The antioxidant and neuroprotective effects of the Psychotria camptopus Verd. Hook. (Rubiaceae) stem bark methanol extract contributes to its antiepileptogenic activity against pentylenetetrazol kindling in male Wistar rats

A substantial number of epileptic patients are resistant to the current medication thus necessitating the search for alternative therapies for intractable forms of the disease. Previous studies demonstrated the acute anticonvulsant properties of the methanol extract of the stem bark of Psychotria camptopus (MEPC) in rats. This study investigated the effects of MEPC on pentylenetetrazole-kindled Wistar rats. Kindling was induced by intraperitoneal injection of pentylenetetrazole (37.5 mg/kg) on every alternate day, 1 h after each daily oral pretreatment of rats (8 ≤ n ≤ 10) with MEPC (40, 80 and 120 mg/kg), vehicle or diazepam (3 mg/kg) for 43 days. The kindling development was monitored based on seizure episodes and severity. Rats' brains were collected on day 43 for the determination of oxidative stress parameters. The histomorphological features and neuronal cell viability of the prefrontal cortex (PFC) and hippocampus were also assessed using H&E and Cresyl violet stains. Chronic administration of pentylenetetrazole time-dependently decreased the latency to myoclonic and generalized seizures, and increased seizure scores and the number of kindled rats. MEPC and diazepam significantly increased the latencies to myoclonic jerks and generalized tonic-clonic seizures. These substances also reduced seizure score and the number of rats with PTZ-kindling. MEPC improved glutathione status and decreased lipid peroxidation in the brains of kindled rats. MEPC also exhibited neuroprotection against pentylenetetrazole-induced hippocampal and PFC neuronal damages. These results suggest that P. camptopus has antiepileptogenic activity, which might be related to the augmentation of antioxidant and neuroprotective defense mechanisms, and further confirm its usefulness in the management of epilepsy.

Administration of ethanolic extract of Erythrophleum ivorense (A Chev.) stem bark to male Wistar rats alters brain areas involved in motor coordination, behavior, and memory

ETHNOPHARMACOLOGICAL RELEVANCE

Erythrophleum ivorense (A Chev.) is a common plant in the tropics. Its use as ordeal poison in folklore medicine is controversial. The incoordination and behavioral changes following consumption are often associated with guilt. This study is aimed at dispelling or upholding this belief by investigating the actions of E. ivorense on the brain and behavior using rat model.

MATERIALS AND METHODS

Sixty male Wistar rats were equally divided into five groups; control group received distilled water, test groups were administered 10, 20, 30 and 40 mg/kg ethanolic extract of E. ivorense in a daily oral dose for 28 days. Cognition (Morris water maze) depression (forced swim test), motor function (hanging wire and inverted wire mesh grid grip tests) and exploratory assessments were done. Brains were stained with H&E, Cresyl violet and immunohistochemistry was done using GFAP, anticalbindin-D28k, Iba-1 and MBP antibodies.

RESULTS

At all doses, E. ivorense significantly (P ≤ 0.05) increased escape latency in the Morris water maze compared to control. Forced swim test showed a dose-related increase in duration of immobility, significant reduction in hanging latency in hanging wire and wire mesh grid grip test was also observed. Depletion of Purkinje cells of the cerebellum and hippocampal neurons was observed with H&E and cresyl violet. Immuno-staining revealed astrocytic activation in the cerebellum, loss of dendritic spines, cortical microglial activation and demyelination in the cerebellum and dentate gyrus of the hippocampus.

CONCLUSION

The ethanolic extract of E. ivorense stem bark caused a dose-dependent deficit in learning, memory and motor coordination with evidences of depression in rats. It is concluded that the plant is neurotoxic and induce several neurobehavioral changes.