ANTICONVULSANT STUDIES OF THE METHANOL EXTRACT AND FRACTIONS OF CASSIA SIAMEA LAM. (FABACEAE) IN MICE AND CHICKS, A RESEARCH PROJECT TOPIC ON MICROBIOLOGY
ABSTRACT
Cassia siamea is a shrub belonging to the Fabaceae family, native of Southeast Asia. The plant is commonly used in traditional medicine to treat hypertension, malaria and diabetes. Due to the easy cultivation of the plant, its widespread and also remarkable biological activities, Cassia siamea has become a worldwide medicine. The study was conducted to assess the anticonvulsant potential of the methanol extract of Cassia siamea (CSME) and its fractions (EAF, NBF and RAF) using Pentylenetetrazole (PTZ) induced seizures in mice and Maximal electroshock (MES) induced seizures in chicks. Acute toxicity was carried out on CSME and fractions. The possible mechanism(s) involved in anticonvulsant action were determined using Picrotoxin and naloxone. The preliminary phytochemical screening of the methanol extract revealed the presence of alkaloids, flavonoids, polyphenols, saponins, steroids, terpenoids and tannins. The LD50 of CSME, its EAF and NBF was found to be greater than 5000mg/kg intraperitoneally (i.p) in chicks and mice, suggesting a non toxic profile of the extractst, while the LD50 of the RAF (i.p) was found to be 1095mg/kg in mice and 3807 mg/kg in chicks implying the RAF is mildly toxic via the intraperitoneal route. The CSME and its EAF were found to have varied anticonvulsant activities; the EAF at 250mg/kg dose protected 40% of mice against hind limb tonic extension induced by maximal electroshock and in convulsed chicks a significant (P < 0.05) decrease in mean recovery time was noted. The ethyl acetate fraction at 250mg/kg and 500mg/kg doses produced a significant (P < 0.05) delay in mean onset of seizures and offered mice a 2/6 and 5/6 quantal protection against mortality, valproic acid the standard anticonvulsant drug used produced a 100% protection against seizures. The EAF did not protect mice against pirotoxin induced seizures indicating lack of activity on chloride ion channels of the GABAA receptor complex. Naloxone did not reverse the anticonvulsant activity of the EAF against Pentylenetetrazole-induced seizures, suggesting lack ogf involvement of GABAA-BDZ receptors and opioid receptors in the anticonvulsant effect of EAF. The CSME and EAF at 100mg/kg dose significantly (P < 0.05) prolonged the total duration of Diazepam induced sleeping time in mice without affecting the mean onset of sleep, indicating sedative action of the extract. The results suggests the presence of bioactive component(s) that posess anticonvulsant and sedative activities. The data may provide pharmacological basis for the use of the plant alone or in combination with other plant(s) in the management of febrile convulsions and insomnia in West African countries including Nigeria.
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background information
Epilepsy is one of the most common afflictions of human beings (Muralidharanet al., 2009). It affects approximately 50 million people worldwide and accounts for about 1% of the global burden of disease (Reynolds, 2002). Epilepsy is coined from the Greek word “epilembanein” which means “to seize”. It is a chronic neurological disorder affecting both sexes (Blume et al., 2001).
