ABSTRACT
A comparative study of the antifungal activities of the leaf extract of Mitracarpus hirtus, and the seed and leaf extracts of Garcinia kola was carried out using the Agar well diffusion method on five fungal isolates (Candida albicans, Penicillium marneffei, Microsporum canis, Rhizomucor pusillus and Aspergillus niger). Different concentrations of the plant extracts (50,100 and 200mg/ml) were used against the five pathogenic fungi. Data collected was subjected to t-test and Analysis of Variance (ANOVA). Means were separated by Duncan Multiple Range Test (DMRT) at p≤0.05. The results show that ethanol used as solvent was effective in extracting the active compounds. Results of the qualitative phytochemical compositions of seeds and leaves of G. kola and the leaves of M. hirtus showed the presence of bioactive compounds of interest such as alkaloids, tannins, flavonoids, saponins, phenols, anthraquinones, terpenoids, phlobatannins, steroids and glycosides. Results show that the extracts from leaf of Garcinia kola contained higher percentage of alkaloids (10.05±0.21), phenols (9.54±0.01) and flavonoids (4.80±0.14), than the leaf of M. hirtus (2.50±0.14, 8.10±0.02 and 3.97±0.03), and the seed of G. kola (0.83±0.05, 0.44±0.06 and 0.36±0.04) respectively. The leaf of M. hirtus contained higher percentage of tannins (7.61±0.01) than the leaf and seed of G. kola (2.83±0.03 and 1.34±0.05) respectively. The seed of G. kola contained higher percentage of saponins (5.52±0.05) than the leaves of M. hirtus and G. kola (2.81±0.05 and 2.25±0.35) respectively. The M. hirtus ethanol extract exhibited the best inhibitory activities against most of the test fungi, producing inhibition zones ranging from 12.05±0.07-17.99±0.01mm. There was resistance from Aspergillus niger. The G. kola seed extract also inhibited most of the test fungi. The inhibition zone observed ranged from 10.08±0.11-15.08±0.11mm. There was also resistance from Rhizomucor pusillus. M. hirtus leaf ethanolic extract significantly inhibited Candida albicans, while G. kola seed ethanolic extract also significantly inhibited Microsporum canis and Penicillium marneffei respectively. The activity index of ethanol extract of M. hirtus leaf (0.86 and 0.90 mm) was higher than that of G. kola seed (0.83 and 0.88 mm) when both fluconazole and ketoconazole were used as standard drugs. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of M. hirtus ethanolic leaf extract on the fungal isolates ranged from 6.25-12.5 mg/ml and 12.5-25 mg/ml respectively. The G. kola ethanolic seed extract has minimum inhibitory concentration (MIC) of 50 to 100 mg/ml and minimum fungicidal concentration (MFC) of 100 to 200 mg/ml respectively. Gas chromatography-mass spectrometry (GC-MS) analysis of the leaf and seed extracts of M. hirtus and G. kola was performed. The major constituents identified in ethanolic leaf extract of M. hirtus are 2,4-Di-tert-butylphenol (3.791%), 2-Octylcyclopropene-1-heptanol (6.230%), cis-11-Hexadecenal (2.179%), Cholestan-3-one,4,4-dimethyl-(5α) (4.154%). The major constituents identified in the ethanolic seed extract of G. kola are Hexadecanoic acid (11.276%), Octadecanoic acid (13.569%), n-Hexadecanoic acid (5.038%), l-(+)-Ascorbic acid 2,6-dihexadecanoate (2.444%), 4,7-Octadecadiynoic acid (2.996%), Falcarinol (4.419%) and 6-Octadecenoic acid (2.595%), which might be responsible for antifungal activity of ethanolic leaf and seed extracts of M. hirtus and G. kola. The implication of these results are discussed in relation to the antimicrobial activities of medicinal plants and the use of Garcinia kola seed and Mitracarpus hirtus leaf in treating some fungal infections affecting man.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of Contents vi
List of Tables x
List of Figures xi
List of Plates xii
Abstract xiii
CHAPTER 1: INTRODUCTION
1.1 Background
of the Study 1
1.2 Ethno-medical History in Nigeria 4
1.3 Plants
of Study 5
1.3.1 Garcinia kola (Heckel) 5
1.3.2 Mitracarpus hirtus (L.) DC 6
1.4 Some Medicinally Important
Phytochemicals 7
1.4.1 Phenolic compounds 8
1.4.1.1 Flavonoids 8
1.4.1.2 Phenolic acids 10
1.4.1.3 Tannins 12
1.4.2 Terpenoids 12
1.4.3 Alkaloids 14
1.4.4 Saponins 15
1.4.5 Glycosides 16
1.4.6 Sterols 17
1.5 Some infections Caused by
Fungi 18
1.6
Justification of Study 22
1.7 Statement of the Problem 23
1.8 Aims and Objectives 24
CHAPTER 2: LITERATURE REVIEW 26
2.1 Antimicrobial
Activities 26
2.2 Phytochemical
Screening 31
2.3 Antioxidant
Activity 33
2.4 Hepato-protective
Activity 34
2.5 Anti-inflammatory
Activity 35
2.6 Anti-infertility
Activity 36
2.7 Anti-cancer
Activity 37
2.8 Anti-diabetic
Activity 37
2.9 Central
Nervous System (CNS) Activity 38
2.10 Gas
Chromatography Mass Spectrometry (GC-MS) Analysis 38
CHAPTER 3: MATERIALS AND METHODS 41
3.1 Study Area 41
3.2 Experimental Design 41
3.3 Source of Plant Materials Used 41
3.4 Test Microorganisms Used and their Sources 42
3.5 Macroscopic
and Microscopic Features of Fungal Isolates Used 42
3.6 Extraction
Method 44
3.7 Preparation of the Media and
Inoculation 44
3.8 Reactivation
of Test Microorganisms (Stock Cultured) 45
3.9 Determination of Zone of Inhibition 45
3.10 Determination
of Minimum Inhibitory Concentration (MIC) 46
3.11 Determination
of Minimum Fungicidal Concentration (MFC) 47
3.12 Determination
of the Activity Indices of Plant Extract and
Antibiotics 47
3.13 Qualitative
and Quantitative Phytochemical Screening of Plants
Extract 47
3.13.1 Qualitative
phytochemical screening 47
3.13.1.1 Test for alkaloids 47
3.13.1.2 Test for saponins 48
3.13.1.3 Test for tannins 48
3.13.1.4 Test for
flavonoids 48
3.13.1.5 Test
for phenols 48
3.13.1.6 Test for anthraquinones 48
3.13.1.7 Test for terpenoids 48
3.13.1.8 Test for steroids 49
3.13.1.9 Test for phlobatannins 49
3.13.1.10 Test for glycoside 49
3.13.2 Quantitative
determination of the chemical constituents 49
3.13.2.1 Alkaloid
determination 49
3.13.2.2 Tannin
determination 49
3.13.2.3 Flavonoid
determination 30
3.13.2.4 Saponins
determination 50
3.13.2.5 Phenols
determination
3.14
GC-MS Analysis of
Ethanol Fraction of Mitracarpus hirtus
Leaves and Garcinia kola Seeds 51
3.14.1 Extraction
process 51
3.14.2 The gas
chromatography-mass spectrometry analysis (GC-MS) 51
3.14.3 Identification
of chemical constituents 52
3.15 Statistical Analysis 52
CHAPTER 4: RESULTS AND DISCUSSION 53
4.1
Results 53
4.2 Discussion 149
4.2.1 Presence of bioactive compounds in seeds and
leaves of G. kola and
the leaves of M. hirtus 149
4.2.2 Percentage
of bioactive compounds in the plant materials studied 150
4.2.3 Diameter
of zone of inhibition 151
4.2.4 Activity indices of M. hirtus and G. kola
extracts in comparison
with fluconazole and
ketoconazole 153
4.2.5 Minimum inhibitory concentration (MIC) and
minimum fungicidal
concentration
(MFC) 154
4.2.6 Phytochemical components of the ethanol leaf
extract of M. hirtus
and the seed extract
of G. kola using GC-MS 155
4.2.7
GC–MS profile and Retention time of
crude leaf ethanol extract of
Mitracarpus hirtus and seed extract of Garcinia
kola 156
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS 158
5.1 Conclusion 158
5.2 Recommendations 159
References 160
Appendices 186
LIST
OF TABLES
4.1 Qualitative
phytochemical screening of the seeds and leaves of
G. kola, and the leaves of M. hirtus. 53
4.2 Comparative
Phytochemical composition of Garcinia
kola seed and leaf 55
4.3 Comparative
Phytochemical composition of Mitracarpus
hirtus leaf
and Garcinia kola seed 57
4.4 Comparative
Phytochemical composition of Mitracarpus
hirtus leaf
and Garcinia kola leaf 59
4.5 Diameter of zone of
inhibition (mm) of ethanol extract of M.
hirtus
leaf
against some pathogenic fungi 61
4.6 Diameter
of zone of inhibition (mm) of ethanol extract of G. kola
seed against some pathogenic fungi 63
4.7 The
activity index of the extract of both plants in comparison with
standard drug (Fluconazole) 65
4.8 The
activity index of the extract of the both plants in comparison with
standard drug (Ketoconazole) 67
4.9 MIC
and MFC (mg/ml) of M. hirtus leaf
ethanol extract on fungal
isolates 69
4.10 MIC
and MFC (mg/ml) of G. kola seed
ethanol extract on fungal isolates 71
4.11 Phytochemical
components of M. hirtus leaf ethanol
fraction
using GC-MS 73
4.12 Phytochemical
components of G. kola seed ethanol
fraction
using GC-MS 121
LIST
OF FIGURES
4.1 Chromatogram of different chemical
compounds identified in the
ethanol extract of Mitracarpus
hirtus leaf using GC-MS. 75
4.2 Generalized GC–MS profile of crude leaf
ethanol extract of
Mitracarpus hirtus 119
4.3 Chromatogram of different chemical compounds identified in the
ethanol extract of Garcinia kola seed 123
4.4 Generalized
GC–MS profile of crude seed ethanol extract of
Garcinia kola 147
LIST
OF PLATES
1 Zones
of inhibition of aqueous and ethanol extracts of
Mitracarpus hirtus leaf against Penicillium marneffei 180
2 Zones of inhibition of aqueous and
ethanol extracts of G. kola
seed
against Penicillium marneffei 181
3 Zones
of inhibition of aqueous and ethanol extracts of G. kola
seed
against Penicillium marneffei 182
4 Zones
of inhibition of aqueous and ethanol extracts of G. kola
seed
against Microsporum canis 182
5 Garcinia kola leaves 183
6 Garcinia kola seeds 184
7 Mitracarpus hirtus
leaves 185
CHAPTER
1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The use of healing powers of plants is as old as man.
Till date, natural plants of various types are used in traditional African medicine
for providing healing to various ailments even before and after the spread of
modern and scientific medicine. Ethno-medicine
is the oldest medicinal system and often traditionally referred to as the
Cradle of Mankind (Van Vuuren, 2008).
Traditional herbal drugs have been used to cure infectious diseases for so many
years in various parts of the world (Adebayo and
Krettli, 2011). There has been a developed interest in local medicine
the whole world because traditional medicine is not used by all people (Adebayo and Krettli, 2011). In developing countries, the health care has
been maintained by other practices based on traditional values attached to them
(Adebayo and Krettli, 2011).
In many developing countries, including Nigeria, 80%
of patients use indigenous herbal remedies to treat infectious diseases (Nasir et al., 2015).
Despite the availability of modern medicine in some communities, herbal
medicines (use of medicinal plants) have continued to maintain popularity for
historical and cultural reasons, in addition to their efficacy and cheaper cost
(Lifongo et
al., 2014). They serve
as essential sources of new pharmacological bioactive substances since the
entire parts of a plant, from roots to seed heads and flowers, are
used in traditional treatments and can, therefore, act as major compounds used
for drug production (Lifongo et al., 2014). Moreover, molecules from natural products
have represented about 80% of drugs that have been put into the market (Ntie-Kang et al.,
2013). The use of plant remedies has steadily grown globally in recent
times as well as the look for new bioactive compounds that eventually could be
produced as important drugs for the cure of infectious diseases (Nasir et al., 2015).
Plants
contain bioactive compounds which are considered the source of active
ingredients for modern and traditional medicine. Plants produce primary metabolites
like proteins, lipids, nucleic acids and starch from substances such as water,
carbon dioxide, nitrogen and numerous nonorganic salts in appreciable amounts. These base metabolites are changed
into secondary metabolites (alkaloids, steroids, terpenoids, saponins,
flavonoids) that are used as drugs (Akerle-Heywood
and Synge, 1991). Long-term history of indigenous plants has offered
good crude materials for many factories such as drug manufacturing companies,
cosmetic, perfumery and dietry (Sathiya et
al., 2008). The presence of many life enhancing
components in plants have stimulated scientists to examine various plants with
hope of determining their potential on antimicrobial effects (Nayak and Lekley, 2006).
It is generally believed that most of the steadily used antimicrobials which are
mainly chemical drugs may not be efficient and some of these agents exhibit
dangerous effects to users of the dugs (Udegbunam et al., 2014). For example,
Stevens-Johnson syndrome and toxic epidermal necrolysis, and hypersensitivity
reactions are associated with the administration of antimicrobials such as
sulfonamide and fluoroquinolones, and penicillin, respectively (Ferrandiz-Pulido and Garcia-Patos, 2013). All the
professionals/scientists that formulated strategies to tackle the antimicrobial
resistance situation knew that production of new and safe antimicrobials is
more important than any other suggested solutions/strategies (Roca et al.,
2015). Many initiatives and programs have been set up by many
countries/organizations with the aim of developing new, effective, and safe
antimicrobials (Roca et al., 2015). Thus, researchers/scientists are now looking
everywhere in the environment including animal, plant, soil, and marine for
potentially new and safe antimicrobial agent (Nasir
et al., 2015). Unfortunately,
the speed at which microbes develop antimicrobial resistance outpaces the rate
of discovery/development of new drugs (Huttner et al., 2013). For instance, the
10x’20 initiative proposed in 2010 is aimed at developing ten new, safe, and
more active antibiotics by 2020 (Infectious
Diseases Society of America, 2010).
Currently, antimicrobial
resistance is primarily the major challenge to world health and factors such as
global climatic change, globalization (increased international travel and food
importation/exportation), and change in demographics are worsening the crisis (Cheng
et al., 2016; WHO, 2014). The rising
and continuous spread (as a result of moving genetic elements) of multiple drug-
and pan-drug-resistant microbes (such as carbapenem-, quinolone-,
extended-spectrum β-lactam-, vancomycin- , methicillin- and colistin-resistant
bacteria) which show resistance to almost all antimicrobial agents presently known to man, have put the
globe in confusion (http://www.amr-review.org/Publications) .
The economic and health conditions of
antimicrobial resistance on a worldwide scale is great and dreadful. A current
review on “global crisis of antimicrobial resistance” organized by
Jim O’Neill, estimated that about 700,000 human beings die globally every year
due to antimicrobial-resistant diseases (http://www.amr-review.org/Publications). The review also
projected that by 2050, the societal and monetary cost of not handling the
antimicrobial resistance challenges could be US$100 trillion (Piddock, 2016). Other current researches
estimated population decrease of between 11 million and 444 million people and
a decrease in the size of the worldwide economic profile by 0.1-3.1% by 2050,
if more active antimicrobial drugs are not developed (Fitchett and Atun, 2016). The sum of money use
in producin a new antimicrobial drugs has been projected to be US$1 billion (Huttner et al.,
2013) and projection of US$30 billion is require to handle antimicrobial
resistance crisis now before it gets out of control (Piddock, 2016). The effect of antimicrobial
resistance is devastating in poor countries, including Nigeria, where the money
spent in managing resistant infections and resultant deaths are not put into
consideration (Huynh et al., 2015).
1.2 ETHNO-MEDICAL HISTORY IN NIGERIA
In spite of the
well-compiled ethnobotanical journals, very limited scientific information
(e.g., efficacy, phyto-chemistry) is available on traditional medicinally used
plants in Nigeria (Adebayo and Krettli, 2011; Conrad et al.,
2014). From journals obtained so far, the oldest documents on
antimicrobial properties of Nigerian plants are those of Dalziel (Dalziel,1956) in 1937 and 1957, respectively.
Twenty years later, few other journals on antimicrobial activities and
chemistry of Nigerian plants appeared in the literature (Odebiyi and Sofowora, 1979). Around 1980s, a
handful of studies on antimicrobial potential of Nigerian plants became
obtainable in the journal (Wolinsky and Sote, 1984;
Aladesanmi et al., 1986).
However, from 1990 till date, there has been overwhelming number of articles in
the literature on the antimicrobial activities and chemistry of Nigerian
medicinal plants. This current development in the scientific authentication of
antimicrobial properties of Nigerian medicinal plants may be as a result of
rise in public enlightenment, technological advancements and a number of
publications in local books supporting the need for such studies (Iwu, 1993; Dalziel, 1955).
Further reasons
for advancement of work on Nigerian medicinal plant include sourcing for new
pharmacological active compounds to be produced as drugs or as templates for
analog production and the evaluation of ethno-medicine and herbal medicinal
products/mixtures (Yuan et al., 2016; Nasir et al., 2015). Medicinal properties of
Nigerian plants are associated to synergetic effects of phytocompounds (like
phenols, flavonoids, alkaloids, saponins, tannins, and essential oils) and
phytochemical compounds contained in their tissues (Okigbo et al.,
2009). Scientific documentations of studies on antimicrobial properties of
Nigerian plants would give clearer understanding of the level of research that
has been done to explain the antimicrobial potentials of these plants.
1.3 PLANTS OF STUDY
1.3.1 Garcinia kola (Heckel)
Garcinia kola (Heckel) (bitter kola) is a species of flowering
plant in the Clusiaceae or Guttiferae family. Bitter kola is found in Benin Republic, Cameroon, Republic of Congo, Ivory Coast, Gabon, Ghana, Liberia, Nigeria, Senegal and Sierra
Leone. Its natural habitat is subtropical or tropical moist lowland forests.
The nuts, fruit, bark and seeds fruit of the plant have been helpful for
hundreds of years in folk medicine
to cure ailments from coughs to fever (Iwu, 1993). Garcinia kola trade
is still important to the tribes and villages in Nigeria.
Seeds of the plant
are mainly used in Southern Nigeria and parts of West Africa as masticatory
regardless of its bitter taste (Iwu et al., 1987). It is also used for
traditional and social ceremonies, traditional way of welcoming guests and
worship of deities among traditionalists in some part of West Africa (Iwu,
1993). Bitter kola is one of those few herbal plant referred to as ‘wonder plant’
because of its’ wide use in fighting numerous infectious diseases in Africa
ethno-medicine. Garcinia kola is
eaten raw as adjuvant of true kola and quoted as Guinea worm remedy and as a
vermifuge (Sofowora, 1982). It prevents colics and particularly known to
improve singing voice, due to its effectiveness for bronchitis and throat
troubles (Iwu, 1993). The uses of other parts of Garcinia kola tree for
traditional medicine have been documented (Adaramoye et al., 2005a;
Sofowora, 1982).
In spite of the socio-economic value of Bitter kola,
planting of the species is not common. Factors that have negatively affected
farmers from cultivating Garcinia kola include seed dormancy or
germination problems that reduces seedling steady existence. Most viable trees
were left in the forest when farmers create plots out of the forest (Adebisi,
2004). Scientists have studied the germination difficulties/challenges of G.
kola seeds and proposed many ways of breaking seed dormancy (Gyimah, 2000; Anegbeh
et al., 2006; Kanmegne and Ndoumou,
2007; Oboho and Ogana, 2011; Oboho and Urughu, 2010). However, there is much
need to investigate easy and practicable strategies that farmers could easily
adopt with low professional input. G. kola seeds has both seeds coat
dormancy and physiological dormancy probably imposed by the chemicals in the
seed (Oboho and Urughu 2010). Seed coat dormancy of bitter kola can be minimized by removing the seed protective
cover before planting, whereas physiological dormancy or endogenous dormancy
can be minimized by soaking in distilled water for 3 days (Yakubu et al.,
2014). Removal of the seed protective cover, soaking in distilled water for 3
days, putting inside air tight transparent polythene bag and watering the seeds
when required for steady moisture gives an early germination period of two
weeks (Yakubu et al., 2014).
1.3.2 Mitracarpus hirtus (L.) DC:
Mitracarpus hirtus belongs to the Rubiaceae family, and is commonly
distributed throughout gardens, farms and fields in tropical and subtropical
regions; United States of America, India, Malaysia, west and east African
countries (Alqasim et al., 2013). In different parts of tropical Africa, it is traditionally
used for treatment of sore throat. It is simply referred to as tropical
girdlepod. In Nigeria, the liquid extract from
the upper parts of the plant above soil is rubbed on the body against skin
diseases and on wounds (Abere et al.,
2007). Orally, it is employed as an antidote to arrow poison, anti-dysentery
and anti-diarrhea (Abere et al.,
2007). Ethno botanical surveys showed wide use of M. hirtus for treating fungal diseases such as ringworm, rashes,
itching, eczema, toothache, venereal diseases, by rubbing leaves on skin or
taken orally (Alqasim et al., 2013).
Mitracarpus
hirtus is
an erect plant. The leaves are opposite and decussate, elliptical and slightly
stalked, with a serrated stipular collar. The flowers are white, sessile,
grouped in axillary glomerules. They have a persistent calyx, fused to the
ovary and surmounted by 4 lobes of which 2 are reduced and 2 are developed, 4
petals welded into a tube topped by four lobes (Akobundu and Agyakwa, 1989). The fruit is a dehiscent capsule,
globular in shape. It is 2 mm long and surmounted by parts of the calyx. The
line of dehiscence is located at the equator of the capsule. The capsule
contains a seed in each loculus. The seeds are elongate, forming a
cross with branches bent towards the center. They are 1 mm long and 0.5 mm
wide. The protective seed coat is light brown and finely tuberculous (Grard et al., 2010).
1.4
SOME MEDICINALLY IMPORTANT
PHYTOCHEMICALS
Phytochemicals
are biological metabolites, which are natural chemical compounds seen in
plants, which shade plant cells from ecological disturbances like stress,
pollution, drought, UV light exposure and pathogenic infections (Ali and
Alqurainy, 2006). These substances are referred to as secondary plant
metabolites and offer health importance to human beings. They are known to act
as synergistic agents, allowing food materials to be used more effectively by the
body. Some of the important roles of phytocompounds are reduced toxicity, easy
availability, reduced cost and their biological properties like antimicrobial
activities, antioxidant properties, modulation of detoxification enzymes, lowering
of platelet aggregation, enhancement of the immune system and modulation of
hormone metabolism and antineoplastic properties (Andre et al., 2010). Phytochemicals are not major nutrients and are not
needed by the human body for maintaining life, but have beneficial effects to
stop or to fight some common infections (Holst and Williamson, 2008). The
pharmarcological activities of some medicinal plants can justifiably be
considered to, among others, the bioactive compounds in them especially the saponins,
alkaloids, sterols, phenolic acids, tannins, terpenoids and flavonoids.
1.4.1 Phenolic compounds
Phenolic
compounds are phytochemicals that have one or more than one aromatic rings with
at least one hydroxyl group. In plants, they play a protective role by
minimizing the effect of aggression by predators, parasites and also protect
plants from ultraviolet radiation. Phenolics and tepernoids are ubiquitous in
fruits, cereals, legumes and vegetables. Plant phenolics include flavonoids,
phenolic acids and tannins (Piero et al.,
2015).
1.4.1.1 Flavonoids
Flavonoids
are low molecular mass polyphenolic antioxidants that are found to be present
in vegetables, fruits and beverages such as astea and wine (Nyamai et al., 2015). Flavonoids are thought to
have many medicinal values. Flavonoids have been revealed to have antihyperglycemic
property (Muriithi et al., 2015).
Flavonoids are thought to enhance cardiac function, reduce anginas and
decreases cholesterol levels. These substances act by regulating inflammation
mediators (Sánchez et al., 2008).
Flavonoids have also been found to decrease production of pathogenic thrombosis
in mice models (Jiang et al., 2010).
A substrate of sea buckthorn which contains high level of flavonoids has been
found to restore cardiac function and enhance blood circulation in patients
with coronary heart disease. Flavonoids have been employed in the management of
hypertension and chronic cardiac insufficiency as they obstruct the enhancement
of necrosis factor kappa-B (Lim et al.,
2006). Flavonoids like flavone C-glycoside, kakonein and caesalpin P enhance
the function of pancreatic islet cells and have diabetic properties (Mohammad et al., 2006). It has been reported that
the flavonoid glycosides cause pancreatic beta cell regranulation and have been
employed in clinical management of diabetes as a result of increased
sensitivity of insulin (Seeram et al.,
2006).
Anthocyanins
and proanthocyanins are flavonoids. Anthocyanins are believed to inhibit
formation of free radicals thus protecting cardiomyocytes after ischemic
episodes (Benkhayal et al., 2009).
These compounds have also been known to reduce the quantity of nitric oxide by
preventing the effect of nitric oxide synthase (Ngugi et al., 2012). Anthocyanins have anti-inflammatory property as they
block cyclooxygenase enzyme. These flavonoids block the impact of VCAM
molecules thereby inhibiting expression and attachment of endothelial cells
with leucocytes. These phytocompounds are also said to reduce the amount of
interferon necrosis factor-gamma, interleukin-2 and prevention of mast cell
degranulation and tumor necrosis factor-alpha (Joseph et al., 2011). Proanthocyanins and anthocyanins have antibacterial
activities and block the sticking of bacteria to the mucous membrane of the
urinogenital passage (Pataki et al.,
2002). Studies have revealed that anthocyanins have hepatoprotective effect towards
hepatocytes of hepatitis B and A patients and paracetamol-induced
hepatotoxicity (Lin et al., 2002).
They reduce prostaglandin levels by blocking COX-2 thereby acting as
anti-inflammatory substance in inflammated connective tissue and joints and
enhance type II collagen production (Howell, 2002). Proanthocyanins are known
to better clinical manifestation of pancreatitis such as abdominal pain, nausea
and vomiting and to reduce the pathological developments that take place (Knox et al., 2000). These chemical compounds
hinder sensitivity of intestinal cells to insulin and inhibits α-glucosidase
enzyme in the intestinal lumen thereby reducing sugar levels (Ali et al., 2003). Proanthocyanins and anthocyanins
inhibit the effect of enzymes that stimulate apoptosis thereby conferring
protective property on cardiomyocytes after ischemic injury (Vinson et al., 2002). Anthocyanins have been
employed in treatment of Epstein-Barr virus induced lymphoma, gastric
adenocarcinoma, ovarian carcinoma and pulmonary carcinomas (Bagchi et al., 2002).
1.4.1.2 Phenolic acids
Phenolic
acid compounds are aromatic secondary plant metabolites evenly distributed in
plants. Phenolic acids that are found in in the environment can be divided into
two major groups; benzoic acid derivatives and cinnammic acid derivatives such
as ferulic acid and caffeic acid. Ferulic acid, a phenolic acid is believed to
have a broad spectrum of therapeutic properties against diseases such as cardiovascular,
diabetes, neurodegenerative, inflammatory diseases and cancer (Uraji et al., 2013). These pharmacological
properties are said to be due to the antioxidant properties of the phenolic
acids (Joshi et al., 2001). Ferulic
acid inhibits lipid peroxidation and destroys superoxide free ion radical. The
structural features of phenolic acids make them to have the antioxidant
activities. These chemical compounds posses a phenolic nucleus and an unsaturated
side chain that can produce a resonance stabilized phenoxy group. Reactive
radicals collide with these substances/elements gaining a hydrogen atom and
producing a phenoxy radical (Iwase et al.,
2000). Phenolic acids and its ester derivatives decrease the amount of
inflammatory mediators such as prostaglandin E2, tumor necrosis factor-alpha
(Appendino et al., 2006). Ferulic acid
derivatives have been said to hinder the effect of cyclooxygenase-2 promoter
property in human colon cancer DLD-1 cells enroute the β-galactosidase reporter
gene assay system (Ronchetti et al.,
2006). Diabetes, an endocrine defect is characterized by hyperglycemia leading
to oxidative stress because of the high synthesis of free radicals. Phenolic
acids lower the harmful effect of streptozotocin by stopping the effect of free
radicals synthesize in the pancreas by streptozotocin (Uttara et al., 2009). The reduction in harmful
effect and oxidative stress in the pancreatic cells make beta cells to grow
vigorously and produce more insulin. Increased insulin production leads to
decrease in glucose levels due to increased glucose utilization by extra
hepatic tissues. Phenolic acids are also said to protect lipids, DNA and proteins
from oxidative stress thereby exerting anticancer activities (Delmas et al., 2006). These phytocompounds also
act on channels that control induction to apoptosis, regulation of
proliferation and reaction to oxidative stress. Phenolic acids have been
revealed to hinder occurrence of pulmonary cancers in mice, inhibit mutagenesis
and lower urinary N-nitrosoproline amount in humans. Phenolic acids restore
normal homeostasis by stimulating apoptosis in cancer cells (Kang et al., 2011). Phenolic compounds absorb
UV light, producing a stable phenoxyl radical radiation thereby ending free
radical chain reactions. These compounds sustain the physiological properties
of cells by scavenging deleterious radicals and chain reactions and hinder
radiation-induced oxidative reactions (Uttara et al., 2006).
Phenolic
compounds sustain the properties of cells exposed to alcohol stress by stopping
the lipid peroxidative chain and scavenging free radicals. The mode of action
is known to be by abstraction of H+ by hydroperoxyl and hydroxyl radicals
through a free phenolic substrate to produce a phenoxyl radical which then forms
products that are passed out in bile (Delmas et al., 2006). Phenolic acids are said to stop oxidative modification
of proteins by lowering the possibility of oxidative attack on them (Delmas et al., 2006). Phenolic acids improve
the endogenous antioxidant defense system, restores the damage caused by
nicotine and prevents cells from oxidative destruction (Uttara et al., 2006). These compounds protect
cell membrane by stopping the free radicals, increase the antioxidant level and
block the leakage of marker enzymes into circulation.
1.4.1.3 Tannins
Tannins are
polyphenols that are produced from different parts of varying plants belonging
to so many species. It is produced in large quantities in the tree fruit pod,
leaves, bark, wood, fruit and roots and also in plant gall. Tannins can be
grouped into two broad categories – condensed tannins and hydrolysable tannins.
The tannin epigallo-catechin-3-gallate is believed to exhibits anti-diabetic
properties (Kang et al., 2011). In
medical terms, all types of tannins may involve in the control of glucose level
in the blood. Tannin has been indicated to enhance the receptor cells to make
use of carbohydrate. It has been revealed that tannins act as an antifungal
substance at increased concentrations by coagulating the protoplasm of the
microbes (Adekunle and Ikumapayi, 2006). Consequently, the possible mode of action
of tannins have been attributed to interference with energy production by
uncoupling oxidative phosphorylation or interference with glycoprotein of cell
surface (Harekrishna et al., 2010).
Ellagic acid and quercetin work in combination to lower viability,
proliferation and trigger apoptosis of MOLT-4 human leukemia cells (Gao et al., 2001). Ellagic acid and
resveratrol are believed to completely inhibit skin tumorgenesis in mice
(Cassidy et al., 2000).
1.4.2 Terpenoids
Terpenoids
are chemical substances produced from five carbon isoprene units majorly
isopentenyl pyrophosphate and its isomerdimethylallyl pyrophosphate by terpene
synthases. Terpenoids have antioxidant potential and also work with most
regulatory proteins. Plant liquid extracts have been employed both culturally
and in modern medicine in the fight of cancer and inflammatory diseases.
Terpenes are important inhibitors of NF-kB in modern medicine (Piero et al., 2015). NF-kB system is a
cytoplasmic sensor that responds to so many internal and external signals such
as genotoxic stress and hypoxia as well as challenges in the immune system.
NF-kB also plays active role in the production of cellular resistance against anti-apoptotic
signalling and apoptosis. Most of the terpenes in plants are in the form of
terpene derivatives (terpenoids). Sesquiterpenoids are the major tepernes and
are said to have NF-kB signaling inhibitory activity whereas diterpenoids and triterpenoids
are also confirmed to have several active inhibitors of NF-kB signaling system
(Mertens-Talcott et al., 2003). Aucubin,
a monoterpenoid that are seen in plants as glycoside derivative stops the
nuclear translocation of P65 subunit of NF-kB complex in enhanced mast cells
and also block the degradation of IkBa protein (Mertens-Talcott et al., 2003). Limonene and their
derivative perillyl alcohol are said to have inhibitory potential on mammary
and pancreatic tumors (Yang et al.,
2003). These two phytocompounds are also said to block proliferation and
metastasis of gastric cancer.
Artemisinin,
a lactone extracted from Artemisia annua is mainly used as an anti-malarial
drug but it is also employed as an antifungal, anticancer, immunosuppressive
and antiangiogenesis properties (Salminen et
al., 2008). Terpenoids also enhance the skin tone, improves the
concentration of antioxidants in wounds, and ressucitate inflammed tissues by
increasing blood flow (Lyss et al.,
1998). Terpenoids also increase lung function (Mujoo et al., 2001). The seeds and leaves of S. spectabilis are
employed in the management of diabetes because of the presence of
phytochemicals including terpenoids (Grace et
al., 2013). Terpenoids have been confirmed to lower diastolic blood
pressure and reduce the amount of sugar in blood in diabetic and hypertensive
patients respectively (Grace et al.,
2013). The anthraquionone in the plant liquid extracts of Polygonum
multiflorum have been employed in the management of peripheral neuropathy,
a complication that is connected with diabetes mellitus (McPartland et al., 2001).
1.4.3 Alkaloids
Alkaloids
are biochemical compounds that have nitrogen and are derived from so many amino
acids. Alkaloids are said to have blood glucose lowering property. Alkaloids
tetrandine and berberine have been indicated to exhibit antioxidant property
responsible for many biological potentials connected with this plant including
antidiabetic effect (Yang et al.,
2003). Alkaloid fractions have exhibited hypoglycemic effect in mice (Cassidy et al., 2000). The alkaloids l-ephedrine
of Ephedra distachya herbs have demonstrated hypoglycemic property in
diabetic mice because of restoration and regeneration of atrophied pancreatic
islets that encourages the production of insulin (Piero et al., 2015). Alkaloids with therapeutic properties usually act by
affecting biochemical transmitters of the nervous system such as γ aminobutyric
acid, acetylcholine, dopamine and serotonin. Alkaloids are also confirmed to be
anti-arrythmic properties, antihypertensive properties, anticancer and anti-malarial
potential (Abdirahman et al., 2015;
Verma et al., 2013). Alkaloids are
said to have neuro-protective, cholinergic and antioxidant properties in
Alzheimer’s disease (O’Brien et al.,
2006). These chemical compounds have retentive-memory and cognitive-enhancing
properties on Alzheimer’s patients. The therapeutic importance of these phytocompounds
is known to be by restricting inflammatory reactions and oxidative stress,
inducing cholinergic transmission, increasing estrogen and other neurotropic
substances and inhibiting β-amyloid toxicity- formation (O’Brien et al., 2006). These chemical compounds
block acetylcholinesterase enzyme. Inhibition of this enzyme enhances
acetylcholine activity which is one of the main methods in the fight of
Alzheimer’s disease. Tetramethylpyrazine, an amide alkaloid is believed to show
hypotensive potentials by preventing platelet aggregation and vasoconstriction
(Guruvayoorappan et al., 2014). This
alkaloid has been confirmed to induce inotropic and chronotropic reactions on
isolated atria. Tetramethylpyrazine is employed in the fight of occlusive cerebral
arteriolar diseases as a result of its vasodilatory potentials. Alkaloids have
also been revealed to have cytotoxic, trypanocidal and antimicrobial properties.
These chemical compounds act by intercalating DNA thereby impairing
transcription and replication causing frame-shift mutations (Guruvayoorappan et al., 2014). Alkaloids are also said
to show antimicrobial and trypanocidal property by blocking of protein
biosynthesis and by association with neuroreceptors (Francis et al., 2002).
1.4.4 Saponins
Saponins are
plant compounds that occur either as steroid alkaloids, glycosides of
triterpenoids or steroids. These phytocompounds are said to have immunostimulant,
hypocholesterolaemic, hypoglycemic potential and anticarcinogenic activities
(Ros, 2000). The hypoglycemic potential of saponins is associated to
enhancement of pancreatic β-cells, prevention of glucose transport across the
brush border cells of the small intestines and hinder the transfer of glucose
from the stomach to the small intestines. Saponins are also revealed to prevent
gastric emptying in a dose dependent manner (Tan and Vanitha, 2004). Saponins
reduce cholesterol level by forming large micelles that are then removed in
bile. These chemical compounds are believed to decrease serum levels of low
density lipoproteins-cholesterol and lower intake of cholesterol in the
intestines (Chung, 2004). Saponins are known to act as adjuvants in improving
antibody synthesis and in the stimulation of cell mediated immune system. These
chemical compounds are known to interact with antigen-presenting cells and
enhance interferon and interleukin production thereby mediating
immune-stimulant properties (Guruvayoorappan et al., 2014). Saponins block tumor cell development by apoptosis
in leukemia cell line and by cell cycle arrest in breast cancer cell line. They
also exert anti-proliferative active to prostate carcinoma cells by inducing
apoptosis and cell cycle arrest at G1 phase. Saponins enhance apoptosis by
promoting cytochrome c-caspase pathway. The nature and position of the sugar
portion in saponins promotes the tumor specificity of cytotoxic action.
Saponins are known to reduce the risk of cancer and other chronic infections.
These chemical compounds are necessary and active for both hormone dependent
cancer and non-hormone dependent cancer (Hostanska et al., 2005). Saponins are also thought to have antifungal and
hypocholesterolemic properties. These properties are said to be as a result of
combination with bile acids to produce micellar aggregates. Saponins hinder
liver injury and hyperlipemia caused by lipid peroxidation (Lee et al., 2004).
The mode of
action of these phytocompounds in this case is by blocking of lipid peroxide
peroxidation and prevention of lipid peroxide formation. Saponins are also said
to prevent HIV infection in vitro in
addition to having antitumor potentials. This property can be associated
to the preventive ability of HIV-induced cell fusion but have no direct action
on reverse transcriptase potential of the virus (Jassim and Naji, 2003).
Saponins have been revealed to have superoxide scavenging property on oxygen
radicals that are implicated in the formation and initiation of several
infections (Zhu et al., 2004). This
pro-oxidative effect makes saponins to behave as hydrogen abstractor leading to
initial reaction of lipid oxidation. Saponins have been known to exhibit strong
antifungal properties (George et al.,
2002). The main mechanism attributed to the antifungal potentials of saponins
is their assocition with membrane sterols.
1.4.5 Glycosides
Glycosides
are secondary metabolites found in plants that have a glycoside unit and act on
the contractile behaviour of the cardiac muscle. These chemical compounds have
been employed traditionally for the management of cardiac arrhythmias and
congestive heart failure as they improve contractile force (Liu et al., 2000). Digitalis is the
commonest cardiac glycoside used both traditionally and in modern medicine.
This glycoside has two glycosides; digitoxin and digoxin whose structures vary
only by an extra hydroxyl group on digoxin. Cardiac glycosides work by
prevention of Na+, K+-ATPase resulting to reduced intracellular K+ions and
increased intracellular Ca2+ and Na+ ions. Digitalis directly prevents
proliferation of androgen dependent and androgen independent prostate cancer
cell lines by forming apoptosis and enhancing intracellular Ca2+ (Newman et al., 2008). Digitoxin suppresses
hyper-secretion of IL8, a protein linked to lung inflammation thereby blocking
the activation of the NF-B signaling pathway in cystic fibrosis (Newman et al., 2007). These phytocompounds have
been confirmed to exert cytotoxic effects in both cell lines derived in
advanced cancer and normal prostate epithelial cells. Oleandrin, a glycoside
obtained from oleander, causes apoptosis by sustaining Ca2+ rise that follows
release of cytochrome c from mitochondrion and caspase activation. Oleandrin is
also known to induce cell arrest at G2-M phase of the cell cycle in a dose
dependent treatment (Hartmann, 1998). Oleandrin potential to prevent cell
development and tumor cell multiplication is known to be due to suppression of
the up-regulation of pERK and pAkt production (Hartmann, 1998).
1.4.6 Sterols
Phytosterols
are subgroup of steroids that have structures and functions similar to
cholesterol. Phytosterols in plants act as nutrient for the production of
secondary metabolites control fluidity and permeability of cell membranes and
also work as biogenic precursors of growth factors (Patel and Thompson, 2006).
Phytosterols appear either as sterols or stanols; the saturated types of
sterols. The intake of stanols in the intestines is lower than that of sterols
resulting to decrease concentrations in blood serum. Phytosterols prevent
intake of cholesterol in the intestines. Phytosterols and cholesterol need
Niemann-Pick C1-like protein for their movement in the intestine cells.
Cholesterol is esterified in the enterocytes by acetyl-coenzyme A, acetyltransferase-2
enzyme and are put into chylomicrons and taken to the lymphatic system. Medical
studies have revealed that phytosterol absorption leads to up to 15% decrease
of LDL-cholesterol (O’Neill et al.,
2005). Intake of plant stanols lowers both plant cholesterol and sterol
concentrations in the serum (Vanhanen et
al., 1993). β-Sitosterol is the main phytosterol in plants and it is also
obtained in human serum in combination with its glycoside at reduced
concentrations. β-sitosterol and β-sitosterol glycoside have been indicated to
lower incidences of inflammatory diseases and carcinogen-induced cancer (Ivorra
et al., 1987). These phytocompounds
are also confirmed to have insulin releasing property, anti-complement and
antipyretic effect (Ivorra et al.,
1987). β-sitosterol and their glycoside have immune modulating properties on
non-infectious conditions such as allergies and rheumatoid arthritis and chronic
infectious diseases such as Human Papilloma Virus and tuberculosis (Harshal and
Prakash, 2014). The mixture is also revealed to increase the lytic effect of
natural killer cells to cancer cell lines in vitro. β-sitosterol and its
glycoside have anti-inflammatory property as they prevent both tumor necrosis
factor alpha and interleukin-6 in a dose dependent manner.
1.5 SOME INFECTIONS
CAUSED BY FUNGI
Mycoses are fungal
infections of animal, including humans. Fungi are members of the class
of eukaryotic living organisms that includes microbes like yeasts and moulds,
as well as the macroscopic mushrooms. Fungi belong to a large group of
organisms that includes yeasts, moulds and dermatophytes (fungi that cause
parasitic skin disease in humans) (Wilson, 2006). Some species grow as
unicellular yeasts that reproduce asexually by budding or binary
fission. There are so many
important fungal diseases in man caused by a number of fungi. These infections
range from superficial skin infections like dermatomycosis to generalized
mycoses such as histoplasmosis and coccidiodomycosis (Kwon-Chung & Bennett,
1992). The normal commensal yeast may become pathogenic whenever
alteration of the skin layer microclimate or host defense response occurs
(Ashbee, 2007). Some fungi are dimorphic in nature. Dimorphic
fungi can change between a hyphal phase and a yeast phase in relation to
environmental conditions (Alexopoulos et
al., 1996). The fungal outer cell wall is made up of chitin
and glucans whereas glucans are also seen in plants and chitin found in
the exoskeleton of arthropods (Bowman, 2006). Fungi are the
known organisms that have these two structural molecules/compounds in their
cell wall.
Fungi are found everywhere in nature and live
as free-living saprobes that has no known gain from parasitizing humans or animals.
Since fungi are found everywhere in the society and are sometimes cultured from
diseased body surfaces, it may be hard to evaluate whether a fungus found
during disease is a disease causing organism or a transient environmental
contaminant.
Infection is penetration
of pathogen into body tissues which is preceded by rapid growth of the
organism. Infection may be clinically unnoticed or may result in disease
because of cellular wound from competitive metabolism, elaboration of harmful
metabolites, replication of the fungus, or an immune reaction. Successful
infection may lead to disease, which is a departure from or interruption of the
normal structure or function of body parts, tissues, organs, or systems that is
seen as a characteristic set of signs and symptoms and whose etiology,
epidemiology, pathology, and prognosis are known or unknown.
Rhizomucor pusillus: Mucormycosis
(sometimes referred to as zygomycosis) is a dangerous but rare fungal infection
caused by some species of moulds called mucormycetes. These organisms
live throughout the environment, mainly in the soil and in decaying plant
remains, such as leaves, compost piles, or decayed wood (Richardson, 2009).
Infection is established
as soon as susceptible host come in contact with the fungal spores in the
environment. For instance, the lung or sinus forms of the infection can occur
after someone inhales the spores. These types of mucormycosis mainly occur in
human beings with health challenges or take drugs that reduce the body’s
capacity to combat germs and sickness (Petrikkos et al., 2012; Ribes et al.,
2000). Mucormycosis can also form on the
skin after the fungus penetrates the skin through a wound, scrape, burn, or
other type of skin trauma.
Aspergillus niger: Aspergillosis is the name used to identify so
many types of diseases caused by fungi of the genus Aspergillus. Aspergillosis affects humans, birds and other animals. Aspergillosis exist in chronic or acute forms which are
clinically very different. Major cases of acute aspergillosis are found
in patients that have seriously compromised immune systems, e.g. those with underlying
respiratory tract infections, like asthma (Denning, 2014). Most commonly, aspergillosis occurs
in the form of chronic
pulmonary aspergillosis (CPA), aspergilloma, or allergic
bronchopulmonary aspergillosis (ABPA) (Goel, 2015). Aspergillosis occurs when the
body defense system fails to stop Aspergillus spores from gaining entrance to the
bloodstream through the lungs. Without the body showing strong immune response, fungal cells are free to spread across the entire body and
can infect major organs such as the kidneys and heart. Most human beings are thought to
breathe in thousands of Aspergillus spores every day, but they
do not cause harm to most people’s health because of strong immune responses.
Penicillium marneffei: Penicilliosis is a disease
normally caused by the fungus Penicillium marneffei. The name of
the organism and the name of the infection have been renamed. P.
marneffei is now called Talaromyces marneffei, and
penicilliosis now called talaromycosis (Yilmaz et al., 2014). Most people who contract talaromycosis have a
medical condition that weakens their immune system, such as HIV/AIDS, or
another condition that lowers the body’s capacity to combat germs and sickness
(Vanittanakom et al., 2006). People
contract talaromycosis after breathing in T. marneffei from
the environment. However,
the exact environmental source is unknown. T. marneffei has
been found in bamboo rats and their burrows, but people who touch or eat these
rats are not more likely to get sick from T. marneffei. The fungus can make people sick weeks to
years after they come in contact with it (Bulterys et al., 2013).
Bumps on the epidermal layer are a common symptom. These bumps are usually
small and painless. The bumps usually appear on the face and neck but can also
appear in other places on the body. Other symptoms include: (Wong and Wong,
2011) fever, general discomfort, weight loss, cough, swollen lymph nodes,
difficulty in breathing, swelling of the liver and spleen, diarrhea and
abdominal pain.
Candida albicans: Candidiasis is a disease
usually caused by yeasts that are seen in the genus Candida. (CDC,
2014). Some of the hundreds of Candida species can cause
disease in humans; notably Candida albicans. Candida usually
stays inside the body (in an environment like the vagina, mouth, gut, and throat)
and on the skin surface without causing any disease. Candida yeasts
can cause diseases once they grow extensively over the body or once they
penetrate deep into the body (for instance, the bloodstream or internal organs
such as the kidney, heart and brain).
Candidiasis
that are found in the mouth or throat is called “thrush” or
oropharyngeal candidiasis. Candidiasis in the vagina is usually called a “yeast infection.” Invasive candidiasis occurs
when Candida species penetrate the bloodstream and cause
disease to the internal organs such as the kidney, heart and brain. Very
uncommon, yeast infections can be invasive, affecting other parts of the body
(CDC, 2014). This can lead to fever together with other signs
depending on the parts attacked.
More than 20 species of Candida are
causing infection with Candida albicans being
the most predominant (CDC, 2014). Infections of the mouth are most common
among children less than one month old, the elderly, and those with weak immune systems. Conditions that result in a weak immune
system include HIV/AIDS, the
medications used after organ transplantation, diabetes, and the
use of corticosteroids. Other
risks include dentures,
following antibiotic therapy,
and breastfeeding (Walker, 2008).
Microsporum canis: Tinea capitis (usually referred as "herpes
tonsurans", "ringworm of the hair" (Rapini et al.,
2007) "ringworm of the scalp", and "tinea tonsurans’’)
is a cutaneous fungal infection (dermatophytosis) of
the scalp
(Freedberg, 2003). The infection is usually caused by dermatophytes in
the Microsporum and Trichophyton genera that attack the hair
shaft. The clinical manifestation is usually single or multiple spots of hair loss,
often with a 'black dot' appearance (often with cut-off hairs), that may be
connected with inflammation, scaling, itching and pustules. Rarely in adults,
tinea capitis is commonly seen in pre-pubertal children,
mainly in boys than girls and is caused by Microsporum canis.
Up to eight species of dermatophytes are connected with tinea
capitis. Diseases from Microsporum species
are common in Africa, Southern and Central Europe, South America and the Middle
East. The disease is infectious and can be spread by human beings, animals, or
objects where the fungus inhabits. The organism can also exist in a carrier
state on the scalp, without clinical manifestation.
1.6 JUSTIFICATION
OF STUDY
Plants
contain bioactive compounds which are considered the source of modern and
traditional medicine (Nasir et al., 2015). Medicinal
plants are important sources of unique antimicrobial molecules.
They are also major sources of strongly important unique
pharmaceutical compounds since every parts of a plant, from roots to seed heads
and flowers, are used in ethno-medicine (Lifongo et al., 2014).
In many developing countries, including Nigeria, 80%
of patients use indigenous herbal remedies to treat infectious diseases (Nasir et al., 2015).
Nigeria have alvalanche of medicinal plants and there are alot of studies that
have been conducted to screen antimicrobial properties of these plants.
Bitter kola has anti-cancer properties and is use in
folklore remedies for the management of ailment such as liver disorders,
hepatitis, diarrhea, laryngitis, bronchitis and gonorrhea (Adaramoye et al.,
2005; Ezeifeka et al., 2004; Okojie et al., 2009).
M. hirtus has been employed for the management of fungal diseases like
ringworm, rashes, itching, eczema, toothache, venereal diseases, by rubbing
leaves on skin or taken orally (Alqasim et
al., 2013).
In recent
times, the cost and availability of various synthetic drugs have hampered the
effort made in the management of mycotic infections as the emergence of drug
resistant microbes is gradually incapacitating current antibiotics.
This ugly
trend therefore calls for the need for cheaper and more available alternatives
such as the use of chemotherapeutics and chemoprophylaxis made from plants; to
combat the disease causing organisms in humans.
1.7 STATEMENT OF THE PROBLEM
Infectious
disease has continued to be a problem militating against the health of man
including farm animals. Despite the progress made in the treatment and control
of the etiologic agents, fungal diseases have remained
serious and hidden causes of illness and death in the world.
The
incidence of diseases because of drug resistant microorganisms and the
emergence of some unknown disease causing microbes pose enormous public health
concern (Idu et al., 2006).
The use of
synthetic medicine is usually expensive and not readily available and the
emergence of drug resistant microbes is gradually affecting current
antibiotics. It is largely noticed that most of the readily used
antimicrobials which are mostly synthetic fall short of combating the enormous
existing and emerging diseases. These existing agents (drugs) are also capable
of eliciting terrible effects to the recipients (Udegbunam
et al., 2014).
According to
Huttner et al. (2013), the frequency level in which
microbes develop antimicrobial resistance outpaces the rate of discovery/development
of new drugs, whereas many plants possess unexploited potentials capable of
handling the drug resistance by many disease-causing microorganisms.
1.8 AIMS AND OBJECTIVES
The
aims of this study are:
1. To compare the antifungal potentials of aqueous and
ethanol extracts of the seeds and leaves of Garcinia kola, and the
leaves of Mitracarpus hirtus
2. To
evaluate the effectiveness of the plant extracts in treating human fungal
infections.
while
the objectives include to:
i. Determine the qualitative and quantitative phytochemical
components of the plants extracts.
ii. Determine the diameter of zone of inhibition of the plant
extracts
iii. Determine
minimum inhibitory concentration value/level of the plant extracts
iv.
Determine minimum fungicidal concentration of the plant extracts
v. Compare the activity indices of both plants extracts with
standard drugs (Fluconazole and Ketoconazole)
vi. Carryout Gas Chromatography and Mass Spectrometry
Analysis of the plants extract
Login To Comment