ANTIMICROBIAL EFFECTS OF HONEY ON SOME FUNGAL PATHOGENS

ABSTRACT

The antimicrobial effect of some honey samples obtained from National Root Crop Research Institute (NRCRI), Umudike and Mbaise were tested on some fungal pathogens such as Aspergillus niger, Penicillium chrysogenum and Candida albicans. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the honeys were also determined. Results obtained reveal that the honey samples showed varying levels of inhibitory activity at various concentrations against the fungi tested with zones of inhibition increasing with increasing honey concentration. Penicillium chrysogenum was the most sensitive of all the fungal isolates studied, value at 21mm at 100% in honey from National Root Crop Research Institute (NRCRI), Umudike and 22mm at 100% in honey from Mbaise. While C. albicans was the least sensitive, value at 18mm at 100% in honey from National Root Crop Research Institute (NRCRI), Umudike and 19mm in honey from Mbaise. The minimum inhibitory concentration (MIC) value from 40 – 60% concentration while the minimum fungicidal concentration (MFC) value from 20 – 40% concentration. The samples of honey used in the study showed broad spectrum and promising antifungal effect. Nigerian honey can serve as sources of antifungal substances for possible development of antifungal drugs for the treatment of fungal infections.  

TABLE OF CONTENTS

Title page ﾿         i

Certification ﾿         ii

Dedication ﾿         iii

Acknowledgements ﾿         iv

Table of contents ﾿         v

List of tables ﾿         ix

Abstract ﾿         x

CHAPTER ONE

1.1 ﾿ Introduction ﾿          1

1.2 ﾿ Aims and Objectives ﾿          2

CHAPTER TWO

2.1 ﾿ Literature Review ﾿           3

2.2 ﾿ Local test for real Honey ﾿           5

2.2.1 ﾿ Classification of  Honey ﾿           5

2.2.2 ﾿ Extraction ﾿           6

2.2.3 ﾿ Preservation ﾿           6

2.3 ﾿ Properties and active ingredients of honey ﾿           7

2.4 ﾿ Mode of action of some of the antibacterial substances in honey ﾿         ﾿           8

2.4.1 ﾿ High osmotic pressure ﾿                                                                       8

2.4.2 ﾿ Low water activity ﾿           8

2.4.3 ﾿ Glucose oxidase enzyme ﾿           8

2.4.4 ﾿ Low pH/ acidic environment ﾿           9

2.5 ﾿ Clinical conditions that respond to treatment with honey      ﾿           9

2.6 ﾿ Honey as an antibacterial agent ﾿ ﾿         10

2.6.1 ﾿ Practical consideration for the clinical use of honey ﾿         12

2.6.2 ﾿ Adverse reaction of honey ﾿         12

2.7 ﾿ Nutritional and health benefits of honey ﾿         13 

2.7.1 ﾿ Health ﾿         13

2.7.2 ﾿ Gastroenterology ﾿                     13

2.7.3 ﾿ Infants ﾿         14

2.8 ﾿ Fungal pathogens ﾿             ﾿         15

2.8.1 ﾿ Aspergillus niger ﾿         15

2.8.2 ﾿ Uses of Aspergillus niger ﾿         15

2.8.3 ﾿ Penicillium chrysogenum ﾿         15

2.8.4 ﾿ Uses of Penicillium chrysogenum ﾿         16

2.8.5 ﾿ Candida albicans ﾿         16

CHAPTER THREE

3.0 ﾿ Material and methods ﾿         17

3.1 ﾿ Material ﾿         17

3.2 ﾿ Methods ﾿         17

3.2.1 ﾿ Collection of samples ﾿         17

3.2.2 ﾿ Microorganisms used  ﾿         17

3.2.3 ﾿ Honey preparation ﾿         18

3.2.4 ﾿ Media used ﾿         18

3.2.5 ﾿ Preparation of Inoculum ﾿         18

3.3 ﾿ Determination of antifungal activities ﾿ ﾿         18

3.4 ﾿ Determination of minimum inhibitory concentration (MIC)  ﾿         19

3.5 ﾿ Determination of minimum fungicidal concentration (MFC) ﾿         19

CHAPTER FOUR

4.1 ﾿ Results  ﾿         21

CHAPTER FIVE

5.1 ﾿ Discussion ﾿   ﾿         26

5.2 ﾿ Conclusion        ﾿         28

REFERENCES ﾿         29

LIST OF TABLES

TABLES ﾿ TITLE ﾿ PAGE

1:  ﾿ The zone of inhibition on the effect of undiluted honey on some 

      ﾿   fungal pathogens. ﾿         22

2:    ﾿ Antimicrobial effect of honey sample on the test organisms. ﾿         23

3:    ﾿ ﾿ Minimum inhibitory concentration of the honey samples

                  ﾿   against test organisms. ﾿         24

4:  ﾿   Minimum fungicidal concentration of the honey samples

              ﾿    against test organisms. ﾿         25