ANTIMICROBIAL EFFECTS OF Croton gratissimus

ABSTRACT

The phytochemical composition, antimicrobial and antioxidant activities of leaf of Croton gratissimus (lavender croton) was studied. Extraction of the leaf were obtained in different solvents (water, ethanol and ethyl acetate) and test at invitro level against, Staphylococcus aureus, Escherichia coli and Candida albicans. Results of preliminary phytochemical screening shows the presence of many phytochemicals including alkaloids, saponins, flavonoid, Taninnis, steroids and cyanogic glucosides at varying levels of detection. Quantative analysis of the leaf showed varied concentrations of the phytochemicals such as alkaloids (0.82%), Flavonoid (1.02%), saponin (0.37%), Tannin (0.58%), Phenols (0.82%), phytate (0.33%) and HCN (6.70mg/kg). The antimicrobial tests result indicated varying levels of inhibition of the three microbial pathogens, (Staphylococcus aureus, Escherichia coli and Candida albicans) by the plant extracts in different solvents. Water extract caused inhibition of diameters 12.33mm, 14.33mm, and 14.33mm, against Staphylococcus aureus, Escherichia coli, Candida albicans respectively while that of ethanol extract were 19.00mm, 24.33mm and 15.67mm and ethyl acetate extract had 16.33mm, 14.33mm and 18.67mm for the same test organisms respectively. The activity of the extracts were lower than that of standard antibiotic, which recorded 24.33mm, 23.33mm and 25.67mm against the same organisms. Further antimicrobial tests show minimum inhibition concentrations (MIC) of 150mg/ml for the water extract against each of the organisms. while, the ethanol extract was active at 100mg/ml 50mg/ml and 100mg/ml against Staphylococcus aureus Escherichia coli and Candida albicans respectively. Concentration of phytochemicals with antioxidant potency in the leaf was 21.38 mg /100g Vitamin C, 1.02% Flavnoid and 0.82 % Phenolics. Results of the antioxidant activity showed scavenging activity of 53.03%, chelating activity of 40.08% and reducing activity of standard antioxidant, Butylated Hydro toluene (BHT). Potential health benefits of Croton gratissimus leaves were recognized.

TABLE OF CONTENTS

Title page ﾿ i

Certification ﾿ ii

Dedication ﾿ iii

Acknowledgements ﾿ iv

Table of contents ﾿ v

List of tables ﾿ xi

Abstract ﾿ xii

CHAPTER ONE

1.1 ﾿ Introduction ﾿ 1

1.2 ﾿ Main Aim and Objective of the Research ﾿ 3

CHAPTER TWO

2.0 ﾿ LITERATURE REVIEW ﾿ 4

2.1 ﾿ Description and Habitat of Croton gratissimus ﾿ 6

2.2 ﾿ Nomenclature of Croton gratissimus ﾿ 6

2.3 ﾿ Growing Croton gratissimus ﾿ 7

2.4 ﾿ UsesVApplications of Croton Species ﾿ 7

2.5 ﾿ Phytochemical composition of Croton ﾿ 8

2.5.1 ﾿ Biological activities of the important phytochemicals found in ﾿ plant ﾿ 9

2.6 ﾿ Mechanism of Antimicrobial Action of Bioactive Components ﾿ of Plants ﾿ 14

2.7 ﾿ Some Phytochemical Groups And Mechanism of Anti-Infective Action ﾿ 15

2.8 ﾿ Plant as Alternative source of Antimicrobials

2.8.1 ﾿ Plants having activity against multi drug resistance ﾿ 17

2.8.2 ﾿ Prospective of plants having activity against multi drug resistance ﾿ 18

CHAPTER THREE

MATERIALS AND METHOD ﾿ 20

3.1 ﾿ Materials ﾿ 20

3.2 ﾿ Methods ﾿ 20

3.2.1 ﾿ Sample and media preparation ﾿ 20

3.2.2 ﾿ Media preparation ﾿ 20

3.3 ﾿ Preparation of Leave Extracts ﾿ 21

3.4 ﾿ Determination of Phytochemicals Content of the Plant Sample ﾿ 21

3.4.1 ﾿ Test for presence of alkaloids ﾿ 21

3.4.2 ﾿ Test for the presence of flavonoid ﾿ 22

3.4.3 ﾿ Test for the presence of phenols ﾿ 22

3.4.4 ﾿ Test for the presence of saponin ﾿ 22

3.4.5 ﾿ Test for the presence of tannin ﾿ 23

3.4.6 ﾿ Test for the presence of cyanogen glycosides ﾿ 23

3.4.7 ﾿ Test for steroid ﾿ 23

3.4.8 ﾿ Test for starch ﾿ 24

3.5 ﾿ Quantitative Determination of Phytochemical Constituents of the Plant Samples 24

3.5.1 ﾿ Determination of alkaloid ﾿ 24

3.5.2 ﾿ Determination of flavonoid ﾿ 25

3.5.3 ﾿ Determination of phenols ﾿ 25

3.5.4 ﾿ Determination of saponins ﾿ 26

3.5.5 ﾿ Determination of tannin ﾿ 27

3.5.6 ﾿ Determination of cyanide ﾿ 27

3.5.7 ﾿ Determination of phytate ﾿ 28 

3.5.8 ﾿ Determination of steroid ﾿ 29

3.6. ﾿ Preparation of Inoculant ﾿ 30

3.6.1 ﾿ Antimicrobial activity test ﾿ 30

3.6.2 ﾿ Minimum inhibitory concentration (mic) test ﾿ 30

3.7. ﾿ Determination of antioxidants ﾿ 31

3.7.1 ﾿ Determination of vitamin c ﾿ 31

3.7.2 ﾿ Chelating activity ﾿ 31

3.7.3 ﾿ Scavenging activity ﾿ 32

3.7.4 ﾿ Reducing activity ﾿ 32

3.8 ﾿ Statistical methods ﾿ 33

CHAPTER FOUR

4.0 ﾿ RESULTS ﾿ 34 

CHAPTER FIVE

DISCUSSION, CONCLUSION AND RECOMMENDATIONS ﾿ 40

5.1 ﾿ Discussion ﾿ 40

5.2 ﾿ Conclusion ﾿ 42

5.3 ﾿ Recommendations ﾿ 43

References

Appendix

LIST OF TABLES

Table ﾿ Title ﾿ Page 

1: ﾿ Phytochemical Screening of Extract of Croton gratissimus ﾿ 34

2: ﾿ Qualitative phytochemical screening ﾿ 35

3: ﾿ Antimicrobial activity of Croton gratissimus extracts ﾿ 36

4: ﾿ Minimum Inhibitory Concentration, (mg/ml) of crude extracts of Croton gratissimus

against Staphylococcus aureus, Escherichia, coli and Candida albicans ﾿ 37

5: ﾿ Antioxidant components of leaf of Croton gratissimus ﾿ 38

6: ﾿ Antioxidant activity of Croton gratissimus ﾿ 39