ABSTRACT
There
is prevalence of Metabolic syndrome, a cluster of cardiometabolic symptoms
including central obesity, hypertension, insulin resistance, chronic low-grade
inflammation and dyslipideamia. The present study evaluated the possible
attenuating role of low (500mg/kg/day) and high (1000mg/kg/day) doses of
methanol extract of turmeric, a common food constituent, in high-sucrose diet-induced
metabolic syndrome in rats. Forty two male Wistar rats were assigned to seven Groups
of six rats each. Group 1 served as normal control and was given standard feed
and distilled water only, Group 2 received standard feed and 500mg/kg/day
of turmeric extract, Group 3 received
standard feed and 1000 mg/kg/day of turmeric extract, Group 4 served as high
sucrose diet (HSD) control and received distilled water and a high sucrose diet
containing 390g of powdered diet
(standard diet), 200g of sweetened condensed milk, 140g of sucrose (table
sugar), and 270mL of water per kilogram of diet, Group 5 received HSD
and 500 mg/kg/day of turmeric extract, Group 6 received HSD and 1000 mg/kg/day
of turmeric extract while Group 7 received HSD and 2mg/kg/day of the standard
drug for 28days. The HSD induced body weight gain and significantly increased
blood glucose levels in Group 4. However, body weights and blood glucose were
significantly reduced in treated Groups compared to Group 4. There was also a
significant (P˂0.05) increase in SOD, GSH and catalase in the groups treated compared
to Group 4. Furthermore the results showed significant (P<0.05) decrease in serum lipid profiles
concentrations (TG, TC, LDL and VLDL) in all treated Groups which increased
significantly relative to the HSD control Group, while HDL was
significantly increased in all treated
groups compared to Group 4. It was also observed from the result that the serum
insulin levels were significantly increased in all treated groups compared to
Group 4. Thus at the tested doses, turmeric attenuated the studied indicators
of metabolic syndrome suggesting that its use could be beneficial in the
management of obesity and related diseases associated with metabolic syndrome.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of contents vi
List of Tables xi
List of Figures xii
List of Plates xiv
Abstract xv
Chapter
1: INTRODUCTION
1.0 Background of Study 1
1.1 Aim of study 2
1.2 Objectives 2
1.3 Justification 2
Chapter 2: LITERATURE REVEIW
2.1 Overview of
Turmeric 4
2.2 Nutritional Value of Turmeric 5
2.3 Medicinal Uses of Turmeric 6
2.3.1 Anti-Inflammatory properties 6
2.3.2 Antioxidant properties 6
2.3.3 Hepatoprotective properties 6
2.3.4 Anticarcinogenic properties 7
2.3.5 Antidiabetic properties 10
2.3.6 Antimicrobial properties 10
2.3.7 Cardiovascular diseases 11
2.3.8 Gastrointestinal disorders 11
2.3.9 Dyspepsia and gastric ulcer 12
2.3.10 Neurological disorders 12
2.4 Metabolic syndrome 13
2.5 Obesity
and the Metabolic Syndrome 16
2.6 Impaired
Fasting Glucose 17
2.7 Dyslipidemia 17
2.8 Hypertension
19
2.9 Insulin
Resistance 19
2.10 Choice of A Suitable Extraction Solvent 21
2.11 Oxidative Stress Markers 21
2.11.1 Reduced glutathione (GSH) 21
2.11.2 Glutathione peroxidase (GPx) 22
2.11.3 Catalase 22
2.11.4 Superoxide dismutase (SOD) activity 22
2.11. 5
Thiobarbituric acid reactive substances (TBARS) 23
2.12 Blood
Lipid Profile 23
2.12.1 Cholesterol 24
2.12.2 Very low-density
lipoproteins (VLDL) 25
2.12.3 Low density
lipoprotein (LDL) 25
2.12.4 High density
lipoprotein (HDL) 25
2.12.5 Triacylglycerols 26
2.13 C-peptide 26
2.14 Hexokinase 27
2.15 Glycogen 27
Chapter 3: MATERIALS AND METHODS
3.1 Animals
28
3.2
Chemicals 28
3.3 Plant material collection and processing 28
3.4 Methanol Extract Preparation 28
3.5 Experimental design 29
3.6
Diets 29
3.7
Ethical Clearance/Approval 30
3.8
Blood Collection and Separation 30
3.9 Determination
of Relative Organ Weights 30
3.10 Histological Study 30
3.11 Determination of biochemical parameters 32
3.11.1 Determination of Serum Insulin 32
3.11.2 Biochemical Assay of Serum Glycogen 32
3.11.3 Biochemical assay of serum hexokinase activity 33
3.11.4 Biochemical Assay of serum C-peptide activity 34
3.11.5 Estimation of blood glucose 34
3.12 Determination of
Lipid Profile 34
3.12.1 Total Cholesterol concentration 35
3.12.2 Triacylglycerol concentration 35
3.12.3 High density lipoprotein
cholesterol concentration 35
3.12.4 Very low density lipoprotein cholesterol concentration 35
3.12.5 Low density lipoprotein cholesterol concentration 36
3.13 Assay of Superoxide Dismutase (SOD)
Activity 36
3.14 Assay of Catalase (CAT) Activity 36
3.15 Assay of Glutathione Peroxidase (GPx) Activity 37
3.16 Estimation of extent of lipid peroxidation
(Malondialdehyde)
Concentration 37
3.17 Assay of reduced Gluthathione (GSH)
Activity 38
3.18 Measurement of Lee Obesity Index 38
3.19 Statistical Analysis 38
Chapter
4: RESULTS AND DISCUSSION
4.1 Results 39 4.1.1 Liver
Histology 57
4.1.2 Pancreas Histology 59
4.2 Discussion 61
Chapter 5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 66
5.2 Recommendation 66
References 67
Appendices 76
LIST
OF TABLES
2.1: The
American Heart Association and the National Heart, Lung and Blood
Institute criteria for defining the
metabolic syndrome. 15
4.1: Body
Weight gain/loss of the experimental rat groups over the experimental
period 39
4.2: Body
Weight gain/loss of the experimental rat groups over the experimental
period 40
4.3: Difference in fasting blood glucose
concentrations at the beginning and
end of the experimental period. 55
LIST
OF FIGURES
2.1 Flow chart showing factors leading to the
metabolic syndrome (MetS). 14
4.
1 Effect of Methanol extract of C. Longa on Total Cholesterol Concentration
of the
rat groups 41
4.2 Effect of Methanol extract of C. Longa on High-density lipoproteins
Concentration of the rat groups 42
4.3 Effect of Methanol extract of C. Longa on Triacylglycerol Concentration of the
rat
groups 43
4.4 Effect of Methanol extract of C. Longa on Low-density lipoproteins
Concentration
of the rat groups 44
4.5 Effect
of Methanol extract of C. Longa on Very-low-density lipoprotein
Concentration of the rat
groups 45
4. 6 Glutathione
peroxidase (GPx ) concentration of the rat groups 46
4. 7 Reduced
Gluthathione (GSH) concentration of the rat groups 47
4. 8 Superoxide
dismutase (SOD) concentration of the rat groups 48
4.9 Catalase
(CAT) concentration of the rat groups 49
4.10 Thiobarbituric
Acid Reactive Substances (TBARS)
concentration of the
rat groups 50
4. 11: Serum
Insulin Concentration of the rat groups 51
4. 12: Glycogen Concentration of
the rat groups 52
4. 13: C-peptide Concentration of the rat groups 53
4. 14: Hexokinase Concentration of the Concentration rat groups 54
LIST
OF PLATES
2.1
Turmeric Plant 5
4.1 Photomicrograph
of the liver section of rats in group 1 (Normal Control Group)
Mag
x100. 57
4.2. Photomicrograph
of the liver section of rats in group 2, Mag x400. 57
4. 3.
Photomicrograph of the liver section of rats in group 3, Mag x100. 58
4.4. Photomicrograph
of the liver section of rats in group 4, Mag x100. 58
4. 5. Photomicrograph
of the liver section of rats in group 5, Mag x400. 58
4.6. Photomicrograph
of the liver section of rats in group 6, Mag x100. 58
4. 7. Photomicrograph
of the liver section of rats in group 7, Mag x100. 58
4.8. Photomicrograph
of the pancreas section of rats in group 1, Mag x400. 59
4. 9. Photomicrograph
of the pancreas section of rats in group 2, Mag x400. 59
4.10. Photomicrograph
of the pancreas section of rats in group 3, Mag x400. 60
4.11. Photomicrograph
of the pancreas section of rats in group 4, Mag x400. 60
4.12. Photomicrograph
of the pancreas section of rats in group 5, Mag x400. 60
4.13. Photomicrograph
of the pancreas section of rats in group 6, Mag x400. 60
4.14 Photomicrograph
of the pancreas section of rats in group 7, Mag x400. 60
CHAPTER 1
INTRODUCTION
1.0 BACKGROUND
OF STUDY
There has been a steady increase in the incidence of diseases associated with
metabolic syndrome also known as syndrome X, insulin resistance syndrome, or
dysmetabolic syndrome. Metabolic syndrome is the clustering of cardiometabolic
symptoms including central obesity, hypertension, insulin resistance, chronic
low-grade inflammation and dyslipideamia (Jaspinder, 2014).
Diabetes mellitus is a chronic metabolic disorder characterized by
hyperglycemia resulting from defect in insulin secretion, insulin action or
both. It is associated with high morbidity and mortality from long-term
micro-vascular and macro-vascular complications (Jeevangi et al., 2013).
Curcuma longa Linn is also known as turmeric. The
plant is a tropical perennial plant which belongs to the same family as ginger
(Zingiberaceae), native to India and Indonesia and is cultivated in many parts
of the world. It is otherwise
called the golden spice of life" and is a standout amongst the most
fundamental spices used throughout the world. Turmeric is the zest that gives
curry its yellow shading. It has been utilized in India for many years as a
zest and restorative herb. Turmeric is utilized in coloring industry to color
garments and textiles. All inclusive, the world production of turmeric is
between 10-15kg every year and out of these production figures, India
represents over 78% of the yearly production for turmeric. India is trailed by
China and Myanmar in Asia. Nigeria is the fourth biggest maker of turmeric with
about 3% of the worldwide yearly production.
The active component of turmeric, curcumin, has caught attention as a
potential treatment for diabetes and its complications primarily because it is
a relatively safe and inexpensive agent that reduces glycemia and
hyperlipidemia in rodent models of diabetes. (Zhang et al., 2013).
1.1 AIM OF STUDY
The aim of this study is to determine the possible
attenuating role of orally administered turmeric grown in the rainforest zone
of South-Eastern Nigeria on bio-indicators of metabolic syndrome in rats fed
high sucrose diet.
1.2 OBJECTIVES
The objectives
of this study were to:
1.
Determine
the effect of methanol extract of Curcuma
longa on the oxidative stress parameters: Superoxide dismutase (SOD),
glutathione peroxidase (GPx), glutathione reductase (GSH), catalase and
thiobarbituric acid reactive substances (TBARS) of high sucrose diet-induced
metabolic syndrome in Wistar rats.
2.
Investigate
the fasting blood glucose, Serum insulin, glycogen, C-peptide, hexokinase and
body weight in normal and high sucrose diet-induced metabolic syndrome in Wistar
rats.
3.
Determine
the effect of methanol extract of Curcuma
longa on the lipid profile (total cholesterol, high density lipoprotein
cholesterol, triacylglycerol, very low density lipoprotein, and low density
liopoprotein) concentrations of high sucrose diet-induced metabolic syndrome in
Wistar rats.
4.
Check
the Lee’s obesity index diet-induced metabolic syndrome in rats and the attenuating
effects of methanol extracts of Curcuma
longa on it.
5.
Examine
the effects of methanol extracts of Curcuma
longa on the histoology of the liver and pancreas of high sucrose
diet-induced metabolic syndrome in rats.
1.3 JUSTIFICATION
Prevalence of metabolic syndrome is rapidly increasing worldwide without
effective management regime. In addition, the currently
available drugs have number of adverse effects necessitating increased search
for indigenous plant – based remedy in line with the WHO recommendation sequel
to beneficial uses of medicinal plants in the treatment of diabetes mellitus, a
compound of metabolic syndrome. The reported availability of bioactive
compounds in turmeric world over warranted this study on turmeric grown in
South Eastern Nigeria.
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