ABSTRACT
Oils extracted from the fruits of two Africa spices- Piper guineense and Xylopia aethiopica were evaluated for their antimicrobial activities using Escherichia coli, Salmonella sp, Aspergillus sp, Bacillus cereus, Penicillum commune and Rhizopus stolonifer as test isolates. Well-in-agar, disc diffusion and dilution susceptibility testing methods were used to assay for their antimicrobial properties. For the bacterial isolates the antimicrobial activity of the oils increased with increase in concentration. B. cereus was more susceptible to the oils than other isolates with zones of growth inhibition measuring 19.5 mm and 18.0 mm for P. guineense and X. aethiopica respectively. However, the disc diffusion method produced lower inhibitory effect on the isolates. The MIC values ranged from 8.0 mg/ml – 16.0 mg/ml while MBC values ranged from 16-32mg/ml. Percentage inhibition against concentration of the oils revealed that percentage inhibition increased with increase in concentration ranging from 91.28% as observed on B. cereus produced by P. guineense to 96.86% on Salmonella sp. produced by X. aethiopica. The antifungal activities of the oils showed moderate to high activities on the isolates. This shows that essential oils of Piper guineense and Xylopia aethiopica has both bactericidal and fungicide effects which can be exploit in disease prevention and control as well as food preservation.
Key words: Antimicrobial activities, Oil extract, Piper guineense, Xylopia aethiopica, Escherichia coli, Salmonella sp, Aspergillus sp.
TABLE OF CONTENT
Title page
Certification
Dedication
Acknowledgements
Abstract
Table of content
CHAPTER ONE
1.0 Introduction
1.1 Background of study
1.2 Statement of problems
1.3 Objectives of the study
1.4 Justification
1.5 Scope
CHAPTER TWO
2.0 Literature review
2.1 Essential oils
2.2 Indigenous spices
2.3 Medicinal uses of indigenous spices
2.4 Antimicrobial effects of extracts from indigenous spices on common bacterial and fungi
CHAPTER THREE
3.0 Materials and methods
3.1 Materials
3.2 Methods
3.2.1 Sample preparation
3.2.2 Extraction of oils from the samples
3.2.3 Media preparation
3.2.3.1 Preparation of nutrient agar
3.3.2 Preparation of eosin methylene blue agar
3.3.3 Preparation of salmonella shigella agar
3.3.4 Preparation mueller hinton agar
3.3.5 Preparation of potato dextrose agar
3.3.6 Characterization of bacterial isolates
2.5.1 Microscopic identification
2.5.2 Biochemical tests
3.4 Antimicrobial susceptibility testing
3.4.1 Well in agar method
3.4.2 Disc diffusion method
3.5 Dilution susceptibility testing
3.5.1 Determination of minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc) of oils from spices.
3.6 Antifungal assay
3.7 Data analysis
CHAPTER FOUR
4.0 Results and discussion
4.1. Antimicrobial susceptibility testing
4.2. Dilution susceptibility testing (dst)
4.3. Antifungal activity of piper guineense and xylopia aethiopica against selected molds
5.0 Conclusion and recommendation
5.1 Conclusion
5.2 Recommendations
5.3 Contribution to knowledge References
Appendix 1
Appendix 2
Appendix 3
Appendix 4
LIST OF TABLE
Table 2.1 Antibacterial activity of the water extracts from the spices, mm 13
Table 2.2 Antibacterial activity of ethanol extracts from the spices, mm 14
Table 3.1 Antifungal activity of ethanolic extracts from the spices, mm 14
Table 4.1. Minimum inhibitory concentration of piper guineense and xylopia aethiopica against selected isolates 33
Table 4.2: Antifungal activity of piper guineense and xylopia aethiopica against selected molds
LIST OF FIGURES
Figure 1(A): Fresh Piper guineense Seeds 7
Figure 1(B): Dried Piper guineense Seeds 7
Figure 2(A): Fresh Xylopia aethiopica Fruit 8
Figure 2 (B): Dried Xylopia aethiopica Fruit 8
Figure 4.1: Antimicrobial Susceptibility Testing of Isolates Using Well in Agar Diffusion Method. 30
Figure 4.2: Antimicrobial Susceptibility Testing of Isolates using the Disc Diffusion Method 31
Figure 4.3: Graph of % Inhibition against Concentration Showing Activity of Piper guineense and Xylopia aethiopica against
Escherichia Coli. 34
Figure 4.4: Graph of % Inhibition against Concentration Showing Activity of Piper guineense and Xylopia aethiopica against
Bacillus cereus.
Figure 4.5: Graph of % Inhibition against Concentration Showing Activity of Piper guineense and Xylopia aethiopica against Salmonella spp.
