ABSTRACT
The antimicrobial activity and phytochemical screening of the leaves of Piper guineense Schumach, Psidium guajava Linn, Gongrenema latifolium Endl and Terminalia catappa Linn was carried out. The four plant species indicated the presence of alkaloid, phenol, tannin, spaonin and flavonoid which are bioactive component. The percentage of the phytochemcials are as follows alkaloid (0.46.139%), phenol (0.37-1.66%, saponin (0.31-0.67%), flavonoid (0.23-0.55%) and tannin (0.13-037%). The antimicrobial activity of the ethanolic and aqueous extracts of the leaves of the plant species were tested against four microorganisms, Candida albican, Klebsiella pneumonia, Escherchia coli and Bacillus subtilis. The sensitivity of the microorganisms was determined using disk diffusion method. Ethanolic plant extract and aqueous extract inhibited the growth of these pathogens. The zone of inhibition of the growth of these microorganisms by the plant extract depends on the concentration of the extract. Ethanolic plant extract had high sensitivity than the aqueous plant extract which shows less. Gongronema latifolium contained more alkaloids (1.39±0.03%) than other phytochemicals and Terminalia catappa had less tannin (0.13±0.00%) than other phytochemicals. The ethanolic extracts of Gongronema latifolium had the highest inhibitory activity (24.00±2.00mm) which shows more sensitivity against the test organisms while the aqueous extracts of Terminalia catappa has low inhibitory activity (8.33±0.58mm) which showed less sensitivity against the test organism. This result reveals that these plant species have potentials as source of raw materials in the pharmaceutical industry.
TABLE OF CONTENTS
Cover
page
Title
page i
Certification
ii
Dedication
iii
Acknowledgement
iv
Table
of content v
List
of tables vii
List
of plates viii
Abstract
ix
CHAPTER ONE
1.0 Introduction
1
1.1.2 Aims
and objective of the research 3
1.1.3 Justification
of the study 4
CHAPTER
TWO
2.0 Literature
review 5
2.1 Phytochemical
screening of plants 5
2.1.2 Antimicrobial
activity of plants 7
2.3 Botany
of plants 9
2.3.1 Botany
of Terminalia catappa 9
2.3.2 Botany of Gongronema latifolium 10
2.2.3 Botany
of Piper guineenses 10
2.2.4 Botany
of Psidium guajava 11
CHAPTER THREE
3.0 Source
of materials 12
3.1 Sample
preparation 12
3.2 Phytochemical
screening 12
3.2.1 Qualitative analysis of phytochemicals 13
3.2.1.1 Test
of tannins 13
3.2.1.2
Test of saponin 13
3.2.1.3
Test of flavonoids 13
3.2.1.4
Test of alkaloids 14
3.2.1.5 Test of Phenols 14
3.3 Quantitative
determination of the phytochemcials 14
3.3.1 Determination
of alkaloids ` 14
3.3.2 Determination
of flavonoids 15
3.3.3 Determination
of tannins 16
3.3.4 Determination
of saponin 17
3.3.5 Determination
of Phenols 18
3.4 Antimicrobial
activity of the leaves of the plants Terminalia
catappa,
Piper Guineenses, Gongronema
Latifolium and Psidium
Guajava. 19
3.4.1 Sample
Preparation 19
3.4.2 Production
of extracts 19
3.4.3 Sources
of test organism 19
3.4.4 Antimicrobial
activity test 20
3.4.5 Determination
of Minimum Inhibition Concentration 20
3.4.6 Statistical
Analysis 21
CHAPTER FOUR
4.0 Results 25
4.1 Phytochemical
components 25
4.1.1 Qualitative
analysis 25
4.1.2 Quantitative
analysis 26
CHAPTER FIVE
5.0 Discussion and conclusion 33
5.1 Discussion 33
5.2 Conclusion 36
References
LIST OF TABLES
Table
1: The qualitative analysis of Piper guineenses, Gongronema latifolium,
Terminalia catappa and Psidum guajava 25
Table 2: The percentage yield of Alkaloid, Saponin,
Tannin, Phenol and flavonoid
of
Piper guineenses, Gongronema latifolium,
Terminalia catappa and
Psidium guajava 26
Table
3: Antimicrobial activity of Aqueous
and Ethanolic extract of Piper
guineenses, Gongronema latifolium, Teminalia catappa and Psidium guajava 27
Table 4: Minimum inhibitory concentration of Candida albican 29
Table 5: Minimum inhibitory concentration of Klebsiella pneumonia 30
Table 6: Minimum Inhibitory concentration of E. coli 31
Table 7: Minimum Inhibitory concentration of Bacillus subtilis 32
LIST OF PLATES
Plate 1: The
leaves of Piper guineenses 22
Plate 2: The
leaves of Gongronema latifolium 22
Plate 3: The
leaves of Terminilia catappa 23
Plate 4: The
leaves of Psidium guajava 23
Plate 5: Solidified
Muller Hinton agar in sterile petri dishes 24
CHAPTER ONE
1.0
INTRODUCTION
Medicinal
plants are considerably useful and economically essential since they contain
active constituents called phytochemicals. Phytochemicals are the non-nutritive
plant chemicals that have protective or disease preventive properties. The most
important of these bioactive constituents of plants are alkaloids, tannins,
flavonoids, saponins and phenolic compounds (Okwu, 2001).
Though
criticized, plant based medicines have survived through ages and it is still
catering for the health needs of millions all over the world (Kapor, 2001).
Herbs and natural products do not possess much of the toxicity that is present
in synthetic chemical thus enhancing their appeal for long term preventive
strategies (Zou, 2005). The use of plant extracts and phytochemicals, both with
known antimicrobial properties can be of great significance in the treatments
of diseases. Many plants have been used because of their antimicrobial traits,
which are chiefly due to syntheses of secondary metabolism by the plant (Prusti,
2008). Discovery of new antimicrobial compounds with diverse chemical
structures and novel mechanisms of action becomes is of urgent attention.
Currently, the development of resistant strains of bacteria has increased the
need for new antibiotics (Eloff, 1998). The antimicrobial compounds produced by
plants are active against plants and human pathogenic microorganisms (Sarac and
Ugur, 2007).
There
are several reports in the literature regarding the antimicrobial activity of
plant crude extracts and bioassay guided fractionations of these extracts that yielded active principles
(Rabe and Van Stadan et al., 2001;
Srinivasan et al., 2001 and El-Seedi et al., 2002).
Isolation
of bacteria less susceptible to regular antibiotics and recovery of resistant isolates
during antibacterial therapy is now a global problem (Muhammad and Muhammad,
2005). In the developing world, the situation is even worse because of poor
sanitation and ignorance of good hygienic practices thus exposing a large
number of people to infectious agents.
Some
of the bacteria implicated in causing enteric infections include but not limited
to E. coli, Salmonella spp, Proteus spp,
Shigella spp, Pseudomonas spp and the
Staphylococci. These bacteria which are usually present as commensals have
several virulent factors and colourize in a biofilm fashion, causing a variety
of intestinal and extra intestinal diseases (Lino and Deogracious, 2006).
There
is therefore the need to develop some newer, safer, effective and above all,
cheaper antimicrobial agents to tackle this problem.
1.1
Aim
and objectives
The
aim and objectives of this work are to:
i)
determine the phytochemicals of Breynia nivosa, Manihot esculenta, Euphorbia
hirta and Euphorbia heterophylla
ii)
determine antimicrobial activities of
the aqueous and ethanolic leaf extracts
of Breynia nivosa, Manihot esculenta,
Euphorbia hirta and Euphorbia
heterophylla on Pseudomonas
aeruginosa, Salmonella pullorum, Proteus vulgaris and Enterobacter aeruginese.
1.2
Justification
The
use of medicinal plants in the treatment of most pathogenic diseases has been a
public discourse, with people having different views on the use of herbal
drugs, stating that it causes more harm than good because it does not have a prescribed
dosage and may lead to serious life threatening diseases. The result of this
study will therefore clarify these views which may lead to the discovery of an
alternative form of treatment by the use of the MIC (Minimum inhibition
concentration) which will take care of the problem of dosage compared to
antibiotics being used at present, to which many of the bacteria are developing
resistance.
1.3
Botany
of the plants
1.3.1
Botany
of Manihot esculenta Crantz(cassava)
Cassava
is a woody shrub native to South America of the spurge family, Euphorbiaceae.
It is extensively cultivated as an annual crop in tropical and subtropical
regions for its edible starchy tuberous root, a major source of carbohydrate
(Oriola and Raji, 2013). In addition to this, it tolerates even long prolonged
drought, high temperature and other adverse environmental conditions following
the initial establishment period after planting to marginal soil and reliable
yields in areas where other crops such as maize, sorghum, beans and soybeans
die or do not perform, well (El-Sharkawy, 2012). Its production worldwide has
increased and is expected to increase further due to the tremendous demand for
good quality food, animal feeds, raw industrial materials as well as its
antioxidant potential. It also possess anticarcinogenic, antidiabetic,
anti-tumor properties (El-Sharkawy, 2012; and Suresh et al., 2011).
Cassava
leaves are largely consumed as African indigenous vegetables rich in nutrients
(Lancaster and Brooks, 1983 and Achidi et
al., 2005). Indeed, cassava leaves are excellent sources of proteins
(21-39%), minerals, antioxidant compounds and vitamins for the human diet
(Ek-Sharkawy, 2012; Balamurugan and Anbuselvi, 2013). Recent findings in plant biochemistry
have proved that the proteins embedded in cassava leaves are equal in quality
to those in eggs (Soudy, 2012).
1.3.2
Botany
of Breynia nivosa W. Bull(Small-Snow
bush)
Breynia nivosa
is a rounded shrub in the family of Euphorbiaceae, about 2m high, that is
primarily used for its attractive foliage and found in villages and towns. It
has mall, mottled, multi-coloured variegated leaves with white green and red
coloured leaves (Smith, 1981). In southern Nigeria, it is used as chewing stick
(Amadi et al., 2007). Ethnomedically, Breynia
nivosa is used in treating headaches, toothaches and tooth infections
(Onyegbule et al., 2014) and in the
treatment of fever and malaria by the Ibibios of Niger Delta region of Nigeria.
The leaf extract of the plant has been reported to contain flavonoids, tannins,
alkaloids, glycosides and starch, saponins and proteins (Onyegbule et al., 2007). Biological activities of
the leaf include; antimicrobial (Amadi et
al., 2014; Onyegbule et al.,
2014), analgesic, anti-inflammatory and antioxidant activities (Onyegbule et al., 2014).
1.3.3
Botany
of Euphorbia hirta Linn (Asthma
plant)
Euphorbia hirta
belongs to the family Euphorbiaceae which is frequently seen occupying open
waste spaces and grasslands, roadsides and pathways. Though native to Central
America, the herb is widely cultivated throughout the tropics especially
Central and East Africa (Adedapo et al., 2005).
It is usually erect slender-stemmed, spreading up to 45cm tall, though
sometimes can be seen lying down (Burkill, 1994). The medicinal usefulness of
the herb has been the subject of numerous chemical and microbial studies. Some
of the reported phytochemicals of the herb included triterpenoids, sterols,
alkaloids, glycosides, flavonoids, tannin, phenols, choline and shikimic acid
while some of the reported scientific uses includes as antispasmodic, antiasthmatic,
expectorant, anti-catarrhal and antisyphilic compounds (Burkill, 1994; Adedapo et al., 2005 and Falodun et al., 2006).
1.3.4
Botany
of Euphorbia heterophylla Linn (Spurge
weed)
Euphorbia heterophylla
is a medicinal plant with the common name “Spurge weed” belonging to the family
Euphorbiaceae. It is native plant to Mexico and its original distribution
includes an area spreading from California to East Texas and Central America.
It is a hardy species, growing between 30cm and 70cm in height. The medicinal
usefulness of the plant has the subject of numerous chemical and
pharmacological studies. It grows in semi-humid places especially in cassava,
cowpea and soybean plantations. Report of previous chemical study on E. heterophylla is however scanty.
Falodun et al. (2004) reported the
isolation of a flavonoid quercetin from the leaves of this plant. The leaves
are known to possess antibacterial activity (Falodun et al., 2003).
In
Igbo community of Nigeria, E. heterophylla
is used as a purgative (Erden et al.,
1999). Extracts of the decoction of the leaves is also used in the treatment of
respiratory tract infections and asthma by traditional medicine practitioners.
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