Phytochemical and anticonvulsant screening of three medicinal plants used in the treatment of epilepsy in the south-western part of Nigeria

The burden of epilepsy in developing countries made medicinal plants like Xylopia aethiopica fruit; Khaya grandifoliola, Alstonia boonei etc an alternative source in epilepsy management in the south-western part of Nigeria. The aim of the study was to provide pharmacological rationale for the ethnomedicinal use of the plants in epilepsy management. The oral medial lethal dose of methanol stem bark extracts of Alstonia boonei (MEAB) and Khaya grandifoliola (MEKG) and methanol fruit extract of Xylopia aethiopica (MEXAF) were done in accordance with the Organization for Economic Cooperation Development guideline. Quantitative and qualitative phytochemical profiling of the extracts was done. Anticonvulsant screening was carried out on the extracts (doses: 75, 150 and 300 mg/kg) using the pentylenetetrazole (PTZ)-induced seizure and maximum electroshock tests (MEST). Results showed that the MEXAF has the highest amount of phytochemicals except for saponins in MEKG; and MEAB with the least amount (but higher alkaloid) than MEKG. The TLC showed different bands of spots of the extracts. In the PTZ test, MEXAF showed 100 % protection against mortality at 300 mg/kg; MEAB with 66.67 % protection at 75 mg/kg and MEKG 0 % protection. MEAB, MEKG and MEXAF nonsignificantly increased the onset of seizure and latency to death. In the MEST, MEXAF, MEKG and MEAB at 75 mg/kg protected 50, 33.3 and 16.67% of the animals against tonic hind limb extension respectively and nonsignificantly (p˃0.05) decreased the recovery time at a dose of 75 mg/kg. It was concluded that the extracts possess anticonvulsant activities hence, the pharmacological credence for the ethnomedicinal use of these plants in treating epilepsy.