ABSTRACT

Plants produce certain bioactive compounds which are naturally toxic to microorganisms and so have been investigated as therapeutic agents. The study was carried out to determine the bioactive compounds contained in the essential oil of Cymbopogon citratus and to evaluate in-vitro the antimicrobial effect of the essential oil on five bacterial species. The essential oil was evaluated quanlitatively for phytochemical analysis and quantitative analysis to determine the chemical composition using Gas Chromatography-Mass Spectrophotometry (GC-MS). The result obtained for Phytochemical Screening revealed 24 compounds such as Limonene, Alpha citral, Aromadendrene, Terpineolcis beta, d-Camphene, Sabinene, Myrene, Caorylic aldehyde, Is-alpha pinene, Cucumber alcohol, Cephrol, Neral, Neryl alcohol, Geranaldehyde, Geraniol acetate Artemiseol. The in-vitro evaluation of the essential oil against five bacterial Pathogens of gastrointestinal tract (enterics) namely Salmonella spp, Eschericheria coli, Proteus spp, Klebsiella spp and Shigella spp showed significant inhibitory activities in each bacteria species, (P=0.50) with varying zones of inhibition in each species which includes Shigellaspp ≥ 14.75mm, Proteus spp≥17.25mm, Klebsiella spp ≥18.25, Samonella spp ≥15.75mm and Escherichia coli ≥16.75mm with the conc. oil. The Minimum Inhibitory Concentration of Cymbopogon citratus oil of all enteric bacterial pathogen is ≥ 0.25ml and the Minimum bacteriocidal concentration of Cymbopogon citratus oil ranged from 0.25 to 1.0ml for all test bacterial isolate.  Gram negative organisms possess peptidoglycan layer and membrane made up of lipoproteins and polysaccharide which make them possess a complex cell wall thus making them resistant to antibiotics, this study of in-vitro testing of antimicrobial activity indicates promising results for the use of essential oil from Cymbopogon citratus against diseases caused by Salmonella spp, Shigella spp, E.coli, Klebsiella spp and Proteus spp.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Table’s viii

Appendices ix

Abstract x

CHAPTER ONE

1.1 INTRODUCTION 1

1.2 Aims and Objectives 5

CHAPTER TWO

2.0 LITERATURE REVIEW 6        

2.1 Botany description of cymbopogon citratus 6

2.1.1 Taxonomical classification 6

2.1.2 Common names 7

2.2 Propagation 7

2.3 Agro-climatic requirements 8

2.4 Oil content of cymbopogon citratus 8

2.5 Storage and packaging of essential oil 8  

2.6 Uses of some plans 9

2.7 Economic importance 9

2.8 Health benefit of C. citratus 9

2.9 Photochemistry of C. citratus 10

2.10 Anti-bacterial potential 12

2.10.1 Anti-fungal activity 12

2.10.2 Anti-oxidant properties 13

2.10.3 Cytotoxicity and mutagenicity 13

2.10.4 Anti-malarial activity 14

2.10.5 Hypoglycemic and hypolipidemic effects 14

CHAPTER THREE

3.0 MATERIALS AND METHOD 15

3.1 Plant materials 15

3.2 Extraction of essential oil 15

3.3 Analysis of essential oil from Cymbopogon citratus using Gas Chromatography – Mass Spectrophotometry (GC-MC) 15

3.4 Media preparation 16

3.4.1 Salmonella Shigella Agar (SSA) 16

3.4.2 MacConkey agar (MCA) 17

3.4.3 Blood Agar 17

3.5 Microorganism collection and maintenance 17

3.6 Isolation and identification of bacteria 17

3.7 Biochemical tests 18

3.7.1 Catalase 18

3.7.2 Indole test 18

3.7.3 Citrate utilization test 18

3.8 Bioassay procedure 19

3.8.1 Preparation of disc 19

3.8.2 Determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) 20

2.9 Data analysis 21

CHAPTER FOUR

4.1 RESULTS 22

CHAPTER FIVE

5.0 DISCUSSION, CONCLUSION AND RECOMMENDATION 28

5.1 discussion 28

5.2 Conclusion 30

5.3 Recommendation 30

References

Appendix