ABSTRACT

In African folk medicine, water infusion of Mangifera indica stem bark are highly valued in thelocal treatment of malaria fever, diarrohea, diabetes mellitus and liver diseases. Various part ofthis   plant   can  also  be   used   in  treatment   of   toothache,  dysentery,  anemia,   hypertension   andinsomnia in different parts of the world. This study was described to determine the activities ofthe stem bark extract of M.indica against some panel of bacterial strains and also to evaluate thephytochemical compounds present in the plant extract.Mangifera indica stem bark was collected at Obafemi Awolowo University Campus, Ile-Ife. Thesample was air dried until constant weight was reached and was later ground into fine powder. The   crude   extract   was   prepared   by   soaking   a   known   weight   of   the   powder   in   mixture   ofmethanol and sterile distilled water in ratio 3:2 (v/v), and left on laboratory bench for 96 h. Themixture   was   filtered   and   concentrated  in   vacuo  using   rotary   evaporator.   The   antimicrobialactivity   of   the   crude   extract   collected   was   determined   by   agar-well   diffusion   method.   Theminimum   inhibitory   concentrations   and   minimum   bactericidal   concentrations   were   alsodetermined in addition to the phytochemical constituents of the plant extract.The extract showed appreciable activities against Bacillus subtilis (NCIB 3610). Bacillus cereus(NCIB   6349),  Pseudomonas   aeruginosa  (NCIB   950),  Klebsiella   pneumoniae  (NCIB   418),Micrococcus luteus  (NCIB 167), Serratia marscescens  (NCIB 1377), Escherichia coli  (NCIB86),  Staphylococcus   aureus(NCIB   8588),  Proteus   vulgaris  (NCIB   418),  Pseudomonasaeruginosa  (LIO),  Staphylococcus aureus  (LIO),  Bacillus polymxa  (LIO),  Shigella  sp. (LIO),Bacillus   anthracis,  Vibrio   fluvialio  (LIO),  Enterococcus   faecalis   (NCIB775),  Pseudomonasx fluorescence  (NCIB)   at   final   concentration   of   20   mg/ml.   The   mean   diameter   of   zones   ofinhibition exhibited by the extract ranged between 11 mm and 25 mm while that of streptomycinwhich was used as the positive control ranged between 15 mm and 28 mm. The MIC exhibitedby the extract against susceptible organisms ranged between 0.16 mg/ml and 2.50 mg/ml whilethe   MBC   between  0.63  mg/ml   and   5.00   mg/ml.   The   phytochemical  analysis  of   the   extractrevealed   the   presence   of   tannins,   saponins,   alkaloids,   carbohydrate,   resins,   glycosides,   andterpenoids.In conclusion, the stem extract of M.indica exhibited appreciable antimicrobial activity againstall of the bacteria used for this work and this supports its usefulness in folklore remedies. Theextract compared favorably with the standard antibiotics (streptomycin) used in this work

TABLE OF CONTENTS

Title page

Title page  i

Certification ii

Dedication iii

Acknowledgments iv

Table of contents vii

List of Tables viii

List of plate                 ix

Abstract xi

CHAPTER ONE

1.0    Introduction and literature review 1

1.1    Introduction 3

1.2     Literature review 4

1.2.1   Microorganisms as casual agents of disease 4

1.2.2   Mechanisms of action of antimicrobial compound 5

1.2.2.1 Injury to cell membrane 6v

1.2.2.2 Inhibition of synthesis of cell wall peptidoglycan 7

1.2.2.3 Degradation of structure and function of cell wall             7

1.2.2.4 Inhibition of metabolic biological compounds synthesis 8

1.2.2 Resistance Mechanism of Antibiotics 8

1.2.3 Studies on the antimicrobial activity of some medicinal plants 10

1.2.4    Mangifera indica (Linn.) 13

CHAPTER TWO

2.0   Materials and Methods 142.1   Materials 14

2.1.1 Microorganisms 142.1.2 The plant specimen 14

2.1.3 Culture media used 142.1.4   Reagents used 15

2.2      Method 152.2.1   Collection and preparation of the stem extract of M.indica 15

2.2.2   Preparation of microorganisms used 16

2.2.3    Antimicrobial sensitivity testing of crude stem extract of M.indica against selected bacterial strains 16                                                                                                                              

2.2.4    Determination of minimum inhibitory concentrations (MICs) of the extract 17vi

2.2.5    Determination of minimum bactericidal concentrations (MBCs) of the extract 17

2.2.6    Phytochemical components of the stem extract of M.indica 19 

CHAPTER THREE

3.0     Results 203.1     The extract obtained from the stem of M.indica 20

3.2      The antimicrobial sensitivity testing of the stem extract of M.indica against selected bacterial strains 21

3.3         The minimum inhibitory concentrations (MICs) exhibited by M.indica stem extract against susceptible bacterial strains 22

3.4     The minimum bactericidal concentrations (MBCs) exhibited by M.indica stem extract against susceptible bacterial strains 22

3.5         Phytochemical components revealed from of M.indica stem extract 23 

CHAPTER FOUR

4.0          Discussion and Conclusion 24

4.1          Discussion 25

4.2          Conclusion 26

REFERENCES 33

APPENDIX 1