Anticonvulsant and analgesic properties of leaf and root extracts of Newbouldia laevis

Abstract

Extracts of various parts of Newbouldia laevis are used traditionally in Eastern Nigeria in management and treatment of several diseases, including some neurological disorders. This study investigated anticonvulsant and analgesic potentials of leaf and root extracts. The extracts were prepared with deionized water and ethylacetate. Extracts doses of 200, 400, 600 and 800 mg kg-1 b.wt. were used for the investigations. Anticonvulsant potential of the extracts against pentylenetetrazole-induced convulsion was tested in albino rats, by measuring time for convulsion onset, duration of convulsion and plasma glucose and Ca2+ levels before, during and after convulsion, using diazepam as standard. The hot plate method was used to investigate the analgesic property of the extracts using morphine sulphate as standard. Pretreatment of the animals with different doses of the extracts delayed the onset of convulsion in a dose-dependent manner. Convulsion was not observed in 800 mg kg-1 b.wt. of Deionized Water Leaf (DWL) extract and in diazepam pretreated groups. The extracts decreased significantly (p<0.05) the severity of convulsion and prolonged the duration of convulsion induced by pentylenetetrazole. The plasma concentration of glucose and Ca2+ decreased significantly (p<0.05) in the test groups through the course of convulsion, while they did not change significantly (p>0.05) in the non-convulsed groups. All the extracts at all doses and 4 mg kg-1 of morphine sulphate (an analgesic) showed a significant (p<0.05) percentage inhibition against hot plate induced pain. The difference between the analgesic potentials of 800 mg kg-1 of DWL extract and 4 mg kg-1 morphine sulphate was not significant (p>0.05). These findings indicate that the extracts may be effective in management/treatment of convulsion and pains.