ABSTRACT
Coconut water is a natural nutritious beverage that contains several biologically active compounds. This study was set up to evaluate the antioxidant potential of coconut water. Twenty five adult male albino rats, used in this work, were grouped into five (A, B, C, D and E), of five rats per group. Groups A, B, C and D were administered orally with 0.5, 1.0, 1.5 and 2.0mg/kg body weight respectively of the coconut water for seven consecutive days. Group E was the control. Giutathione peroxidase (GPX) and Malondialdehyde (MDA) were measured to examine antioxidant activity of the coconut water. There was a general increase in the average body weight of the treated groups unlike the control group which showed slight increase in body weight. The total protein concentrations of administered groups were not significantly different (P > 0.05) from those of the control. GPX activity was significantly higher (P < 0.05) in the administered groups than in untreated group, while MDA levels decreased significantly (P < 0.05) in the treated groups relative to the control. This increase in GPX activity and decrease in MDA levels were found to be dose dependent. These results indicate that coconut water can reduce oxidative stress, due to its antioxidant property, and may be useful in the management of free radical related disorders.
TABLE OF CONTENT
Title Page……………………………………………………………...............1
Certification ……………………………………………………………………….2
Dedication………………………………………………………………………….3
Acknowledgement…………………………………………………………….4
Abstract……………………………………………………………………………..5
Table of Content……………………………………………………………….6
List of Tables…………………………………………………………………..10
List of Figures…………………………………………………………………10
CHAPTER ONE
Introduction………………………………………………………………........……..11
1.2 Aims and Objectives…………………………………………………….13
CHAPTER TWO
Literature Review………………………………………………………......………..14
2.1Coconut Palm………………………………………………………………..14
2.1.1 Types of Coconut Palm…………………………………………………………15
2.1.1.1 Tall Coconut………………………………………………………………......…..15
2.1.1.2 Dwarf Coconut………………………………………………………….....……..15
2.1.2 Other Species of Coconut………………………………………………………16
2.1.3 Scientific Classification of Coconut Palm……………………...……16
2.1.4 Common Names of Coconut…………………………………………………17
2.1.5 Coconut Water………………………………………………………………….........17
2.1.6 Nutritional values of Coconut Water…………………………………..…18
2.1.7 Uses of Coconut Water…………………………………………………………..18
2.1.7.1 Antioxidant Benefits of Coconut…………………………………………19
2.1.7.2 Medical Values of Coconut Water………………………………………..19
2.1.7.3 Effect of Coconut Water on Exercise and hydration…...……..20
2.1.7.4 Clinical Significance of Coconut Water………………………………….20
2.1.8 Chemical Composition of Coconut Water…………………………….….21
2.1.8.1 Phytohormones……………………………………………………………........……21
2.1.8.2 Auxin………………………………………………………………………...............…..21
2.1.8.3 Cytokinins…………………………………………………………………...........…...22
2.1.8.4 Kinetin (N6- Furfuryladnine)…………………………………………………...23
2.1.8.5 Trans-zeakin…………………………………………………………….........………24
2.1.8.6 Gibberellins (GAs)………………………………………………………......…….25
2.1.9 Inorganic Ions……………………………………………………………........………25
2.1.10 Vitamins…………………………………………………………………...........……..26
2.2 Other Parts of Coconut………………………………………………………....……27
2.2.1 Coconut Milk……………………………………………………………..........………27
2.2.2 Coconut Oil……………………………………………………………..............……..27
2.2.3 Toddy and Nectar…………………………………………………………......……27
2.3 Antioxidants………………………………………………………………….........…...27
2.3.1 Antioxidant Metabolites…………………………………………….…………..30
2.3.1.1 Ascorbic Acid………………………………………………………….......………31
2.3.1.2 Glutathione………………………………………………………………........……32
2.3.1.3 Melatonin……………………………………………………………….........…….32
2.3.1.4 Tocopherol and Tocotrienols (VIT. E)……………………………….33
2.4 Free Radicals ………………………………………………………………..........…….34
2.4.1 Generation of Free Radicals…………………………………………………..34
2.4.2 Free Radicals Scavenger Systems…………………………………….…..36
2.5 Glutathione Peroxidase (GPX)………………………………………………..….37
2.5.1 Isozymes of Glutathione Peroxidase…………………………………….37
2.5.2 Reaction Catalyze by GPX………………………………………………....……38
2.5.3 Reaction Mechanism of GPX………………………………………..…………38
2.5.4 Co-factor of GPX…………………………………………………………........….....39
2.5.5 Species Distribution………………………………………………………........……39
2.5.6 Role of GPX in Disease…………………………………………………….......…..40
2.5.6.1 Levels of Glutathione Peroxidase……………………………………………40
2.5.7 Lipid Peroxidation…………………………………………………………..........…...40
2.5.8 Oxidative Stress and Disease Conditions………………………………………42
2.6 Malondialdehyde (MDA)………………………………………………….............……..44
2.6.1 Action of ROS on Polyunsaturated Acid………………………………….……44
2.6.2 Analysis of MDA…………………………………………………………...............….…45
2.6.3 Hazards and Pathology …………………………………………………..........……..45
CHAPTER THREE
Materials and Methods…………………………………………………………..................47
3.1 Materials………………………………………………………………………............….47
3.1.1 Apparatus/Equipment…………………………………………………..………..47
3.1.2 Chemicals and Reagents………………………………………………………..47
3.1.3 Biological Samples……………………………………………………….....……..48
3.2 Methods…………………………………………………………………….............…….48
3.2.1 Collection of Samples……………………………………………………....…….48
3.2.1.1 Collection of Albino Rats……………………………………………..………48
3.2.1.2 Collection of Coconut…………………………………………………...……..48
3.2.1.3 Extraction of Coconut…………………………………………………….....…..48
3.2.2 Animal Handling and Treatment……………………………………………….48
3.2.2.1 Measurement of Weight…………………………………………………….....48
3.2.2.2 Animal Treatment…………………………………………………………........….49
3.2.2.3 Collection of Blood Samples for Analysis………………………………49
3.2.3 Preparation of Working Reagent………………………………………………..49
3.2.3.1 Phosphate Buffer…………………………………………………………........…..49
3.2.3.2 NADH Solution………………………………………………………….............……49
3.2.3.3 Copper Reagent………………………………………………………...........……….49
3.2.3.4 Sodium Dodecy Sulfate………………………………………………........………49
3.2.3.5 Sodium Hydroxide………………………………………………………............……50
3.2.3.6 Lowry Concentrate……………………………………………………............……...50
3.2.3.7 Preparation of Serum……………………………………………………...........……50
3.3 Measurement of Glutathione Peroxidase Activity…………………………….50
3.4 Determination of Malondialdehyde Levels…………………………………...……50
3.5 Determination of Total Protein……………………………………………….....…...51
3.6 Statistical Analysis…………………………………………………………....,........……..52
CHAPTER FOUR
4.0 Results…………………………………………………………………………......................….53
4.1 Physical Observation………………………………………………………...............……..53
4.2 Changes in Body Weight…………………………………………………..............…..……54
4.3 Levels of Glutathione Peroxidase (U/L) and Malondialdehyde……….….56
CHAPTER FIVE
5.0 Discussion and Conclusion…………………………………………………..................…….58
5.1 Discussion…………………………………………………………………............................………58
5.2 Conclusion…………………………………………………………………….............................……60
References………………………………………………………………………...............................……..61
Appendices………………………………………………………………………................................…….75
LIST OF TABLES
Table Page
2.1 Nutritional Value of Coconut Water…………………………………………....................……..18
2.2 Examples of Antioxidant……………………………………………………............................………31
2.3 Levels of GPX………………………………………………………………...................................………40
4.1 Changes in Body Weight (g) of Animals during Seven days of Treatment with Coconut Water………………………………………………………………………………...........................……..53
4.2 Levels of Lutathione Peroxidase (GPX), Specific Glutathion (Specific-GPX), (moles/mg/ptn), and Protein…………………………………………………………...........................……56
LIST OF FIGURES Pages
Figure………………………………………………………………………………......................................…..31
2.1 Vitamin C Structure………………………………………………………….........................…….32
2.2 Structure of Glutathione…………………………………………………….....................……...35
2.3 Bacterialcidal action of Antioxidant Enzyme………………………………...........…….37
2.4 Reaction Mechanism of GPX………………………………………………....................……..39
2.6 Lipid Peroxidation Reaction ………………………………………………....................………42
