ABSTRACT

The ethanolic and aqueous extracts of Alchornea cordifolia and Sida acuta were screened for antibacterial activities against some bacterial isolates from meat. Five (5) genera of bacteria were isolated and used for this work and they included; Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella spp and Shigella spp. A weight of 50g of the plants leaves powder was soaked in the solvents for 48-72 hours. The aqueous extract of A. cordifolia gave the highest yield of 10.5g (21%) while the aqueous extract of S. acuta gave the least yield of 7.0g (14%).  The cold maceration extraction method was used for the extraction of the active components in the plant leaves used. For the antibacterial activities, the disc diffusion method was employed while the macro broth dilution method was used to determine the minimum inhibitory concentrations and minimum bactericidal concentrations. The ethanol and aqueous extracts of the two plants showed broad spectrum of activities. The aqueous extract of Alchornea cordifolia had larger zones of inhibition ranging from 3.0 mm – 17 mm and lower M.I.C and M.B.C values that ranged from 3.125 mg/ml - 6.25 mg/ml, while the ethanolic extract had zones of inhibition that ranged from 4.0 mm- 15 mm and M.I.C and M.B.C values that ranged from 6.25 mg/ml- 12.5mg/ml. This result was in contrast to Sida acuta which had higher zones of inhibition that ranged from 5 mm – 18 mm and lower M.I.C and M.B.C values that ranged from 1.563 mg/ml - 3.125 mg/ml in the ethanolic extract. The aqueous extract of S. acuta had lower zones of inhibition that ranged from 5 mm – 15 mm and M.I.C and M.B.C values that ranged from 6.25 m-g/ml – 12.5 mg/ml. The biochemical determinations of the plants revealed the presence of Tannin, Saponin, Terpernoids, Steroids, Alkaloids, Flavonoids, Phenol, and Hydrogen Cyanides in the plants at varying quantities. Steroids were absent in Sida acuta. The results of this this study revealed that the extracts of the leaves of the plants had antibacterial activities against the test organisms hence justifying their forkloric use in the treatment of food borne diseases caused by bacteria.

   TABLE OF CONTENTS

Title page i

Certification page ii

Dedication iii

Acknowledgements iv

Abstract v

Table of Contents vi

CHAPTER ONE                   

1.0 Introduction 1

1.1 Aim and Objectives             3

CHAPTER TWO 

2.0 Literature Review 4

2.1       Herbal medicine in Nigeria 4

2.1.1 Safety and Standardization of Herbal Medicine 5

2.1.2 Status of Herbal Medicine in Nigeria 6

2.2       Alchornea cordifolia (Euphorbiaceae) 7 

2.2.1 Plant Description 7                                                                                                                                                                   

2.2.1 Ethno-medicinal Properties of Alchornea cordifolia 8

2.2.2 Phytochemical Constituents of Alchornea cordifolia 9

2.3       Sida acuta (Malvaceae) 9

 2.3.1   Plant description 10

2.3.2    Traditional uses in folk medicine 10

2.3.3    Ethano-medicinal properties of Sida acuta 11

2.3.3.1 Antibacterial activities 11

2.3.3.2 Antifungal activities 12

2.3.3.3 Antiplasmodial activity 12

2.3.3.4 Anti-inflammatory activity 13

2.3.3.5 Analgesic activity 13

2.3.3.6 Antiulcer activity 13

2.3.3.7 Hypoglycemic activity 13

2.3.3.8 Antipyretic activity 14

2.3.3.8 Hepatoprotective activity 14

2.3.3.9 Wound healing activity 14

2.3.3.10    Neuropharmacological effects - 15

2.3.3.11     Antioxidant activity 15

2.3.3.12     Cytotoxicity 15

2.3.3.13     Insecticidal properties 16

2.3.3.14     Inhibitory effect on calcium oxalate crystal growth 16

2.3.3.15     Cardio-vascular activity 16

2.3.3.16 Neutralizing activity against snake venom 17

2.3.3.17 Phytochemical Constituents of sida acuta 17

2.4         Phytochemistry of Medicinal Plants 17

2.4.1      The Journey of Medicinal Plant Research 19

2.4.2      Biological Activities of Phytochemicals 20

2.4.3      Classification of Phytochemicals 20

2.4.4      Phenolics 21

2.4.5      Phenolic acids 21

2.4.5.1   Activity of Phenolic Acids 22

2.4.6.     Flavonoids 23

2.4.6.1   Activity of Flavonoids 23

2.4.7.     Tannins 24

2.4.7.1   Activity of Tannins 25

2.4.8.     Alkaloids 25

2.4.8.1  Activity of Alkaloids 27

2.4.9.     Terpenoids 27

2.4.9.1   Activity of Terpenes 28

2.4.10    Saponin 29

2.4.10.1 Activity of Saponins 29

2.5         Mode of Resistance by Some Bacteria Antibiotics 30

2.5.1      Staphylococcus aureus Resistance. 30

2.5.2      Moraxella catarrhalis Resistance to Beta-lactams. 31

2.5.3      Streptococcus pneumoniae Resistance to Macrolides. 32

2.5.4     Pneumococcal Resistance in Tetracyclines and Other Agents 33

CHAPTER THREE

3.0    Materials and Methods 34

3.1      Study Area 34

3.2 Collection, Identification and preparation of plant leaves. 34

3.3    Source of Meat 34

3.4 Sterilization of Materials 34

3.4 Media Used 34

3.5    Preparation of Media 34

3.6    Isolation of Bacteria                                                                                                   35

3.7       Purification of Isolates and Storage  35

3.8    Identification and Characterization 35

3.9  Gram Staining 35

3.10 Biochemical Tests 36

3.10.1   Motility Test 36

3.10.2   Catalase Test 36

3.10.3   Oxidase Test 36

3.10.4   Coagulase Test 26 

3.10.5   Citrate Test 37

3.10.6   Indole Test 37

3.10.7   Urease Test 37

3.10.8   Methyl Red- Voges- Proskauer Test 38

3.10.9  Triple Sugar Iron Test 38

3.11  Ethanol and Aqueous Extraction of Plant Material 38

3.12     Susceptibility Testing 39

3.13    Determination of Minimum Inhibitory Concentration (M.I.C) 39

3.14    Determination of Minimum Bactericidal Concentration (M.B.C) 40

3.15    Phytochemical Analysis 40

3.15.1   Qualitative analysis for the Presence of Phytochemicals in the Plants Studied. 40

3.15.1.1  Test for the Presence of Alkaloids         40

3.15.1.2  Test for the Presence of Flavonoid 40

3.15.1.3  Test for the Presence of Phenols. 41

3.15.1.4  Test for the Presence of Saponin 41

3.15.1.5  Test for the Presence of Steroid 41

3.15.1.6  Test for the Presence of Tannin. 41

3.15.1.7  Test for the Presence of Terpenoids 42

3.15.1.8  Test for the Presence of Hydogen Cyanide (HCN) 42

3.15.2    Quantitative determination of the phytochemical constituents of the 

           plants studied 42

3.15.2.1  Alkaloid Determination. 42

3.15.2.2  Flavonoid Determination. 43

3.15.2.3  Determination of Phenols. 44

3.15.2.4  Determination of Saponins. 44

3.15.2.5 Steroid Determination 45

3.15.2.6 Tannin Determination 46

3.15.2.7  Determination of Terpenoids 47

3.15.2.8  Determination of Hydrogen Cyanide 47

3.16    Statistical Analysis 47

CHAPTER FOUR

4.0   Results 48

CHAPTER FIVE

5.0   Discussions 61

5.1   Conclusion 65 

5.2   Recommendations 65 

REFERENCES 66

Appendixs 83