Chemical Composition and Antimicrobial Properties of
Oregano, Garlic, and Echinacea Essential Oils
LYNN ATWATER AND CAYLEIGH COLE
Abstract: Nature’s Sunshine™ Yeast/Fungal Detox supplement claims
to fight bacterial and fungal infections because of the antimicrobial
properties of its ingredients, including oregano, garlic, and Echinacea.
These claims were investigated by analyzing the essential oils of
oregano, garlic, Echinacea, and the detox itself using GCMS to
determine the chemical components responsible for their respective
antimicrobial components. The oils were introduced as bacterial growth
inhibitors in Escherichia coli, Staphylococcus aureus, and Saccromyces
yeast cultures. When comparing the essential oils tested, oregano was
found to be the most effective in Saccromyces yeast growth inhibition as
well as restricting the growth of S. aureus and E.coli.
Introduction
There has always been a demand
for “natural” products that aid the body in
fighting infection and promote general
health without introducing synthetic
chemicals into the body’s systems. As a
result of this demand, there are many
products on the market that claim to fight
bacterial infections through natural organic
products, without any added chemicals.
One such product is marketed by Nature’s
Sunshine™ and is called Yeast/Fungal
Detox. This product advertises its ability to
“inhibit the growth of unhealthy hormones
and help restore the body to optimal
performance.” It also claims to maintain
the healthy balance of microorganisms in
the body, specifically yeast and fungal
cultures, both by stimulating the body’s
immune system and by directly fighting
the bacterial growth.
However, this
supplement along with many other natural
supplements has reached the public market
unapproved by the FDA and, as such, have
not been tested to verify the claims they
make. [careful here to not overstate; too
much information – maybe be more
concise. I’d spend more time focused on
previous primary literature relating to this
area of research – this material, methods of
isolation, methods of analysis eventually
leading you to the research GAP – then
state how your work attempts to fill that
gap] This brings up a question concerning
this supplement: does it indeed fulfill the
promises it makes concerning the fighting
of bacterial infections? [restate not in the
form of a question]
The ingredients in the supplement
include oregano, caprylic acid, propionic
acid, sorbic acid, Echinacea angustifolia
root, garlic, pau d’arco bark, in addition to
selenium and zinc. Selenium and zinc were
disregarded because they are inorganic
compounds. Regarding the organic
ingredients, oregano, garlic, and echinacea
were selected for analysis by microbial
growth inhibition testing in order to
substantiate the claims made by this
product. It was surmised that if these
ingredients could be determined to possess
antimicrobial properties, then the claims of
the supplement would be supported
sufficiently.
However, if these organic
compounds were analyzed and found to
not have any effect on microbial growth,
then further experimentation would be
necessary before the claims could be
refuted. [not in the correct location – you
need to think about the MOVE structures
and the HOURGLASS progression of
ideas]
In studies done concerning the
antibacterial activity of essential oils,
terpenoids like carvacrol and thymol show
the greatest antibacterial properties. [ref]
These terpenoids are major components of
oregano essential oil, as quantified by
Dadalioglu and Evrendilek1. Many sources
indicate that oregano is a good source of
natural antibacterial properties2. In order to
test claims concerning bacteria fighting
properties, the essential oils of oregano,
garlic, and Echinacea were analyzed by
GC/MS to identify the presence of
terpenoids, specifically carvacrol and
thymol. FILL THE GAP STATEMENT –
at the end of the INTRO
Figure 1. Carvacrol (left) and thymol (right),
antibacterial terpenoids
The presence of terpenes in the
essential oils would suggest antibacterial
properties in the oils due to the terpenoid
constituents. A lack of terpenoids would
indicate antimicrobial activity from some
other source, if the oils showed and
antimicrobial properties at all.
In order to link the presence or
absence of terpenoids with antimicrobial
properties of the essential oils, the oils
were introduced individually as bacterial
growth inhibitors to E. coli, S. aureus, and
Saccromyces yeast cultures. A distillation
of the original detox was also used for a
bacterial growth inhibitor in order to verify
its claims as a mixture. Control cultures of
bacteria with no inhibitors were compared
with the experimental cultures. Sounds like
METHODS
Materials
Where did you obtain the materials,
standards,
information
@
GCMS
instrument, etc
Dried oregano, garlic bulb, and Echinacea
capsules containing fine powdered
Echinacea were purchased from Wegmans
Food Markets. Additional oregano was
obtained from Sauders Markets in Seneca
Falls, NY. Additional Echinacea was
purchased from Lori’s Natural Foods in
Rochester, NY. Yeast/Fungal detox was
made available from Laura Kokanvich, a
certified holistic practitioner. E. Coli,
staph, and Saccromyces yeast cultures
were obtained from the Biology
Department
of
Nazareth
College,
Rochester, NY
Methods
. E. Coli and staph were transferred
into Mueller-Hinton nutrient broth and
incubated
overnight
before
being
transferred to Mueller-Hinton agar plates.
Saccromyces
yeast
cultures
were
transferred into Sabouraud dextrose broth
and incubated overnight before being
transferred to Sabouraud Dextrose agar
plates.
The essential oils from oregano,
garlic, and Echinacea were isolated by
steam distillation using an original
apparatus based on an essential oil steam
distillater3.
Figure 2. Steam distillation apparatus
I’d produce something other than a
hand drawn figure.
Each distillation was completed
over a 3.5 h period. After various attempts
to separate the oil from water, the samples
were extracted with 2 x xxx mL of
dichloromethane, ethyl acetate, and diethyl
ether, respectively. The solvents were
removed from each sample and the
remaining residue was dissolved in ether
and analyzed by GCMS. Inlet temperature
was 200 °C and detector temperature was
set at 250 °C with a 5 min solvent delay at
an initial oven temperature of 50 °C. The
temperature was increased to 90 °C at a
rate of 2 °C/min and increased again to 210
°C at a rate of 5 °C/min, where it was held
for 40.0 min. Helium gas was used as the
carrier gas with a flow rate of 1.2 mL/min.
(materials section?)
The oils from the yeast/fungal
detox were isolated by Soxhlet extraction
using ethanol as solvent. Solvent was
removed by rotary evaporation and the
sample was analyzed by GCMS using
identical parameters to the previous
samples.
Bacterial growth inhibition was
done by saturating paper disks with an
individual essential oil for 24 h. A
microbial lawn was made and the saturated
disks introduced to E. coli, staph, and
Saccromyces yeast, respectively with
incubation for 3 days at 37 °C.
Results
[reset the experiment and then
introduce your first piece of data/first
result] The oregano essential oil produced
an inhibitory effect on E. coli, S. aureus,
and Saccromyces yeast during the
microorganism
growth
inhibition
test.[discussion] The essential oil of the
detox supplement also produced an
inhibitory effect on both E. coli and S.
aureus. It had no effect on the
Saccromyces yeast. [discussion – here I’d
recommend using an integrated R and D:
introduce result and then discuss it]
Figure 3. Detox (left column) in E. coli, S.s aureus,
and Saccromyces yeast cultures, respectively.
Oregano (right column) in the same cultures.
No data could be gathered from the
Echinacea
samples.
[1
sentence
paragraph?]
GCMS analysis of garlic oil, looking for
terpenoids, was inconclusive. [1 sentence
paragraph?]
GCMS analysis of oregano
displayed peaks that corresponded strongly
with the peaks of both thymol and
carvacrol. [you need to provide results
statements which carefully move the
reader between text and graphics BEFORE
you discuss/interpret them]
Figure 4: GC/MS spectra from oregano
Figure 5: GC/MS peaks from samples
Are you going to refer anywhere in your text to
either of these figures? IF so, then leave them, if
not delete.
GC/MS analysis of yeast/fungal
detox yielded little information about the
components of the mixture. None of the
peaks matched with the carvacrol peaks
found in oregano.
Table 1. GCMS peaks from samples
compound
carvacrol
thymol
oregano
garlic (1)
garlic (2)
Detox
retention time (min)
26.21
25.44
26.30
no other significant peaks
24.97
8.62
8.81
14.41
18.93
24.92
30.16
35.70
40.53
40.71
The table is the best approach here to
summarize/compile your data. However, it
must be 3 x 3 and must be formatted
correctly – see examples of tables by
looking in JAFC
GC/MS analysis of yeast/fungal
detox yielded little information about the
components of the mixture. None of the
peaks matched with the carvacrol peaks
found in oregano.
These shortened
paragraphs will be circumvented by taking
a different tact with the integrated R and D
Discussion
The initial Echinacea samples had
to be discarded due to the dissolving of the
powdered plant matter into the reservoir.
[is this really where you want to start your
discussion – with error analysis?] The
second Echinacea steam distillation
became overheated and the sample was
scorched. No oil could be extracted due to
the contamination. Further experimentation
into the antibacterial effects of Echniacea
is suggested.
There is no research to suggest the
presence of terpenoids in garlic oil, as
supported by the lack of correlation with
the standards of thymol and carvacrol in
the GC/MS data from garlic oil. The
antibacterial component in garlic is
believed to be allicin, and further testing is
suggested for verification of the
antimicrobial
properties
of allicin.
(implication/application)
The mass spectrum from oregano
corresponded with the spectra from thymol
and carvacrol, which indicates the presence
of these terpenoids in oregano essential oil.
Further researching concerning terpenoids
and their antibacterial properties is needed
before additional conclusions can be drawn
regarding the properties of oregano.????
[NOT FLUID!!!!] Again, you need
to employ the correct MOVE structures –
see WLAC chapters IV and V Oregano
had a significant inhibitory effect on
growth all three cultures: E. Coli, staph,
and Saccromyces yeast. There was the
greatest inhibition [refer to a figure] of
growth in Saccromyces yeast. Difficulty in
comparing results between cultures was
experienced due to the lack of a reliable
method of quantifying bacterial growth.
Future research to develop a consistent
method of measuring the relative
inhibitory effects on microorganism
cultures is recommended.
The detox supplement appears to
be effective in prohibiting bacterial
growth. However, it appears to have little
or no effect on Saccromyces yeast. This
would suggest the claims of the
supplement were false. However, it is
possible that the supplement is effective
against other strains of yeast. Further
experimentation is recommended to
authenticate claims in regard to the
Candida albicanus or other yeast strains.
Sources of Error
 Ignorance of experimenters
o Interpretation of spectra
o Nature of terpenoids
o Poor labeling
o Leaving samples uncovered
 GC/MS
o Different results from garlic
oil in different solvents
 Apparatus
o Not as efficient as hoped
 Lack of adequate quantification
method
o Couldn’t identify which
solvent was best for
extractions b/c couldn’t
quantify amount of oil
o (bacteria growth) Made
comparison
between
cultures difficult
Literature Cited
(1) Balch, Phyllis. Prescription for
Nutritional Healing; Penguin Group: New
York, 2006; Part One
(2) Dadalioglu, Itir; Evrendilek, G. A.
Chemical Compositions and Antibacterial
Effects of Essential Oils of Turkish
Oregano (Origanum minutiflorum), Bay
Laurel (Laurus nobilis), Splanish Lavender
(Lavandula stoechas L.), and Fennel
(Foeniculum vulgare) on Common
Foodborne Pathogens. J. Agric. Food
Chem. 2004, 52, 8255-8260
(3) Dorman, H. J. D.; Deans, S. G.
Antimicrobial Agents from Plants:
Antibacterial Activity of Plant Volatile
Oils. J. Appl. Microbio. 2000, 88 (2), 308316
(4) Mondy, N.; Naudin, A.; Christides,
J.P.; Mandon, N.; Auger, J. Comparison of
GC/MS and HPLC for the Analysis of
Allium Volatiles. Chromatagraphia. 2001,
53, Suppl, S-356—S-360
(5) Paradise, Lee Ann Oregano Essential
Oil. Answers.com accessed October, 2007
written 2007?
(6) Essential Oil Distiller Operating
Instructions.
Crucible.org
http://www.crucible.org/essential_oil_distil
ler_operation.htm accessed October, 2007