Anticonvulsant activity of Carissa edulis (Vahl) (Apocynaceae) root bark extract.
OBJECTIVE
To investigate the anticonvulsant activity of root bark extract of Carissa edulis.


METHODS
The median lethal dose (LD(50)) of Carissa edulis extract was determined using Lork's method (1983). The anticonvulsant activity of the extract was assessed in pentylenetetrazole (PTZ)-induced convulsion in mice and maximal electroshock test (MEST) in chicks, with benzodiazepine and phenytoin as standard drugs, respectively. While mechanistic studies were conducted using both flumazenil, a GABA(A)-benzodiazepine receptor complex site antagonist and naloxone a non-specific opioid receptor antagonist.


RESULTS
The median lethal dose (LD(50)) of Carissa edulis was 282.8mg/kg and over 5000mg/kg following intraperitoneal and oral administration, respectively. Carissa edulis produced 40% and 20% protection against convulsion at 5 and 20mg/kg, respectively, compared with 100% protection with benzodiazepine. The mean onset and percentage protection against convulsion in Carissa edulis extract-treated mice were reduced by flumazenil and naloxone. Carissa edulis exhibited dose-dependent inhibition of the convulsion induced by MEST with 20mg/kg providing 90% protection while phenytoin (20mg/kg) produced 100% protection.


CONCLUSIONS
These results suggest that Carissa edulis possesses biologically active constituent(s) that have anticonvulsant activity which supports the ethnomedicinal claims of the use of the plant in the management of epilepsy.
Ya'u
J
J
Department of Pharmacology and Clinical Pharmacy, Ahmadu Bello University, Zaria, Nigeria. jameelyau@yahoo.com
Yaro
A H
AH
Abubakar
M S
MS
Anuka
J A
JA
Hussaini
I M
IM
D000284:Administration, Oral; D000818:Animals; D000927:Anticonvulsants / Q000008:administration & dosage* / Q000302:isolation & purification / Q000633:toxicity; D029062:Apocynaceae / Q000737:chemistry*; D002645:Chickens; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D005442:Flumazenil / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D007928:Lethal Dose 50; D008297:Male; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D010672:Phenytoin / Q000494:pharmacology; D024301:Plant Bark; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D018517:Plant Roots; D012640:Seizures / Q000188:drug therapy*; D023382:Toxicity Tests, Acute
D000927:Anticonvulsants; D010936:Plant Extracts; D009270:Naloxone; D005442:Flumazenil; D010672:Phenytoin