PHYTOCHEMISTRY, ANTIMICROBIAL, ANTI-INFLAMMATORY, ANTI-PYRETIC AND ANALGESIC PROPERTIES OF THE STEM BARK EXTRACTS OF PENTACLETHRA MACROPHYLLA BENTH
1.1 Background of the study
Plants have long been used as medicinal agents before the isolation of morphine from opium in the early 19th century (WHO/AFRO,1976). Subsequently other drugs such as cocaine, codeine, digoxin and guanine of which many are still in current use were isolated (Newman et al., 2000; Butler, 2004).
These discoveries in the different use of plants have provided the basis for the modern day medicine and have been termed medicinal plants. Medicinal plants have been described by the World Health Organization (WHO) as plants in which some or all of its parts can be used directly or indirectly in the management of disease (Acharya and Shrivastava, 2008).
The therapeutic properties of medicinal plants are characterized by the presence in their organs of secondary metabolites such as alkaloids, tannins, flavonoids, glycosides, vitamins and coumarin compounds which physiologically affect the bodies of humans and animals or which are biologically active in relation to the causative agents of various diseases. The plant part like fruit, leaves, stem, bark and roots or even the whole plants are themselves used in the treatment of illnesses, the plant may also form biological template for its eventual development of which is referred to as orthodox medicines. Isolation and characterization of pharmacological active constituents from medicinal plants are among the leading research trends of today. (Acharya and Shrivastava, 2008).
Drug discovery from plant origin entails the in-cooperation of so many approaches which is likely to combine botanical, phytochemical and biological techniques. Medicinal Plant constituents combine to provide us with new chemical entities (lead molecules) for the development of drugs against various pharmacological targets (Acharya and Shrivastava, 2008).
Pentaclethra macrophylla Benth. (African oil bean) is a tropical tree crop found mostly in the southern rain forest zone of West Africa. It belongs to the Fabaceae family and sub-family Mimosoidae (Keay et al., 1989). The plant is cultivated by farmers in southern and middle belt regions of Nigeria for its soil improvement properties and as a component of an agro-forestry system (Okafor, 1990). The seeds are dorso-ventrally flattened, hard brown in colour and about 6cm long and 3cm wide (Achinewhu,1986).
Pentaclethra macrophylla is normally called African Oil bean (Oliver, 1960).It Contains 8-10% carbohydrate and 47-48% of fatty acid (Odoemelain, 2005).
Ethno-pharmacological literature has shown Pentaclethra macrophylla to have medicinal uses and has been used for various parasitic infections, inflammations, and related illnesses (Cousins and Huffman, 2002). The plant has also been confirmed as a medicinal plant used in traditional herbal practice for the treatment of disorder of both domestic and wild animals and human diseases (Akah et al., 1999). The bark fruits, seeds and the leaves are used as antihelminitics for gonorrhea, convulsion and as analgesic (Githens, 1948; Bouquet and Debray, 1974; Iwu, 1993).
Despite these various uses of the plant, there has been insufficient information on its exact antimicrobial properties.
1.2 Statement of Research Problems
The search for the healing properties of plant is an ancient idea that has remained even till date. In recent years, drug resistance to human pathogenic bacteria has been commonly reported all over the world and accounts for approximately one half of all deaths in tropical countries (Alavijeh et al., 2012).
This research therefore, intends to determine the phytochemistry, antimicrobial, anti-inflammatory, anti-pyretic and analgesic properties of the stem bark extracts of Pentaclethra macrophylla Benth. The results of this study may lead to the discovery of drug that could reduce or eliminate drug resistance to human pathogenic bacteria.
- Justification of The Study
Pentaclethra macrophylla Benth (Fabaceae) is used in Nigeria widely and generally in Africa. Some ethno-pharmacological values of Pentaclethra macrophylla have been evaluated to include the bark infusion as an abortifacient, the ability of the leaf or bark to treat diarrhea and toothache, also the crushed seed for abortion, smoked or burnt leaves as an anti-convulsant and the fermented seed cooked and served as food in Africa especially Nigeria. (Oboh, 2007).
In Nigeria, the stem bark of Pentaclethra macrophylla is used to traditionally treat skin infections, headache, pains, fever, boils and swellings. Natural products particularly plants remain an important source of new drugs, new drug leads and new chemical entities allowing the design and rational planning of new drug biomimetic, synthetic development and the discovery of new therapeutic properties not yet attributed to known compounds. (Hamburger and Hostettman, 1991; Newman et al., 2000, 2003 and Butler, 2004). Thus, this work seeks to validate the ethno-medicinal use of the plant.
1.4 Objectives of the Study
- To extract the dried pulverized bark of Pentaclethra macrophylla with n-Hexane, dichloromethane, ethylacetate and 70% methanol via cold maceration.
- To evaluate the presence of phytochemicals such as Alkaloids, Saponins, Flavonoid, Terpenes, Cyanogenic glycoside, Cardiac glycoside, Carbohydrate, Polyphenols, Steroidal glycosides, Phlobatanins, Anthraquinones, Balsam and Tannins using standard procedures.
- To screen for Antimicrobial activity using agar well diffusion method against Staphylococcus aureus, Candida albicans, Streptococcus gordonii, Escherichia Coli, Salmonella typhi and Bacillus subtilis.
- To evaluate the anti-pyretic, anti-inflammatory and antinociceptive effects in mice after establishing the toxicity profile using Lorke’s Method.
- To isolate compounds using chromatographic techniques such as: Column chromatography and preparative thin layer chromatography
To elucidate the structures of the compounds isolated.