Anticonvulsant activity of methanol leaf extract of Combretum hypopilinum Diels (Combretaceae) in laboratory animals

The use of plants as medicine is an ancient practice common to all societies especially the African society and this practice continues to exist in developing nations. Combretum hypopilinum is harvested from the wild for local use of its gum, medicinal uses and timber, it is one of the eight most widely used plants for management of epilepsy in northern Nigeria. This study aimed at examining the anticonvulsant properties of methanol leaf extract of Combretum hypopilinum (MECH) in acute animal models as well as the possible mechanism involved in its anticonvulsant activities.

The LD50 of the extract was calculated using OECD 423 starting with the limited dose of 5000mg/kg while the anticonvulsant activity of the extract was examined using maximal electroshock (MES), pentylenetetrazole (PTZ), strychnine and picrotoxin induced seizure models. For investigating the possible mechanism of the extract in PTZ model, flumazenil, naloxone, L-Argenin and sildenafil were administered to interact with the extract.

The LD50 of the extract was found to be greater than 2000mg/kg but less than 5000 mg/kg (oral). In maximal electroshock test, the extract protects only 30% of chicks against tonic hind limb extension (THLE) at the dose of 600 mg/kg. However, it significantly (p <0.05) and dose dependently decreased the mean recovery time of the convulsed chicks. In PTZ model, the extract at the dose of 600mg/kg, protected mice by 66.66% and significantly (p <0.005) delayed the mean onset of seizure. The extract significantly (p <0.005) delayed the mean onset of seizure and increased the mean latency of mortality for unprotected mice in both strychnine and picrotoxin models. Flumazenil, naloxone, L-argenine and sildenafil reversed the anticonvulsant activity of MECH.

The study suggested that MECH possessed bioactive component(s) responsible for its anticonvulsant effect, therefore, justify its use for the management of epilepsy amongst herbalists in Northern part of Nigeria.