CHAPTER ONE
1.1 Background of the Study
Plants have long been a source of nutrition and therapy to man (Solomons, 2000; Schippmann, 2002; Denny and Buttriss, 2007; Salim et al., 2008; Rao et al., 2011). Good health and reduced risk of developing chronic diseases have long been associated with the consumption of plant-derived foods. The presence of vitamins, antioxidants and bioactive compounds in plant foods have been linked to systemic functions such as reproduction and immunity. The potential of managing disease using nutritional therapy has generated numerous epidemiological studies (Solomons, 2000; Denny and Buttriss, 2007). Globally, about 85,000 plant species have been recognized as medicinally useful (Bhattarai et al., 2009)
The history of plants being used for medicinal purpose is probably as old as the history of mankind. The use of medicinal plant s in the industrialised societies has been traced to the extraction and development of several drugs from these plants as well as from traditionally used folk medicine (Shrikumar and Ravi, 2007). Extraction and characterization of several active phytocompounds from these green factories have given birth to some high activity profile drugs ( Mandal et al., 2007 ). The use of traditional medicine is widespread in India (Jeyachandran and Mahesh, 2007). A growing body of evidence indicates that secondary plant metabolites play critical roles in human health and may be nutritionally important (Hertog et al., 1993). It is believed that crude extract from medicinal plant s are more biologically active than isolated compounds due to their synergistic effects (Jana and Shekhawat, 2010). Phytochemical screening of plants has revealed the presence of numerous chemicals including alkaloids, tannins, flavonoids, steroids, glycosides and saponins etc. Secondary metabolites of plants serve as defense mechanisms against predation by many microorganisms, insects and herbivores (Cowan, 1999). Herbal medicines have become more popular in the treatment of many diseases due to popular belief that green medicine is safe, easily available and with less side effects. Indeed, the market and public demand has been so great that there is a great risk that many medicinal plant s today, face either extinction or loss of genetic diversity (Misra, 2009). Normally free radicals of different forms are generated at a low level in cells to help in the modulation of several physiological functions and are quenched by an integrated antioxidant system in the body. However, if free radicals are produced in excess amount they can be destructive leading to inflammation, ischemia, lung damage and other degenerative diseases (Halliwell et al., 1992; Cavalcanti et al., 2006). Free radical reactions, especially with participation of oxidative radicals, have been shown to be involved in many biological processes that cause damage to lipids, proteins, membranes and nucleic acids , thus giving rise to a variety of diseases (Lee et al., 2005 ; Campos et al., 2006 ).
One of such medicinal plants is Rauwolfia vomitoria whose discovery is accredited to the 16th century German physician, Leonhart Rauwolf. (Malik, 1977). It is also called African Serpent wood, African-snake root or swizzle stick. In Yoruba it is called asofeyeje, ira in Igbo, and wadda in Hausa, while it is either called mmoneba or utoenyin in Efik and Ibibio languages respectively (Mecha et al., 1980; Ehiagbonare, 2004). Rauwolfia vomitoria Afzer, of Apocynaceae, is a rain forest shrub that grows in Nigeria, having onal leaves with straight venation and clusters of time flowers (Akpanabiatu et al., 2006). Major phytochemical constituents of this plant include alkaloids, glycosides, polyphenols, and reducing sugars (Akpanabiatu, 2006). The alkaloids have been reported to include reserpine, a well-known antihypertensive substance found in this plant. However, about 30 additional alkaloids have been detected in tissue cell culture of this plant (Gubar et al., 1993). It is well documented that some herbal extracts have influenced serum enzymes as seen by their activities on experimental animals (Udosen et al., 1998; Akpanabiatu et al., 2005). Medicinal plants are re-emerging health aid which has been observed in developing countries probably fuelled by the rising costs of orthodox drugs in the maintenance of personal health and well being (Dasilva and Hoareau, 2005). The alkaloids of R. vomitoria are used mainly as anti-hypertensive agent and sedatives. Uses of its root, root bark and bark of stem are extensive, particularly for their aphrodisiac, antipsoric, abortive and insecticidal properties. They also include; anti-helmintic, apercent, dysenteric, astringent, bechic, cardiotonic, diaphoretic, emetic, emminagogic, expectorant, haemostatic, hypotensive, vulnerary and febrifugic. It adverse effects include; decreased heart rate and blood pressure, which is due to dilatation of blood vessels. It also have an effect on sex hormone, increase appetite, weight loss, swellings, stomach upset, hallucinations, poor co-ordination, dizziness, impairment of physical abilities and psychotic depression (Perry and Metzger, 1980). Reserpine is the most abundant and most active alkaloid in R. vomitoria whose action dominates the other alkaloids. It is an indole alkaloid known to irreversibly bind to storage vesicles of neurotransmitters in synapses. In low doses, it acts as an antidepressant while high doses cause monoamine depletion and depression.
1.2 Statement of the Problem
Various medicinal properties have been attributed to natural herbs. Medicinal plants constitute the main source of new pharmaceuticals and healthcare products. One of these medicinal plants is Rauwolfia vomitoria. The medicinal value of these plants is attributed to their phytochemical compound. The therapeutic values of Rauwolfia vomitoria to health and disease prevention have been reported (Perry and Metzger 1980; Udosen et al., 1998; Gubar et al., 1993; Akpanabiatu, 2006) but it role in sex hormones has not been reported. Thus knowing the medical impact of the root bark extract of this plant (Rauwolfia vomitoria) to the progesterone, estradiol and testosterone sex hormone is my major goal.
1.3 Aim and Objectives
The aim of the study was to identify the role of rauwolfia vomitoria root bark extract on the sex hormones of wistar rat.
To achieve the stated aim the following objective were pursue:
- To identify and document the medicinal impact of Rauwolfia vomitoria root bark extract on male and female rat.
- To evaluate the hormonal efficacy of Rauwolfia vomitoria root bark extracts on male and female rat reproductive hormones.
1.4 Significance of the Study
This work will help the general public
To know the constituents of this plant
To know its role in sex hormones
The findings of this study are expected to find application in the following:
Drug producers (pharmaceuticals) would hopefully benefit from the findings of this study by fitting in for the purpose of drug production.
The study will serve as bedrock for further study by researchers in order to discover more medicinal application of the Rauwolfia vomitoria.
1.5 Justification of the study
In the present era, researcher have worked in the field of medicinal plant extensively as they are low cost and easily available and their phytochemical compound present have play a key role in health and disease treatment.
