ABSTRACT

Medicinal plants are of great importance to the health of individuals and the communities. Leaf extract of Ocimum gratissimum was analysed against 3 pathogenic organisms; Staphylococcus aureus, Escherischia coli, and Pseudomonas aeroginosa. Fresh leaves of Ocimum gratissimum (scent leave) was procured from a local market in Ndoru, Ikwuano, L.G.A. of Abia state and transferred to the laboratory for microbiological analysis. The plant was identified authenticated at the Herbarium of the department of plant science and biotechnology, Michael Okpara University of Agriculture Umudike. Clinical isolates of Staphylococcus aureus, Escherischia coli, and Pseudomonas aeroginosa used in the study were obtained from the Microbiology laboratory, Federal Medical Center Umuahia and confirmed by Gram-staining method, biochemical test, morphological appearance and motility. The crude extract of 20mg/ml was double diluted in ethanol and water to the following concentrations 100%, 50%, 25%, 12.5%, 6.25% and 3.625%%. Antimicrobial susceptibility testing was done by agar well dilution method.    MIC and MBC of the crude extract was done under standard technique. The Minimum Inhibitory Concentration (MIC) of the aqueous extract of Occimum gratissimum against Staphylococcus aureus, 100%, Escherichia coli, 100mg/ml and Pseudomonas aeruginosa was 50% while their Minimum Bactericidal Concentration (MBC) was 50%, 100% and 50% respectively. Conversely the ethanolic extract of Occimum gratissimum  showed a concentration dependent gradient increase in the level of inhibition against the isolates with MIC values of 50mg/ml for each isolate and MBC values of 25%, 50% and 25% against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa respectively This study justifies the use of the leaves in traditional medicine practice as therapeutic agents and can explain the long history use of these plants. This research work has shown that Ocimum gratissimum has potential antibacterial components that are responsible for it’s antibacterial activities. 

TABLE OF CONTENTS

Title Page   i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Tables vii

Abstract viii

CHAPTER ONE

1.0 Introduction 1

1.1 Aims and Objectives of Study 3

CHAPTER TWO

2.0 Literature Review 4

2.1 The Genus Ocimum 5

2.2 Test Organisms 7

2.2.1 Escherichia coli 7

2.2.2 Staphylococcus aureus 9

2.2.3 Pseudomonas aeruginosa 10

CHAPTER THREE

3.0 Materials and Method 12

3.1 Study Area 12

3.2 Materials 12

3.3 Sample Collection 12

3.4 Test Organisms 13

3.5 Confirmation of Test Isolate 13

3.5.1 Morphological appearance 13

3.5.2 Gram Staining 13

3.5.3 Motility test 14

3.5.4 Biochemical tests 14

3.6 Preparation of Crude Extracts 17

3.7 Preparation of Concentration of Plant Extract 17

3.8 Antimicrobial Susceptibility Testing 17

3.8.1 Agar-Well Diffusion Method 17

3.8.2 Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal 

Concentration (MBC) Test 18

CHAPTER FOUR

4.0 Result 19

CHAPTER FIVE

5.0 Discussion, Conclusion and Recommendation 28

5.1 Discussion 28

5.2 Conclussion and Recommendation 29

5.3 Recommendation 29

References 33