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Cardiotoxicity has become a major challenge for cancer patients undergoing chemotherapy.  Examples of potentially cardiotoxic anticancer agents are 5-fluorouracil and anthracyclines.  The leaves of Pterocarpus santalinoides have been shown to possess among other pharmacological properties, the ability to lower serum levels of low density lipoprotein cholesterol (LDL-C) which suggests a cardio protective potential.  This study was aimed at experimenting the cardioprotective potential of the ethanol leaf extract against cardiotoxicity side effect of 5-fluorouracil in wistar rats. The study was done in two phases. 36 albino rats were employed for the first phase of the study, they were separated into 6 groups (groups 1, 2, 3, 4, 5 and 6) of 6 animals which received (distilled water, distilled water, 25 mg/kg Aspirin, 34.54 mg/kg crude extract, 69.28 mg/kg crude extract and 103.92 mg/kg crude extract for groups 1, 2, 3, 4, 5 and 6 respectively) orally for a period of 14 days. On the 15th day, groups 2, 3, 4, 5, and 6 were given 5-fluorouracil (150 mg/kg) via intra-peritoneal route to induce cardiotoxicity.  After a period of 24 hours, the animals were sacrificed, the sera were analyzed for troponin T, CK-MB, Lipid profile, the whole blood samples were subjected to haematology while the hearts were subjected to histopathological scrutiny, the result obtained revealed significant (p<0.05) increase in HDL-C and decrease in LDL-C, Troponin T and CK-MB across groups compared to positive control which indicates cardioprotective potential, hence the second phase was conducted. In the second phase, the crude extract was fractionated into n-butanol, ethyl acetate and chloroform fractions, 36 albino wistar rats were also used for the study.  They were also separated into 6 groups of 6 animals each. The animals were equally given treatments (distilled water, distilled water, 25 mg/kg Aspirin, 69.28 mg/kg n-butanol fraction, 69.28 mg/kg ethyl acetate fraction and 69.28 mg/kg chloroform fraction for groups 1, 2, 3, 4, 5 and 6 respectively) orally for 14 days. On the 15th day, groups 2, 3, 4, 5 and 6 were given 5-FU (150 mg/kg) via intraperitoneal route to induce cardiotoxicity. The animals were sacrificed after 24 hours, and the sera analyzed for troponin T level, CK-MB activity; lipid profile; urea, creatinine and electrolytes concentrations; ALP, AST and ALT activity; malondialdehyde concentration, catalase, glutathione peroxidase, superoxide dismutase activity; the whole blood samples were haematologically analyzed and the heart, kidney and liver tissues were histologically studied. Result revealed significant decrease (p<0.05) in TnT, CK-MB, LDL-C, TG, WBC, platelets, ALP, AST, ALT, urea, creatinine, Na+, K+, Cl-, HCO-3 and significant (p<0.05) increase in HDL-C, RBC, Ca2+, catalase, SOD and GSPx activity across groups as compared to the positive control. Histopathological results revealed that the low and medium dose of crude extract and chloroform fraction yielded more effective protection from cardiotoxicity more than the other doses and fractions.  The crude ethanol extract of P. santalinoides and its fractions conferred on the albino rats appreciable protection against 5-FU induced cardiotoxicity with the medium dose and chloroform fraction producing the overall highest cardioprotective effects.


Title Page                                                                                                                    i

Declaration                                                                                                                  ii

Certification                                                                                                                iii

Dedication                                                                                                                  iv

Acknowledgements                                                                                                    v

Table of Contents                                                                                                       vi

List of Tables                                                                                                              xii

List of Figures                                                                                                             xiii

List of Plates                                                                                                               xii

List of Appendixes                                                                                                     xv

List of Abbreviations                                                                                                  xvii

Abstract                                                                                                                      xix


1.1       Background of the Study                                                                               1

1.2       Pterocarpus santalinoides (PS)                                                                       7

1.3       Scope of the Study                                                                                         10

1.4       Statement of Problem                                                                                     11

1.5       Justification of the Study                                                                               12

1.6       Relevance of the Study                                                                                  13

1.7       Aim of the Study                                                                                            14

1.8       Objectives of the Study                                                                                  14


2.1       Phytochemical and Proximate Composition of Pterocarpus santalinoides   15

2.1.1    Phytochemistry of Pterocarpus santalinoides                                                            15

2.1.2    Proximate composition of Pterocarpus santalinoides                                                16

2.2       Pharmacological Activities of Pterocarpus santalinoides                              17

2.2.1    Analgesic activity                                                                                           17

2.2.2    Insecticidal activity                                                                                         17

2.2.3    Antitrypanosomal activity                                                                              19

2.2.4    Haematological effects                                                                                   19

2.2.5    Hypolipidemic activity                                                                                   19

2.2,6    Anti-cancer activity                                                                                        20

2.2.7    Antimicrobial activity                                                                                     21

2.2.8    Anti-diarrhoeal and antispasmodic activity                                                    22

2.3       Cardioprotective Effect of Aspirin                                                                 24

2.4       Anti-Cancer agents and their Cardiotoxicity Potential                                  25

2.4.1    5-Fluorouracil and other antimetabolites                                                        25

2.4.2    Trastuzumab (Herceptin)                                                                                27

2.4.3    Anthracyclines                                                                                                28

2.4.4    Taxanes                                                                                                           30

2.4.5    Interleukin-2 (IL-2) therapy                                                                            31

2.4.6    Tyrosine kinase inhibitors (TKIs)                                                                    31

2.4.7    Checkpoint inhibitors  immune therapy                                                          32

2.4.8    Angiogenesis inhibitors                                                                                   33

2.4.9    Radiation therapy                                                                                           34

2.5       Biomarkers of Cardiotoxicity                                                                         35

2.5.1    Cardiac function status                                                                                   35 Troponin                                                                                                          35 Creatine kinase (EC                                                                           36 Lactate dehydrogenase (EC                                                                        37 Natriuretic peptide                                                                                          38

2.5.2    Peripheral blood mononuclear cell gene expression profile                            40

2.5.3    Lipid profile (cardiovascular risk factor assessment)                                      41 Cholesterol                                                                                                      41 Triglycerides                                                                                                   43

2.5.4    Liver function status                                                                                       43 Alkaline Phosphatase (ALP) (EC                                                      44 Aminotransferases: ALT (EC and AST (EC                        45

2.5.5    Oxidative stress status                                                                                                47 Malondialdehyde (MDA)                                                                               47 Catalase (EC                                                                                    48 Superoxide dismutase (EC                                                              50 Glutathione peroxidase (EC.                                                                        51

2.5.6    Haematological indices                                                                                   52 Red blood cell (erythrocytes) count and haemoglobin (Hb)                          54 White blood cell (WBC) count                                                                      56 Platelet count                                                                                                  56

2.5.7    Kidney function status                                                                                   57 Serum potassium                                                                                             57 Serum sodium                                                                                                 59 Serum bicarbonate                                                                                          60 Serum creatinine                                                                                             61 Serum urea                                                                                                      62


3.1       Materials                                                                                                         64

3.1.1    Chemicals and reagents                                                                                  64

3.1.2    Equipment                                                                                                       64

3.1.3    Research hypothesis                                                                                        65

3.2       Methods                                                                                                          65

3.2.1    Plant leaf collection, identification and extraction of

            the crude ethanol extract                                                                                65

3.2.2    Extract fractionation by partitioning                                                              66

3.2.3    Determination of median lethal dose (LD50) for the crude ethanol

extract                                                                                                             66


3.2.4    Phytochemical screening                                                                                 68 Test for alkaloids                                                                                            68 Test for saponins                                                                                             68 Test for tannins                                                                                               68 Test for flavonoids                                                                                          69 Test for cardiac glycosides                                                                             69 Test for anthraquinones                                                                                  69

3.2.5    Experimental design                                                                                       70

3.2.6    Experimental animals treatment                                                                      71

3.2.7    Animal sacrifice and preparation of sera for phase one studies                      72

3.2.8    Animal sacrifice and preparation of sera for phase two studies                     73

3.3       Biochemical Analysis                                                                                      75

3.3.1    Estimation of serum troponin-T concentration                                               75

3.3.2    Estimation of CK-MB concentration                                                             76

3.3.3    Estimation of alkaline phosphatase activity                                                    78

3.3.4    Estimation of serum superoxide dismutase activity                                       79

3.3.5    Estimation of serum glutathione peroxidase activity                                      80

3.3.6    Estimation of serum catalase activity                                                             82

3.3.7    Estimation of serum malondialdehyde (MDA) level                                      83

3.3.8    Estimation of total serum cholesterol                                                             84

3.3.9    Estimation of serum high density lipoprotein cholesterol                               85

3.3.10  Estimation of serum level of total triglyceride                                               86

3.3.11  Estimation of haematological indices                                                             88

3.3.12  Estimation of serum electrolytes level                                                            89

3.3.13  Determination of aspartate amino transferase (AST) activity in serum          90

3.3.14  Estimation of alanine aminotransferase (ALT/SGPT) activity                       91

3.3.15  Estimation of urea (BUN)                                                                              92

3.3.16  Estimation of serum creatinine concentration                                                 92

3.3.17  Histological procedures                                                                                  94

3.3.18  Statistical analysis                                                                                           94


4.1                   Results                                                                                                96

4.1.1                Phytochemical screening                                                                     96

4.1.2                Phase one results                                                                                 98             Effect of CELEPS on serum troponin-T concentration and

CK-MB activity  in albino rats                                                           98             Effect of CELEPS on serum lipid profile in albino rats                     99             Effect of CELEPS on haematological parameters in albino

rats                                                                                                      102             Effect of CELEPS on the histopathology of the heart tissues           104

4.1.3                Phase two results                                                                                112             The effect of FELEPS on cardiovascular indices in albino rats         112          The effect of FELEPS on serum troponin T concentration in

albino rats                                                                                            112          The effect of FELEPS on serum CK-MB activity in albino

rats                                                                                                      114             The effect of FELEPS on serum lipid profile in albino rats               116             The effect of FELEPS on liver function status in albino rats             120          The effect of FELEPS on serum ALP, AST and ALT activity         120             The effect of FELEPS on the oxidative stress status in albino

 rats                                                                                                     122          The effect of FELEPS on the serum MDA concentration in

albino rats                                                                                            122          The effect of FELEPS on serum levels of oxidative enzymes;

Catalase, Superoxide Dismutase and Glutathione Peroxidase in

Albino Rats                                                                                         124             The effect of FELEPS on the haematological Indices in albino       

Rats                                                                                                     125             The effect of FELEPS on kidney function status in albino rats         132          The effect of FELEPS on the serum electrolytes concentration                       in albino rats                                                                                     132          The effect of FELEPS on the serum urea and creatinine                  

concentration in albino rats                                                                 135             Histopathological results                                                                     137

4.2                   Discussion                                                                                           155


5.1                   Summary                                                                                             180

5.2                   Conclusion                                                                                          182

5.3                   Recommendation                                                                                183

References                                                                                          184

Appendix                                                                                            220     

                                                LIST OF TABLES

3.1       Dose Regimen for Phase One Studies (Treatment with Crude Ethanol

            Extract)                                                                                                           70

3.2       Dose Regimen for Phase Two (Treatment with Fractionated Portions of the

Crude ethanol extract)                                                                                                72


3.3       Sample and Blank Regimen for Determination of SOD activity                   79


3.4       Reagent Blank, Standard, Controls and Samples Regimen for Estimation

             of Serum Creatinine Concentration                                                               92

4.1       Result of Phytochemical Screening                                                                95


4.2       Effect of CELEPS on Serum of Troponin Concentration and

CK-MB Activity in Albino rats                                                                      97


4.3       Effect of CELEPS on Serum Lipid Profile in Albino Rats                            99       


4.4       Effect of CELEPS on Haematological Parameters in Albino Rats                101


4.5       The Effect of FELEPS on Serum Lipid Profile in Albino Rats                     116

4.6       The Effect of FELEPS on Lipid Profile Assessment (cardiovascular risk                 index)                                                                                                              117

4.7       The Effect of FELEPS on Serum ALP, ALT and AST Activities                                        in Albino Rats                                                                                                     119


4.8       The Effect of FELEPS on the Serum MDA Concentration in Albino Rats  121


4.9       The Effect of FELEPS on Serum Activities of Oxidative Enzymes;                        Catalase, Superoxide Dismutase and Glutathione Peroxidase in Albino                       Rats                                                                                                                 123

4.10A  The Effect of FELEPS on the Haematological Indices in Albino Rats         127

4.10B  The Effect of FELEPS on the haematological Indices in albino rats                         continued                                                                                                        128

4.11     The Effect of Fractions of Ethanol Leaf Extract of P. santalinoides on                    the Serum Electrolytes in Albino Rats.                                                    131

4.12:    The Effect of FELEPS on the Serum Urea and Creatinine Concentration                   in Albino Rats in Wistar rats                                                                               133




4.1       The effect of fractions of ethanol leaves extract of p. santalinoides

(FELEPS) on serum troponin levels (ng/ml) in albino rats.                            111


4.2       The effect of fractions of ethanol leaf extract of P. santalinoides

(FELEPS) on serum CK-MB activity (u/l) in albino rats                                113     








1.1       Pterocarpus santalinoides                                                                               7

4.1       Photomicrograph of Heart Tissue of Normal Control Rats (Treated with                             Distilled Water Only)                                                                                        104


4.2       Photomicrograph of Heart Tissue Treated with Distilled Water and                                     150 mg/kg bw 5-Fluorouracil (Positive Control)                                      105


4.3       Photomicrograph of Heart Tissue Treated with 25 mg/kg bw Aspirin                                   (AS) and 150 mg/kg bw 5-Fluorouracil (Standard Control)                              106


4.4       Photomicrograph of Heart Tissue Treated with Low Dose (LD)                        (34.64 mg/kg bw) of CELEPS and 150 mg/kg bw 5-Fluorouracil                        (Low Dose)                                                                                                        107


4.5:      Photomicrograph of Heart Tissue Treated with Medium Dose                                              (69.28 mg/kg bw) of CELEPS and 150 mg/kg bw 5-Fluorouracil               108


4.6       Photomicrograph of Heart Tissue Treated with High Dose (HD)                              (103.92 mg/kg bw) CELEPS and 150 mg/kg bw 5-Fluorouracil.              109


4.7       Photomicrograph of the Longitudinal Section of the Distilled Water

(Control) Heart Tissue                                                                         134


4.8       Photomicrograph of the Longitudinal Section of the Heart Tissue of the                 Distilled Water + 150 mg/kg bw 5-Fluorouracil Treated Rats                                        (Positive Control)                                                                                            135                                                                             

4.9       Photomicrograph of the Longitudinal Section of the Heart tissue of the                  25mg/kg bw aspirin + 150mg/kg bw 5-Fluorouracil Treated Rats                          (Standard Control)                                                                                          136


4.10     Photomicrograph of the Longitudinal Section of the Heart Tissue of the                             N-Butanol Fraction + 150mg/kg bw 5-Fluorouracil Treated Rats                                    (Group 4)                                                                                                        137


4.11     Photomicrograph of the Longitudinal Section of the Heart Tissue of the                 Ethyl-acetate Fraction + 150mg/kg bw 5-Fluorouracil Treated Rats                                    (Group 5)                                                                                                        138


4.12     Photomicrograph of the Longitudinal Section of the Heart Tissue of the                    Chloroform Fraction + 150mg/kg bw 5-Fluorouracil Treated Rats                                    (Group 6)                                                                                                       139

4.13     Photomicrograph of the Longitudinal Section of the Kidney Tissue of the              Distilled Water Treated Rats (Normal Control)                                               140                                                                                                     

4.14     Photomicrograph of the Longitudinal Section of the Kidney Tissue of the              Distilled Water + 150 mg/kg bw Treated Rats (Positive Control).                     141     


4.15     Photomicrograph of the Longitudinal Section of the Kidney Tissue of                    the 25mg/kg bw Aspirin + 150mg/kg 5-Fluorouracil Treated Rats                     (Standard Control)                                                                                        142


4.16     Photomicrograph of the Longitudinal Section of the Kidney Tissue of                    the n-Butanol Fraction + 150 mg/kg bw Treated Rats (Group 4)                 143


4.17     Photomicrograph of the Longitudinal Section of the Kidney Tissue of the              Ethyl-acetate Fraction + 150 mg/kg bw Treated Rats (Group 5)                 144


4.18     Photomicrograph of the Longitudinal Section of the Kidney Tissue of the              Chloroform Fraction + 150 mg/kg bw Treated Rats (group 6)                     145


4.19     Photomicrograph of the Transverse Section of the Liver Tissue of the                                  Distilled Water Treated Rats (Normal Control).                                               146


4.20     Photomicrograph of the Transverse Section of the Liver Tissue of the                                  Distilled Water + 150 mg/kg bw 5-Fluorouracil Treated Rats                                      (Positive Control)                                                                                            147


4.21     Photomicrograph of the Transverse Section of the Liver Tissue of the                                  25mg/kg bw Aspirin + 150 mg/kg bw 5-Fluorouracil Treated Rats                                    (Standard Control)                                                                                          148


4.22     Photomicrograph of the Transverse Section of the Liver Tissue of the                                  N-Butanol Fraction + 150 mg/kg bw 5-Fluorouracil Treated Rats                                   (Group 4)                                                                                                        149


4.23     Photomicrograph of the Transverse Section of the Liver Tissue of the                                  Ethyl-acetate Fraction + 150 mg/kg bw 5-Fluorouracil Treated Rats                                  (Group 5)                                                                                                        150

4.24     Photomicrograph of the Transverse Section of the Liver Tissue of                            the Chloroform Fraction + 150 mg/kg bw 5-Fluorouracil Treated                               Rats (Group 6)                                                                                                            151




I           Estimation of Serum Troponin                                                                        217

II         Estimation of Serum CK-MB Concentration                                                 218

III        Estimation of Serum Level of Triglyceride (TG)                                            220

IV        Estimation of Total Serum Cholesterol                                                           221

V         Estimation of Serum Level of  HDL-Cholesterol                                           221

VI        Estimation of Haematological Indices                                                            222

VII      Estimation of Serum Malondialdehyde (MDA) Level                                   223

VIII     Estimation of Serum SOD Activity                                                                224

IX        Estimation of Serum Glutathione Peroxidase (GSPx) Activity                     224     

X         Estimation of Serum Catalase (CAT) Activity                                               225

XI        Estimation of Alkaline Phosphatase (ALP) Activity                                      225

XII      Estimation of Aspartate Amino Transferase (AST) Activity                         226

XIII     Estimation of Alanine Amino Transferase (ALT) Activity                            226

XIV     Estimation of Serum Urea Nitrogen (BUN) Concentration                           227

XV      Estimation of Serum Creatinine Concentration                                              227

XVI     Preparation of Extracts Doses (mg/kg bw)                                                     228

XVII   Preparation of Aspirin 25 Mg (mg/kg bw)                                                      228

XVIII  Calculation of 5-Fluorouracil Doses (mg/kg bw)                                            228







5-FU                            5-Fluorouracil

ACE                            Angiotensin Converting Enzyme

ALP                            Alkaline Phosphatase

ALT                            Alanine Transaminase

AST                             Aspartate Transaminase

BUN                           Blood Urea Nitrogen

CAD                           Coronary Artery Disease

CAT                            Catalase

CBC                            Complete Blood Count

CDC                            Center for Disease Control and Prevention

CELEPS                     Crude ethanol extract of Pterocarpus santalinoides

CHF                            Congestive Heart Failure

CKD                           Chronic Kidney Disease

CK-MB                       Creatine Kinase-MB Fraction

CVD                           Cardiovascular Disease

DNPH                         Dinitrophenyl Hydrazone

FBC                            Full Blood Count

FDA                            Food and Drug Administration

FELEPS                      Fractions of Ethanol Extract of Pterocarpus santalinoides

GGT                            Gamma-Glutamyl Transferase

GSPx/GPx                  Glutathione Peroxidase

H &E                           Hematoxylin and Eosin

Hb/HGBS                   Haemoglobin

HDL-C                        High Density Lipoprotein Cholesterol

HER2                          Human Epidermal Growth Factor Receptor 2

HF                               Heart Failure

HIV                             Human Immunodeficiency Virus

LD50                                     Lethal Dosage

LDL-C                                    Low Density Lipoprotein Cholesterol

LV                               Left Ventricle

LVD                            Left Ventricular Dysfunction

LVEF                          Left Ventricular Ejection Fraction

Mabs                           Monoclonal Antibodies

MDA                           Malondialdehyde

MEPS                          Methanol Leaf Extract of Pterocarpus santalinoides

MI                               Myocardial Infarction

NO                              Nitric Oxide

NSAID                       Nonsteroidal Anti-inflammatory Drug

PMBC                         Peripheral blood Mononuclear Cells

PS                                Pterocarpus santalinoides

RBC                            Red Blood Cell

SGOT                          Serum Glutamic Oxaloacetic Transaminase

SGPT                          Serum Glutamic Pyruvic Transaminase

SOD                            Superoxide Dismutase

TC                               Total Cholesterol

TKIs                            Tyrosine Kinase Inhibitors

TnI                              Troponin I

TnT                              Troponin T

UA                              Uric Acid

VEGF                         Vascular Endothelial Growth Factor

VLDL                         Very Low Density Lipoprotein

WBC                           White Blood Cell












In many nations of the world, cardiovascular diseases (CVD) are leading causes of deaths despite several advancements in the medical interventions. Some of the CVDs include: coronary heart disease, peripheral arterial disease, rheumatic heart disease, congenital heart disease, strokes, myocardial ischemia and myocardial infarction (heart attack) (Arnett et al., 2014). Myocardial ischemia (MI) remains a major pathological cause of death globally despite rapid advancements continously made in the treatment of coronary diseases (Murray and Lopez, 1997; Boudina et al., 2002).  Most cancer therapies have been linked with risk of causing cardiotoxicity (Curgliano et al., 2010; Hahn et al., 2014).  Over the years and even in recent times, the number of deaths caused by cardiovascular diseases (CVD) have been on the increase even in developed nations such as USA, UK, Germany and others.  It’s a leading cause of death in the United States. According to the Centers for Disease Control and Prevention (CDC), one American dies from cardiovascular disease every 37 seconds.  The most common factors that can increase the risk for cardiovascular disease include high blood pressure, high blood cholesterol, diabetes, smoking, sedentary lifestyle (physical inactivity), and obesity.

Cardiotoxicity refers to toxicity that affects the heart.  It can be defined as new onset or worsening of myocardial damage or ventricular function from baseline during follow-up (Sanz and Zamorano, 2020).  It can also be referred to as the damage to the myocardium induced by medication, which can precipitate pathological conditions such as heart failure (HF), hypertension and structural damage.  Cardiotoxicity can also be defined as either the presence of symptoms of heart failure with greater or equal to five percent (≥5%) reduction in ejection fraction to less than fifty - five percent (<55%) or the absence of symptoms with an ejection-fraction reduction ≥10% to <55% (Csapo and Lazar, 2014).  Cardiotoxicity is a known adverse effect of many conventional chemotherapeutic agents. many of the new cancer drugs also interact with cardiovascular signalling and have important side effects, particularly during times of increased cardiac stress (Suter and Ewe, 2013).  Cardiac dysfunction and heart failure are among the most serious cardiovascular side effects of systemic cancer treatment (Suter and Ewe, 2013). When cancer patients undergo chemotherapy or radiotherapy they eventually suffer from cardiotoxicity as a result of the treatment, their quality of life and overall survival is severely affected, but suspending the treatment of cancer for fear of the cardiotoxicity risk is actually not the best option, therefore early detection of such condition by pharmacists and physicians during chemotherapy is very crucial.  Most already established and newer anticancer drugs have this cardiotoxicity side effect.  In other not to deny a patient the the ability to benefit from cancer treatment, a new field of medical specialty known as Cardio-oncology has been established in other to manage the cardiotoxicity side effect while the patient continues with the cancer treatment (Suter and Ewe, 2013). Cardio-oncology has emerged as a sub-specialty to meet the challenges posed by a complex interaction between cancer and the cardiovascular system and the cardiotoxicity of conventional and newly developed cancer therapies (Fiuza et al., 2016; Diwakar et al., 2017).

Cardiotoxic drugs are divided into four categories:

1) Drugs that cause direct cytotoxicity on the heart resulting to cardiac dysfunction: examples of such drugs include the alkylating agents, anthracyclines, tyrosine kinase inhibitors (TKIs), interferon alfa and monoclonal antibodies (Mabs)

2)  Drugs that can cause cardiac ischemia: examples include antitumor antibiotics, fluorouracil (5-FU), topoisomerase inhibitors.

3) Drugs that can precipitate cardiac arrhythmias: e.g. anthracyclines, etc.

4) Drugs that can cause pericarditis: e.g. bleomycin, cyclophosphamide, cytarabine (Csapo and Lazar, 2014)

According to the system proposed by Ewer et al. (2013), cardiotoxicity of cancer drugs can be categorized based on their potential to cause irreversible damage (type 1) or reversible damage (type 2). Type 1 damage is usually caused by a cumulative dose; type 2 damage is not related to a cumulative dose.  Examples of anti-cancer agents that can cause irreversible toxicity include anthracyclines (daunorubicin, idarubicin, doxorubicin, epirubicin); taxanes (docetaxel, paclitaxel, cabazitaxel); topoisomerase inhibitors (etoposide, tretinoin, vinca alkaloids); alkylating agents (busulfan, carboplatin, mitomycin, carmustine, chlormethine, cisplatin, cyclophosphamide); and antimetabolites (cladribine, cytarabine, 5-FU) (Csapo and Lazar, 2014; Romond et al., 2005).

The most common chemotherapy agents associated with irreversible damage to the heart are the anthracyclines. Anthracyclines, especially doxorubicin, are used to treat several types of cancer, including breast, gynecologic, sarcoma, and lymphoma. Csapo and Lazar (2014) reported that the mechanisms by which anthracyclines cause cardiotoxicity is by inducing necrosis and apoptosis of cardiac myocytes and subsequent myocardial fibrosis.  Doxorubicin-induced cardiotoxicity involves several processes, such as the formation of iron-dependent oxygen free radicals and peroxidation of lipids in the membrane of myocardial mitochondria, which results in suppression of DNA, RNA, and proteins; thereby causing altered adenylyl cyclase activity and disrupted calcium homeostasis (Romond et al., 2005).   Cumulative doses are responsible for increasing the risk of anthracyclines-induced cytotoxicity.

Monoclonal antibodies (Mabs) are the main cause of type 2 damage.  They are commonly used in the management of many types of cancer. Chemotherapy agents that can cause reversible cardiotoxicity are trastuzumab, lapatinib, sunitinib and bevacizumab. These anticancer agents can also cause hypertension. The mechanism could be by causing a decrease in vascular endothelial growth factor (VEGF) which in turn results in a reduction of nitric oxide (NO) in the arteriolar wall hence causing increased vascular resistance.  In breast cancer, aggressive disease and a worse prognosis have been attributed to human epidermal growth factor receptor 2 (HER2)–positive receptors (Suter and Ewer, 2013).   Csapo and Lazar (2014) reported in their review that trastuzumab, a humanized Mab, has shown a 50% reduction in recurrence rates and a 33% improvement in survival (Csapo and Lazar, 2014).  Available data suggest that the cadiotoxicity induced by trastuzumab is as a result of blockage of HER2 receptors.  HER2 receptors are important for embryonic cardiac development and for protection of the heart from cardiotoxins, hence they are present on cardiac myocytes (Groarke and Nohria, 2015). As a result, when the gene of these receptors are suppressed, dilated cardiomyopathy develops. This helps identify the difference between type 1 and type 2 cardiotoxicity; type 1 has a greater association with cardiac dysfunction and clinical heart failure (HF), and type 2 leads to an increased loss of contractility and less death of cardiomyocytes and can reverse (Suter and Ewer, 2013).

Suter and Ewer (2013) proposed a system to identify drugs that cause the different types of damage, and they defined cardiotoxicity as a serial decline in left ventricular ejection fraction (LVEF).  The American Society of Echocardiography defined cardiotoxicity as an LVEF drop from >10% to <53%. The Cardiac Review and Evaluation Committee proposed a definition of left ventricular dysfunction (LVD) to be “a decline in cardiac LVEF; presence of symptoms of congestive heart failure (CHF); associated signs of CHF, including but not limited to S3 gallop, tachycardia, or both; and decline in LVEF of at least 5% to less than 55% with accompanying signs or symptoms of CHF, or a decline in LVEF of at least 10% to below 55% without accompanying signs or symptoms (Groarke and Nohria, 2015).

Many cancer survivors are living with long-term adverse effects of cancer therapy with pathological organ systems.  Cardiovascular toxicity of anticancer drugs is one of the most life-threatening adverse effects. Several anticancer agents, such as anthracyclines (daunorubicin, doxorubicin, epirubicin, idarubicin), trastuzumab, cyclophosphamide, antimetabolites (cladribine, cytarabine, 5-fluorouracil), alkylating agents (busulfan, carboplatin, carmustine, chlormethine, cisplatin, cyclophosphamide, mitomycin), angiogenesis inhibitors, taxanes (docetaxel, cabazitaxel, paclitaxel), topoisomerase inhibitors (vinca alkaloids, etoposide, tretinoin,) and tyrosine kinase inhibitors (TKIs) have been linked with an increase in the risk of cardiovascular morbidity and mortality (Panjrath and Jain, 2007; Saif et al., 2009; Frickhofen et al., 2002; Cardinale et al., 2015; Rowinsky, et al., 1991; Dutcher, et al., 2001;Chu, et al., 2007).

Childhood cancer survivors face a high lifetime risk of late cardiovascular disease (Reulen et al., 2010; Lipshultz, et al., 2012). Patients with pre-existing cardiovascular diseases are at higher risk of cardiotoxicity compared to those that have healthy cardiovascular systems. The spectrum of cardiovascular complications of cancer therapy includes left ventricular (LV) dysfunction, congestive heart failure (CHF), coronary vasospasm, angina, myocardial infarction (MI), arrhythmias, systemic hypertension, pericardial effusion, pulmonary fibrosis and pulmonary hypertension (Schwartz et al., 2013). A newly emerging subspecialty known as cardio-oncology is designed to address the complex interaction between cancer and cardiovascular system through monitoring, early detection, prevention and treatment of cardiotoxicity of cancer therapies; development of newer therapies with lower or no cardiotoxicity; and careful planning of cancer therapy in patients with pre-existing cardiovascular disease to avoid overt cardiotoxicity and heart failure (Albini et al., 2010; Russell et al., 2016). 

About 80% of worldwide populations depend on traditional medicines to meet their primary health-care needs (Ullah et al., 2010).  Plants are primary sources of medicines, food, shelters and other items that are daily made use of by humans. Their stems, leaves, flowers, roots, fruits and seeds provide food for humans (Amaechi, 2009).  Nigeria is not left out in the medicinal application of plants as plants are employed in Nigeria for the treatment of many kinds of disease conditions. Infact public opinion has it that nature has given the cure of every disease in one way or another (Tiwari et al., 2011).  Pterocarpus santalinoides is one of such plant species used for the management and treatment of ailments (Iwu, 1993; Dieye et al., 2008).   The people of South Eastern part of Nigeria use the leaves of this plant to prepare soup especially for women who just gave birth, the leaves are also used to treat gastro-intestinal diseases, diabetic syndrome and skin diseases (Anowi et al., 2012).  In North Central Nigeria, the leaves of this plant are used in treatment of pain and inflammation of lower abdomen, stomach ache and other infectious diseases (Igoli et al., 2003).  In India, fruit extracts of this plant are used traditionally in treating skin diseases, boils, fevers, headache, etc (Jain et al., 2013).  The stem bark extracts of Pterocapus santalinoides were reported to have anti-diabetic, antibacterial and hepatoprotective activities (Jain et al., 2013).

Various parts of Pterocarpus santalinoides are employed in traditional medicine in many African countries, to treat an array of human ailments. The ethno-medical use of leaves of Pterocarpus santalinoides in the treatment of diarrhoea and other gastrointestinal disorders as well as its triglyceride and glucose lowering properties has been experimentally verified (Prado, 2000; Okpo et al., 2011).   The leaves of Pterocarpus santalinoides have antimicrobial activity and contain phytochemicals such as alkaloids, tannins, saponins, terpenoids, flavanoids and anthraquinones which might be responsible for this activity (Ukwueze et al., 2018).   Ethanol extract of the leaves of Pterocarpus santalinoides has been shown to significantly increase the levels of haematological parameters such as haemoglobin, packed cell volume and platelets (Offor et al., 2015).   The leaves of Pterocarpus santalinoides are used in the treatment of skin diseases such as eczema, candidiasis and acne, the bark extracts are used in the treatment of diabetes, cough and sore (Osuagwu and Akomas, 2013; Igoli et al., 2005; Ama, 2010; Okwuosa et al., 2011).  Methanol leaf extract of Pterocarpus santalinoides (MEPS) does not cause significant toxicity in albino rats, when administered for a short duration, rather long term therapy with the extract could precipitate liver and kidney damage (Madubuike et al., 2020).

1.2       Pterocarpus santalinoides