Phytochemical Screening and Antimicrobial Activity of Four Nigerian Medicinal Plants

ABSTRACT

The antimicrobial activity and phytochemical screening of the leaves of Piper guineense Schumach, Psidium guajava Linn, Gongrenema latifolium Endl and Terminalia catappa Linn was carried out. The four plant species indicated the presence of alkaloid, phenol, tannin, spaonin and flavonoid which are bioactive component. The percentage of the phytochemcials are as follows alkaloid (0.46.139%), phenol (0.37-1.66%, saponin (0.31-0.67%), flavonoid (0.23-0.55%) and tannin (0.13-037%). The antimicrobial activity of the ethanolic and aqueous extracts of the leaves of the plant species were tested against four microorganisms, Candida albican, Klebsiella pneumonia, Escherchia coli and Bacillus subtilis. The sensitivity of the microorganisms was determined using disk diffusion method. Ethanolic plant extract and aqueous extract inhibited the growth of these pathogens. The zone of inhibition of the growth of these microorganisms by the plant extract depends on the concentration of the extract. Ethanolic plant extract had high sensitivity than the aqueous plant extract which shows less. Gongronema latifolium contained more alkaloids (1.39±0.03%) than other phytochemicals and Terminalia catappa had less tannin (0.13±0.00%) than other phytochemicals. The ethanolic extracts of Gongronema latifolium had the highest inhibitory activity (24.00±2.00mm) which shows more sensitivity against the test organisms while the aqueous extracts of Terminalia catappa has low inhibitory activity (8.33±0.58mm) which showed less sensitivity against the test organism. This result reveals that these plant species have potentials as source of raw materials in the pharmaceutical industry.   

TABLE OF CONTENTS

Cover page

Title page ﾿ i

Certification ﾿ ii

Dedication ﾿ iii

Acknowledgement ﾿ iv

Table of content ﾿ v

List of tables ﾿ vii

List of plates ﾿ viii

Abstract ﾿ ix

CHAPTER ONE 

1.0 ﾿ Introduction ﾿ 1

1.1.2 ﾿ Aims and objective of the research ﾿ 3

1.1.3 ﾿ Justification of the study ﾿ 4

CHAPTER TWO

2.0 ﾿ Literature review ﾿ 5

2.1 ﾿ Phytochemical screening of plants ﾿ 5

2.1.2 ﾿ Antimicrobial activity of plants ﾿ 7

2.3 ﾿ Botany of plants ﾿ 9

2.3.1 ﾿ Botany of Terminalia catappa  ﾿ 9

2.3.2 ﾿ Botany of Gongronema latifolium ﾿ 10

2.2.3 ﾿ Botany of Piper guineenses ﾿ 10

2.2.4 ﾿ Botany of Psidium guajava ﾿ 11

CHAPTER THREE

3.0 ﾿ Source of materials ﾿ 12

3.1 ﾿ Sample preparation ﾿ 12

3.2 ﾿ Phytochemical screening ﾿ 12

3.2.1 ﾿ Qualitative analysis of phytochemicals ﾿ 13

3.2.1.1 ﾿ Test of tannins ﾿ 13

3.2.1.2 ﾿ Test of saponin ﾿ 13

3.2.1.3 ﾿ Test of flavonoids ﾿ 13

3.2.1.4 ﾿ Test of alkaloids ﾿ 14

3.2.1.5 Test of Phenols ﾿ 14

3.3 ﾿ Quantitative determination of the phytochemcials ﾿ 14

3.3.1 ﾿ Determination of alkaloids ﾿ ` ﾿ 14

3.3.2 ﾿ Determination of flavonoids ﾿ 15

3.3.3 ﾿ Determination of tannins ﾿ 16

3.3.4 ﾿ Determination of saponin ﾿ 17

3.3.5 ﾿ Determination of Phenols ﾿ 18

3.4 ﾿ Antimicrobial activity of the leaves of the plants Terminalia catappa, ﾿

Piper Guineenses, Gongronema Latifolium and Psidium Guajava. ﾿ 19

3.4.1 ﾿ Sample Preparation ﾿ 19

3.4.2 ﾿ Production of extracts ﾿ 19

3.4.3 ﾿ Sources of test organism ﾿ 19

3.4.4 ﾿ Antimicrobial activity test ﾿ 20

3.4.5 ﾿ Determination of Minimum Inhibition Concentration ﾿ 20

3.4.6 ﾿ Statistical Analysis ﾿ 21

CHAPTER FOUR

4.0 ﾿ Results ﾿ 25

4.1 ﾿ Phytochemical components ﾿ 25

4.1.1 ﾿ Qualitative analysis ﾿ 25

4.1.2 ﾿ Quantitative analysis ﾿ 26

CHAPTER FIVE

5.0 ﾿ Discussion and conclusion ﾿ 33

5.1 ﾿ Discussion ﾿ 33

5.2 ﾿ Conclusion ﾿ 36

References