INVESTIGATE THE ANTICONVULSANT AND SEDATIVE EFFECT OF THE METHANOLIC ROOT EXTRACT OF NEWBOULDIA LAEVIS P. BEAUV AGAINST PTZ AND AMPH INDUCED CONVULSION AND ITS EFFECT ON PHENOBARBITONE INDUCED SLEEP IN MICE
CHAPTER ONE
INTRODUCTION
Background of Study
The term “epilepsy” denotes any disorder characterized by recurrent unprovoked seizures. A seizure is a transient disturbance of cerebral function due to an abnormal paroxysmal neuronal discharge in the brain (Papadakis et al., 2014).
The disease affects 1% of the population worldwide, being the second most common neurological disorder after stroke. It has a variety of causative factors such as; trauma, oxygen deprivation, tumors, infection and metabolic derangements which produce
long lasting plastic changes in the brain affecting neurotransmitters release and transport, the properties of receptors and channels, regulation of gene expression, synaptic reorganization and astrocyte activity. (Scheuer et al., 2009)
There exist several options in the pharmacological treatment of the disease. However, the available synthetic Anti-epileptic drugs (AEDs) are associated with side effects, dose-related chronic toxicity and approximately 30% of patients continue to have seizures with current AED therapy (Stefan and Wang, 2004).
In the light of this, plants already used in traditional medicine can be a good place to start in the search for safer and more effective options. Numerous plants used for the treatment of epilepsy traditionally have been shown to be potent in models of epilepsy and several such plants remain to be scientifically validated (Raza et al., 2001).
Medicinal plants used in traditional medicine for the treatment of epilepsy have been scientifically shown to possess promising anticonvulsant activities in animal models for screening for anticonvulsant activity and can be a source of newer anticonvulsants (Twinomujuni et al., 2016).
Newbouldia laevis (Bignoniaceae) commonly known as African border tree or boundary tree (Gbile and Adesina, 1986) is a fast growing evergreen shrub or small tree which grows to the height of about 7-8m in the west and upto 20m in the east of the west African region (Barwick M., 2004). It is native to Tropical Africa and grows from Guinea savannahs to dense forest, or moist and well drained soils (Burkill, 1984). Traditionally, it is used in the treatment of dysentery, malaria, elephantiasis, migraines and seizures. The bark and twigs are used to treat women pelvic pain, peptic ulcer disease, earache, skin ulcer, epilepsy, hemorrhoids and constipation. It has also been found useful for epilepsy and children’s convulsion (Akunyili, 2000).
This study was aimed at providing experimental support for the traditional medicinal use of the root methanolic extracts of N. laevis in the management of epilepsy as well as its sedative effect.
Traditional Medicine in Nigeria
According to The World Health Organization(WHO), traditional medicine is defined as “the sum total of the knowledge, skills and practices based on the theories, beliefs and experiences indigenous to different cultures, whether explicable or not, used in the maintenance of health, as well as in the prevention, diagnosis, improvement or treatment of physical and mental illnesses” (WHO, 2000).
Traditional medicine dates back to the origin of mankind. Herbs had been used by all cultures throughout history. The ancient man tried various plants and herbs in an attempt to solve some illnesses that disturbed him. The use of specific plants for specific illnesses was usually based on instinct, revelation, observation of effects on animal etc. The presence of several plants with medicinal properties in a Neanderthal tomb in Iraq suggests that herbs may have been used therapeutically for more than 60 000 years (Solecki, 1975). This proves that herbal medicine had been with man before the discovery of orthodox medicine and rightly, most orthodox medicines were developed from known herbal medicine.
In Nigeria, traditional medicine was seen as a fetish way of curing diseases in the past. It is believed that poor and illiterate individuals are the patronizers of traditional medicine. This thought is supported by the point that most of its practioners were regarded as witch doctors who took care of their patient with occultic powers. Practitioners of traditional medicine were not in any way seen as doctors; even the western trained doctors saw them as a threat to the well being of their patient. It should be however be noted that before now, quacks bedevilled the Nigerian traditional medicine practice. This was largely due to lack of necessary legislations to control and regulate the practice. But regulation of herbal medicines was introduced in Nigeria in 1993 in Decree No.15 and was revised in 1999. Under this decree herbal medicines are regulated as dietary supplements, health foods, functional foods and as an independent regulatory category (Falodun and Imieje 2013).
Herbal medicine/traditional medicine practice permeates every tribe in Nigeria. In a research involving Eighty nine species, plants belonging to forty six families were identified from fifty respondents, with herbal recipes recorded for thirty five ailments or therapeutic indications/uses.
Individual plant species with highest frequency of prescription include Nauclea latifolia and Pilliostigma thonningii, Ageratum conyzoides, Newlboldia laevis, Phyllanthus muererianus Cochlospermum planchonii, Ocimum gratissimum and Parkia biglobosa. (Igoli et al., 2005).
As at 2013, Nigeria had developed phytomedicines from herbal medicines obtained from local traditional healers for ulcers, anaemia, contraception, malaria and HIV, and it now holds patents for some of these medicines in several countries. (Falodun and Imieje 2013).
Traditional medicine needs to be further explored as it still has many untapped therapeutic potentials. Sadly, the custodians of these traditional medicines knowledge are growing old every day and we are gradually losing them. Most of them pass on without passing this precious knowledge to their predecessor or anyone. To salvage this situation, traditional medicine should be embraced, developed to meet modern therapeutic standards and integrated into the healthcare system.
Plant Description
Newbouldia laevis (Bignoniaceae) is native to tropical Africa and grows from Guinea savannahs to dense forest, or moist and well drained soils (Burkill, 1984). It inhabits the secondary forest extending from Senegal to Cameroon, Gabon, Congo and Angola (Aladesanmi et al., 1998). It is commonly known as African border tree or boundary tree (Gbile and Adesina, 1986).
It is a fast growing evergreen shrub or small tree which grows to the height of about 7-8m in the west and upto 20m in the east of the west African region (Barwick M., 2004).
The bole can be up to 90cm in diameter, but is usually less (Burkill, 1984). It is easily recognized by its short branches, coarsely toothed leaflets and purple and white flowers (Iwu, 1983). It has many streamed forming clumps of gnarled branches (Aladesanmi et al., 1998) it has a shiny dark green leaves. The plant is drought tolerant (Barwick, 2004) hence the hardly die so they are used to indicate boundary marks among the south and south-eastern people of Nigeria (Gill, 1992).
INVESTIGATE THE ANTICONVULSANT AND SEDATIVE EFFECT OF THE METHANOLIC ROOT EXTRACT OF NEWBOULDIA LAEVIS P. BEAUV AGAINST PTZ AND AMPH INDUCED CONVULSION AND ITS EFFECT ON PHENOBARBITONE INDUCED SLEEP IN MICE