Investigation of Some Possible Mechanisms Involved in the Anticonvulsant Activity of Tulbaghia violacea Harv

Even though Tulbaghia violacea has been used to treat and manage epilepsy in South Africa by traditional medicine practitioners, no evidence in any literature has shown any scientific scrutiny of the effectiveness of the plant species in therapy. This study was intended, therefore, to investigate the anticonvulsant effect of the leaf methanol extract of Tulbaghia violacea by studying its effect against tonic convulsion induced by either PTZ (pentylenetetrazole), bicuculline, picrotoxin, strychnine or NMDLA (N-methyl-DL-aspartic acid) in mice. Qualitative phytochemical analysis, acute toxicity and HPLC studies were also carried out on the plant species. Leaf methanol extract of Tulbaghia violacea, phenobarbitone, diazepam or muscimol significantly antagonised PTZ, bicuculline or picrotoxin-induced convulsion. Combined treatment of sub-effective doses of T. violacea and muscimol significantly antagonised tonic convulsion induced by PTZ. T. violacea or phenobarbitone significantly antagonised strychnine-induced tonic convulsion. T. violacea or LY233053 significantly antagonised NMDLA-elicited tonic convulsion. Phenytoin or DMSO (dimethylsulfoxide) did not significantly affect the tonic convulsion produced by PTZ, bicuculline, picrotoxin, strychnine or NMDLA. The phytochemical qualitative analysis of the plant species showed the presence of alkaloids, saponins, reducing sugars, flavonoids, cardiac glycosides, triterpene steroids, quinones and tannins. The LD50 value obtained following oral administration of the plant extract was over 4000 mg/kg. The data in the present study indicate that the leaf methanol extract of T. violacea has anticonvulsant activity which is probably underpinned by GABAergic, glutaminergic and glycinergic mechanisms.