ABSTRACT

Antibacterial activity of ethanol extract of Alchornea laxiflora and Citrus aurantifolia on selected pathogenic bacteria Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Salmonella typhi, and Enterococcus faecalis (ATCC 7080) was evaluated by disc diffusion method. The antibacterial activity of the ethanol extract of Alchornea laxiflora showed a diameter zone of inhibition on Enterococcus faecalis of 15.5mm, 12.5mm and 11.5mm at the concentrations of 100µg, 50µg and 25µg respectively while the selected organisms were not susceptible to Citrus aurantifolia. The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of Alchornea laxiflora extract against the susceptible test organism was 6.25mg/ml and 12.5mg/ml respectively. Qualitative phytochemical screening of Alchornea laxiflora leaf extract revealed the presence of tannins, saponins, flavonoids and the absence of terpenoids. The results obtained from this study suggest that the extract has low potential for use in the treatment of diseases caused by Staphyococcus aureus, Escherichia coli, Salmonella typhi but could be used in the treatment of diseases caused by Enterococcus faecalis.

TABLE OF CONTENTS

Title page                                               i

Certification          ii     

Dedication         iii

Acknowledgements         iv

Table of contents          v

List of tables         vi

Abstract        vii

CHAPTER ONE

1.1 Introduction                                 1

1.2 Phytochemical properties of medicinal plants                                               3

1.3 Aims and objective of study                                   3

CHAPTER TWO

2.0 Literature review                                   4

2.1 Brief history of Alchornea laxiflora and uses                                               4

2.2 Brief history of Citrus aurantifolia                                                                                            4

2.3 Domestic uses of Citrus aurantifolia                                   5

2.4 Medicinal uses of Citrus aurantifolia                                               6 

2.5 Antibacterial activities of Citrus aurantifolia                                               7

2.6 Anti-cancer and cytotoxic activities of Citrus aurantifolia                                                       7

2.7 Antioxidant activity of Citrus aurantifolia                                               7

2.8 Antifungal and antiaflatoxigenic activity of Citrus aurantifolia                                               8

2.9 Effects on the bone                           8

2.10 Phytochemical constituents of Citrus aurantifolia                                                                                9

2.11 Nutritional content of Citrus aurantifolia fruit juice                                                                           10

2.12 Health benefits of phytochemicals obtained from citrus                                                                     10

CHAPTER THREE

3.0 Materials &methods                                    11

3.1 Collection of plant samples                                    

3.2 Preparation and extraction of plant materials                                                              11

3.3 Reactivation of stock culture of test organism                                                 12

3.4 Preparation of stock solution of extracts                                                 12

3.5 Antimicrobial testing                       12

3.6 Determination of MIC (Minimum Inhibitory Concentration)                                                              13

3.7 Qualitative analysis of plant extract         13

CHAPTER FOUR

4.1 Results                                                 14

CHAPTER FIVE

5.1 Discussion                                                                                                                                                18

5.2 Conclusion                             19

REFERENCE