents of the extract and the fractions were screened by thin layer chromatography. Among the extracts, only A. obtusifolius extract showed low toxicity and protective effect against clonic seizures with ED50 value of 3.97 g/kg. Fractionation of the extract led to increase in anticonvulsant activity and ED50 value of 2.86 g/kg was obtained for the aqueous fraction. Phytochemical screening revealed the presence of alkaloids, flavonoids, anthrones and saponins in the aqueous fraction. The presence of anticonvulsant compounds in A. obtusifolius suggests further activity-guided fractionation and analytical studies to find out the potential of this plant as a source of anticonvulsant agent