CHAPTER ONE
INTRODUCTION
- Background of the study
The study of herbal medicines and the use of plant leaves, stems, roots, seeds and the latex, for human benefits, is an age long event for human benefits (Okafor et al., 1994).Herbal medicine is fast emerging as an alternative treatment to available synthetic drugs for the treatment of diseases possibly due to lower cost, availability, fewer adverse effects and perceived effectiveness (Ubaka et al., 2010). The exploitation of cheap agricultural materials to manufacture industrial products will enhance the development of rural agro-based economy (Kronbergs, 2000; Sain and Panthapulakkal, 2006). The historic role of medicinal plants in the treatment and prevention of diseases and their role as catalysts in the development of pharmacology do not however, assure their safety for uncontrolled use by an uninformed public (Matthews et al., 1999). The use of plants in the management and treatment of diseases started with life. In more recent years, with considerable research, it has been found that many plants do indeed have medicinal values. Some medicinal plants used in Nigeria include Garcina kola, used in the treatment of asthma, Carica papaya, used as a remedy for hypertension, Ocimum basilicum, a cure for typhoid fever, and Cola nitida, for treatment of pile (FAO, 1996). In Nigeria, fermented Prosopis africana seeds are popularly used as food seasoning. It is evident that fermented food condiments are good sources of nutrients and could be used to produce complementary food supplements (Achi, 2005). The food flavouring condiments are prepared by traditional methods of uncontrolled solid substrate fermentation resulting in extensive hydrolysis of the protein and carbohydrate components (Fetuga et al., 1973; Eka, 1980). Apart from increasing the shelf life, and a reduction in the anti-nutritional factors (Odunfa, 1985; Barimalaa et al., 1989; Achi and Okereka, 1999), fermentation markedly improves the digestibility, nutritive value, and flavours of the raw seeds. Fermented products remain of interest since they do not require refrigeration during distribution and storage. The traditional condiments have not attained commercial status due to the very short shelf life, objectionable packaging materials, stickiness and the characteristic putrid odour (Arogba et al., 1995). Fermented condiments often have a stigma attached to them; they are often considered as food for the poor.
Liver damage due to ingestion or inhalation of hepatotoxins such as drugs is increasing worldwide, and conventional drugs used in the management of drug induced liver damage are mostly inadequate and have serious adverse effects (Ozougwu, 2011). In spite of the tremendous strides in modern medicine, there are grossly few drugs that stimulate liver function, offer protection to the liver from damage or help regeneration of hepatic cells. Chronic hepatic diseases is one of the foremost health problems worldwide, with liver cirrhosis and drug induced liver injury accounting for the ninth leading cause of death amongst the western and developing countries population (Mohamed Saleem et al., 2010). About 20,000 deaths are reported every year due to liver disorders (Gupta and Misra, 2006). As said earlier conventional drugs used in the management of drug induced liver damage are mostly inadequate and have serious adverse effects (Ozougwu, 2011). It is, therefore, necessary to explore the herbal options in the management of drug induced liver damage to replace currently used drugs of low efficacy and safety.
1.1 Prosopis africana
1.1.1 Ecological and some pharmacological importance of Prosopis africana seed
Prosopis africana is a leguminous plant of the Fabaceae family. It is a flowering plant that is locally called “kiriya” in Hausa, “okpehe” in Ibo and Idoma and “gbaaye” in Tiv languages of Nigeria. The leaves, branches, bark and roots are used for several purposes in traditional medicines (Kalinganire et al., 2007). Prosopis africana plant is a tropicalleguminous tree that is readily distinguishedby its dark, pale drooping foliage with smallpointed leaflets. The tree is about 12m to 18mhigh and up to 2.2m in girth. The dry podswhich are between 10cm and 15cm long andabout 2cm thick contain numerous ellipsoidseeds of about 15 to 18 (Ogunshe et al., 2007).The only knownusage of these seeds, presently in Nigeria, isas food seasoning, which is particularlycommon among the Idomas of Benue State.The seeds are processed in the same way aslocust bean seeds. The seeds have proteincontent of between 39 and 40 per cent (Balogun, 1982). It is traditionally used for formulation of animal feeds and preparation of local condiments through boiling and fermentation processes (Aremu et al., 2006).
The tree is of great economic value to man and animal, it fixes nitrogen to enrich the soil, generates hardy timbers, produces protein rich leaves and sugary pods used as feed stuffs for ruminants (Annongu et al., 2004). However, the disadvantage of Prosopis is the high content of anti-nutritive factor such as tannins, haemagglutinins, prosopine and toxic amino acids which are capable of inducing adverse effect on simple stomached animals when consumed without adequate processing (Cheeke and Shull, 1985). The seeds could be used as a protein supplement for low-protein foods and seeds such as cereal grains for animals (Maragoni and Alli, 1987). The seeds could also serve as a good source of carbohydrate concentrate for all classes of livestock.
1.1.2 Pharmacological Properties of Prosospis africana.
The methanol stem bark extract of Prosopis africana is used for anti-inflammatory and pain relief medicine in humans. Likewise, the tannins and dye in the bark is utilized in the leather industry (Ayanwuyi et al., 2010). The leaves and stem are used for treating toothache. The fruits (pods) are used as fodder for ruminant animals (Amusa et al., 2010). In the middle belt states of Nigeria, fermented Prosopis africana seeds are popularly used as food seasoning. It is a source of low cost protein. Gels that could be used for pharmaceutical tablet formulation is obtained from Prosopis africana gum. The endocarp gum of Prosopis africana seed contains high content of galactose and mannose. Galactose is a special type of natural sugar that gives sustained energy for a longer time compared to other sugar. Mannose is important for treatment of urinary tract infections (Achi and Okolo, 2004). Likewise, the seeds have been reported to have 4445 kcal/kg of food energy which is higher than the 2500 to 3000 kcal/kg daily requirement by humans (Barminas et al., 1998).
According to (Kolapo et al., 2009) the stem and root of P. africana indicates a potential candidate plant parts in dentrifice production. The bark of Prosopis africana in this study is used to treat pile (Lawal et al., 2010).
Anticonvulsant properties of Prosopis africana were seen on strychnine (STR) and pentylenetetrazol (PTZ) induced convulsion. Plant extract were effective against PTZ and STR induced convulsions (Ngo-Bum et al., 2009).
Prosopis africana plant extract was pre-screened and evaluated as anti-trypanosomal agents. The result suggests that the plant with promising bioactivity may possess component that may provide the chemical lead towards the discovery of new generation trypanocides that are more potent and less toxic than the currently available and marketed trypanocidal drugs (Osho and Lajide, 2012).
Prosopis africana belonging to the family Fabaceae is being used traditionally as medicine in many African homes. This includes the leaves used in treatment of headache and toothache; leaves and bark are combined in the treatment of rheumatism, skin disease and eyewashes; the roots are used as diuretic, and in the treatment of dysentery, bronchitis and stomach cramps (Gilbert and Neil, 1986; Arbonnier, 2002). The prosopis gum has been used in the present day research as bio-adhesive agent in delivery of metformin, this show a synergistic effect (Adikwu and Nnamani, 2005).
Prosopis gum can be used to treat infection, skin irritation and in the management of wound. These studies suggest that a mixture of bovine mucin, cicatrin and prosopis gum has a better healing effect than cicatrin powder alone (Momoh et al., 2008). According to Ojo et al. (2006), Prosopis africana leaf extract was observed to have hepatoprotective potentials, this could be related to the high concentration of tannin in the leaf.
