ABSTRACT

The antibacterial activity of aloe vera extract was tested on pathogenic bacteria (Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus) at different concentration of 40, 80, 120mg/ml by using agar well diffusion method. Two extracts aqueous and ethanol were used. The ethanol and aqueous extracts showed zones of inhibition on the test organism depending on the concentration used. The ethanol extracts shows a high inhibition activity which shows maximum inhibition on E. coli at the average of (11.3 ± 1.52 to 21.6 ± 2.08) Pseudomonas aeruginosa (15.6 ± 1.15 to 23.6 ± 0.58) and Bacillus cereus (15.6 ± 1.52 to 19.3± 1.52) compared with the average of the pathogenic organism on aqueous extract which show the minimum inhibition on E. coli (8.6 ±1.24 to 13.3 ±1.53), Bacillus cereus (12.6 ± 0.41 to 16. 3 ± 0.59), and Pseudomonas aeruginosa (11.5+ 1.00 to 17.7+ 1.52). Ethanol extract of aloe vera has a better inhibition than the aqueous extract. The minimum inhibitory concentration (MIC) of the aqueous extracts on the test organism was between 12.5 to 25mg /ml and ethanol extract between 6.25 to 12.5mg/ml. The minimum bactericidal concentration (MBC) of the aqueous extract on the test organisms ranged between 25 to 50mg/ml and on ethanol extract between 12.5 to 25mg/ml. This results suggest that aloe Vera gel extract with ethanol can be used as antibactericidal agent on human pathogens for medication, cosmetic and food purposes.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables viii

Abstract ix

CHAPTER ONE

1.1 INTRODUCTION 1

1.2 Description of aloe vera plant 2

1.3 Aims and objectives of the study 4

CHAPTER TWO

LITERATURE REVIEW

2.1 Growth requirement 5

2.2 Phytochemical properties of aloe vera 6

2.2.1 Anthraquinones 6

2.2.2 Saponins 6

2.2.3 Lignin 6

2.2.4 Salicyclic acid 6

2.2.5 Amino acids 7

2.2.6 Enzymes 7

2.2.7 Minerals 7

2.2.8 Vitamins 8

2.2.9 Sugars 8

2.3 Therapeutic use of aloe vera 8

2.3.1 Wound healing 8

2.3.2 Effects on the immune system 9

2.3.3 Anti-tumor activity 10

2.3.4 Anti-inflammatory action 10

2.3.5 Moisturizing and anti-aging agent 11

2.4 Medicinal uses of aloe vera 11

2.4.1 Anti-diabetic 11

2.4.2 Anticancer properties 12

2.4.3 Antiseptic 12

2.4.4 Stress 13

2.4.5 Cosmetic and skin protection application 13

2.4.6 Heart diseases 14

2.4.7 Arthritis 14

2.4.8 Hepatitis 15

2.5 Antimicrobial activities 15

2.5.1 Antibacterial activity 15

2.5.2 Antiviral activity 16

2.5.3 Antifungal activity 16

2.6 Commodity use of Aloe vera 17

CHAPTER THREE

MATERIALS AND METHOD

3.1 Materials 18

3.2 Ethanol extraction method 18

3.3 Hot water extraction method 18

3.4 Preparation of Media 19

3.5 Test organisms used 19

3.6 Determination of the antibacterial activity of aloe vera gel extract using 

agar well diffusion method 19

3.7 Determination of the Minimum Inhibitory Concentration (MIC) 20

3.8 Determination of Minimum Bactericidal Concentration (MBC) 20

CHAPTER FOUR

4.1 RESULT 21

CHAPTER FIVE

5.1 DISCUSSION                                                                                                           26

5.2 Conclusion                                                                                                                 27

5.3 Recommendation                                                                                                       28

References