ABSTRACT 

The antimicrobial activity of the crude leaf extract of Carica papaya on some human pathogens (Staphylococcus aureus, Pseudomonas aeroginosa, Escherichia coli) were carried out using agar well diffusion method. The bioactive compounds of the leaf was extracted using Water and Ethanol. The aqueous and ethanol extract were tested at 200mg/ml, 100mg/ml, and 50mg/ml concentration on the bacterial isolates. The result showed that only the ethanolic extract were effective in inhibiting all the test organism. Pseudomonas aeroginosa had the highest susceptibility to the ethanolic extract at 200mg/ml with a zone of inhibition of 15.5mm and Escherichia coli had the least susceptibility at 200mg/ml with a zone of inhibition of 7.0mm. The test organisms had a higher susceptibility to the standard antibiotic levofloxacin than the leaf extract. Demonstration of the antimicrobial activity on the isolates is an indication that there is a possibility of sourcing for an alternative antibiotic substance in this plant for the development of newer antibacterial agents. 

TABLE OF CONTENTS

Title Page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables vii

List of Figures viii

Abstract ix

CHAPTER ONE

1.1   Introduction 1

1.2    Aim and Objectives 3

CHAPTER TWO

Literature Review 5

2.1     Antimicrobial Agents 5

2.2     Plant As Source Of Antimicrobial Agents 6

2.3     Plants Product As Therapeutic Agentse 8

2.4     Carica papaya 9

2.4 1  The Plant Family-  Caricaceae 10

2.4.2  Botanic Description 11

2.4.3  Constituent of different parts of Carica Papaya 12

2.4.4  Medicinal uses of  each  Division  of  Carica Papaya 13

2.5     Phytochemical constituents of  Carica papaya  16

2.5.1   Alkaloids 17

2.5.2   Flavonoids 19

2.5.3   Glycoside 20

2.5.4   Tannins 21

2.5.5   Saponins 23

2.6      Pharmacology of Carica papaya 24

2.7 Antioxidant Properties of Carica papaya 25

2.8 Antimicrobial properties of Carica papaya 26

CHAPTER THREE

Materials And Methods 28

3.1.  Sterilization of Materials 28

3.2  Collection of Plant Materials 28

3.3   Preparation of Plant Material 28

3.4   Collection and Maintenance of Test Organisms 29

3.5   Standardization of Test Organisms 29

3.6   Preparation of The Stock Solution Of The Extract 29

3.7   Antimicrobial Assay of Extracts 30

CHAPTER FOUR

4.0   Results 31

CHAPTER FIVE

5.1  Discussion 35

5.2   Conclusion 36

References 38