Anticonvulsant activity of Cotyledon orbiculata L. (Crassulaceae) leaf extract in mice

The anticonvulsant activity of Cotyledon orbiculata L. (Crassulaceae) was investigated by studying the effects of both aqueous and methanol extracts of the plant species on seizures induced by pentylenetetrazole, bicuculline, picrotoxin and N-methyl-dl-aspartic in mice. Aqueous extract of Cotyledon orbiculata (50–400 mg/kg, i.p.) and methanol extract (100–400 mg/kg, i.p.) significantly prolonged the onset of tonic seizures induced by pentylenetetrazole (95 mg/kg, i.p.). Methanol extract (400 mg/kg, i.p.) also significantly reduced the incidence of the seizures. One hundred to two hundred milligrams/kilogram (i.p.) of aqueous extract of Cotyledon orbiculata significantly delayed the onset of the tonic seizures induced by bicuculline (40 mg/kg, i.p.), picrotoxin (12 mg/kg, i.p.) and N-methyl-dl-aspartic acid (NMDLA, 400 mg/kg, i.p.). Similarly, methanol extract (100–400 mg/kg, i.p.) significantly delayed the onset of the tonic seizures induced by bicuculline (40 mg/kg, i.p.) and picrotoxin (12 mg/kg, i.p.) while 100 mg/kg (i.p.) significantly delayed the onset of N-methyl-dl-aspartic acid (NMDLA, 400 mg/kg, i.p.)-induced seizures. Methanol extract (200 mg/kg, i.p.) significantly reduced the incidence of the seizures induced by bicuculline (40 mg/kg, i.p.). Phenobarbitone (12 mg/kg, i.p.) and diazepam (0.5 mg/kg, i.p.) effectively antagonized only seizures induced by PTZ (95 mg/kg, i.p.), bicuculline (40 mg/kg, i.p.) and picrotoxin (12 mg/kg, i.p.). Phenytoin (30 mg/kg, i.p.) did not affect any of the seizures to any significant extent. The data obtained suggest that both aqueous and methanol extracts of Cotyledon orbiculata have anticonvulsant property and may probably be affecting both gabaergic and glutaminergic mechanisms to exert its effect. The phytochemical analysis carried out revealed the presence of cardiac glycosides, saponins, tannins, reducing sugar and triterpene steroids in the plant extract.