GROWTH INHIBITION COMPARISON OF CINNAMOMUM SPECIES,
CINNAMOMUM ZEYLANICUM AND CINNAMOMUM CASSIA, ESSENTIAL OIL
EXTRACT AGAINST ESCHERICHIA COLI (Please don’t forget to bold your title and
abstract)
Anna Flores, Christopher Mayorga
Department of Biological Sciences
Saddleback College, Mission Viejo, CA, 92692
Cinnamomum species are known for their pleasing aroma, distinguishable taste, and
medicinal qualities. Research studies progress (may replace with “advocate”) the
medicinal practicality of using Cinnamomum species’ essential (delete) oils as an
antimicrobial agent against pathogenic microbes such as Escherichia coli and
Staphylococcus species. A comparison of two Cinnamomum species, Cinnamomum
zeylanicum and Cinnamomum cassia was conducted to distinguish if there would be a
significance difference between zone(s) of inhibitions against E. coli. Based on previous
research, the experimental data should have a significant difference between the
Cinnamomum species. The disk diffusion method was implemented for the (delete) both
experimental groups, C. zeylanicum and C. cassia, and control. Sterile paper disks were
treated with 5 l of either deionized water for (as a control?) control, or essential oil from
either C. zeylanicum or C. cassia for experimental groups. Agar plates were then
incubated at 37° Celsius for 48 hours. The mean zone of inhibition diameter in mm for
control C. zeylanicum and C. cassia groups were 0.00 mm ± 0.00 (±SE, n=39), 18.3 mm
± 0.19 (±SE, n=39), 27.1 mm ± 0.31 (±SE, n=39) respectively. An analysis of variance
(ANOVA) and Bonferroni correction test were conducted and concluded that there was a
shared significant difference between all groups (p<0.0001 ANOVA, and Bonferroni
correction).
Introduction
Cinnamomum species have been one of the many spices that have been researched
(studied) for its many health-benefiting properties. Essential oils in plants have been used
in many pharmaceutical therapies, alternative medicines, food preservation, and other
natural therapies for thousands of years (Burt, 2007, Nuryastuti, 2009, Saraf, 2011).
Recent studies show that Cinnamomum essential oils have promising antimicrobial
effects against antibiotic resistant bacteria such as Escherichia coli and Staphylococcus
species. E. coli, a Gram-negative bacteria found in commercial food items such as raw
meat and liquid juices, is one of the main causes of food poisoning in humans. In some
serious cases it may lead to the destruction of red blood cells or other problematic
situations in the liver and kidney’s. On account of the increasing number of antibiotic
resistant bacteria in E. coli, concerns have been raised by consumers (Nuryastut, 2009,
Rojas-Grau, 2007).
Cinnamaldehyde, an organic compound found in the essential oils of Cinnamomum,
seem to play a major part in the antimicrobial properties of Cinnamomum species
essential oils (Ciftci, 2010, El-Baroty, 2010,, Gende, 2008, Hoque, 2007, Nuryastuti,
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2009, Rojas-Grau, 2010). It has been found that E. coli is not able to develop resistance to
the essential oils of many plant species. Studies show that Cinnamomum essential oils
have greater antimicrobial activities against E. coli compared to other essential oils of
thyme, lemon grass, clove, etc. (Rojas-Grau el al. 2007). Two of the common species of
Cinnamomum that are used in antimicrobial studies are Cinnamomum zeylanicum and
Cinnamomum cassia (Burt, 2007, Gende, 2008).
Since both species of cinnamon show promising results against bacteria, research
between the potency of the two species will be conducted to see if there will be any
statistical difference between the essential oil’s zones of inhibition on E. coli
Methods
Thirty-nine nutrient agar plates were prepared in a biology laboratory located at
Saddleback College. An even amount of agar (Hardy Diagnostics CRITERION™ Agar)
was poured into thirty-nine Petri dishes. Aseptic techniques were used in order to prevent
any accidental contamination, in which the rim of the flask was sterilized by the flame of
a Bunsen burner before and after each agar plate was made.
Cultured Escherichia coli was provided by the Saddleback College Biology
Department. Test tubes containing E. coli were sterilized over the flame of a Bunsen
burner before and after obtaining the bacteria. The lawn-spread method was performed
on each agar plate. Gilson PIPETMAN® P-1000 pipettes were used to transfer 0.4 mL of
E. coli onto the agar plates. Glass spreaders were placed in a 95% ethanol, sterilized over
a flame, and were used to evenly distribute the bacteria onto the nutrient agar plate. The
thirty-nine Petri dishes were divided into three groups: the control group, Cinammomum
zeylanicum group, and Cinammomum cassia group. There were thirteen dishes for each
experimental group.
The disk diffusion method will (tense) be used to measure the antibacterial activity of
the essential oils. One hundred and seventeen paper chads were prepared and autoclaved
for sterilization. Each experimental group had a total of thirty-nine disks per group and
three chads per agar plate. The chads were treated with solutions and oils prior to being
placed on the agar plates. Oils and other fluids for treating sterile paper disks transferred
via Gilson PIPETMAN® P-20. The control group was treated with 5 l of deionized
water per chad and were placed on each dish using sterilized tweezers. Five mL of both
pure essential oils (Frontier Natural Products Co-op, Aura Cacia 100% pure essential
oils) were measured in a graduated cylinder, subsequently boiled in a flask to be
sterilized and then closed with a cork to prevent any further contamination. The C.
zeylanicum group was treated with 5 l of sterile C. zeylanicum essential oil and also
placed on each dish using sterilized tweezers. The same procedure was performed again
for the species C. cassia.
Once the chads were properly treated and situated in the agar, Petri dishes were
labeled with a wax pencil according to group and placed into one of the three metal
holders provided. They were then incubated at 37° Celsius for 48 hours. After 48 hours,
the cultures were removed from the incubator. Data were then collected and the diameters
for the zone of inhibitions were measured in millimeters.
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Results
The mean zone of inhibition for the control group containing deionized water and
E.coli after 48 hours was 0.00 mm ± 0.00 (±SE, n=39). After a 48-hour period, the
average zone of inhibition was 18.3 mm ± 0.19 (±SE, n=39) for C. zeylanicum
experimental group with E.coli. C. cassia experimental group had an average zone of
inhibition of 27.1 mm ± 0.31 (±SE, n=39) after the 48-hour incubation period.
An analysis of variance (ANOVA) was run on the measured diameters for zone of
inhibition. The results of the ANOVA reported the p-value to be less than 0.0001,
indicating that there was a significant difference. A Bonferroni correction test was
conducted and indicated that there was a significant difference between all the three
groups supporting the ANOVA results.
Figure 1. The zone of inhibitions of the control, C. zeylanicum, and C. cassia groups
after a 48-hour incubation period. There is a shared statistical difference between all three
groups (p<0.0001 ANOVA, and Bonferroni correction)
Discussion
In examination of the experimental data, there was a shared significant difference
between all three groups (p<0.0001 ANOVA, and Bonferroni correction, Figure 1). The
control group’s data indicated no detrimental variables that maybe associated with
bacteria or agar used for experiment. Both C. zeylanicum and C. cassia experimental
groups data contain a significant difference, therefore supporting the hypothesis of a
significant difference between the Cinammomum species (p<0.0001 ANOVA, and
Bonferroni correction, Figure 1). Although there have been many experiments on the
antimicrobial effects of the Cinammomum species, little research has been done in
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regards to a direct comparison of C. cassia and C. zeylanicum. Data from some (delete)
previous experiments reported C. cassia essential oils contained a larger zone of
inhibitions against E.coli than C. zeylanicum essential oil (Ciftci et al. 2010, El-Baroty et
al. 2010, Gende et al. 2008, Hoque et al. 2007, Lee & Ahn 1998, Nuryastuti et al. 2009,
Rojas-Grau el al. 2007, Saraf et al. 2011). Speculation that may contribute to the results
of the experiment would be the concentration of antimicrobial compounds in essential
oils, such as trans-cinnamaldehyde (El-Baroty et al. 2010, Gende et al. 2008, Saraf et al.
2011). Preparation of each essential oil may also be a major factor. For example, C.
zeylanicum essential oils are mostly extracted from the leaves of the plant compared to C.
cassia, which is usually prepared from the bark and branches (Ciftci et al. 2010, Gende et
al. 2008, Lee & Ahn 1998, Nuryastuti et al. 2009, Rojas-Grau el al. 2007, Saraf et al.
2011). Further experimental research would be necessary to evaluate any organic
compound concentration differences between the two Cinammomum species essential
oils.
As studies of the Cinammomum genus continues, health benefits derived from
ingestion of the spice seem to be increasing. From anti-inflammatory to antimicrobial
properties in most species the benefits for human health has potential for further medical
research (Burt, 2004, Ciftci et al. 2010, Hoque et al. 2007, Lee & Ahn 1998, Rojas-Grau
el al. 2007). Awareness on the use of natural antimicrobial additives to food products for
perseveres is leading to more research regarding the Cinammomum genus (Burt, 2004,
Gupta et al. 2008, Hoque et al. 2007). This experiment supports that C. cassia would be a
favored species for antimicrobial uses than C. zeylanicum.
Acknowledgements
We are sincerely grateful to Saddleback College Biology Department and Professor
Steve Teh for providing guidance, materials, and assistance that greatly assisted the
experiment.
Literature Cited
Burt, S. 2004. Essential oils: their antibacterial properties and potential applications in
foods - a review. International Journal of Food Microbiology 94:223-253.
Ciftci, M., Simsek, U. G., Yuce, A., Yilmaz, O., & Dalkilic, B. (2010). Effects of
Dietary Antibiotic and Cinnamon Oil Supplementation on Antioxidant Enzyme
Activities, Cholesterol Levels and Fatty Acid Compositions of Serum and Meat in
Broiler Chickens. Acta Veterinaria Brno. University of Veterinary and
Pharmaceutical Sciences LA - English.
El-Baroty G.S., El-Baky A., Farag R.S., Saleh M. A. 2010. Characterization of
antioxidant and antimicrobial compounds of cinnamon and ginger essential oils.
African Journal of Biochemistry Research Vol. 4(6): pp. 167-174.
Gende L., Floris I., Fritz R., Eguaras M. J. (2008)- Antimicrobial activity of cinnamon
(Cinnamomum zeylanicum) essential oil and its main components against
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Paenibacillus larvae from Argentine. Bulletin of Insectology, 61 (1): 1-4
Gupta C., Garg A.P., Kumari A., Uniyal R C. 2008.Comparative analysis of the
antimicrobial activity of cinnamon oil and cinnamon extract on some food-bone
microbes. African Journal of Biochemistry Research Vol. 2(9): pp. 247-251.
Hoque M. D., Inatsu M. L., Juneja, Vijay and Kawamoto S. (2007) Antimicrobial
activity of clove and cinnamon extracts against food borne pathogens and
spoilage bacteria and inactivation of Listeria monocytogenes in ground chicken
meat with their essential oils. J. Food Sci.& Tech.72: 9-21
Lee, H.S. and Ahn, Y.J., Growth-inhibiting effects of Cinnamomum cassia barkderived materials on human intestinal bacteria. J Agric Food Chem, 46:8-12,
1998.
Nuryastuti T, van der Mei HC, Busscher HJ et al. (2009) Effect of cinnamon oil on
icaA expression and biofilm formation by Staphylococcus epidermidis. Applied
Enviromental Microbiology 75: 6850-6855.
Rojas-Grau ̈ MA, Avena-Bustillos RJ, Olsen C, Friedman M, Henika PR, Mart ́ınBelloso O, Pan Z, McHugh TH. 2007. Effects of plant essential oils and oil
compounds on mechanical, barrier and antimicrobial properties of alginate-apple
puree edible films. Journal Food Engineering 81(3):634–41
Saraf A., Mishra M.S., and Sharma K., (2011) Antibacterial Activity of Commercial
and Wild Cinnamon Species. Journal of Phytology 2011, 3(2): 102-106.
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Review Form
Department of Biological Sciences
Saddleback College, Mission Viejo, CA 92692
Author (s): Chris Mayorga and Anna Flores
Title: GROWTH INHIBITION COMPARISON OF CINNAMOMUM SPECIES,
CINNAMOMUM ZEYLANICUM AND CINNAMOMUM CASSIA, ESSENTIAL OIL
EXTRACT AGAINST ESCHERICHIA COLI
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the
paper.
Two species of cinnamon are being used in a study in order to evaluate the
ability of these two species in the hindrance of e.coli growth. The researchers
examined the growth of inhibition as they added the oil extracts of the cinnamon to
the bacteria in agar plates. They presented their findings with ANOVA analysis and
Bonferroni corrections. The researchers concluded through analysis that there was
an actual significant difference to be recorded.
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important
to our current state of knowledge.
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The papers major weaknesses lie primarily in the realm of grammar and
sentence structure. I believe the researchers have presented and interesting
experiment which seems to have run well with strong observations. The errors are
not too serious, that being said, I believe the integration of their findings with the
research utilized can be presented more smoothly, but it is relevant and should be
kept in the paper, just tweaked.
Technical Criticism
Review technical issues, organization and clarity. Provide a table of typographical errors,
grammatical errors, and minor textual problems. It's not the reviewer's job to copy Edit the paper,
mark the manuscript.
This paper was a final version
Recommendation
 This paper should be published as is
 This paper should be published with revision
 This paper should not be published
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This paper was a rough draft