ABSTRACT

In this study, the antihyperlipidemic and antioxidants activities of the extract and fractions of Phaseolus vulgaris L. were evaluated. The crude extract (PVE) of dried pulverized plant material was obtained by maceration in methylene chloride/methanol (1:1) while the solvent fractions were obtained by successive solvent-solvent partition in separating funnel between the crude extract suspended in aqueous medium and solvents of increasing polarity to obtain the n-hexane fraction (PVHF), ethylacetate fraction (PVEF), and butanol fraction (PVBF) in that order.Antihyperlipidemic effects of the extracts and fractions were investigated using acute, subacute and chronic models. In all threemodels, treatment with (PVE) caused significantreduction (P<0.05) in the lipid profile parameters with the most significance seen in the sub acute study where total cholesterol was decreased by 38.44%. Triglycerides level was significantly decreased (P<0.05) by 18.18% in the acute study model.Similarly, very low density lipoprotein (VLDLC) and low density lipoprotein (LDL-C) wasrespectively decreased by 18.18% and 48.73% in the acute antihyperlipidemia model. In contrast, high density lipoprotein (HDL-C) level was significantly (P<0.05) increased in the acute phase by 20.85%.In all study protocols involving the various fraction there were significant increase(P<0.05) in lipid profile. PVEF (400 mg/kg) produced- the most significant reduction in total cholesterol level in the acute study with percentage decrease of 22.10% compared to the control treatment. Triglycerides level was similarly reduced by 21.59% and 15.91% at PVHF (200 mg/kg) and PVEF (200 mg/kg) with the acute study.The sub-acute protocol showed significant decrease at PVBF 200 mg/kg percentage decrease of 17.28%. VLDL-C level for the fraction study showed significant decrease (P<0.05) at PVHF 200 mg/kg and PVEF 200 mg/kg with percentage decrease of 21.59% and 15.91% during the acute protocol, the sub-acute protocol showed significant decrease at PVBF 200 mg/kg percentage decrease of 17.28. LDL-C level for fraction extract study showed dose dependent significance decrease (P<0.05) seen at PVHF 100 mg/kg, PVEF100 mg/kg, and 200 mg/kg with percentage decrease of 47.19%, 41.62% and 53.39% respectively during the acute protocol, Finally in the chronic protocol a significant decrease was seen with PVHF 200mg/kg, PVEF 100 mg/kg, and PVBF 200 mg/kg with percentage decrease of 26.03%, 24.82% and 20.05% respectively. HDL-C level for extract study showed dose dependent significant increase (P<0.05) seen at PVHF 100 mg/kg, PVEF 100 mg/kg and 200 mg/kg with percentage increase of 30.44%, 28.88% and 30.86%. DPPH reduction and nitric oxide scavenging assays were used in the investigation of the extract and fractions for the in vitro antioxidant activities study, the antioxidant activities of the extract and fractions were further determined in vivo in rats.
Antioxidant enzymes and factors such as catalase, glutathione peroxidase, and lipid peroxidation activities were measured in carbon tetrachloride-treated rats treated with or without the extract and fractions studies. The highest percentage reduction of DPPH was 80.61% seen with PVEF and PVBF fraction at 400 mg/kg. The highest percentage reduction of nitric oxide was 75.86% seen with PVHF at 200 mg/kg. The in vitro study showed significant increased (P<0.05) scavenging activity with the PVHF and PVEF having scavenging activity comparable with ascorbic acid. In in-vivo antioxidant assay showed that the Lipid peroxidation levels estimated by thiobarbituric acid reaction showed no significant (P>0.05) increase or decrease in the serum MDA of both the treated and untreated group, while in catalase activity estimation showed significant (P<0.05) increase was seen with PVE 100 mg/kg of 71.05%, Glutathione peroxidise activity showed the most significant percentage (P<0.05) increase of 76.19% for PVBF 100 mg/kg.The results of the study showed that the extracts and fractions of Phaseolus vulgaris posses anti-hyperlipidemic and antioxidant with the PVEF showing better and more consistent effects with all protocols used in the investigation.

CHAPTER ONE
1.0. INTRODUCTION
A large volume of scientific research suggests that in situations of oxidative stress, reactive oxygen species (ROS) are generated and a homeostatic environment between anti-oxidant and oxidation is created, which are known to be an important concept for maintaining a healthy biological system (Davies, 2000). Reactive oxygen species (ROS) such as superoxide anions (O2), nitric oxide (NO) and hydroxyl radical (OH-) aids in the inactivation of enzymes and this result in damage to important cellular components which leads to complication such as coronary heart diseases (Gessin et al., 1990).
Disease of coronary origins such as stroke, atherosclerosis, etc., continues to be a leading cause of death in most countries of the world (Davey, 1993).One of the greatest risk factors in the severity and prevalence of coronary heart diseases is disorders of lipid metabolism known as hyperlipidemia (Grundy, 1986). According to reports by the World Health Organization approximately 56% of coronary heart diseases are as a result of hyperlipidemia and this result in about 4.4million deaths each year worldwide (World Health Organization, 2002).

Hyperlipidemia is a disorder of lipoprotein metabolism, including lipoprotein overproduction or deficiency and manifested by elevation of the serum total cholesterol, low-density lipoprotein (LDL) cholesterol and triglyceride concentrations with a decrease in the high-density lipoprotein (HDL) cholesterol concentration (Adam, 2005).
Man as always looked for a way to fight and control diseased state with inspiration and aid from his immediate natural environment; this guidance’s have been used for centuries as remedies for human diseases because they contain components of therapeutic value (Nostro et al., 2000). The use of medicinal plants in the management of diseases is common around the world (Aliyu et al.,2007). Herbal medicine, the study and use of medicinal properties of plants, is an aspect of modern medicine (World Health Organization, 2008).The use of traditional medicine is recognized as the most viable method of identifying of new medicinal plants species (Farnsworth, 1966; Ajanahoun et al., 1991).
Medicinal plants are used for their beneficial antioxidant and lipid lowering effects thus reducing the risk of cardiovascular diseases in many countries. HMG-CoA reductase inhibitor that is the statins is the most recent lipid lowering drugs. They are very effective in lowering total and LDL- cholesterol and have been shown to reduce coronary events and mortality. They have very few side effects and are now usually the drugs of first choice (Neal, 2002). Also, ascorbic acid and tocopherols are widely used anti-oxidants. In recent times antioxidants derived from natural sources mainly plants have been intensively used to prevent oxidative damage because of its advantage over synthetic ones; as they are easily obtained, economical and have slight or negligible effects (Onay-ucar et al., 2006). Although the adverse effect of statins is relatively low, one rare effect called rhabdomyolysis can be very serious (Miller, 2001). Statins and fibrates both used in elevated cholesterol, especially in combination; cerivastatin (Baycol) was withdrawn in 2001 after numerous incidence of rhabdomyolysis (Armitage, 2007). Hence, there.is an urgent need to research natural products that would have minimal or no lipid lowering side effects.
Phaseolus vulgaris (family: Fabaceae) is a plant whose leaf, bark, roots and seeds are used for medicinal purposes. It is commonly known as kidney bean, various parts of the plant have been used extensively for the treatment of diabetes mellitus traditionally (Chopra et al., 1958).
Previous studies have reported the hypolipidemic activities of the aqueous extract (Roman-Ramos et al., 1995), as well as, the anti-inflammatory, antimutagenic, antioxidant, antimicrobial and antioxidant activities of the extract (Jorgeet al.,2013). The present study aims to establish the anti-hyperlipidemic and antioxidants effects of various fractions of Phaseolus vulgaris L. fruit and determine the most active of the fractions