Antiepileptogenic and Anticonvulsant Actions of Dalbergia saxatilis (Hook, F.) in Sub-toxic Chemical Kindling and Toxic Convulsant Models

Aims: The aqueous root extract of Dalbergia saxatilis (DS) is used in traditional African medicine to manage convulsions and epilepsies. This study aimed at investigating DS action against models that mimic seizure development in the neurons of epileptics, the sub-toxic dose kindling models.

Study Design: Sub-toxic doses of strychnine and picrotoxin chemical kindling models; as well as single-dose toxic bicuculline convulsive models in mice.

Place and Duration of Study: Neuropharmacology Unit Laboratory, Department of Pharmacology, College of Medicine, University of Lagos, Lagos, Nigeria, between July 2006 and March 2008.

Methodology: Strychnine kindling was produced by a 48h interval, i.m administration of 1.5mg/kg strychnine for 9 trials. The mice were treated with 200mg/kg, p.o. DS, before strychnine thus: Group I: throughout the 1st - 9th kindling; group II: During the 1st - 5th kindling; and group III: during the 6th - 9th kindling trials. Control group received distilled water instead of DS throughout the 1st - 9th kindling trials. For picrotoxin study, a subconvulsant dose of 1.5mg/kg picrotoxin was injected i.p. 3 times a week for 10 weeks, 200mg/kg of DS was administered orally before picrotoxin thus: Group I: throughout the 1st - 30th kindling trials; group II: during the 1st - 12th kindling trials; group III: during the 13th - 30th kindling trials; control group received distilled water instead of DS throughout the 30 trials. Behavioural seizures were classified for seizure stages. In another study, DS (50-200 mg/kg, p.o.) was administered to mice, 30 min. before 10mg/kg, s.c. bicuculline and onset to seizures and time to death noted.

Results: DS significantly (P=.05) retarded the development and progression of strychnine kindling, but did not reverse already reached kindled state. Moreover, DS significantly (P=.05) retarded the development of picrotoxin kindling, decreased the scoring from kindling progression and prevented convulsion in fully picrotoxin-kindled mice. A significant delay of seizure onset, with complete protection at 200mg/kg DS was produced against bicuculline seizures in mice.

Conclusion: DS may attenuate development of seizures in both GABAergic and glycinergic mechanisms and be useful in the prevention of seizures as well as neuroprotection in epileptics, justifying its use in the folkloric management of epilepsies.