In vitro ANTIFUNGAL POTENTIAL OF ROSEMARY (Rosmarinus officinalis), EUCALYPTUS (Eucalyptus globulus) and LEMON (Citrus limon) ESSENTIAL OILS ON ANTHRACNOSE OF TOMATO (Colletotrichum).

ABSTRACT

Antifungal activities of rosemary (Rosmarinus officinalis), Eucalyptus (Eucalyptus globulus) and Lemon (Citrus limon) essential oils evaluated, suppressed the mycelial growth of postharvest pathogenic fungus Colletotrichum. The experiment carried out using the Agar well diffusion method in 75% and 100% concentration of the essential oils on SDA culture at 250C and growth measured after 3days showed that the essential oils did not have much antifungal activities on the test fungus. The Agar incorporation method showed that the three (3) essential oils had effect on the fungus. The antifungal activity was replicated three times with Eucalyptus essential oil having the highest inhibition of 100% on the mycelial growth of Colletotrichum followed by rosemary essential oil which had 95.24% inhibition on the growth of the fungus Colletotrichum, Lemon essential oil had the least antifungal activity of 76.19%. The GC-MS analysis of the essential oils revealed the presence of Eucalyptol, Oleic acid, Bicyclo[2.2.1] heptan-2-one,1, 7,7-trimethylethyl, 1R-alpha-pinene, D-Limonene which could be responsible for the antifungal activities of the different essential oils. These essential oils could be used as possible biofungicides as an alternative to synthetic fungicides against pathogenic fungi on tomato fruits.

TABLE OF CONTENTS

Certification ﾿ i

Dedication ﾿ ii

Acknowledgement ﾿ iii

Table of Contents ﾿ iv

List of Tables ﾿ viii

List of Appendix ﾿ ix

Abstract                                                                                                      ﾿ x 

CHAPTER ONE ﾿

INTRODUCTION

1.1 ﾿ Introduction ﾿ 1

1.2 ﾿ Aims and objectives ﾿ 3

CHAPTER TWO

LITERATURE REVIEW

2.1    Essential oils ﾿ 4

2.1.1 Extraction of essential oils  ﾿ 4

2.1.2   Therapeutic benefits of essential oils ﾿ 6

2.1.3   Absorption through the skin ﾿ 7

2.1.4    Inhalation ﾿ 7

2.1.5    Ingestion ﾿ 7

2.1.6    Mechanism of the biological activities of essential oils ﾿ 8

2.1.7    Antibacterial and antifungal action ﾿ 8

2.1.8    Antiviral activity ﾿ 9

2.2       Methods of extraction of essential oils ﾿ 9

2.2.1    Maceration ﾿ 10

2.2.2    Cold pressing ﾿ 10

2.2.3    Solvent extraction ﾿ 10

2.2.4     Enfleurage ﾿ 11

2.2.5     Hydrodistillation ﾿ 11

2.2.6     CO2 and supercritical CO2 extraction ﾿ 11

2.2.7      Steam distillation ﾿ 12

2.3         Spoilage of tomato ﾿ 13

2.4         Colletotrichum species ﾿ 14

2.4.1      General characteristics of Colletotrichum ﾿ 14

2.5         Description of plant materials and fruit ﾿ 15

2.5.1      Rosmarinus officinalis          ﾿ 15

2.5.1.1   Description of the oil ﾿ 16

2.5.1.2    Experimental pharmacology ﾿       ﾿ 16

2.5.2       Citrus limon ﾿ 17

2.5.2.1    Lemon essential oil ﾿ 17

2.5.3       Description of Eucalyptus globulus ﾿ 18

CHAPTER THREE

MATERIALS AND METHODS

3.1         The study area ﾿ 20

3.2         Sample collection and identification ﾿ 20

3.3         Gas chromatography- Mass Spectometry (GC-MS) ﾿ 20

3.4         Identification of isolate ﾿ 20

3.5         Assays for antimicrobial activity ﾿ 21

3.5.1      Agar well diffusion assay ﾿ 21

3.5.2      Agar incorporation assay ﾿ 22

3.6        Statistical analysis ﾿ 22

CHAPTER FOUR

RESULTS ﾿                                  23

CHAPTER FIVE

DISCUSSION AND CONCLUSION

5.1    Discussion ﾿ 33

5.2    Conclusion ﾿ 35

References                                                                                                                36

Appendix

LIST OF TABLES

Table ﾿                 Title ﾿                  Page

1 ﾿ Colonial features of isolate ﾿        24

2 ﾿ Microscopic observation of isolate    ﾿        25

3 ﾿ Agar well diffusion method ﾿        26

4 ﾿ Agar incorporation method ﾿        27

5 ﾿ Comparison of the mean difference of the test groups and the control group      28

6          Characterization of Rosmarinus officinalis (ROSEMARY) essential oil ﾿        29

7          Characterization of Eucalyptus globulus (EUCALYPTUS) essential oil ﾿        30

 8         Characterization of Citrus limon (LEMON) essential oil      ﾿        32

LIST OF APPENDIX

Appendix                Title ﾿

1                Chromatogram-Rosmarinus officinalis

2                Chromatogram- Eucalyptus globulus

3                Chromatogram- Citrus limon

4                Zone of inhibition of Citrus limon essential oil

5                Zone of inhibition of Eucalyptus globulus essential oil    ﾿

6                Zone of inhibition of Rosmarinus officinalis essential oil      

7                Colonies of Colletotrichum on incorporation of Rosmarinus officinalis essential oil           

8                Colonies of Colletotrichum on incorporation of Citrus limon essential oil    

9                Colonies of Colletotrichum on incorporation of Eucalyptus globulus essential oil 

10              Colonies of Colletotrichum on incorporation of Eucalyptus globulus essential oil ﾿                                           ﾿