Anticonvulsant and Depressant Activity of Methanol Leaf Extract of Croton zambesicus

Abstract

Aims: To study anticonvulsant and central nervous system depressant activity of methanol leaf extract of Croton zambesicus (MECZ) in Swiss albino mice and investigate the role of serotonin in these activities.  Methodology: Anticonvulsant activity of graded doses (200, 300 and 400 mg/kg p.o) of MECZ was assessed through seizures induced by picrotoxin and pentylenetetrazole (PTZ). Effects of the extract on pentobarbitone-induced sleep and amphetamine-induced stereotype behavior were also evaluated. Possible involvement of serotonergic pathways was studied using cyproheptadine (4mg/kg i.p), a non-selective serotonin antagonist (5-HT1/5HT2).  Results: In both picrotoxin and PTZ-induced seizures, the extract significantly delayed onset of seizure (p<0.05) in a dose-dependent manner and provided significant protection against death. There was a dose-dependent increase of pentobarbitone sleeping time and a significant reduction (p<0.05) in the sleep latency. The extract also produced a significant reduction in amphetamine-induced stereotype behavior. Pretreatment with cyproheptadine abolished the anticonvulsant effect of the extract. The inhibitory effect of the extract on amphetamine-induced hyperactivity and its potentiation of pentobarbitone-induced sleep were also reversed by cyproheptadine.  Conclusion: The results of this study showed that methanol extract of Croton zambesicus leaf possesses anticonvulsant activity and other CNS depressant activities and these activities are possibly mediated through interaction between serotonergic and GABAergic transmissions.