CHAPTER ONE
1.0 INTRODUCTION
Natural
products have been, and have remained the cornerstone of health care. Present
estimates show that 80% of the world’s population still rely on traditional
medicine for their health care needs (Farnsworth et al. 1985).
It
is estimated that there are between 200 000 and 700 000 species of tropical
flowering plants that have medicinal properties, this has made traditional
medicine relatively cheaper than modern medicine. Over the years there have
been alarming reports of multiple drug resistant in medically important strains
of bacteria and fungi (Gill, 1992). The persistent increase in antibiotic
resistant strains of organisms has led to development of more potent synthetic
antibiotics such as the 3rd and 4th generations of cephalosporins by
pharmaceutical companies. These new antibiotics are scarce, costly and not
affordable particularly in the developing countries and therefore make
compliance difficult. There is therefore need for continuous search for new
effective and affordable antimicrobial drugs. Local medicinal plants provide a
source of new possible antimicrobial drugs (Iwu, 1993). Among plants believed
traditionally to have therapeutic effect but which receives little or less
scientific research is Enantia chlorantha. Traditionally the bark extract is
applied to ulcers and leprous spots for quick healing, decoction is used for
washing wounds, bark sap is taken as decoction against diarrhea (Nostro et al.
2000).
Much attention
has been recently directed towards plant extracts and biologically active
compounds isolated from plants. The use of medicinal plants play a vital role
in combating diseases in developing parts of the world where poverty and drug
resistance limit access to, and effectiveness of synthetic drugs for
chemotherapy. This study is necessary; coming on the heels of an explosion of
trado-medicine in Nigeria, as plant-based drugs are seen marketed and sold on
the street, offices and even on radio and television. With strong claims being
made by trado-medical practitioners about these plants treating a wide array of
diseases. Worthy of note is the large number of people who patronize the
practitioner without concern to the potency and safety of the said plant
product.
The advantages of herbal medicine over orthodox drugs include; minimal or no side effect, consistence potency and the fact that they are well absorbed and distributed in the area of infection. The success story of chemotherapy lies in the continuous search for the new drugs to counter the challenges posed by resistant strains of microorganisms. Natural products of higher plants may provide a new source of antimicrobial agents with potentially novel mechanisms of action. Secondary metabolites from higher plants could serves as defense agents against invading microorganisms (Oyagade et al., 1999).
Studies have reported the possible use of the plant in conditions such as rickettsia fever, cough and wounds, typhoid fever and infective hepatitis or jaundice (Gill, 1992). It has also been revealed that the plant possesses antipyretic as well as antimicrobial and anti-malarial activities (Adesokan et al., 2007). In Cameroon, stem bark extract of Enantia chlorantha is used to treat jaundice and urinary tract infections (Adjanohoun et al., 1996).
1.1 ENANTIA CHLORANTHA DESCRIPTION
Enantia chlorantha is an ornamental tree belonging to the Annonaceae family commonly known as African yellow wood. It can grow up to 30m high, with dense foliage and spreading crown. It has a fluted and aromatic stem, thick and brown bark with a dark yellow color beneath the bark while the elliptic leaves are about 0.14-0.15m long and 0.05-0.14m broad. It is commonly found in the forest and coastal areas of West Africa, and the Democratic Republic of Congo (Vivien et.al, 1985). Enantia chlorantha, locally known as “Erumeru’’ in igbo land; “Awopa”, or “Dokita Igbo” in Yoruba land helps in the treatment of yellow fever infections. The plant is used in trado-medicine for the treatment of conditions such as rickettsia fever, typhoid fever and infective hepatitis (Fasola et.al, 2011).