Anticonvulsant activity of Pseudospondias microcarpa (A. Rich) Engl. hydroethanolic leaf extract in mice: The role of excitatory/inhibitory neurotransmission and nitric oxide pathway

Ethnopharmacological relevance: Pseudospondias microcarpa (A. Rich) Engl. is a plant used for managing
various diseases including central nervous system disorders.
Aim of the study: This study explored the anticonvulsant activity of P. microcarpa hydroethanolic leaf extract
(PME) as well as possible mechanism(s) of action in animal models.
Methods: Effects of PME was assessed in electroconvulsive (the maximal electroshock and 6-Hz seizures) and
chemoconvulsive (pentylenetetrazole-, picrotoxin-, isoniazid-, 4-aminopyridine-, and strychnine-induced
seizures) models of epilepsy. In addition, effect of the extract on the nitric oxide pathway and GABAA receptor
complex was evaluated.
Results: The extract (30, 100 and 300 mg kg−1
, p.o.) significantly delayed the onset as well as decreased the
duration and frequency of pentylenetetrazole-, picrotoxin- and strychnine-induced seizures. In addition, PME
pre-treatment significantly improved survival in the 4-aminopyridine- and isoniazid-induced seizure tests.
Furthermore, the extract protected against 6-Hz psychomotor seizures but had no effect in the maximal
electroshock test. The anticonvulsant effect of PME (100 mg kg−1
, p.o.) was also reversed by pre-treatment with
flumazenil, L-arginine or sildenafil. However, L-NAME or methylene blue (MB) augmented its effect.
Conclusion: Results show that PME has anticonvulsant activity and may probably be affecting GABAergic,
glycinergic, NMDA, K+ channels and nitric oxide-cGMP pathways to exert its effect.