ABSTRACT
The study investigated the nutrient composition and effect of aqueous extracts of ginger (Zingiber officinale) and lemongrass (Cymbopogon citratus) on the blood glucose and lipid profile of alloxan-induced hyperglycemic rats. The proximate, mineral and vitamin content of Zingiber officinale and Cymbopogon citratus extracts were investigated. Albino Wistar rats, 100-150g weight, fed on standard animal feed and water ad libitum were divided into six (6) groups of six (6) animals each. Group 1: Non-diabetic control rats, Group 2: Non-treated diabetic control rats, Group 3: Glibenclamide (anti-diabetic drug) treated diabetic rats, Group 4: Ginger-treated diabetic rats, Group 5: Lemongrass-treated diabetic rats, Group 6: Ginger-lemongrass-treated diabetic rats. Group 2, 3, 4, 5 and 6 were induced diabetes by intraperitoneal injection of 160mg/b/w of alloxan. Rats having blood glucose of 150 mg on day 3 (72 hours after alloxan injection) were considered diabetic and selected for the experiment. Blood samples was drawn from the tail of the rats and used to estimate the fasting blood sugar level day at 1, 7, 14 and 21 using a glucometer. On day 21, the animals were sacrificed by cervical dislocation, blood was collected by cardiac puncture and serum separated for lipid estimation. Data was statistically analyzed by Duncan’s post hoc and ANOVA. The proximate analysis showed that minerals and vitamin composition of the extracts (Zingiber officinale and Cymbopogon citratus) are good sources of nutrients with great potentials. The result obtained from the experiment showed that administration of aqueous ginger and lemongrass extracts significantly (p< 0.05) restored blood glucose level to normal when compared to the normal group. The group treated with ginger extract (400 mg/kg dose) showed a reduction (from 416.83±5.76 to 79.20±14) while the group treated with lemongrass extract of 400 mg/kg dose showed a reduction of blood glucose from 435.16 ± 41.35 to 73.00±13.60. Lemongrass and ginger extracts of 400 mg/kg dose for 21 days showed a reduction in the level of TC, TG and LDL-C, but elevated level of HDL concentration. Ginger and lemongrass extract exhibited hypocholesterolemic effect on the alloxan-induced diabetic rats. The weights of the rats after induction showed that the group treated with ginger extract, lemongrass extract, combined ginger and lemongrass extract and glibeanclamide (standard drug) significantly regained their weight by day 14. Weight increase progressed to day 21. This might be as a result of restoration of normal glucose metabolism. Findings in this study therefore showed that the administration of aqueous extracts of ginger (Zingiber officinale) and lemongrass (Cymbopogon citratus) has significant ameliorative effect on alloxan-induced hyperglycaemic and hyperlipidemic diabetic rats and this may be of immense benefits in the management of diabetes and its associated complications.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of Contents vi
List of Tables xi
List of Plates xii
Abstract xiii
CHAPTER
1: INTRODUCTION 1
1.1 Background of the Study 1
1.2 Statement
of the Problem 4
1.3 Objectives of the Study 5
1.3.1 General objective of the study 5
1.3.2 Specific
objectives of the study 5
1.4 Significance
of the Study 6
CHAPTER 2: LITERATURE REVIEW 7
2.1 An Overview of Diabetes Mellitus (DM) 7
2.1.1 Types
of diabetes mellitus 7
2.1.1.1 Type 1 diabetes mellitus 7
2.1.1.2 Type 2 diabetes mellitus 8
2.1.1.3 Gestational diabetes mellitus (GDM) 9
2.1.2 Signs
and symptoms of diabetes 10
2.1.3 Diagnosis
of diabetes mellitus 10
2.2 Complications
of DM 12
2.2.1 Acute
complications of diabetes 12
2.2.1.1 Diabetic ketoacidosis (DKA) 12
2.2.1.2 Hypoglycaemia 14
2.2.2 Chronic complications of diabetes 16
2.2.2.1 Microvascular (microangiopathic) disease 17
2.2.2.2 Macrovascular disease 20
2.3 Management of Diabetes 22
2.3.1 Lifestyle 23
2.3.2 Medications 23
2.3.3 Surgery 24
2.4 Taxonomy
of Zingiber officinale 25
2.4.1 Botanical
description of ginger (Zingiber
officinale) 25
2.4.2 Scientific
classification of ginger 26
2.4.3 Chemical and nutrient composition of ginger 26
2.4.4 General
uses of ginger 27
2.4.5 Health benefits of ginger and its constituents 28
2.5 Taxonomy of Cymbopogon citratus 37
2.5.1 Botanical description of lemongrass (Cymbopogon citratus) 37
2.5.2 Scientific
classification of lemongrass 38
2.5.3 Nutritional
value of lemongrass 38
2.5.4 Uses
of lemongrass 38
2.5.5 Pharmacological
benefits of lemongrass 40
CHAPTER 3: MATERIALS AND METHODS 42
3.1 Experimental Materials 42
3.2 Sample
Preparation, Packaging and Storage 42
3.2.1 Preparation
of ginger extract 42
3.2.2 Preparation
of lemongrass extract 44
3.3 Chemical
Analysis 45
3.3.1 Determination
of proximate composition of ginger and lemongrass 45
3.3.1.1 Determination of moisture content 45
3.3.1.2 Determination
of ash content 46
3.3.1.3 Determination
of crude fibre content 46
3.3.1.4 Determination of
protein content 47
3.3.1.5 Determination
of fat content 48
3.3.1.6 Determination of
carbohydrate content 48
3.3.2 Determination
of minerals content of samples 49
3.3.2.1 Determination phosphorus content 49
3.3.2.2 Determination of calcium content 50
3.3.2.3 Determination of zinc content 51
3.3.2.4 Determination of iron content 52
3.3.3 Determination
of vitamins content of samples 52
3.3.3.1 Determination of vitamin A content 53
3.3.3.2 Determination of thiamin content 54
3.3.3.3 Determination of riboflavin content 55
3.3.3.4 Determination of niacin
content 56
3.3.3.5 Determination of vitamin C content 57
3.4 Animal
Ethics 58
3.5 Animals
Grouping and Experimental Design 58
3.6 Animals
and Housing 59
3.7 Induction of Diabetes in Rats 60
3.8 Blood Glucose Determination 60
3.9 Determination of Body Weight 61
3.10 Relative
Organ Weights Determination 61
3.11 Blood Sample Collection and Preparation 61
3.12 Biochemical Analysis 63
3.12.1 Lipid profile determination 63
3.12.1.1 Serum total cholesterol
determination 63
3.12.1.2 Serum triacylglycerol
concentration determination 63
3.12.1.3 Serum high density
lipoprotein-cholesterol concentration determination 64
3.12.2 Heamatological determination 64
3.13 Data Analysis 64
3.14 Statistical Analysis 64
CHAPTER 4: RESULT
AND DISCUSSION 65
4.1 Proximate
Composition of Samples 65
4.2 Mineral
Composition of the Samples 69
4.3 Vitamin Composition of the Samples 75
4.4 Acute Effect of the Extracts on Blood
Glucose of Alloxan-Induced
Hyperglycaemic
Rats 79
4.5 Sub-acute Effect of Ginger and Lemongrass
Extracts on Blood Glucose
of
Alloxan-Induced Hyperglycaemic Rats 81
4.6 Lipid Profile Parameters of the
Experimental Animals 85
4.7 Effect of the Extracts on Body Weights of
Alloxan-Induced
Hyperglycaemic
Rats 88
4.8 Effect of the Extracts on Relative Organ
Weights of Alloxan-Induced
Hyperglycaemic
Rats 90
4.9 Effect of the Extracts on the
Heamatological Parameters of
Alloxan-Induced
Hyperglycaemic Rats 92
CHAPTER
5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 95
5.2 Recommendations
95
References 97
Appendix 119
LIST
OF TABLES
|
TABLE
|
|
PAGE
|
|
2.1
|
Criteria
for Diagnosis of Diabetes and Pre-diabetes
|
11
|
|
4.1
|
Energy and Macronutrient Composition of Zingiber officinale and Cymbopogon citratus Extracts
|
68
|
|
4.2
|
Mineral Composition of Zingiber officinale and Cymbopogon citratus Extracts
|
74
|
|
4.3
|
Vitamin
Composition of Zingiber officinale
and Cymbopogon citratus Extracts
|
78
|
|
4.4
|
Acute Effect of Aqueous Ginger and
Lemongrass Extracts on Blood Glucose Level of Alloxan-induced Hyperglycaemic
Rats
|
80
|
|
4.5
|
Sub-acute
Effect of Aqueous Ginger and Lemongrass Extracts on Alloxan-induced
Hyperglycaemic Rats
|
84
|
|
4.6
|
Effect of Aqueous Ginger and Lemongrass
Extracts on the Lipid Profile Parameters of Alloxan-induced Hyperglycaemic
Rats
|
87
|
|
4.7
|
Effect of Aqueous Ginger and Lemongrass
Extracts on the Body Weight of Alloxan-induced Hyperglycaemic Rats
|
89
|
|
4.8
|
Effect of Aqueous Ginger and Lemongrass
Extracts on the Organ Weight of Alloxan-induced Hyperglycaemic Rat
|
91
|
|
4.9
|
Effect of Aqueous Ginger and Lemongrass
Extracts on the Heamatological Parameters of Alloxan-induced Hyperglycaemic
Rats
|
94
|
LIST OF PLATES
|
PLATE
|
|
PAGE
|
|
1
|
Ginger Herb
|
26
|
|
2
|
Fresh Ginger Root
|
26
|
|
3
|
Lemongrass Leaves
|
37
|
|
1
|
Peeled Zingiber
officinale (Ginger) Roots
|
43
|
|
2
|
Sliced Zingiber
officinale (Ginger) for Drying
|
43
|
|
3
|
Ground Zingiber officinale (Ginger)
|
43
|
|
4
|
Lemongrass
Leaves Under Drying
|
44
|
|
5
|
Ground
Lemongrass
|
44
|
|
6
|
Sacrificed Experimental Animals
|
62
|
|
7
|
Researcher
Collecting Blood Sample from the Experimental Rats
|
62
|
|
8
|
Sample Bottles with the Collected Blood Sample
|
63
|
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Diabetes
mellitus (DM) is a chronic non-communicable (NCDs) disease which occurs when
the pancreas fails to produce adequate insulin (a hormone that regulates blood
sugar) or when the body is unable to efficiently use the insulin it produces
(WHO, 2010).
Diabetes
is characterized by numerous defects in its pathophysiology (Dheer and
Bhatnagar, 2010) and abnormalities in carbohydrate, protein and fat metabolism
(Anoja et al., 2013). It is obvious
that this disease results to hyperglycemia (abnormal high blood glucose
level) and other numerous complications
such as hyperlipidemia (abnormal increased concentration of lipid in the
blood), hypertension (abnormally high pressure in the blood vessel),
atherosclerosis (hardening and narrowing of the arteries caused by buildup of
plagues), retinopathy (persistent impairment of the retina of the eye
especially in people with diabetes), neuropathy (damage or malfunctioning of
the nerves in the peripheral nervous system) and nephropathy (damage to the
kidney) (Anfenan, 2014).
Medicinal
plants that show hypolipidaemic, hypoglycaemic and antioxidant activities may
have possible roles in diabetes management. These plants are therefore becoming
more widespread because of their potential efficacy, minimal or no side-effects
and synergistic actions (Panda et al.,
2013). Some of the plants usually used in African traditional medicine diabetes
mellitus management are Zingiber officinale (ginger), Allium sativum
(garlic), and Cymbopogon citratus (lemongrass). These three spices have
been used globally as culinary spices since ancient times (Eidi et al., 2006). Each of the species is also extensively used in the preparation of
medicines due to its reported healing properties against many ailments (Amagase,
2006; Antonious et al., 2006).
Tropical
grass such as Cymbopogon citratus (lemongrass) grows well in warm and
humid environments. It is a tall grassy-like plant with broad lemon-scented
leaves and thick stalks which grows in clusters. It is originally grown in the southeast
and south regions of Australia and Asia, however because of its widespread popularity,
is now grown in some other parts of the world (Ewenighi et al., 2015).
Zingiber officinale
(ginger) is a well-known herbaceous species which is consumed in most areas of
the world. Antioxidants in ginger include shogaols, gingerols, and some related
phenolic ketone derivatives. The dried extract of ginger comprises of sesquiterpenes
and monoterpenes. Ginger extract has antioxidative properties and scavenges hydroxyl
and superoxide anion radicals (Gao et al., 1993; Krishnakanta and
Lokesh, 1993). The medicinal properties reported for ginger include anti-arthritic
(Bliddal et al., 2000), anti-migraine (Cady et al., 2005),
anti-thrombotic (Thomson et al., 2002), hypolipidemic (Fuhrman et al.,
2002; Bhandari et al., 2005), anti-inflammatory (Thomson et al.,
2002; Penna et al., 2003), and anti-nausea properties (Portnoi et al.,
2003).
Alloxan, also known as alloxan monohydrate, refers to
the organic
compound with the formula C4H4N2O5.
Alloxan has been noted to exert its diabetogenic action when administered
parenterally, i.e., intravenously, intraperitoneally or subcutaneously.
Furthermore, to effectively induce diabetes with the right dose, the animal
species, nutritional status and route of administration must be considered
appropriately (Federiuk et al.,
2004). Moreover, varying glucose uptake
mechanisms in rodents and humans may be the reason alloxan is believed to be
non-toxic to human beta cells, even at high doses (Tyrberg et al., 2001).
Alloxan is a toxic glucose analogue, capable of inducing
insulin-dependent diabetes mellitus in animals with related features to type 1 diabetes
in humans. It does so by selectively destroying insulin-producing cells in the
pancreas (beta cells) when administered to rodents and other experimental
animals, because it preferentially stores in beta cells via uptake by glucose
transporter-2 (GLUT2) (Szkudelski,
2001).
Alloxan due to
its selectively killing of the insulin-producing
beta-cells found in the pancreas, it is used
to induce diabetes in laboratory animals
(Danilova et al., 2015; Loreto and Elina, 2009). This occurs most
likely because of selective uptake of the compound due to its structural
similarity to glucose
as well as the beta-cell's highly efficient uptake mechanism. Alloxan’s
structure resembles that of glucose, which makes it possible to be absorbed by
the pancreas. Once inside the target organ, it destroys insulin-producing
β-cells and produces a disease similar to type 1 diabetes in humans. In
addition, alloxan has a high affinity to sulfhydryl (SH)-containing cellular
compounds and, as a result, reduces glutathione content. Furthermore, alloxan
inhibits glucokinase, an SH-containing protein essential for insulin secretion
induced by glucose (Szkudelski, 2001).
The use of
experimental animal models is one of the best approaches for the understanding
of pathophysiology of any disease in order to design and develop drugs for the
treatment of such diseases (Kruger et al.,
2012). In spite of the significant progress recorded in controlling and
monitoring of diabetes using conventional drugs and management strategies, its
complications still remains a key medical problem. Most synthetic oral hypoglycaemic
drugs available for the disease management has been reported to have serious
side-effects, cannot be used during pregnancy, and also they are expensive
(Kumari et al., 2013). As a result, many
people have resorted to traditional herbal medicines to prevent and treat
diabetes worldwide (Broadhurst et al.,
2000; Shetti et al., 2012). Therefore, there is a growing need to seek for more efficient
antidiabetic agents with little or no side-effects. Hence, this experimental
study was intended to determine and compare the effect of ginger and lemongrass
extracts on blood glucose level and serum lipid profile in normal and
alloxan-induced hyperglyceamic rats.
1.2 STATEMENT OF THE PROBLEM
Diabetes
mellitus (DM) is a chronic non-communcable disease widely prevalent in all
parts of the world. It is among the top 10 causes of death in adults, and was
estimated to have caused four million deaths globally in 2017 (International
Diabetes Federation (IDF), 2017). The
World Health Organization estimates that over three hundred (300) million
people worldwide will have diabetes mellitus by the year 2025 (WHO, 2006).
The
burden of type 2 diabetes mellitus, which is characterized by insulin
resistance and hyperglycemia, is on the increase worldwide (Razieh et al.,
2007). Diabetes mellitus is known to be a significant public health challenge
in developing countries (Djrolo et al.,
1998). Diabetes is the leading cause of cardioascular diseases. Individuals with
diabetes are two times prone to developing cardiovascular problems compared to those
without diabetes (WHO, 2006).
The
present mode of management which is centered on synthetic medicines is costly
and causes metabolic and genetic alterations. However, safe method of treatment
is required to control the disease development and progression (Arshad et al., 2014). There is therefore,
the increasing search for new anti-diabetic agents, preferably herbal medicinal
product, to protect people from this silent killer metabolic disease without
creating health hazard. Reliance on herbs as medicine by individuals, doctors
and nurses, for the management of diabetes mellitus is still much practiced by large
proportion of the world’s population because they are readily available and
affordable with reduced toxicity, thus, the need to investigate the effect of
aqueous extracts of Cymbopogo citratus and Zingiber officinale on
blood glucose and lipid profile levels. The
above facts underscore the reason for the present study.
1.3 OBJECTIVES OF THE STUDY
1.3.1 General objective of the study
The
general objective of this present study is to explore the nutrient composition
and effect of aqueous extracts of ginger (Zingiber
officinale) and lemongrass (Cymbopogon
citratus) on the blood glucose level and lipid profile of alloxan-induced
hyperglycemic rats.
1.3.2 Specific objectives of the study
The
specific objectives of the study is to determine the:
1. proximate
composition of ginger (Zingiber officinale)
and lemongrass (Cymbopogon citratus)
extract.
2. mineral
and vitamin composition of ginger (Zingiber
officinale) and lemongrass (Cymbopogon
citratus) extracts.
3. effect
of ginger (Zingiber officinale)
and lemongrass (Cymbopogon
citratus) extracts on blood glucose level of alloxan-induced hyperglycemic
rats respectively.
4. effect
of ginger (Zingiber officinale)
and lemongrass (Cymbopogon
citratus) extracts on the lipid profile of alloxan-induced hyperglycemic
rats respectively.
5. effect
of ginger (Zingiber officinale)
and lemongrass (Cymbopogon
citratus) extracts on body weight and relative organ weight of alloxan-induced
hyperglycemic rats.
6. effect
of ginger (Zingiber officinale)
and lemongrass (Cymbopogon
citratus) extracts on the hematological parameters of alloxan-induced
hyperglycemic rats.
1.4 SIGNIFICANCE OF THE STUDY
The use of herbal therapies is on the
increase. The result from this study would provide scientific evidence on the
safety and the use of ginger and lemongrass extract in the prevention and
management of diabetes mellitus. The study will reveal the potential properties
of locally available Nigerian plant foods in the management of chronic
non-communicable diseases (NCD). The result of this work will help reduce
economic burden of diabetes as the plants are cheap and readily available. It
will also serve as a guide for clinicians and other health care providers on
better approaches in the management of diabetes mellitus as well as reduce and
avert diabetic complications. The study will also make the general public to be
aware of diabetes management using low cost medicinal herbs.
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