1.0 INTRODUCTION

1.1       Background of the Study

Since the beginning of human civilization, medicinal plants have been used for their therapeutic

value. Nature has been a source of medicinal agents for thousands of years and an impressive

number of modern drugs have been isolated from natural sources. Many of these isolations were

based on the uses of the agents in traditional medicine. The plant-based, traditional medicine

system continues to play an essential role in health care, with about 80% of the world‟s

inhabitants relying mainly on traditional medicines for their primary health care (Shaikh and

Hatcher, 2005).

According to the World Health Organization “a medicinal plant” is any plant, which in one or

more of its organs contains substances that can be used for the therapeutic purposes or which, are

precursors for the synthesis of useful drugs(WHO, 2001). This definition distinguishes those

plants whose therapeutic properties and constituents have been established scientifically and

plants that are regarded as medicinal but which have not yet been subjected to thorough

investigation. The term “herbal drug” determines the part/parts of a plant (leaves, flowers, seeds,

roots, barks, stems, etc.) used for preparing medicines (Anonymous, 2007). Furthermore, WHO

defines medicinal plant as herbal preparations produced by subjecting plant materials to

extraction, fractionation, purification, concentration or other physical or biological processes

which may be produced for immediate consumption or as a basis for herbal

products(WHO,2004). Medicinal plants are plants containing inherent active ingredients used to

cure disease or relieve pain (Okigboet al., 2005). 1

The use of traditional medicines and medicinal plants in most developing countries as

therapeutic agents for the maintenance of good health has been widely observed (UNESCO,

1998). Modern pharmacopoeia still contains at least 25% of drugs derived from plants and many

others, which are synthetic analogues, built on prototype compounds isolated from plants.

Interest in medicinal plants as a re-emerging health aid has been fuelled by the rising costs of

prescription drugs in the maintenance of personal health and well-being and the bioprospecting

of new plant-derived drugs. The growing recognition for medicinal plants use is due to several

reasons, including escalating faith in herbal medicine (Kala, 2005). Furthermore, an increasing

reliance on the use of medicinal plants in the industrialized societies has been traced to the

extraction and development of drugs and chemotherapeutics from these plants as well as from

traditionally used herbal remedies (UNESCO, 1998).

The medicinal properties of plants could be based on the antioxidant, antimicrobial, antipyretic

effects of the phytochemicals in them (Ayodele, 2005). According to World Health

Organization, medicinal plants would be the best source to obtain a variety of drugs. Therefore,

such plants should be investigated to better understand their properties, safety and efficacy

(Nascimentoet al., 2000).

Medicinal plants produce bioactive compounds used mainly for medicinal purposes. These

compounds either act on different systems of animals including man, and/or act through

interfering with the metabolism of microbes infecting them. The microbes may be pathogenic or

symbiotic. In either way, the bioactive compounds from medicinal plants play a determining role

in regulating host-microbe interaction in favour of the host. So the identification of bioactive

compound in plants, their isolation, purification and characterization of active ingredients in

crude extracts by various analytical methods is important. The instant rising demand of plant-

2

based drugs is unfortunately creating heavy pressure on some selected high-value medicinal

plant populations in the wild due to over-harvesting. Several of these medicinal plant species

have slow growth rates, low population densities, and narrow geographic ranges (Kala et al.,

2006); therefore they are more prone to extinction. Conversely, because information on the use