ABSTRACT

The antimicrobial activity and phytochemical screening of the bark of Tetrapleura tetraptera and Xylopia aethiopica were carried out. The two plant species indicate the presence of reducing sugar, tannins, saponins, flavonoids, alkaloids, anthraquinones, phlobatannins and steroids which are bioactive components. The antimicrobial activity of the methanol and aqueous extracts of the bark species were tested against three organisms; Staphylococcus aureus, Echerichia coli and Salmonella typhi. The sensitivity of the microorganisms was determined using minimum inhibitory concentration and standard disc diffusion method; this was carried out to evaluate the efficacy of the plant extracts using positive control. The methanol extract of the plants undertaken in the study showed strong anti-microbial activity against human bacteria. Methanol and aqueous plant extracts inhibited the growth of these pathogens. The zone of inhibition of the both extracts depends on the concentration of the extract. The methanol plant extract had high sensitivity than aqueous plant extract which showed less. The methanol extract of Xylopia aethiopica (19 μg/ml) which showed more sensitivity against the test organisms while the aqueous extract of Tetrapleura tetraptera had lower inhibitory activity (12 μg/ml) showing less sensitivity against the test organisms. These results reveal that these plant species have potentials as source of raw materials in the pharmaceutical industry.

TABLE OF CONTENTS

Title page i

Declaration ii

Certification iii

Dedication iv

Acknowledgments v

Table of content vi

List of tables viii

List of figures ix

List of plates x

Abstracts xi

CHAPTER ONE: INTRODUCTION

1.1 Background of the study 1

1.2      Aims and objective of the research 4

CHAPTER TWO: LITERATURE REVIEW

2. 1 Phytochemical of plant 5

2.2 Botany of plants 7

2.2.1 Botany of Xylopia aethiopica 7

2.2.2   Botany of Tetrapleura  tetraptera 8

2.3 Antimicrobial activity of plants 9

CHAPTER THREE: MATERIALS AND METHOD

3.1      Materials 11

3.1.1 Source of material 11

3.1.2   Sample preparation 11

3.2 Methods 11

3.2.1 Phytochemical screening 11

3.2.1.1 Test of Alkaloid 12

3.2.1.2 Test of Saponin 12

3.2.1.3 Test of flavonoids 12

3.2.1.4 Test of  Phlobatannins 12

3.2.1.5 Test of Tannin 13

3.2.1.6 Test of Reducing sugar 13

3.2.1.7 Test of Anthroquinones 13

3.2.1.8 Test of Steroids 13

3.2.2 Antimicrobial activity of the bark of the plant Tetrapleura tetraptera and 

Xylopia aethiopica 14

3.2.2.1 Sample preparation 14

3.2.2.2 Preparation of extracts 14

3.2.2.3 Source of test organisms 14

3.2.2.4 Antimicrobial activity test 14

3.2.2.5 Determination of Minimum Inhibition Concentration 15

3.2.3 Statistical Analysis 16

CHAPTER FOUR: RESULTS

4.1 Phytochemical components 17

4.1.1   Qualitative analysis 17

4.1.2 Anti-microbial activity of extracts against isolated bacterial 18

4.1.3 Minimum inhibitory concentration 19

CHAPTER FIVE: DISCUSION AND CONCLUSION

5.1 Discussion 20

5.2 Conclusion 22

References

Appendices

LIST OF TABLES

Table Title Page

1: The qualitative analysis of phytochemical contents of Tetrapleura 

tetraptera and Xylopia aethiopica 17

2: Anti-microbial activity of extracts Tetrapleura tetraptera and 

Xylopia aethiopica 18

3: Minimum inhibitory concentration of aqueous and methanol extracts 

of Tetrapleura tetraptera and Xylopia aethiopica 19

LIST OF FIGURES

Figure Title Page

1 Minimum Inhibitory concentration of aqueous and methanol 

extracts of Tetrapleura tetraptera and Xylopia aethiopica 19

LIST OF PLATES

Plate Title Page

1 Xylopia aethiopica bark 28

2 Pulverized Xylopia aethiopica bark 28

3 Terapleura tetraptera bark 29

4 Pulverized Terapleura tetraptera bark 29

5 Zone of inhibition of Staphylococcus aureus 30

6 Zone of inhibition of Salmonella 30

7 Zone of inhibition of Escherichia coli 30