ANTIMICROBIAL ACTIVITY OF Capsicum annuum (CHILI PEPPER) EXTRACT ON PATHOGENIC MICROORGANISMS

ABSTRACT

Extracts of Capsicum annuum were studied for their antimicrobial potency against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Shigella spp and Candida albicans using the disc diffusion technique. Qualitative and quantitative phytochemical screening of the ethanol and aqueous extracts of the plant showed the presence of alkaloids, flavonoids, saponins, tannins, steroids, cyanogens and phenols with alkaloids being the dominant compound with a percentage composition of 0.52%. Both the aqueous and ethanolic extracts of Capsicum annuum showed antimicrobial activity against all the test organisms. In aqueous extract, Capsicum annuum showed good inhibitory activity mainly against Escherichia coli and Shigella  spp with zone of inhibition of 19.67 mm ±1.16b and 14.33 mm ±1.52b respectively. The ethanol extract of the plant performed better against Staphylococcus aureus and Pseudomonas aeruginosa with zone of inhibition of 20.33 mm ± 3.06b and 14.33 mm± 0.58b respectively. Based on this finding, this extract may be an alternative to chemical preservatives and used as natural antimicrobial preservatives to reclaim the shelf-life of food.

TABLE OF CONTENTS

Title page ﾿ i

Certification ﾿ ii

Dedication ﾿ iii

Acknowledgement ﾿ iv

Table of Contents ﾿ v

List of Tables ﾿ viii

List of Figures ﾿ ix

Abstract ﾿ x

CHAPTER ONE

Introduction ﾿ 1

1.1 ﾿ Background of the Study ﾿ 1

1.2 ﾿ Objectives of the Study ﾿ 4

CHAPTER TWO

Literature Review ﾿ 5

2.1 ﾿ Description of Capsicum annum (Chilli Pepper) ﾿ 5

2.2 ﾿ The Origin of Chilli Pepper ﾿ 5

2.3 ﾿ Varieties of Pepper ﾿ 5

2.4 ﾿ Intensity of Pepper ﾿ 7

2.5 ﾿ Characteristics of Chilli Pepper ﾿ 7

2.6 ﾿ Classification of Chilli Pepper ﾿ 8

2.7 ﾿ Uses of Pepper ﾿ 8

2.7.1 ﾿ Culinary Uses ﾿ 8

2.7.2 ﾿ Medicinal Uses ﾿ 9

2.7.3 ﾿ Nutritional Uses ﾿ 9

2.7.4 ﾿ Crop Defense Uses ﾿ 10

CHAPTER THREE

Materials and Methods ﾿ 11

3.1 ﾿ Collection of Materials ﾿ 11

3.2 ﾿ Preparation of Samples ﾿ 11

3.3 ﾿ Media Preparation ﾿ 11

3.4 ﾿ Production of Extract ﾿ 12

3.5 ﾿ Preliminary Phytochemical Screening ﾿ 12

3.5.1 ﾿ Qualitative Analysis of Phytochemicals ﾿ 13

3.5.1.1 ﾿ Test For Tannins ﾿ 13

3.5.1.2 ﾿ Test For Saponins ﾿ 13

3.5.1.3 ﾿ Test For Flavonoids ﾿ 13

3.5.1.4 ﾿ Test For Alkaloids ﾿ 14

3.5.1.5 ﾿ Test For Steroids ﾿ 14

3.5.1.6 ﾿ Test For Phenol ﾿ 15

3.5.2 ﾿ Quantitative Determination of the Phytochemicals ﾿ 15

3.5.2.1 ﾿ Determination of Alkaloids ﾿ 15

3.5.2.2 ﾿ Determination of Flavonoids ﾿ 16

3.5.2.3 ﾿ Determination of Tannins ﾿ 16

3.5.2.4 ﾿ Determination of Saponin ﾿ 18

3.5.2.5 ﾿ Determination of Phenols ﾿ 19

3.5.2.6 ﾿ Determination of Cyanogenic Glycoside (HCN) ﾿ 20

3.6 ﾿ Antimicrobial Activity Test ﾿ 21

3.7 ﾿ Statistical Analysis ﾿ 22

CHAPTER FOUR

Results ﾿ 22

4.1 ﾿ Qualitative Phytochemical Screening of Capsicum annuum ﾿ 22

4.2 ﾿ Quantitative Phytochemical Screening of Capsicum annuum ﾿ 24

4.3 ﾿ Antimicrobial Activity of Capsicum annuum ﾿ 26

4.4 ﾿ Relative Potencies of Capsicum annuum Extract ﾿ 29

CHAPTER FIVE

Discussion and Conclusion ﾿ 31

5.1 ﾿ Discussion ﾿ 31

5.2 ﾿ Conclusion ﾿ 33

References