COMPARATIVE STUDY OF THE BIOACTIVE COMPONENTS OF FIVE ASCERSIONS OF Vernonia amygdalina (DEL) IN SOUTH EASTERN NIGERIA

CHAPTER ONE

INTRODUCTION

1.1   Background information      

Vernonia amygdalina commonly known as “bitter leaf” is found in different locations in Nigeria. It is known in Yoruba as ‘Ewuro’, in Efik/Ibibio as ‘Etidot’, in Igbo as ‘Onugbu’, in Edo as ‘Oriwo’, and in Hausa as ‘Chusardoki,’. In Ugep, Cross River State, it is referred to as ‘Kedemiti sekedali’ in their native language (Egedigwe, 2010).

        Vernonia amygdalina is a shrub or small tree of 2.5cm tall, much branched; trunk up to 40cm in diameter; bark grey to brown, smooth becoming fissured; young branches, densely pubescent, leaves alternate, simple, stipules absent; petiole 6mm in diameter and elliptic shape. The leaves are green with a characteristic odour and a bitter taste. The bitterness is caused by sesquiterpene lactones (e.g. Vernodalin, Vernolepin and Vernomygdin) and steroid glycosides (Vernoniosides) (Challand et al.; 2009). It is propagated by seed but most farmers use stem cuttings. Cutting used for propagation from mature stems are selected on the basis of attributes such as degree of bitterness, leaf size and growth characteristics. Cutting may be planted erect or slanting at an angle of 45⁰C to obtain more side shoots, and cutting grows faster than seedlings (Kalanda and Ligowski, 1995).

1.2   Taxonomy of Vernonia amygdalina        

Vernonia amygdalina belongs to the family Asteraceae and genus Vernonia and it is fully classified as follows:

Kingdom   -        Plantae

Class                   -        Dicotyledone

Order         -        Asterales

Division     -        Angiospermae

Subclass    -        Gamopetalae

Family       -        Asteraceae

Genus        -        Vernonia

Species      -        V. amygdalina

Botanical name   - Vernonia amygdalina (Dutta, 2005).  

1.3   Ethnobotany of Vernonia amygdalina

In Nigeria, Vernonia amygdalina is commonly found in the South East ecological zones of Cross River, Akwa Ibom, Rivers, Bayelsa, Anambra, Abia, Imo and Enugu States. It is found in some countries in Africa, namely, Togo, Kenya, Tanzania, Cameroon, Ghana, etc.   (Egedigwe, 2010).

1.4   Economic importance of Vernonia amygdalina

Vernonia amygdalina is commonly used in traditional medicine for various purposes. Leaf decoctions are used to treat fever, malaria, diarrhoea, dysentery, hepatitis and cough. It is also used as a laxative and as fertility inducer. Other people use it to treat scabies, headaches and stomach-ache. Root extracts are also used as treatment against malaria and gastro intestinal disorders (Abosi and Raseroka, 2003).  In Nigeria leaves are placed on a wound as a substitute for iodine. One of the most common medicinal use of Vernonia amygdalina is as a treatment against intestinal worms including nematodes. Not only humans but also Chimpanzees ingest the pith of Vernonia amygdalina for the control of intestinal nematode infections (Attangwho et al., 2007a). Bark infusions are also taken to treat fever and diarrhoea, and dried flowers as a cure against stomach disorders. Vernonia amygdalina is also useful as a control agent against disease in plants. The ash from burnt branches is used to control seed-borne fungi (Curvularia, Aspergillus, Fusarium and Penicillum spp); thus ameliorating seed viability and germination capacity. It has also been used for brewing beer as a substitute for hop (Heywood, 2007).

1.5   Justification of the study                              

        The potency of Vernonia amygdalina as an herbal medicine is undebatable but there is little or no information on the ascersions being administered by traditional medicine practitioners (TMPs) in South Eastern Nigeria. This informed the carrying out of this comparative study on five (5) of the most common ascersions found in South Eastern Nigeria.     

1.6   Aims and objectives of the study

The aim and objectives of this study is to identify and quantify the bioactive components of five (5) ascersions of Vernonia amygdalina and to carryout comparative studies on the five ascersions of V. amygdalina in an attempt to present the most valuable ascersion for inclusion into tradomedicine database in the country.