V. N. Osabor , R. A. Etiuma and M. U. Ntinya
INTRODUCTION
Right from the creation, plants and its products derived from parts of plants such as stem bark, leaves, fruits and seeds have been parts of phytomedicine, thus indicating that any part of a plant may contain useful active compounds. Medicinal plants constitute the main source of raw pharmaceuticals and healthcare products.
S. dulcificum has been found as an important source of phytomedicine. S. dulcificum is commonly known as miracle fruit. S. dulcificum is a plant with a berry that when eaten, causes sour foods (such as lemons and limes) consumed to taste sweet. The sweetening property is due to miraculin (a glycoprotein) which is used commercially as a sugar substitute. Apart from miracle fruit, it is also commonly known as miracle berry.
S. dulcificum (sapotaceae) is an evergreen shrub native to tropical West Africa, and the fruits, and red berries have the property of modifying sour taste into sweet taste remarkably. The active material of the berry is the glycoprotein, miraculin, which has no taste in itself. The most outstanding property of the fruit is its effect on the taste buds of the tongue that causes every sour or acidic food eaten to taste very sweet. The test modifying effect lasts up to two hours or more, causing acidic food substances such as sour lime, lemon, grape juice and even vinegar to taste sweet.
The fruits are small approximately 2-3 cm long ellipsoid berries that are bright red when ripe and composed of a thin layer of edible pulp surrounding a single seed. The leaves are thin, papery, leathering and evergreen. It is reported that African here used S. dulcificum to sweeten a sour gruel made from stale bread, sour palm wine and pito, a sour alcoholic beverage made from fermented grain. It has also been used before eating a certain type of sour corn bread.
MATERIALS AND METHODS
2.1 Sample Collection and Preparation
The fresh leaf and root samples of S. dulcificum were collected, identified and stored in a polyethylene bag and dried at 160°C in an oven. After drying, both leaves and roots were blended to powder with a manual blender. The blended samples were put in a desiccator and labeled accordingly and stored in a desiccator.
2.2 Sample Extraction
Petroleum ether and distilled water were used to extract each of the leaf and root samples. In each process, 20 g of the powdered samples were washed and packed into an extraction thimble and fitted into a soxhlet extractor. The samples were Soxhlet extracted for three (3) hours. The petroleum ether and water extracts obtained were put in the reagent bottles. Each bottle was distinctively labeled and kept in the laboratory for phytochemical screening.
2.3 Digestion of Sample
Five grams (5 g) of the powdered samples were accurately weighed into a conical flask. 25 ml of concentrated nitric acid was added to the sample. 5 ml of perchloric acid was then added to the sample. The conical flask with its content was gently heated (50-70°C) on a Stuart hot plate until the colour changed from brown to colourless. The digest was made up to 100 ml with deionized distilled water. Appropriate dilutions were made for each element. All determinations were carried out in triplicates.
2.4 Proximate Analysis
Proximate analysis involves determination of moisture, ash, crude fibre, crude protein, fat and carbohydrate contents. Ash, moisture fat, fibre and crude protein were determined through methods prescribed. The percentage available carbohydrate (CHO) was calculated using expression % CHO = 100 – (% ash + % crude protein + % crude lipid + % crude fibre).
2.5 Phytochemical Screening
The phytochemical screening procedures carried out on the leaves and roots of S. dulcificium were adapted from the previous work on medicinal plant analysis. Alkaloids, saponins, flavonoids, cardiac glycosides, polyphenols, phlobatannins, anthraquinones, anthranoids, tannins and reducing compounds were screened.
2.6 Quantitative Determination of Some Phytochemicals
Quantitative determination of the following phyto constituents; alkaloids, saponins, flavonoids, cardiac glycosides, polyphenols, anthraquinones and tannins were determined using methods described by A.O.A.C, Sofowora, Obadoni and Ochuko and Soladoye and Chukwuma.
Mineral Element Analysis
The methods of AOAC were used in these determinations. Standard solutions were prepared for each element. Sodium and potassium were determined by a flame photometer (Gallen Kamp). Calcium, magnesium, iron, chromium, lead, mercury, nickel, cadmium, cobalt, manganese, zinc and copper, were determined using atomic absorption spectroscopy (AAS).
RESULTS AND DISCUSSION
The moisture content of food is usually used as a measure of stability and susceptibility to microbial contamination. These compositions indicate that S. dulcificum can be stored for a long time without spoilage.
S. dulcificum has a very high percentage of fibre. Emphasis has been placed on the importance of keeping fibre intakes low in the nutrition of infants and pre-school children. The crude lipid contents of the leaves and roots of S. dulcificum are monounsaturated and considered healthy when consumed in moderation. They are essential because they provide the body with maximum energy. The result obtained is that S. dulcificum is rich in carbohydrates. If carbohydrate is sufficient in food, it prevents the unnecessary usage of protein and allows it to be used for the body building processes.
The phytochemical screening of the leaves and roots of S. dulcificum show that cardiac glycosides were present in higher concentration in both petroleum ether and water extracts. Carnolides is a type of cardiac glycosides which is abundant in the asclepiadaceae and apocynaceae. Their actions are anti-inflammatory, antiseptic and analgesic and are used in the treatment of rheumatism.
The leaves of S. dulcificum are very rich in saponins. S. dulcificum is also rich in flavonoids. Flavones are a class of flavonoids and are commonly attached to sugar to form glycosides. The result indicated that leaves and roots of S. dulcificum are not rich in reducing compounds compared to the seeds, which is evidence of the taste modifying activity. Phlobatannins were absent in both petroleum ether and water extracts of the leaf and root samples. Similarly, the screening for anthranoids showed the absence of anthranoids in both extracts (petroleum ether and water) of the leaf and root samples.
CONCLUSION
The leaves of S. dulcificum are rich in carbohydrates and moisture. Similarly the roots are rich in carbohydrate, moisture and fibre. Ash, fat and protein were appreciably present. Phytochemical screening of the extracts (petroleum ether and water) revealed that S. dulcificum is highly rich in cardiac glycosides and polyphenols when compared to other detected bioactive compounds. From the quantitative analysis of the phytochemicals, tannins, cardiac glycosides, polyphenols, flavonoids and saponins showed a high level in the both leaves and roots. Elemental analysis revealed that all the detected mineral elements were present in a moderate concentration in both leaves and roots.
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