PHYTOCHEMICAL SCREENING AND ANTIBACTERIAL ACTIVITIES OF THE ETHANOLIC AND AQEUOUS LEAF EXTRACTS OF Alchornea cordifolia (Euphorbiaceae) AND Sida acuta (Malvaceae) AGAINST SOME BACTERIAL ISOLATES FROM MEAT

 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