1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Food of plant origin constitute the major source of food for man due to mainly their availability and low cost (Obizoba, 1998). Most people in developing countries derive their protein supplies from legumes and cereals. One of the underutilized legumes that come to mind is Mucuna sloanei. M. sloanei commonly called “horse eye bean” or “hamburger seed” is an annual leguminous climber with pods that are covered with hairs that irritate the skin when the fruit is mature and dry (Tuleun et al., 2008). Its consumption by humans is localized and in many cases, it appears to be a last resort legume in circumstances of famine or scarcity of more popular legumes (Ukachukwu and Obioha, 1997).
Mucuna is a genus of around one hundred (100) accepted species of climbing vines and shrubs of the family fabaceae, found worldwide in the wood lands of tropical areas (Bressani R; 2002). The leaves are tripalmate, alternate or spiral and the lowers are pea-like but larger with distractive curved petals bear pods which are covered with microscopic velvety hairs called trichomes.
Mucuna sloanei seeds are usually toasted for 5-10 minutes before grinding and flouring to supplement as thickener in sauce or soup. It is used by the igbo community in sub-sahara, Africa as condiments or part of the main dish (Ukachukwu et al., 2002). Seeds of M. sloanei popularly called “Ukpo” by igbo communities are used as thickener of soup and vegetable oil, beverages and food items (Waryekeche et al., 2003). Its seeds are cracked by hitting with a hard object before cooking then dehulled, ground, mixed with red oil palm to obtain yellow powder and marketed as soup thickener. After draining the cooking water, softened seeds are dehulled, ground into paste and mixed with other ingredients e.g chilles, egg plants, onions, meat or fish to prepare soup which is eaten along with starchy staples. Consumption of Mucuna as food has also been reported from Mozambique and Malawi (Gilbert; 2002). A black dye is obtained from all parts of Mucuna sloanei which is used in Nigeria to dye fiber and leather back. Cooked young fruits are eaten as vegetable; In Nigeria, M sloanei is occasionally cultivated for that purpose. The ripe seeds are eaten, pounded and cooked preferably in soups. All parts Mucuna plant are said to posses phytochemicals of high medicinal value of human and vertinary importance and also constitute as an important raw material in Ayurvedic and folk medicines. Mucuna sloanei seeds constitute as a good source of several alkaloids, antioxidants, anti-tumor and anti-bacteria compounds. Seeds are the major source of L-DOPA which serve as a potential drug in providing symptomatic relief for parkinson’s diseases (Molloy et al., 2006). The seeds are highly resistant to diseases and pests and exhibit good nutritional qualities. Its medicinal properties include anti-diebetic, anti-parkinsonism, anti-oxidant and anti-microbial (Rajeshwar et al., 2005), it enhances learning and memory (Poornachandra et al., 2005) and anti-helminthic (Jalapure, 2007). Methanolic seed extract of M. sloanei has a beneficial effect on serum testosterone and improved sperm count in humans and mammals. Therefore, it can be considered in the management of infertility in males (Egwurugwu et al., 2012).
Mucuna sloanei seeds consist of high protein, high carbohydrate, high fiber, low lipids and adequate minerals and meet the requirement of essential amino acids. Hydrothermal treatments, fermentation and germination have been shown to be most effective in reducing the anti- nutrients of the seeds. Several anti- nutritional compounds of the seed serve in health care and considerably have been drawn toward their anti-oxidant properties and potential health benefits (Adebowale et al., 2005). It has nutritional potential as a rich source of protein (23-35%) (Bressani R, 2002).
Mucuna is used as a minor food crop in several countries of Asia and African. Owing to its high protein content, it could be used to supplement cocoyam, which is a high carbohydrate soup thickener and melon which has high oil content. These soup thickeners could increase the caloric content of soup, thereby increasing the risk of weight gain. Protein energy deficiency has been recognized as the most common form of malnutrition in regions where people depend on starch based diets (Michaelsen et al., 1998). Incorporation of this underutilized legume which is inexpensive and which meets the requirement of essential amino acids into the diet will no doubt improve the nutritional status and help reduce malnutrition. Its low lipid content (about 7%), high fiber content (about 9.6%) and its high concentration of polyunsaturated fatty acid adds to its nutritional potential and increases the benefits derived on consumption.
Besides typical medicinal properties, several anti-nutritional compounds of Mucuna seeds serve in health care in a variety of ways. The phytic acid of Mucuna sloanei possess anti-oxidant, anti-cacinogenic and hypoglycemic activities (Richard et al.,1997) and are effective at low concentrations. Saponins are recently shown to have hypocholestrolemic as well as anti-carcinogenic effects. Tannins are known to possess health benefits, where they are 15-30 times more efficient in free radical quenching activity than Trolex and other simple phenolics (Hurrel et al.,1999). The seeds of Mucuna sloanei possess good functional properties and invitro protein digestibility (Adebowale et al., 2005).
1.2. STATEMENT OF PROBLEM.
One of the major problems with legume utilization is the presence of anti-nutritional factors (Oke et al., 2002). Mucuna sloanei seeds have been reported to contain crude proteins, carbohydrates, fat, crude fibers, moisture, ash, phosphorus, magnesium, calcium, sodium, iron, magnesium, copper, tannins, glycosides, L-Dopa and zinc (Giama and Wachuku, 1997; Akpata and Miachi, 2001; Ijeh et al.,2004; Tuleun et al., 2008; Nwosu, 2011).
The toxicity on consumption of Mucuna sloanei seeds and their preparations result in dizziness, diarrhea, pathological changes in organs, growth depression and death. (Emenalom O.O and Udebibie A.B.I; 1998).
It is therefore, the aim of this study to investigate the phytochemical compositions of aqueous extract of Mucuna sloanei (fabaceae).
1.3. AIM AND OBJECTIVES OF STUDY
The aim of this study is to investigate the phytochemical compositions of the Mucuna sloanei seed (ukpo) bought at Eke Oko, Federal Polytechnic, Oko, Anambra state.
Specifically, this work will:
1.4. SCOPE OF STUDY
The scope of this study entails:
1)The collection of Mucuna sloanei seed from Eke Oko, Anambra state.
2) Preparation of Mucuna sloanei extract which would be used in phytochemical study using standard procedures as described by Akintayo et al. (2000).
3) Identification of phytochemicals found in Mucuna sloanei and their quantitative characteristics.
4) Collection of data analysis.
5) The usage of the analyzed data to make relevant recommendations.
1.5 SIGNIFICANCE OF THE STUDY
Mucuna sloanei is a vital food in the society with a lot of nutritional values. Research into it would enlighten us into more knowledge of its nutritional value and anti-nutritional factors and how it can be managed.
The result from this present work will benefit the following: a) Our society will through this work know the different compositions of M. sloanei and at what quantity it can be taken into the body.
1.6. RESEARCH QUESTIONS
1) What are the phytochemical constituents of Mucuna sloanei?
2) At what quantity should Mucuna sloanei be taken into the body based on its constituents?
3) What are the anti-nutritional compounds of Mucuna sloanei and how can they be converted into useful body substances?