ABSTRACT

In this study, the antihyperlipidemic and antioxidants activities of the extract and fractions ofPhaseolus vulgaris L. were evaluated. The crude extract (PVE) of dried pulverized plant materialwas obtained by maceration in methylene chloride/methanol (1:1) while the solvent fractionswere obtained by successive solvent-solvent partition in separating funnel between the crudeextract suspended in aqueous medium and solvents of increasing polarity to obtain the n-hexanefraction (PVHF), ethylacetate fraction (PVEF), and butanol fraction (PVBF) in thatorder.Antihyperlipidemic effects of the extracts and fractions were investigated using acute, subacuteand 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 studywhere 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 theacute antihyperlipidemia model. In contrast, high density lipoprotein (HDL-C) level wassignificantly (P<0.05) increased in the acute phase by 20.85%.In all study protocols involvingthe 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 withpercentage decrease of 22.10% compared to the control treatment. Triglycerides level wassimilarly reduced by 21.59% and 15.91% at PVHF (200 mg/kg) and PVEF (200 mg/kg) with theacute study.The sub-acute protocol showed significant decrease at PVBF 200 mg/kg percentagedecrease 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 200mg/kg percentage decrease of 17.28. LDL-C level for fraction extract study showed dosedependent significance decrease (P<0.05) seen at PVHF 100 mg/kg, PVEF100 mg/kg, and 200mg/kg with percentage decrease of 47.19%, 41.62% and 53.39% respectively during the acuteprotocol, 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% and20.05% 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 increaseof 30.44%, 28.88% and 30.86%. DPPH reduction and nitric oxide scavenging assays were usedin the investigation of the extract and fractions for the in vitro antioxidant activities study, theantioxidant activities of the extract and fractions were further determined in vivo in rats.Antioxidant enzymes and factors such as catalase, glutathione peroxidase, and lipid peroxidationactivities were measured in carbon tetrachloride-treated rats treated with or without the extractand fractions studies. The highest percentage reduction of DPPH was 80.61% seen with PVEFand 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 withascorbic acid. In in-vivo antioxidant assay showed that the Lipid peroxidation levels estimated bythiobarbituric acid reaction showed no significant (P>0.05) increase or decrease in the serumMDA of both the treated and untreated group, while in catalase activity estimation showedsignificant (P<0.05) increase was seen with PVE 100 mg/kg of 71.05%, Glutathione peroxidiseactivity showed the most significant percentage (P<0.05) increase of 76.19% for PVBF 100mg/kg.The results of the study showed that the extracts and fractions of Phaseolus vulgarisxivxivposses anti-hyperlipidemic and antioxidant with the PVEF showing better and more consistenteffects with all protocols used in the investigation.1

CHAPTER ONE

1.0. INTRODUCTION

A large volume of scientific research suggests that in situations of oxidative stress, reactiveoxygen species (ROS) are generated and a homeostatic environment between anti-oxidant andoxidation is created, which are known to be an important concept for maintaining