ABSTRACT

Phytochemistry of Acalypha wilkisiana maginata leaf was studied as well as an evaluation of antimicrobial activities of the leaf extracts in different solvents, against Methycilin Resistant Staphylococcus aureus (MRSA) from clinical samples. Extracts were obtained in water, ethanol and ethyl acetate and their yield, phytochemical content and antimicrobial activity were determined. Results showed yields of 11.62, 16.43 and 8.97% in water, ethanol and ethyl acetate respectively. Phytochemical composition showed Tannin (0.05% to 0.96), alkaloid (0.97 to 1.97), phenol (0.07 to 0.33), saponin (0.15 to 0.55) and flavonoid (0.15 to 0.27) percent. Hydrogen cyanide (HCN, 0.00 – 2.48mg/kg) was highest in the water extract. While the other phytochemicals had varied highest concentrations in the different solvents. Variations were also recorded in the antimicrobial activity of extracts against the staphylococcus aureus isolates. Water extract recorded the highest mean diameter of inhibition of 15.17mm (19.0mm to 20.3mm) while ethyl extract had the least inhibition of 13.1mm (9.0 to 16.7mm). All the extracts had lower inhibition relative to the standard drug (vancomycin) which recorded 18.28mm. Average resistance of 15% and 10% were exhibited by the isolates against the water extract whereas no resistance was recorded with ethanol extract and the standard drug (Vancomycin). Also 75% susceptibility was recorded for ethanol extract as against 65% each for water and ethyl acetate extracts. The minimum inhibition concentrations (MIC) was 100mg/ml for ethyl acetate extract 50mg/ml for water and ethanol extracts each. Again, the minimum bactericidal concentrations (MBC) of the extracts 250mg/ml, 300mg/ml and 350mg/ml for ethanol, water and ethyl acetate extracts respectively.    

TABLE OF CONTENTS

Title Page                                                                                                                                i

Certification                                                                                                                            ii

Dedication                                                                                                                              iii

Acknowledgments                                                                                                                  iv

Table of Contents                                                                                                                   v

List of Figures                                                                                                                         viii

List of Tables                                                                                                                          ix

Abstract                                                                                                                                  x

CHAPTER ONE

INTRODUCTION                                                                                                                1

Aims and Objectives                                                                                                               5

Objectives                                                                                                                               5

CHAPTER TWO

LITERATURE REVIEW

2.1       The Plant Acalypha Wilkisiana                                                                                  6

2.1.1    Phytocomponents of Acalypha wilkisiana                                                                  6

2.1.2    Phytochemical Studies and Isolated Constituents from Acalypha wilkesiana           8

2.1.3    Botanical Features                                                                                                      8

2.1.4    Pharmacological Properties                                                                                        8

2.1.5 Therapeutic Potentials of Acalypha wilkisiana                                                              10

2.1.6    Research Commenced on Acalypha wilkesiana                                                         11

2.2       Toxicity of Acalypha wilkesiana                                                                                13

2.2.1    Medicinal value of Acalypha wilkisiana                                                                    14

2.2.2 Traditional use of Acalypha wilkesiana                                                                         16

2.3       Phytochemistry                                                                                                           18

2.3.1    Useful Phytochemicals                                                                                               18

2.3.2    Alkaloids                                                                                                                     18

2.3.3    Flavonoids                                                                                                                  19

2.3.4    Phenol                                                                                                                         19

2.3.5    Tannins                                                                                                                       20

2.3.6    Other Phytochemicals                                                                                                 20

2.4       Plants and Antimicrobial Activity                                                                              20

2.5       Antibacterial Agents from Flowering Plants                                                              22

2.5.1    Infectious Diseases                                                                                                     22

2.5.2    Infections Due to Staphylococcus aureus                                                                   23

2.5.2.1 Staphylococcal Food Poisoning                                                                                 25

2.5.2.2 Skin and Soft-tissue Infections                                                                                  25

2.6       Methicillin Resistant Staphylococcus aureus                                                             27

2.6.1    Risk Factors of MRSA                                                                                               27

CHAPTER THREE

3.0       MATERIALS AND METHODS

3.1        Source of Materials                                                                                                    28

3.2       Sample and Medium Preparations                                                                              28

3.2.1    Media Preparation                                                                                                       28

3.2.2   Plant Preparation                                                                                                          28

3.2.3    Extraction of Plant Extract                                                                                         29

3.3.0    Methods of Analysis in Qualitative Phytochemical Screening                                  29

3.3.1    Test for Alkaloids                                                                                                       29

3.3.2    Test for Flavonoids                                                                                                     29

3.3.3    Test for Saponin                                                                                                          30

3.3.4    Test for Tannin                                                                                                            30

3.3.5    Test for Phenols                                                                                                          30

3.3.6    Confirmation of MRSA                                                                                              31

3.3.6.1 Colony                                                                                                                       31

3.3.6.2 Microscopic Examination                                                                                          31

3.3.6.3   Biochemical Tests                                                                                                    31

3.3.6.4   Sugar Utilization Tests                                                                                             31

3.4.0    Reconstitution of Extract                                                                                            32

3.4.1    Antibiotic Sensitivity Test                                                                                          32

3.4.2    Determination of MIC                                                                                                            33

3.4.3    Determination of MBC                                                                                               33

CHAPTER FOUR

4.0       RESULTS                                                                                                                 34

CHAPTER FIVE

DISCUSSION AND CONCLUSION

5.1       Discussion                                                                                                                   43

5.2       Conclusion                                                                                                                  46

References                                                                                                                  47