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Phytochemical and Antimicrobial Activity of (Crassula ovata) Jade Plant on Different Strains of Bacteria

Authors:
_____________________________________________________________________________________________________
*Corresponding author: E-mail: mwangidmuiruri@yahoo.com;
European Journal of Medicinal Plants
11(1): 1-12, 2016, Article no.EJMP.19753
ISSN: 2231-0894, NLM ID: 101583475
SCIENCEDOMAIN international
www.sciencedomain.org
Phytochemical and Antimicrobial Activity of
(Crassula ovata) Jade Plant on Different Strains of
Bacteria
Mwangi Denis Muiruri
1*
and Wambura Mwangi
1
1
Jomo Kenyatta University of Agriculture and Technology, P.O.Box 62,000 – 00200 Nairobi, Kenya.
Authors’ contributions
This work was carried out in collaboration between both authors. Author MDM designed the study,
performed the statistical analysis, wrote the protocol and wrote the first draft of the manuscript.
Authors MDM and WM managed the analyses of the study and the literature searches. Both authors
read and approved the final manuscript.
Article Information
DOI: 10.9734/EJMP/2016/19753
Editor(s):
(1) Marcello Iriti, Professor of Plant Biology and Pathology, Department of Agricultural and Environmental Sciences, Milan State
University, Italy.
Reviewers:
(1)
Daniela Hanganu, "Iuliu Hatieganu"University of Medicine and Pharmacy, Romania.
(2)
Francis O. Shode, Cape Peninsula University of technology, South Africa.
(3)
Armando Cuéllar Cuéllar, Havana University, Cuba.
(4)
Armando Zarrelli, University of Naples, Italy.
Complete Peer review History:
http://sciencedomain.org/review-history/11727
Received 25
th
June 2015
Accepted 24
th
August 2015
Published 7
th
October 2015
ABSTRACT
The Crassula ovata plant has been used for many years as an ornamental plant, and also as a
medicinal plant in some communities like the Khoi of South Africa and in Chinese culture. Locally
the plant is being used by homeowners who have it in their vicinity as a remedy for diarrhea and
disinfecting wounds. However, the major problem of using this plant is its ineffectiveness to heal
wounds and diarrhea in most cases where it is being used. It brings about questions like does the
Crassula ovata plants inhibit certain specific microorganisms, or is the concentration of the extract
to blame, or the method used to extract the plant. The mode of extraction used in this study
involved both aqueous extraction and methanolic extraction, to ensure all plant constituents are
extracted for better results. The microorganisms that were tested against the plant extracts are the
major day to day sources of diarrhea and wound infection. The plant extracts are used at varying
concentrations. The observable results were quantitatively analyzed to see which plant extract and
at which concentration causes the most inhibition on the microorganisms. The plant extract with the
Original Research Article
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
2
most inhibition was found to be the water extraction at the concentration of
×
10
, and it would be
recommended that the Crassula ovata plant be used to the specifications as observed in the study.
Keywords: Crassula ovata; phytochemical; antimicrobial; traditional medicine; jade plant.
1. INTRODUCTION
Plants have been used as medicines since time
in memorial. Plants having medicinal value are
widely and successfully used on every continent.
In Asian countries, the practice of herbal
medicine is extremely well established and
documented. As a result, most of the medicinal
plants that are internationally recognized come
from this region, particularly from China and
India. For Europe and North America, the use of
herbal medicine is increasing fast, especially for
correcting imbalances such as diabetes caused
by modern diets and lifestyles. Many people now
take medicinal plant products on a daily basis, to
maintain good health as much as to treat illness.
In Africa, attitudes towards traditional, herbal
medicines vary strongly mostly due to diversity in
cultures and traditions. Another reason for this is
the confusion between herbal medicine and
witchcraft. The use of medicinal plants is
commonly associated with superstition, and
therefore rejected by some people in favor of
western medicine. On the other hand, there are
millions of Africans who prefer traditional
methods of treatment.
The valuable medicinal properties contained in
certain plants are not in doubt. In recent years,
for example, the Chinese plant Artemisia annua,
has become the essential ingredient in a new
generation of anti-malaria drugs. East African
countries have adopted the plant and growing it
to supply pharmaceutical manufacturers in
Europe. The bark of the tree Prunus africana is
used mostly in making treatments for prostate
cancer. Sutherlandia, a native plant of South
Africa, is being increasingly recognized for its
value to HIV/AIDS diagnostics and treatment.
Other African plants, such as the Devil’s Claw
and the African Geranium, are gaining popularity
as herbal medicines, particularly in Europe.
Medicinal plants hence represent an important
opportunity to rural communities in Africa as in
Kenya, as a source of affordable medicine and
as a source of income for those who grow the
plants. Governments too need to be thinking
about how to promote the benefits that medicinal
plants have to offer, which may involve
integrating herbal medicine into conventional
healthcare systems, and funding more effective
research into possible applications of the plants.
This raises important issues, such as regulation
of traditional healers and ensuring certain
standards are met.
Many plants grown in Kenya have valuable
medicinal properties. Paw paws, for instance,
can be used to treat asthma, rheumatism and
intestinal worms. Lemongrass helps in relieving
fever. Sap from the Aloe vera is excellent for
treating burns. These plants, and many others,
are easily grown in home gardens for domestic
use. Moringa oleifera is another plant with great
potential, both in terms of home use and as a
source of income. It has high levels of iron,
calcium and Vitamin A, and can be used to boost
the immune system, as well as treat a range of
illnesses. It is normally prepared by drying the
leaves and then pounding them into a powder.
This can then be mixed with flours, or with other
foods such as meat. For HIV/AIDS patients it
offers an excellent source of nutrients which can
help to support their immune system and slow
down the advance of the disease.
Having a selection of different medicinal plant
products can broadens the market and the
economy of the region as well. For example, the
Mondia whytei processors in Kenya sell the raw
roots of the plant, but also produce a powdered
form. This is preferred by hospitals, which use it
to increase patient’s appetite and to increase
milk production in nursing mothers. The powder
is also used to make fortified foods for the sick.
Other products for sale include Mondia seeds
and seedlings. Once products have been
formulated for sale, gaining official recognition
and approval from the authorities is valuable. In
Kenya, the organization Action for Natural
Medicine (NAMEDO) is working with the National
Drug Authority to have its products such as
soaps, creams and oils approved. The
organization is also working with the National
Bureau of Standards, so that the products are
standardized. This makes it much easier to
market the products, for example through clinics
or supermarkets.
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
3
Herbal and conventional doctors are enemies of
each other. Each having little respect for the
skills and knowledge of the other. For example,
hospitals and clinics can be swamped by people
with relatively minor ailments, some of which
might be treated with herbal remedies. This
would allow hospitals to devote more of their
resources to deal with serious diseases and
operations. However, for a government health
ministry to promote or encourage people to use
herbal medicines normally requires a radical
change in thinking of its people and policy
implementation. In The Gambia, this process is
already underway, with the government working
to have traditional healers registered in union
and/or associations. This makes it easier for their
practice to be monitored, and to ensure that it is
in accordance with the national traditional
medicine policy. The policy aims to protect the
patient’s rights, and to introduce standards for
traditional medicine, and to protect the
intellectual property rights of traditional healers.
Integrating plant medicine into national policy
involves the health, agriculture, environment and
trade ministries. In order to ensure farmers are
supported in growing the plants. Harvesting from
the wild can be controlled and quality standards
introduced for those trading in medicinal plants
and their products.
2. LITERATURE REVIEW
2.1 Brief Description of Crassula ovata
2.1.1 Scientific classification and morpho-
logical description
Crassula ovata, commonly known as the jade
plant or the money tree, belongs to the
Crassulaceae or the Orpine family. They are a
family of dicotyledonous plants, succulent with
small white or pink flowers. Their main water
reservoir is in their succulent leaves [1].
The jade plant is an evergreen plant up to 1 - 3 m
tall, with thick branches and smooth, rounded,
fleshy leaves that grow in opposite sides along
the branches which are also short, stubby and
well-proportioned. The leaves are a rich jade
green color, 30 -90 mm long and 18 - 40 mm
wide, egg-shaped to elliptic, often with a red
margin and a somewhat pointed end. They are in
opposite pairs, the one pair arranged at right
angles to the next, and they are clustered
towards the ends of the branches. New stem
growth is the same color and texture as the
leaves, but becomes brown and woody with age.
Under the right conditions, they may produce
small white or pink star-like flowers in early
spring. The flowers later develop into small
capsules, each of which hold many tiny seeds
[2].
2.2 Ecology and Distribution
The Crassula ovata plant is able to maintain
minimum water loss while photosynthesizing
efficiently through Crassulacean Acid Metabolism
(CAM). Its stomata are closed during the day but
open at night where Cois taken in and stored in
the form of organic crassulacean acids. In
daytime, these acids are broken down and the
Co released is recycled in the photosynthetic
process. This way the plants lose much less
water yet can photosynthesize normally during
the daytime hours. However, during extremely
dry periods they will not even open their stomata
at night, and will re-cycle the Co within their
cells. This causes slow metabolism hence little
growth but at the same time keeping the cells
healthy. This is called CAM-idling [3].
The plants succulent water-storing leaves, stems
and roots give it the ability to survive droughts,
being grazed on, trampled on or knocked over,
as it is able to root from any piece of its stem,
and even a single leaf. Any discarded leaves left
around the foot of the plant send down roots and
grow into new plants [4].
The flowers of Crassula ovata attract wasps,
flies, bees, butterflies, and beetles. Wind helps
disperse the fine dust-like seeds. The stems also
make good bases for wasps to build their nests
[5].
Crassula ovata is a native plant to South Africa. It
is also a common houseplant all over the world,
but it is mostly located in the Northern
Hemisphere particularly in cold and/or dry areas
where water is scarce. Crassula ovata is a
vibrant part of the Eastern Cape and KwaZulu-
Natal valley thicket vegetation, together with a
variety of euphorbias, aloes, Portulacaria afra
and other succulent plants. It strives from
Willowmore to East London then northwards to
Queenstown and KwaZulu-Natal where it grows
on rocky hillsides [6].
In Kenya the Crassula ovata is found growing in
areas with adequate rainfall which is well
distributed throughout the year. These are areas
within the Central, Rift Valley, Nyanza, and few
areas in the Eastern region of Kenya. The
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
4
Crassula ovata rarely grows in the North Eastern
part of the country due to the scarce availability
of precipitation. Also in the coastal region it’s very
rare to find this plant. There is no variation in the
Crassula ovata’s phytochemical composition
regardless of where they are from. The only
difference might occur in their succulence
depending on the geographical location which
will affect water availability in the area where the
plant is found [2].
2.3 Mode of Propagation
Crassula ovata is famously propagated either by
leaf cuttings or stem cuttings. Both of these types
of cuttings require high humidity. In the wild,
stems and leaves will often break off and fall to
the ground, and after a few weeks, they may
grow roots and form a new plant. They can also
be cut and placed in a water container until roots
grow usually in about two weeks, then planted in
soil.
In cultivation, new plants are made by cutting
new growth (stems or leaves) and letting them
dry. Roots will develop in or out of soil, though
inserting the stem into moist soil will increase
rooting [7].
2.4 Traditional Uses and Cultural Aspects
Traditionally many communities have developed
a habit of using the fluid extract from the leaves
to treat warts which are small circumscribed
tumor of the outer layer of the skin. Warts are flat
or elevated from the surrounding skin and are
firm. They are caused by forms of the contagious
human papilloma virus (HPV); warts vary in size
and may be accompanied by pain, particularly if
they occur on the feet (plantar warts). The leaf of
Crassula ovata was sliced in half and attached
the moist inside to the wart for a few hours, or
overnight. The unsightly growth would fall off with
just three applications [1].
In Asian cultures particularly in China (700AD),
jade plant is a popular element. Medicine-men
prescribed a tea of the jade plant to treat
symptoms of diabetes. Because of its abundance
and its softness in ancient times, it could easily
be shaped into various forms thus it was used in
the art of Bonsai. The plant was spread around
as luxurious gift to royalties all over the Chinese
empire [8].
The jade plant is used in the Chinese ritual
practice of Feng Shui to attract the flow of
money. Feng Shui creates balance and harmony
of energies within a space. Practitioners believe
that the money tree brings about balance to the
southeastern corner of a home. The jade plant is
one of the plants used in this ritual practice. In
many businesses, a jade plant is often placed
near a cash register as in Chinese tradition as a
way to attract prosperity [9].
In Africa, jade leaves are boiled in milk and
consumed to stop diarrhea. The Khoi and other
African tribes ate the roots and stems of the jade
plant. The plant was grated and cooked after
which they were eaten with thick milk. The leaves
were also boiled in milk as a remedy for diarrhea,
treating epilepsy, corns and as a purgative.
The Jade plant has attracted more common
names including the Penny Plant, Money Tree,
Dollar Plant, and Tree of Happiness in the Far
East, United States and Germany. The plant is
traditionally grown in square porcelain tubs with
lion feet to bring good financial luck, and general
prosperity [10].
The Crassula ovata plant is in Kenya mostly
grown in local homesteads for its ornamental
value. However some people keep this plant also
for its medical values. The Kamba community
believe that the juice extracted from this plant
help heal burn wounds on the skin. Other
communities like the Maasai use it as a relief for
stomach upsets.
2.5 Diseases Controlled by Crassula
ovata Plant
Microorganisms are a common human skin, gut
flora, soil, water, and gastrointestinal tract
inhabitant. However, these microorganisms can
also be major causes of abnormalities in the
human body system. Bacteria such as some
Staphylococcus species live on normal skin and
on mucous membranes and cause no harm.
Some bacteria; however, invade normal skin,
broken skin or wounds causing wound infection.
The most common causative organisms
associated with wound infections include
Staphylococcus aureus and Pseudomonas
aeruginosa [11].
Staphylococcus aureus is a Gram-positive
bacteria and a potential pathogen. It is a leading
cause of bacterial disease in humans. It can be
transmitted from the nasal membranes of an
asymptomatic carrier to a susceptible host. This
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
5
bacterium causes Furunculosis, a medical
condition in which large areas of the skin are
covered in persistent boils. Folliculitis is also
caused by the Staphylococcus aureus bacterium.
It’s an inflammation of one or more follicles,
especially of the hair, producing small boils.
These infections are commonly found in young
children aged 5-12, or any 5vate5-suppressed
person. Staphylococcus aureus can cause
impetigo (skin infection), scalded skin syndrome
and food poisoning [7].
Pseudomonas aeruginosa is an opportunistic
pathogen of humans that can invade virtually any
tissue. It is a leading cause of hospital-acquired
(nosocomial) gram-negative infections, but its
source is often exogenous (from outside the
host). Pseudomonas aeruginosa causes wound
infections, athlete’s foot, gram negative
folliculitis, chronic paronychia, and pneumonia
[12].
Escherichia coli are a Gram-negative, rod-
shaped bacterium, a consistent resident of the
small intestine. Some strains of Escherichia coli
are pathogens that cause intestinal infections,
urinary tract infections and neonatal meningitis.
Some serotypes can be a source of severe food
poisoning in humans. But there are harmless
strains that are part of the normal flora of the gut,
which benefit their hosts by producing vitamin K
2
,
and by preventing the establishment of
pathogenic bacteria within the intestine.
Escherichia coli and related bacteria constitute
about 0.1% of the gut flora, and fecal–oral
transmission is the major route through which
pathogenic strains of the bacterium cause
disease [7].
Candidiasis is an overgrowth of a fungus hence
causing irritation and swelling. Pathogenicity
among yeast-like fungus is extremely variable;
however, the most virulent and harmful is
Candida albicans. Involvement of the Candida
albicans may be localized to the mouth, throat,
skin, toes, scalp, fingers, vagina, nails, bronchi,
lungs or gastrointestinal tract. It may also be
systemic as in septicemia (circulating in the
blood and causing damage to blood vessels and
blood cells), endocarditis and meningitis. Factors
predisposing people to candidiasis include AIDS,
burn wounds, young individuals and/or infants,
pregnancy, oral birth control, high fruit diets,
antibiotic therapy, immunosuppressants, cancer
treatments, steroids, heart surgery, genetic
deficiency, endocrine deficiency diabetes, use of
catheters, and use of dirty needles [13].
Bacillus subtilis cells are rod-shaped, Gram-
positive bacteria that are naturally found in soil
and vegetation. Bacillus subtilis bacteria are non-
pathogenic. They can contaminate food;
however, they seldom result in food poisoning
[3].
2.6 Statement of the Problem
The main problem or general question pertaining
the Crassula ovata is whether it has relevantly
effective antibiotic or antifungal traits. Crassula
ovata plants are mostly used as house plants
and do not have many commercial uses other
than for ornamental value. However it’s usually
integrated into most homesteads also because of
its healing properties or medicinal values. In
many occurrences, the plant extracts do not
always treat some stomach upsets or even fresh
wounds, despite its prominent successful use in
other past communities from different nations.
Even after continuous application of the plant
extracts, the stomach upset or wound still
continues to persist.
The question left unanswered is whether the
extraction procedure is efficient, or maybe the
concentration of the extract is too high or too low
to be effective. Or perhaps which part of the
Crassula ovata plant is most effective to use.
The Crassula ovata has had successful ratings in
its past ancient uses, but very much limited
success in present time. There is need to
research further why this has come to be. Among
the many reasons for these changes might be
the fact that since these plants were originally
from what we now know as highly productive
nations (China and South Africa), due to the
industrial advancements and resulting increased
environmental pollution, the plant genome has
been altered. This could to a great deal alter the
overall efficiency of the plants antibiotic traits.
2.7 Justification
This research was conducted so as to test the
medicinal value of Crassula ovata plant, and
whether it has any phytochemical components
which inhibit growth of microorganisms. There is
also the need for more research on the evolution
of the specific microorganisms Crassula ovata is
said to inhibit. This is because it is a known fact
that these microorganisms and others are
mutating almost every day, thereby increasing
their survival and reducing the effects of any
antibiotic stimuli. Unfortunately, no much
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
6
research has been put in effect to solve this
riddle.
2.8 Objectives
2.8.1 Broad objectives
To determine the phytochemical
components and antibiotic traits of the
Crassula ovata plant.
2.8.2 Specific objectives
1. To determine the phytochemical
components of the Crassula ovata plant.
2. To test the antibiotic activity of the
Crassula ovata plant extracts against a
range of selected microorganisms.
2.9 Hypothesis
2.9.1 Null hypothesis
There is no difference in the phytochemical
components of the Crassula ovata plant and the
proliferation of the selected microorganisms.
3. MATERIALS AND METHODS
3.1 Sample and Sampling Technique
The samples for experimentation include the
fresh leaves and stem of the Crassula ovata
plant. The Crassula ovata plant species were
acquired randomly from a local homestead in
Ruiru, Kenya. The plant samples were stored not
more than two hours before extraction.
3.1.1 Extraction of crude extracts from the
plant
This was carried out according to [3].
3.1.2 Methanolic extraction
2 grams of the plants leaves and stem were cut
into smaller pieces and put in 100ml of 90%
methanol to dissolve the crude extracts and left
overnight. The plant material was then separated
from the methanol by washing with 100ml of
sterile distilled water. Serial dilution of the extract
was then done four to five times starting with a
dilution of ×10° to × 10
ିସ
.
3.1.3 Aqueous extraction
2 grams of the plants leaves and stem were
crushed using a pestle and mortar while adding
100 ml sterile distilled water to dissolve the crude
extracts. The extracts were then put into sterile
conical flasks and stored at room temperature.
Serial dilution of the extract was then done four
to five times starting with a dilution of ×10° to ×
10
ିସ
.
Small circular paper discs were put into the
containers containing the different plant extracts
from the aqueous extraction and the methanolic
extraction. The discs with the methanolic extracts
were then put in an oven at 40ºC for 30minutes
to dry.
3.2 Phytochemical Tests
The phytochemical tests were carried out as per
procedures explained in [9]. Fresh plant samples
were obtained, weighed and divided for the
various assays. Plant extracts required in some
assays were obtained from prior extractions.
3.3 Alkaloid Test
0.05 g of the sample was added to 1% HCL and
filtered. The filtrate is tested carefully with various
alkaloid reagents as follows;
3.3.1 Mayer’s test
To 1ml of the filtrate, a drop or two of Mayer’s
reagent was added by the side of the test tube. A
white or creamy precipitate indicates the test as
positive.
3.3.2 Dragendorff’s test
To 1ml of the filtrate 1 or 2 mls of Dragendorff’s
reagent was added. A prominent yellow
precipitate confirms the test as positive.
3.4 Carbohydrate Test
3.4.1 Barfoed’s test
To 1 ml of filtrate, 1 ml of Barfoed’s regent was
added and heated in a boiling water bath for 2
minutes. A red precipitate confirms sugar
presence.
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
7
3.4.2 Benedict’s test
To 0.5 ml of filtrate, 0.5 ml Benedict’s reagent
was added and the mixture heated in a boiling
water bath for 2 minutes. A characteristic colored
precipitate confirms the presence of sugar.
3.5 Detection of Saponins
1 ml of plant extracts were dissolved in
anhydride-tetrachloride to which 4 drops of
concentrated sulfuric acid was added to the
mixture. A blue, green or red color accompanied
by a pink ring shows presence of Saponins.
3.6 Flavanoids Test
1 ml of the extract was put into a test tube
followed by addition of Hydrochloric acid (4
drops) and Magnesium turnings. Development of
a pink or magenta red indicates the presense of
Flavanoids.
3.7 Tannins Test
1 ml of the crude extract was dissolved in water
which contains 1% gelatin and 10% NaCl. The
presence of tannins is indicated by the presence
of a blackish blue color. Catecol tannins are
indicated by a greenish black coloration.
3.8 Sterols and Steroids Test
1 ml of the extract was put in a test tube in which
0.5 ml sulfuric acid, acetic anhydride and
chloroform in similar amounts were added. A red
coloration would indicate presence of sterols. A
green color indicates presence of steroids.
3.8.1 Media preparation and incorporation
with bacteria
Based on [10], Mueller Hinton agar was prepared
by measuring 28.5 g and dissolving it in 750 ml
distilled water. Nutrient broth was also prepared
and put into glass bottles. The prepared media,
nutrient broth, pipette tips, paper discs, distilled
water, the pestle and mortar were autoclaved at
121°C for 15 minutes. The agar was left to cool
to about 40-37°C then aseptically poured into
sterile Petri dishes. This was done on the bench,
using flame to keep media bottle sterile.
Sterile nutrient broth was inoculated with fresh
bacteria strains. Bacteria was picked from a
frozen culture by scratching the sterile loop
across the surface of the culture or they were
picked from a liquid culture by immersing loop in
it. The bacteria were evenly spread across the
surface of the plate using a glass spreader.
3.8.2 Disc diffusion method
Several circular sterile paper discs, were each
infused with the different dilutions of the crude
extracts, then evenly spaced over the surface of
the plate. The discs were gently pushed down
into the agar to make contact with the bacteria.
The plates were left to grow overnight in an
incubator at 37°C. Colonies would be visible after
12-16 hours growth at 37°C. Plates should be
inverted in the incubator to prevent condensation
from dripping on the colonies.
The colonies that form would be then counted as
colonies per unit after incubation. The zones of
inhibition were also measured on each plate. The
minimal inhibitory concentration (MIC) of the
crude extract to specific bacteria can then be
determined.
4. RESULTS AND DISCUSSION
4.1 Phytochemical Tests Results
The biologically active compounds of the
Crassula ovata plant are tested so as to draw
valuable conclusions from the observed results.
4.2 Antimicrobial Activity Results
From the observations, it is clearly evident that
the action of the Crassula ovata extracts against
the selected microorganisms was very minimal.
4.3 Discussion
Based on the observations made during the
study, it was observed that the Crassula ovata
plant had active components of carbohydrates,
alkaloids, sterols, steroids and saponins. These
are active chemical components that are
involved in inhibition of microbial activity.
However the degree of the effect of these active
components depends on the plant species and
the overall concentration used.
The antimicrobial activity of the Crassula ovata
leaf and stem extracts were studied at different
concentrations against four pathogenic bacterial
strains and one fungal strain.
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
8
Table 1. Phytochemical test results of the Crassula ovata plant crude extracts
Test
Observations
aqueous
extracts
Observations
methanolic
extracts
Alkaloid test
i. Mayer’s test
ii. Dragendorff’s test
+
-
-
-
Flavanoids test - -
Sterols and steroids test + +
Saponins test + +
Tannins test - -
Carbohydrate test
i. Barfoed’s test
ii. Benedict’s test
+
+
+
+
The phytochemical screening of Crassula ovata stem and root extracts showed the presence of carbohydrates,
saponins, steroids, and alkaloids
Table 2. Observations for the aqueous plant leaf extracts at various concentrations
Bacteria Inhibition in mm per dilution
×
૚૙
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
Bacillus subtilis 0 0 0 0 0
Escherichia coli 6.4 6.2 6.1 6.1 6.1
Candida albicans 0 0 0 0 0
Staphylococcus aureus 0 0 0 0 0
Pseudomonas aeruginosa 0 0 0 0 0
The zones of inhibition of the different microorganisms after exposure to aqueous plant leaf extracts. The E coli
bacteria showed the only inhibition at the normal concentration of × 10
Table 3. Observations for the aqueous plant stem extracts at various concentrations
Bacteria Inhibition in mm per dilution
×
૚૙
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
Bacillus subtilis 0 0 0 0 0
Escherichia coli 6.1 0 0 0 0
Candida albicans 0 0 0 0 0
Staphylococcus aureus 0 0 0 0 0
Pseudomonas aeruginosa 0 0 0 0 0
The zones of inhibition of the different microorganisms after exposure to aqueous plant stem extracts. The E coli
bacteria showed the only inhibition at the normal concentration of × 10
Table 4. Observations for the methanolic plant leaf extracts at various concentrations
Bacteria Inhibition in mm per dilution
×
૚૙
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
Bacillus subtilis
0
0
0
0
0
Escherichia coli 6.5 6.2 0 0 0
Candida albicans 0 0 0 0 0
Staphylococcus aureus 0 0 0 0 0
Pseudomonas aeruginosa 0 0 0 0 0
The zones of inhibition of the different microorganisms after exposure to methanolic plant leaf extracts. The E coli
bacteria showed the only inhibition at the normal concentration of × 10
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
9
Table 5. Observations for the methanolic plant stem extracts at various concentrations
Bacteria
Inhibi
tion in mm per dilution
×
૚૙
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
×
૚૙
ି
Bacillus subtilis 0 0 0 0 0
Escherichia coli 6.1 0 0 0 0
Candida albicans 0 0 0 0 0
Staphylococcus aureus 0 0 0 0 0
Pseudomonas aeruginosa 0 0 0 0 0
The zones of inhibition of the different microorganisms after exposure to methanolic plant stem extracts. The E
coli bacteria showed the only inhibition at the normal concentration of × 10
Table 6. Anova (Single factor) analysis of methanolic and aqueous extracts of Crassula ovata
plant
Summar
y
Groups
Count
Sum
Average
Variance
Escherichia coli 2 12.3 6.15 0.005
Bacillus subtilis 2 0 0 0
Candida albicans 2 0 0 0
Staphylococcus aureus 2 0 0 0
Pseudomonas aeruginosa 2 0 0 0
Anova
Source of Variation
SS
df
MS
F
P
-
va
lue
F crit
Between groups 60.516 4 15.129 15129 2.17E-10 5.192168
Within groups 0.005 5 0.001
Total 60.521 9
The anova analysis of the effects of the plant extract on the various microorganisms. These shows a difference in
the calculated F value and tabulated F value
The antimicrobial activities of the extracts
increased linearly with increase in concentration
of the extracts. The Escherichia coli bacteria
were fairly sensitive than any other microbes to
the plants extracts especially the leaf aqueous
extracts. The growth inhibition zones measured
an average of 6.2 mm for all the sensitive
microbes, although not a strong value to show
activity. The results show that the aqueous leaf
extracts of Crassula ovata were found to be fairly
effective against Escherichia coli, but no
effectiveness on the other microbes tested.
The bacteria E. coli was greatly inhibited at
concentration, with leaf extract being at 6.4 mm
and stem extracts at 6.2 mm. Inhibition declined
for the stem extracts instantaneously while for
the leaf extracts it was gradual up to 6.1 mm.
The aqueous extracts of Crassula ovata showed
strong activity against Escherichia coli. The
results also revealed the presence of different
phytochemical compounds with biological activity
that can be of valuable therapeutic index. It has
been shown from earlier experiments that plants
rich in phenolic compounds have been shown to
have antimicrobial activities.
From the anova analysis, the tabulated F value
was lesser than the calculated F values did not
match, and hence the null hypothesis had to be
rejected. The aqueous leaf extracts of the
Crassula ovata plant gave a promising
effectiveness of antimicrobial growth on
Escherichia coli bacteria alone. This is attributed
to the presence of alkaloids like Berberine and
Sanguinarine, and saponins as observed during
the phytochemical testing of the plant. This
showed that the Crassula ovata plant is effective
only to the Escherichia coli bacteria. In this light,
more bioprospecting questions arise on whether
the plant extracts can be manipulated further to
completely inhibit Escherichia coli growth and
development.
The Crassula ovata plant is a common home
plant in most parts of Kenya. However, the
claims that it can heal wounds are most likely not
true. Scientific experimentation carried out in this
study helps prove that point. However, due to the
plants effect on Escherichia coli, the Crassula
ovate plant’s potential to control stomach upset is
yet to be further looked into.
Fig. 1. Antimicro
bial activity against different microbes exposed to methanolic extracts
The methanolic extracts only showed inhibition of E.
observ
Fig. 2.
Antimicrobial activity aga
The aqueous extracts showed an average inhibition on only E. coli bacteria alone.
0
1
2
3
4
5
6
7
leaves
Inhibition (mm)
0
1
2
3
4
5
6
7
leaves
Inhibition (mm)
Muiruri and Mwangi; EJMP, 11(1): 1-12
, 2016; Article no.
10
bial activity against different microbes exposed to methanolic extracts
The methanolic extracts only showed inhibition of E.
coli bacteria at concentration
only. No inhibition was
observ
ed for the other microorganisms
Antimicrobial activity aga
inst different microbes exposed to aqueous extracts
The aqueous extracts showed an average inhibition on only E. coli bacteria alone.
stems
B.subtilis
E.coli
C.albicans
S. aureus
P.aeruginosa
stems
B.subtilis
E.coli
C.albicans
S. aureus
P.aeruginosa
, 2016; Article no.
EJMP.19753
bial activity against different microbes exposed to methanolic extracts
only. No inhibition was
inst different microbes exposed to aqueous extracts
The aqueous extracts showed an average inhibition on only E. coli bacteria alone.
B.subtilis
E.coli
C.albicans
S. aureus
P.aeruginosa
B.subtilis
E.coli
C.albicans
S. aureus
P.aeruginosa
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
11
Fig. 3. A Chart of Inhibition against Concentration of
E. coli
by aqueous plant extracts
5. CONCLUSIONS AND RECOMMENDA-
TIONS
5.1 Conclusions
It is evident from the results that the plant
extracts of the Crassula ovata plant, both from
the leaves and stems, methanolic and aqueous,
are only able to inhibit the Escherichia coli
bacteria. Also being a gram negative bacterium,
Pseudomonas aeruginosa was not affected by
the plant extracts. Meaning that there was an
active compound in the plants extracts that acted
specifically against E. coli bacteria. This results
also led to the rejection of the null hypothesis
since a significant difference was observed in the
microbial proliferation and the active compounds
in the Crassula ovata plant. Other than
Escherichia coli, the Crassula ovata plant is none
effective to the other microbes that were tested
against.
The objectives of this study were met, both the
broad and specific objectives. There were active
phytochemical compounds in the Crassula ovata
plant. This included the Carbohydrates,
saponins, steroids, and alkaloids. The plant was
found to have an antimicrobial effect on
Escherichia coli bacteria.
This study proved that there are active
phytochemical compounds in the Crassula ovata
plant, and that these compounds have a
relatively minimal effect on microbial activity.
5.2 Recommendations
Since the Crassula ovata plant is fairly effective
to inhibit growth of only Escherichia coli bacteria.
It would be highly recommended that further
research is done to ascertain to which degree the
Crassula ovata plant extracts can inhibit the
Escherichia coli bacteria. And also how the
different growth stages of the plant could
influence this activity.
Other recommendations that the author would
suggest include;
Research on different Crassula plant
species varieties from different locations
and how effective they inhibit different
microorganisms.
Use of more gram negative bacteria
against the Crassula ovata extracts.
Isolating the Crassula ovata’s active
compound inhibiting the E. coli bacteria
and molecularly engineer it using
bioinformatics tools to test its potential as a
possible drug.
CONSENT
It is not applicable.
ETHICAL APPROVAL
It is not applicable.
0
1
2
3
4
5
6
7
Inhibition (mm)
×10^0 ×10^-1 ×10^-2 ×10^-3 ×10^-4
Concentration
Leaves Stem
Muiruri and Mwangi; EJMP, 11(1): 1-12, 2016; Article no.EJMP.19753
12
ACKNOWLEDGEMENTS
The author wishes to express his deepest
appreciation to Mr. Wambura Mwangi, family and
friends, for their constant support and influence
on his continued life experience.
COMPETING INTERESTS
Authors have declared that no competing
interests exist.
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_________________________________________________________________________________
© 2016 Muiruri and Mwangi; This is an Open Access article distributed under the terms of the Creative Commons Attribution
License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.
Peer-review history:
The peer review history for this paper can be accessed here:
http://sciencedomain.org/review-history/11727
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