ABSTRACT
Studies were carried out on the phytochemical compositions and in-vitro antimicrobial activities of crude extract of Chassalia kolly and Sida veronicaefolia against 20 isolates of Methicillin resistant Staphylococcus aureus (MRSA). This involved phytochemical screening and antimicrobial testing of methanol, ethyl acetate and aqueous extracts of Chassalia kolly and Sida veronicaefolia using basic pharmacognostic procedures and agar well diffusion assay and broth dilution techniques on Methicillin resistant Staphylococcus aureus. Alkaloids, flavonoids, saponins and tannins were detected in all extracts.Tannin was the phytochemical that had the highest concentration in percentage (3.29% and 2.98% ) in the leaves of Chassalia kolly and Sida veronicaefolia respectively while flavonoid had the lowest concentration in percentage (0.88%) in the leaves of Sida veronicaefolia and saponin (0.14%) in the leaves of Chassalia kolly.The agar well diffusion assay showed that the methanolic and ethyl acetate crude extract of Chassalia kolly plant showed antimicrobial activities while the methanolic crude extract of Sida veronicaefolia exhibited little inhibitory action against few of MRSA isolates. There was a corresponding decrease in the zone of inhibition of the growth of the test organism as the concentration of the extracts decreased. The lowest minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) values of the methanolic extracts of Chassalia kolly and Sida veronicaefolia plants were 12.5mg/ml and 25mg/ml respectively and the highest being 100mg/ml while the lowest MIC and MBC of the ethyl acetate extract of Chassalia kolly was 25mg/ml and 50mg/ml respectively with the highest as 25mg/ml for MIC and 50mg/ml for MBC. Findings from this study revealed that methanolic extracts of Chassalia kolly exhibited significant antimicrobial activities on methicillin resistant Staphylococcus aureus and thus suggests need to refine and standardize these extracts as alternative source of antimicrobial medicines.
TABLE OF CONTENTS
Title page
Certification i
Dedication ii
Acknowledgement iii
Table of contents iv
Lists of tables vii
Abstract viii
CHAPTER ONE
1.0 INTRODUCTION 1
1.2 Aims and Objectives 4
CHAPTER TWO
2.0 LITERATURE REVIEW 7
2.1 Role of Traditional Medicine 7
2.2 Sida veronicaefolia (Family: Malvaceae) 9
2.2.1
Description 9
2.2.2 Medicinal value 9
2.3 Chassalia kolly
(Family: Rubiaceae) 10
2.3.1 Description 10
2.3.2 Medicinal value 10
2.4 Phytochemicals of medicinal plants 11
2.4.1
Flavonoids 12
2.4.2 Saponins 13
2.4.3
Tannins 13
2.4.4
Alkaloids 14
2.5 Mechanism
of Action of Phytochemicals 15
2.6 Importance of medicinal plants in drug
discovery 15
2.6.1
Plants Antagonism against Bacterial Pathogens 17
2.7 Antimicrobial Assay 18
2.8
Overview of test organism 19
2.8.1 Staphylococcus aureus 19
2.8.2.1 Invasion 21
2.8.2.2
MRSA pathogenesis 22
CHAPTER THREE
3.0
MATERIALS AND METHODS 23
3.1 Collection, authentication and processing of
plant materials 23
3.2
Extraction of Plant Material 23
3.3
Quantitative Determination of the Phytochemicals 24
3.3.1
Determination of Saponins 24
3.3.2
Determination of Flavonoids 25
3.3.3
Determination of Tannins 25
3.3.4
Determination of Alkaloids 26
3.4 Screening of the Extracts for
Antibacterial Activity 27
3.5
Determination of MIC and MBC of the Crude Extracts 28
CHAPTER FOUR
4.0
RESULTS 29
CHAPTER FIVE
5.0
DISCUSSION 37
5.1 Conclusion 41
5.2
Recommendation 41
REFERENCES 42
TABLE TITLE
PAGE
4.1 Yield
(g/ml) of 30g of Sida veronicaefolia and
50g Chassalia kolly plants
after extraction 31
4.2 Percentage
yield (%) of the phytochemical constituents in each 32
4.3 Antibacterial
activities of different concentrations(mg/ml)
of extracts of
Sida veronicaefolia showing its
diameter zone of inhibition against methicillin
resistant Staphylococcus aureus isolates. 33
4.4 Antibacterial
activities of different concentrations(mg/ml)
of extracts of Chassalia kolly showing its diameter zone of inhibition
against methicillin resistant
Staphylococcus aureus isolates. 34
4.5 MIC
and MBC values (mg/ml) of methanol extract of Chassalia kolly and Sida veronicaefolia plants against methicillin resistant Staphylococcus aureus
isolates at varying concentrations. 35
4.6
MIC and MBC values (mg/ml) of Ethylacetate
extract of Chassalia kolly against
MRSA isolates at varying concentrations 36
CHAPTER ONE
1.0
INTRODUCTION
Plants
have formed the basis of traditional systems of medicine that has been in
existence since time immemorial and continue to provide mankind with new
remedies (Jonathan et al., 2007). A
medicinal plant is one which contains substances that can be used for
therapeutic purposes. Plants act generally to stimulate and supplement the
body’s forces, they are the natural food for human beings (Akinnibosun and
Itedgere, 2012). Plants have traditionally provided a source of hope for novel
drug compounds, as plant herbal mixtures have made large contributions to human
health and well-being (Iwu et al.,1999). The knowledge of traditional
medicine is a custom which has preoccupied mankind since his creation from
generation to generation to maintain health and wellbeing. According to the
World Health Organisation (WHO, 2005) the definition of traditional medicine
may be summarized as the knowledge, skills and practices based on the theories,
beliefs and experiences indigenous to different cultures, used in the
maintenance of health and in the prevention, diagnosis, improvement or
treatment of physical and mental illness. Traditional medicine covers a wide
variety of therapies and practices which vary from country to country and
region to region. For thousands of years before the advent of modern medicine,
herbs and substances derived from plants have been the mainstay of traditional
medicine around the world.
According
to World Health Organization, medicinal plants would be the best source to
obtain varieties of drugs. About 80% of individuals from developed countries
have used traditional medicine, which has compounds derived from plants
(Chintamunnee and Mahomoodally, 2012).
Herbal therapy, or “phytomedicine,” the
therapeutic use of plants, plant parts, or plant-derived substances, is generally
considered a form of complementary medicine. In traditional medical systems
different plant parts are believed to have specific medicinal properties that
were identified over centuries. Among these properties are the ability to
stimulate the body’s disease fighting mechanisms (Jonathan et al., 2007).
The Sida veronicaefolia plant
is used in popular folk medicine for the treatment of
several diseases (Nacoulma, 2006). Ethnobotanical
investigations have shown that Sida
veronicaefolia is frequently and widely used in traditional medicine to
treat various kinds of diseases such as infectious diseases in children such as
malaria, fever, pain, variola, antibacterial, anti-inflammatory, analgesic
activities and hepatoprotective (Karou et
al., 2006).
The
Chassalia kolly plant is used in ethno-medical practices particularly in Nigeria
and the West African sub-region. In the tropics, the leaves are cooked and
eaten as vegetable with nutritional value,
it is used to detect pregnancy in Remo and Ijebu areas of Ogun state (Adediwura
and Jolaade., 2011). In addition, the plant has been reported to possess antimicrobial
properties and this explains the reason for its use in the treatment of human
diseases (Simplice et al., 2011; Govind, 2011).
The
medicinal value of these plants lies in bioactive phytochemical constituents
that produce definite physiological action on the human body. Some of the most
important bioactive phytochemical constituents are alkaloids, essential oils,
flavonoids, tannins, terpenoid, saponins, phenolic compounds and many more
(Akinnibosun and Itedgere, 2012).
A
single plant may be used for the treatment of various disease conditions
depending on the community. Several ailments including fever, asthma,
constipation, oesophageal cancer and hypertension have been treated with
traditional medicinal plants (Saravanan et
al, 2010). The plants are applied in
different forms such as poultices, concoctions of different plant mixtures,
infusions as teas or tinctures or as component mixtures in porridges and soups
administered in different ways including oral, nasal (smoking, sniffing or
steaming), topical (lotions, oils or creams), bathing or rectal (enemas).
Different plant parts and components (roots, leaves, stem barks, flowers or
their combinations, essential oils) have been employed in the treatment of
infectious pathologies in the respiratory system, urinary tract,
gastrointestinal and biliary systems, as well as on the skin (Rıos and Recio,
2005; Adekunle and Adekunle, 2009).
Infectious
diseases are one of the main reasons which cause the death, killing almost 50,000
people every day (Doughari et al., 2009). Based on common belief, drugs
from higher plants and shrubs occupy an important niche in modern medicine.
Because of an increasing interest in plants as source of agents to fight
microbial diseases and the alarming incidence of antibiotic resistance of
pathogenic microbes in particular, there is still constant need for discovering
new and effective therapeutic agents (Mouhssen, 2013). The control of
infectious diseases is badly endangered by the rise in the number of
microorganisms that are resistant to antimicrobial agents. This is because
infections caused by resistant microorganisms often fail to respond to
conventional treatment, resulting in prolonged illness and greater risk of
death.
Antibiotics
resistance is a type of drug resistance where microorganisms are able to
survive exposure to an antibiotic. The primary causes of antibiotic resistance
are genetic mutation in bacteria (Fernando and Martinez, 2013). Inappropriate and irrational use of
antimicrobial medicines provides favourable conditions for resistant
microorganisms to emerge, spread and persist. The greater the duration of
exposure to the antibiotic, the greater the risk of the development of
resistance, irrespective of the need for the antibiotics as resistance toward
antibiotics becomes more common, a greater need for alternative treatment
arises. However, despite the push for new antibiotic therapies there has been a
continued decline in the number of newly approved drugs (Manikkam et al., 2015). Antibiotic resistance
therefore poses a significant problem, nevertheless efforts are in place to
solve the problem.
Due
to the development of bacterial super resistant strains currently used,
antibiotic failed to cure the infectious diseases (Stein et al., 2005). Solution
of antibiotic resistance is the development of new drugs from synthetic or
natural sources. Therefore, discovery of new antibiotic sources that can act
either by direct antimicrobial activity or by preventing resistance of
microorganism with minimal side effects is emerging and is of paramount need
(Khan et al., 2009). Researchers turned their attention towards herbal
products, which is the most promising area in search of new biologically active
compounds with better activity against multi drug resistant strains and reduced
antibiotic related side effects (Khan et al., 2009).
Methicillin-resistant
Staphylococcus aureus (MRSA) has been recognized as one of the major pathogens in
both hospital and community settings.
There has been an escalating rate of infections caused by MRSA worldwide
resulting in increased mortality and morbidity statistics. Resistance towards antibiotics has become a
problem on a global scale. Methicillin resistant Staphylococcus aureus (MRSA) are a major cause of
morbidity and mortality in hospitalized patients. Methicillin
resistant Staphylococcus aureus
(MRSA) have emerged as a major epidemiological problem in hospitals throughout
the world (Akande, 2010). This had led to the search of new antimicrobial source.
Since medicinal plants are good sources
of chemical compounds with diverse biological activities, they provide great opportunity
for the discovery of compounds with high activity against pathogenic micro-organisms
with novel mechanism of action that is less susceptible to resistance by
microbes.
To overcome resistance, many traditional plants are being investigated
as source of alternative agents.
Antimicrobial
potential of some plants had been accepted long before mankind discovered the
presence of microbes (Anwar et al., 2009). The healing power of plants
is usually due to presence of secondary metabolites. Plant extracts and large
number of phytochemicals exhibit strong inhibiting effect on a broad spectrum
of microorganisms (Cowan, 1999; Nascimento et al., 2000; Anwar et al.,
2009).
1.1 Aims and Objectives
The rationale
for this study is to establish the antimicrobial potentials of Sida veronicaefolia
and Chassalia kolly and support its use as alternative
medicine for infections caused by Methicillin resistant Staphylococcus
aureus (MRSA) especially in
resource limited settings.
The
objectives of this study include:
1. To determine the quantitative phytochemical constituents of
methanol, aqueous and ethyl acetate leaf extracts of Sida veronicaefolia and Chassalia
kolly.
2. To investigate the antibacterial
activity of the leaf extracts of Sida
veronicaefolia and Chassalia kolly
against Methicillin resistant Staphylococcus
aureus
3. To determine the Minimum Inhibitory Concentrations and Minimum
Bactericidal Concentrations of the leaf extracts of Sida veronicaefolia and Chassalia
kolly against the test organism.
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