Protective Role of Aqueous Leaf Extract of Vernonia Amygdalina Del. (Asteraceae) and Ocimum Gratissimum Linn (Lamiaceae) in Cyclophosphamide Induced Urotoxicity and Myelosuppression

ABSTRACT 

Cyclophosphamide (CP) is one of the most potent and widely used alkylating anticancer agents. Urotoxicity and myelosuppression is known as the most prevailing dose-limiting toxicity associated with CP. In the present study, the protective potential of Vernonia amygdalina and Ocimum gratissimum aqueous leaf extracts in CP-induced urotoxicity and myelosupression were evaluated using biochemical and histopathological approaches. Sodium -2-macarptoethane sulfonate (MESNA) was used as a positive control. Forty (40) male Sprague-Dawley outbred albino rats weighing between 130 g – 200 g were randomly separated into eight different groups (n=5). Rats in group 1 received only normal saline orally for gavage for ten consecutive days. Animals in group two were injected with CP only on the tenth day intraperitoneally (i.p) at 200 mg/kg body weight. Animals in group 3 were given MESNA (67 mg/kg) and CP (200 mg/kg) i.p on the tenth day at 5 minutes interval. Rats in groups 4 and 5 received two different doses of O. gratissimum orally by gavage at 250 mg/kg and 500 mg/kg respectively for ten consecutive days before administering CP (200 mg/kg) on the tenth day. Rats in group 6 and 7 received different doses of V. amygdalina orally by gavage at 250 mg/kg and 500 mg/kg respectively for ten consecutive days before administering CP (200 mg/kg) on the tenth day. Rats in group (8) received combination of V. amygdalina and O. gratissimum at a dose of 250 mg/kg each for ten consecutive before administering CP (200 mg/kg) on the tenth day. Results showed that the extract of V. amygdalina protected significantly (P < 0.05) the urothelium and the myeloid system as observed in the biochemical and hematological parameters evaluated. This protection is comparable to MESNA, but MESNA protection was not adequate to prevent myelosupression as observed with V. amygdalina. O. gratissimum did not show significant protection of the urothelium and myeloid system. The protective effects of V. amygdalina was further evident through decreased histopathological alteration of the urinary bladder, kidney and liver tissues unlike the CP and O. gratissimum treated groups. The result of the present study revealed that aqueous leaf extract of V. amygdalina has the potential to prevent urotoxicity and myelosuppression induced by CP and thus can be used as therapeutic adjuvant in the management of CP and other oxazaphosphorine toxicities.

TABLE OF CONTENT

Title page i

Certification page ii

Dedication iii

Acknowledgement iv

Abstract v

Table of content vi

Tables and figures vii

CHAPTER ONE 1

1.0 Introduction 1

1.1 Pharmacology of cyclophosphamide 2

1.1.1 Pharmacodynamics/mechanism of action of cyclophosphamide 3

1.1.2 Pharmacokinetic profile of cyclophosphamide 4

1.1.3 Pharmacokinetic variability 9

1.1.4 Therapeutic uses 12

1.1.5 Drug Interaction 14

1.2.0 Mechanism of cyclophosphamide toxicity 15

1.2.1 Outcomes of cyclophosphamide toxicity 16

1.2.2 Pathophysiology and consequences of urotoxic effects of cyclophosphamide 17

1.2.3 Pathophysiology and consequences of myelosuppressive effects of cyclophosphamide 20

1.3 Chemoprevention and amelioration of cyclophosphamide -induced toxicities 24

1.3.1 The Role of MESNA (sodium 2-mercaptoethane sulfonate) in amelioration of cyclophosphamide -induced toxicities 27

1.3.2 Mechanism of action of MESNA 27

1.3.3 Other potential uroprotective agents 29

1.3.4. Medicinal plants used in preventing or ameliorating cyclophosphamide-induced toxicity 29

1.4. Botanical profile of Vernonia amygdalina Del 39

1.4.1 Taxonomy 39

1.4.2 Description 40

1.4.3 Geographical Distribution 40

1.4.4 Ethnomedicinal Uses 40

1.4.5 Documented research findings on V. amygdalina 40

1.5. Botanical profile of Ocimum gratissimum Linn. 45

1.5.1 Taxonomy 45

1.5.2 Description 46

1.5.3 Geographical Distribution 46

1.5.4. Ethnomedicinal uses. 46

1.5.5 Documented research findings on O. gratissimum. 47

1.6 Aim of the Study 48

CHAPTER TWO 49

2.0 Materials and Methods 49

2.1 Animals 49

2.2 Drugs and Chemicals 49

2.3 Preparation of extracts 50

2.4 Induction of cyclophosphamide -induced toxicity 50

2.5 Blood sample collection 51

2.6 Haematological test 52

2.7 Biochemical analysis 52

2.7.1 Analysis of glutathione (GSH) 52

2.7.2 Superoxide dismutase analysis 52

2.7.3 Catalase assay 53

2.7.4 Malondialdehyde (MDA) Assay 53

2.8 Histopathological Examination 53

2.9 Statistical Analysis 53

CHAPTER THREE 54

3.0 Results 54

3.1. Effects of extracts on cyclophosphamide-induced urotoxicity 54

3.1.1 Effects of extract on glutathione 54

3.1.2 Effects of extracts on Superoxide dismutase analysis activity. 54

3.1.3 Effects on catalase activity 54

3.1.4 Effects of extracts lipid peroxidation (LPO) 55

3.2. Effects of extract on cyclophosphamide -induced myelosupression. 55

3.2.1. Effect on total red blood cell count, total Leucocyte count, absolute neutrophil and absolute lymphocyte counts. 55

3.2.2 Effect on platelet count, absolute basophils and eosinophils 56

3.3 Effect on histopathology of tissues 60

CHAPTER 4 66

4.0 Discussion 66

4.1 Conclusion 71

References 72