PHARMACOLOGICAL RATIONALE FOR THE USE OF SOME MEDICINAL PLANTS AS ANTIEPILEPTIC AGENTS IN ZARIA, NIGERIA

PHARMACOLOGICAL RATIONALE FOR THE USE OF SOME MEDICINAL PLANTS AS ANTIEPILEPTIC AGENTS IN ZARIA, NIGERIA

Abstract:

The effects of the hydro-alcoholic root bark extracts of C. edulis and B. aegyptiaca were studied on pentylenetetrazole (PTZ) and Maximal electroshock (MES)-induced seizures in animal models. The effects of Flumazenil and Naloxone were studied on the anticonvulsant activity of the plant extracts to determine their possible mechanisms of anticonvulsant action. The intraperitoneal LD50 of the hydro-alcoholic root bark extracts of C. edulis and B. aegyptiaca were found to be 282.8 mg/Kg and 1131.3 mg/Kg respectively, this suggests that the extracts are mildly toxic by this route. Oral LD50 of the extracts were both greater than 5000 mg/Kg, suggesting non toxic profile. The C. edulis extract produced 40% while B. aegyptiaca offered 20% protection against seizures induced by PTZ when given intraperitoneally while the standard anticonvulsant drug used, diazepam offered 60% protection at 0.5 mg/kg and 100% protection at 1 mg/kg. Similarly, in the oral route no protection was obtained in both extracts. In MES-induced seizures, C. edulis extract protected the chicks by 90% while B. aegyptiaca showed no protection. Flumazenil and Naloxone reversed the anticonvulsant activities of both C. edulis and B. aegyptiaca extracts suggesting involvement of GABAA-BDZ receptors and opioid receptors in the extracts anticonvulsant activities. C. edulis extract fractions aqueous portion (AP), diethyl ether filtrate (BP), diethyl ether precipitate (CS), ethyl acetate (EA) and n-butanol (NB) were found to have varied anticonvulsant activities; AP fraction showed 80%, BP 40%, CS 40%, EA 40% protection in a non dose dependent manner and NB offered no protection against PTZ-induced seizures in mice while fraction CS 60% seizure protection in an inverse dose dependent pattern, fractions AP, BP, EA and NB CS did not produce any significant seizure protection against MES-induced seizures in chicks, similarly phenytoin, standard anticonvulsant drug used produced 100% protection. There was no significant difference between the fractions treated and the control groups in the duration of seizure. All the C. edulis fractions when tested against 4-aminopyridine-induced seizures showed no protection indicating lack of activity on potassium channels. Various phytochemical constituents such as anthraquinones, tannins, saponins, glycosides were found to be present and consistently alkaloids were absent in the extracts and the fractions. The results suggest the presence of bioactive component(s) that possess anticonvulsant activities. The data may provide pharmacological basis for the use of the plants in the management of epilepsy in Zaria, Nigeria.

PHARMACOLOGICAL RATIONALE FOR THE USE OF SOME MEDICINAL PLANTS AS ANTIEPILEPTIC AGENTS IN ZARIA, NIGERIA