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
LIST
OF TABLES
Table
4.1 Biochemical
Test and Morphological Characteristics of Isolates 50
Table
4.2 Percentage Yield of the Plants 52
Table
4.3 Antibacterial Activity (Zone of
inhibition (mm)) Values of Ethanol
Extract of A.cordifolia against Bacteria Isolates
from Meat 53
Table
4.4 Antimicrobial
Activity (Zone of inhibition (mm) Values of
Aqueous Extract of A.
cordifolia Against Bacteria Isolates from Meat 54
Table
4.5 Antibacterial
Activity (Zone of inhibition (mm) Values of Ethanol
Extract of S.
acuta Against Bacteria Isolates from Meat 55
Table
4.6 Antibacterial Activity (Zone of
inhibition (mm) Values of Aqueous
Extract of S. acuta Against Bacteria Isolates from
Meat. 56
Table 4.7 Minimum Inhibitory Concentration (MIC)
and Minimum
Bactericidal Concentration (MBC) of Ethanol and
Aqeuous Leaf
Extracts of Alchornea
cordifolia Against Bacterial Isolates from Meat. 57
Table
4.8 Minimum
Inhibitory Concentration (MIC) and Minimum
Bactericidal Concentration (MBC) of Ethanolic and
Aqeuous Leaf Extracts
of Sida acuta on
Bacterial Isolates from Meat 58
Table
4.9 Qualitative Phytochemical Analysis of Alchornea cordifolia and
Sida acuta Leaves 59
Table
4.10 Quantitative Pytochemical Analysis of Alchornea cordifolia and
Sida acuta Plant Leaves 60
CHAPTER ONE
1.0
INTRODUCTION
The
history of the use of herbs in the management of diseases dates back to the
time of the early man (Sofowora, 2002; Kafaru, 2004). In herbal medicine,
herbs/plants are used in their unaltered form for the treatment of disease. A
variety of plants or materials derived from plants have been used for the
prevention and treatment of diseases virtually in all cultures (Adedapo et
al., 2005). It is also reported that herbs have been used as sources of
food and medicinal purposes for centuries and this knowledge has been passed
from one generation to another (Adedapo et al., 2005). Medicinal plants
also represent a rich source from which antimicrobial agents can be obtained
(Kubmarawa et al., 2007). Many pharmaceuticals currently available to physicians
have a long history of use as herbal remedies (Elumalai and Eswariah, 2012).
Pravin, (2006) reported that about 70% of the human population is dependent
(wholly or partially) on plant-based medicines and the World Health Organisation
(WHO) estimates that 80% of the population in some Asian and African countries
depends on herbal medicine for some aspect of primary health care (WHO, 2008).
A majority of Nigerian population still rely on herbal medicine
(Eliakim-Ikechukwu and Riman, 2009). Available evidence suggests that some
herbal remedies and traditional therapeutic regimes are efficacious and affordable
(TMP, 2007).
Antimicrobial
drug resistance is a global challenge for the 21st century with the emergence
of resistant bacteria strains worldwide (Furin et al., 2011). The
increasing prevalence of multi-drug resistant strains of bacteria and the
recent appearance of strains with reduced susceptibility to antibiotics raised
the specter of untreatable bacterial infections and adds urgency to the search
for new infection-fighting strategies (Zy et al., 2005; Rojas et al.,
2006).
Medicinal
properties of plants are hinged on the presence of bioactive principles such as
alkaloids, phenols, tannins, glycosides, saponins, terpeniods, flavonoids,
steroids, hydrogen cyanide and essential oils among others. This necessitates
the continued screening of medicinal plants, not only to determine the
scientific basis for their usage, but also to discover possible new active
principles (Karou et al., 2006). The primary benefits of using plant derived
medicines are that they are relatively cheaper than synthetic alternatives,
offering profound therapeutic benefits and more affordable treatments. Many of
the plant materials used in traditional medicine are readily available in rural
areas and this has made traditional system of medicine relatively cheaper than
modern medicine. Many works have been carried out with the aim of knowing the
different antimicrobial and phytochemical constituents of medicinal plants and
using them for the treatment of microbial infections as possible alternatives
to antibiotics and other chemotherapeutic agents to which many infectious microorganisms
have become resistant.
An example is Hydratics Canadensis, not
only does it have antimicrobial activity but also increases blood supply to the
spleen releasing mediating compounds (Ijeh et
al., 2004). Xytopia aethiopica have an attractive aroma and has been applied in ethno medicine
in the treatment of cough, bronchitis, dysentery and female fertilization. Garcina
biflavonone have been found to be active against variety or organism like Staphylococcus
aureus and Escherichia coli (El-said et al., 2006). It is used in the treatment of liver disorder,
bronchitis, as a chewing stick and throat infections (Iwu, 2003). Some extracts
of green pepper, garlic and onion have been observed to inhibit the growth of Shigella
dysentria, Salmonella typhosa (Lamidi et al., 2005). Ocimum gratissimum is used as vegetable for
soup preparations which exhibits hot and spicy taste and are consumed during
cold season. It is claimed that spicies and herbs assist in the concentration
of the uterus in post-partum women (Murray, 2005). Alchornea cordifolia and Sida acuta are also
medicinal herbs in Nigeria used in in treatment of some infectious disease
(Lamidi et al., 2005).
The
genus Alchornea belongs to the spurge family Euphorbiaceae, which
contains about 7500 species in all parts of the world, including trees, shrubs
and herbs (Dos et al., 2010). The
plant stem extracts have been reported to possess antimicrobial activity and
its spectrum of activity has been shown to include the Gram negative bacteria
and the Gram positive bacteria (Tona et
al., 2000; Banzouzi et al., 2002;
Hassan et al., 2006). Its antifungal
activity was reported [Kubmarawa et al.,
2007].
However Sida acuta is a marvelous weed
that frequently dominates improved pastures, waste and disturbed places such as
roadsides (Okwu and Ekeke, 2003). The described pharmacological properties of
the plants involve the antiplsamodial, antimicrobial, antioxidant and many
other properties. Some studies resulted in the isolation of single compounds
while others just demontrated the activity of the crude extracts (Okwu and
Ekeke, 2003).
Medicinal
plants such as Alchornea cordifolia
and Sida acuta have been asserted to provide various culinary and
medicinal properties. These medicinal properties exerts bacteriostatic and bacteriocidal
effects on some bacteria. These effects have been attributed to the peptides,
alkaloids essential oil, flavonoids amongst others which are the major
compounds in these plants (Onajobi, 2006).
2.1 AIM AND OBJECTIVES
The
aim of this work is to evaluate the antibacterial activity of the ethanol and
aqueous extracts of Alchornea cordifolia and Sida acuta leaves against some pathogenic organisms
isolated from meat. The
objectives are;
1.
To characterize and identify pathogenic organisms isolated from meat.
2.
To determine the effect of the aqueous and ethanolic extracts of S. acuta and A. cordifolia on some bacteria isolates from meat.
3.
To determine the minimum inhibitory concentration and minimum bactericidal
concentration of ethanolic and aqueous leaf extracts of Sida acuta and Alchornea
cordifolia.
4.
To determine the phytochemical composition of Alchornea cordifolia and Sida
acuta leaves.
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