PHYTOCHEMICAL AND ANTIMICROBCIAL ACTIVTY OF TWO NIGERIAN MEDICINAL PLANTS (Xylopia aethiopica and Tetrapleura tetraptera)

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