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Research Article
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Antibacterial Activity of an Effective Spice Essential Oil Formulated in Foot
Deodorant Gel against Bacillus subtilis
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Pilanthana Lertsatitthanakorn
and
Bhuddhipong Satayavongthip
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ABSTRACT
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Skin bacterial flora, namely Staphylococcus epidermidis,
are able to metabolise sweat that hence leads to foot odor. Moreover, Bacillus
subtilis was found in the plantar skin of subjects possessing strong foot
odor. The synthetic antibacterial agent generally used in various foot deodorant
formulations is triclosan which tends to cause bacterial tolerance. To avoid
that shortcoming, researchers in this study developed a natural foot deodorant
gel from essential oils. Previous research of our group revealed that cinnamon
oil showed a higher antibacterial activity against S. epidermidis than
the essential oils obtained from kaffir lime, lemongrass, sweet basil, galanga
and ginger. In the present study, the susceptibility of B. subtilis
to the mentioned essential oils was determined and the results showed that cinnamon
oil possessed the highest activity. Foot deodorant gel containing cinnamon oil
was formulated and studied for its biological stability for 90 days at accelerated
conditions. The lethal effect of the cinnamon oil gel exposed to B. subtilis
for 1 h, was studied at day 0, 15, 30, 60 and 90. It was found that on all
sampling days, cinnamon oil gel could decrease by at least 90% the initial bacterial
population after 1 h of contact time. In conclusion, cinnamon oil foot deodorant
gel demonstrated a good ability to decrease the bacteria involved in strong
foot odor. The cinnamon oil foot deodorant gel might be an alternative cosmetic
for people who have strong foot odor.
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Received: March 15, 2012;
Accepted: July 13, 2012;
Published: September 06, 2012
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INTRODUCTION
Foot odor has been characterized as a health problem. Its etiology attributes
to degradation of the leucine found in sweat by the skins normal bacteria
flora, namely, Staphylococcus epidermidis which is the most Staphylococcal
species investigated on glabrous skin (Rath et al.,
2001; Troccaz et al., 2009). The major produced
metabolites are short chain fatty acids including isovaleric acid, acetic acid,
butyric acid and isobutyric acid which derived to foot odor (Ara
et al., 2006; Caroprese et al., 2009).
Moreover, Bacillus subtilis is also found in the plantar skin of people
having strong foot odor (Ara et al., 2006). Some
of these people rely on deodorant to eliminate body odors such as axillary and
foot odor. Deodorant is a type of cosmetic used to eliminate these body odors.
Numerous dosage forms of foot deodorant have been distributed to the marketplace
such as sprays (Kalavala et al., 2007) and creams
(Caroprese et al., 2009). The antibacterial agent
widely used in these various types of antibacterial cosmetics is triclosan.
However, triclosan is a synthetic biocide which tends to cause bacterial tolerance
(Cottell et al., 2009). As an alternative, researchers
have explored natural antibacterials and subsequently reported on the antibacterial
activity of essential oils from Citrus hystrix DC. (kaffir lime) fruit
peel, Cymbopogon citratus Stapf. (lemongrass) grass, Cinnamomum zeylanicum
Nees (cinnamon) bark, Ocimum basilicum L. (sweet basil) leaves, Alpinia
galanga (L.) Willd. (galanga) and Zingiber officinale Rosc (ginger)
rhizome (Inouye et al., 2001; Lertsatitthanakorn
et al., 2006; Luangnarumitchai et al.,
2007; Chanthaphon et al., 2008; Wannissorn
et al., 2009). In our previous study, the susceptibility of S.
epidermidis to these mentioned essential oils was determined. It was found
that cinnamon oil showed the highest activity against S. epidermidis while
kaffir lime oil and lemongrass oil revealed the second and third highest potencies,
respectively (Chimmalee and Lertsatitthanakorn, 2010).
The purpose of this study is to determine the antibacterial activity of these
essential oils against B. subtilis by the broth microdilution method.
Foot deodorant gel containing the oil most active against both B. subtilis
and S. epidermidis was formulated and studied for its biological
stability for 90 days. Hopefully, this cosmetic preparation might serve as an
alternative foot deodorant for people with strong foot odor.
MATERIALS AND METHODS
Materials: Essential oils from Citrus hystrix DC. (kaffir lime)
fruit peel, Cymbopogon citratus Stapf. (lemongrass) grass, Cinnamomum
zeylanicum Nees (cinnamon) bark, Ocimum basilicum L. (sweet basil)
leaves, Alpinia galanga (L.) Willd. (galanga) and Zingiber officinale
Rosc (ginger) rhizome were purchased from Thai China Flavors and Fragrances
Industry Co. (Thailand). Mueller-Hinton agar and Mueller-Hinton broth were provided
by Himedia (India). Dimethyl sulfoxide was purchased from Analar (UK). Glycerin,
carbomer 937, sodium chloride, propylene glycol, triethanolamine, polysorbate
80, methyl paraben, propyl paraben and lavender oil were purchased from local
suppliers in Thailand.
Culture and growth condition: B. subtilis DMST 15896 strain was
obtained from the Department of Medical Science, Ministry of Public Health,
Thailand. A culture was maintained and grown in Mueller-Hinton broth at 37°C.
Determination of MIC and MBC values of the six essential oils against
B. subtilis: A broth microdilution method was used to determine the
Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentrations
(MBCs) of the six essential oils in the same manner of the methods used by Lertsatitthanakorn
et al. (2006) and Tarawneh et al. (2010).
Muller-Hilton broth was added with 10% dimethyl sulfoxide to dissolve the oils.
Fifty microliters of two folded dilutions of each oil sample were prepared in
a 96-well plate. Fifty microliters of B. subtilis culture were added
to each well to make a final concentration of approximately 108 CFU
mL-1. In each test, B. subtilis in Mueller-Hinton broth and
Mueller-Hinton broth alone were used as a positive and negative growth control,
respectively. The plates were then incubated at 37°C for 24 h before the
MICs were determined. The MIC value was defined as the lowest concentration
of the oil inhibiting visible growth of bacteria. Ten microliters of broth were
removed from each well and spotted onto Mueller-Hinton agar to determine the
MBC value. After incubation at 37°C for 24 h, the number of surviving B.
subtilis was counted. The lowest concentration, where less than 0.1% of
the initial inoculum survived, was defined as the MBC value. Each experiment
was performed in triplicate.
Determination of the lethal effect of the selected essential oil against
B. subtilis: The lethal effect determination was modified from the
method previously described by Lertsatitthanakorn et
al. (2010). A suspension of 0.1 mL of B. subtilis, approximately
108 CFU mL-1, was added to 0.9 mL solution of the selected
essential oil. The oil solution was composed of 10% dimethyl sulfoxide in Mueller-Hinton
broth mixed with the selected oil to give the two desired concentrations of
the oil. A 0.9 mL solution of 10% dimethyl sulfoxide in Mueller-Hinton broth
mixed with a 0.1 mL suspension of B. subtilis, approximately 108
CFU mL-1, was used as control. Two 0.1 mL samples and one 0.1 mL
control were stirred carefully and transferred to three separate 0.9 mL tubes
of normal saline solution at 0, 10, 20, 30 and 60 min. The samples were serially
10-fold diluted in normal saline solution and 100 μL of each sample were
spread on Mueller-Hinton agar for viable counting. The experiment was performed
in triplicate. Results are presented as time-log survivors curves with
bars representing the standard deviation.
Formulation of foot deodorant gel containing the selected essential oil:
Various formulations of hydrogel containing a suitable concentration of the
selected oil were prepared using carbomer as a gelling agent. To overcome the
spicy odor of the selected essential oil, various perfume oils such as lavender
and jasmine were added to the preparation. The foot deodorant gel with the best
odor was chosen for determination of its physical stability using the freeze-thaw
cycling method. The freeze-thaw cycling method consisted of keeping the selected
deodorant at 4°C for 24 h and at 45°C for 24 h. The time frame for one
complete cycle was two days; ten days was allocated for 5 cycles. Color, odor,
pH and feeling, after applying deodorant gel on the foot, were recorded before
the first cycle and after the fifth cycle. The deodorant gel (Table
3) that was selected was determined following the steps outlined in the
next section.
Biological stability study of foot deodorant gel containing the selected
essential oil against B. subtilis: The developed deodorant gel was
stored in two separate environments for 90 days: room temperature with natural
light and 45°C without light. At day 0, 15, 30, 60 and 90, the biological
stability of the deodorant gel was studied by lethal effect determination as
previously described by Lertsatitthanakorn et al. (2008).
A bacterial suspension of 0.1 mL (approximately 108 CFU mL-1)
was added to 0.9 mL of the deodorant gel and mixed well in a vortex mixer. The
samples were kept at 37°C. A sample of 0.1 mL was collected for serial 10-fold
dilution at 0 and 1 h of contact time. The sample was then placed on Mueller-Hinton
agar and counted for survival bacteria after 24 h incubation. The results were
presented as log reduction of bacteria after 1 h exposure (log survivors of
bacteria at 0 min contact time - log survivors of bacteria at 1 h contact time)
and the storage time.
Data analysis: SPSS 11.5 for windows was used to perform statistical
analysis. The statistical difference of the biological stability, in term of
B. subtilis reduction ability, between the foot deodorant gel containing
the selected oil stored at room temperature with natural light and the one kept
at 45°C without light was analyzed by Student t-test. The p-value of less
than 0.05 was considered statistically significant.
RESULTS
Susceptibility of B. subtilis to six essential oils: MIC and
MBC values of six essential oils against B. subtilis are shown in Table
1. Cinnamon oil exhibited the highest antibacterial activity to B. subtilis
with the lowest minimum inhibitory concentration (MIC) at 0.049 μL
mL-1. However, the Minimum Bactericidal Concentration (MBC) of all
tested oils to B. subtilis was 100 or more than 100 μL mL-1.
Lemongrass and kaffir lime oils showed the second and third highest activity
to B. subtilis, respectively. Therefore, the susceptibility of B.
subtilis to the six essential oils showed a similar pattern as that of
S. epidermidis obtained from our previous study. In that study, among the
six essential oils, cinnamon oil exhibited the lowest MIC and MBC against S.
epidermidis at the same range of 0.391-1.562 μL mL-1 (Chimmalee
and Lertsatitthanakorn, 2010). Notably, cinnamon oil was the most active
oil against both bacterial strains involved in foot odor and it will be scrutinized
in the following section.
The lethal effect of cinnamon oil against B. subtilis: The lethal
effect of cinnamon oil against the tested bacteria was measured to determine
a suitable concentration of oil for foot deodorant preparation.
Table 1: |
MIC and MBC values of six essential oils against B. subtilis |
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According to our previous work, 3.125 and 9.375 μL mL-1 of
cinnamon oil could decrease 1.5 log and 3 log of initial S. epidermidis
population within 1 h, respectively (Chimmalee and Lertsatitthanakorn,
2010). Therefore, the desired concentrations for studying the lethal effect
of cinnamon oil against B. subtilis were 3.125 and 9.375 μL mL-1.
As shown in Figure 1 and Table 2, both concentrations
of cinnamon oil were able to reduce B. subtilis population rapidly. Because,
the initial bacterial count was approximate 108 CFU mL-1
and reduced to less than 102 CFU mL-1 within 10 min after
cinnamon oil exposure. By contrast, the solvent could not decrease B. subtilis
population and contributed to the control curve in Fig.
1. Therefore, both concentrations of cinnamon oil were able to decrease
at least 6 log of the initial population of B. subtilis within 10 min
and this lethal effect was constant for 1 h of contact time. Therefore, 3.125
and 9.375 μL mL-1 of cinnamon oil were selected as suitable
concentrations to decrease the population of B. subtilis. The gel base
however, retards the release of the essential oil, so the higher concentration
(9.375 μL mL-1) was chosen to incorporate into a suitable gel
base.
Formulation of foot deodorant gel containing cinnamon oil: An amount
of 9.375 μL mL-1 of cinnamon oil was incorporated into a suitable
hydrogel base for foot application. Cinnamon oil foot deodorant gel using lavender
oil as a perfume produced the most favorable odor and was chosen for further
study (Table 3).
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Fig. 1: |
Time-killing curves of cinnamon oil on B. subtilis
Mean±SD, n = 3 |
Table 2: |
Log reduction of initial B. subtilis population after
1 h exposure with cinnamon oil |
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Table 3: |
Ingredients of the selected cinnamon oil foot deodorant gel |
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*Paraben concentrated consisted of 10 g methyl
paraben and 2 g propyl paraben dissolved in 100 mL propylene glycol |
Table 4: |
Physical properties of the selected cinnamon oil foot deodorant
gel before the first cycle and after the fifth cycle of freeze-thaw cycling
storage |
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*pH of the foot deodorant gel was measured in triplicate
by pH meter |
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Fig. 2: |
Biological stability of cinnamon oil foot deodorant gel expressed
as log reduction of B. subtilis after 1 h exposure with the gel,
Mean±SD, n = 3 |
To prepare the gel, 2 g of carbomer 937 was dispersed in 80 mL of deionized
water and continuously stirred. 0.12 g of triethanolamine was used to neutralize
carbomer until a clear gel base was achieved. Glycerin (4 g), polysorbate 80
(2 g) and 937.5 μL of cinnamon oil were then added and mixed. Paraben concentrated
(1 g) and lavender oil (0.44 g) were added and mixed well. Finally, the volume
of the gel was adjusted to 100 mL with deionized water. The physical stability
of the cinnamon oil deodorant gel was studied using a freeze-thaw cycling method.
The results in Table 4 revealed that the selected cinnamon
oil foot deodorant gel possessed a physical stability. Because, the physical
properties of the gel including color, odor and feeling after applying on the
foot, did not change after the fifth cycle of freeze-thaw cycling storage. On
the one hand, the pH of the gel was rather constant due to a minute changing
from 5.04 (before the first cycle) to 5.02 (after the fifth cycle).
Biological stability study of the selected cinnamon oil foot deodorant gel
against B. subtilis: As shown in Fig. 2, the log
reduction of the tested bacteria exposed to cinnamon oil deodorant gel was more
than 90% (1 log) for all sampling times. The bacterial reduction ability between
the gel kept at room temperature with natural light and the gel kept at 45°C
without light was not statistically significant different (p>0.05).
DISCUSSION
Cinnamon oil exhibited the highest antibacterial activity against the bacteria
(B. subtilis) found in the plantar skin of subjects having strong foot
odor. The MIC value of cinnamon oil to B. subtilis was rather low and
compared well with the work of Prabuseenivasan et al.
(2006). In our previous research, the major components in cinnamon oil,
determined by Gas Chromatography-Mass Spectrometry, were cinnamaldehyde (32.66%)
and eugenol (36.49%) respectively (Chimmalee and Lertsatitthanakorn,
2010). In the present research, it was suggested that the prominent antibacterial
activity of cinnamon oil against B. subtilis might be attributable to
both of these major constituents. The previous antibacterial activity study
of cinnamon leaf and bark essential oils and their components clearly supported
our results. Since, Singh et al. (2007) found
that E-cinnamaldehyde and eugenol were the main components of cinnamon bark
oil and cinnamon leaf oil, respectively. They determined antibacterial activity
of these chemicals against six pathogenic bacteria including B. subtilis
by agar well diffusion method. The results of anti- B. subtilis demonstrated
that E-cinnamaldehyde showed a comparable inhibition zone with that of cinnamon
bark oil at the same concentration. On the one hand, eugenol revealed a comparable
zone with that of cinnamon leaf oil. Lu et al. (2011)
found that cinnamon bark oil, rich in trans-cinnamaldehyde, showed a strong
antibacterial activity against B. subtilis with the low MIC of 0.2 μL
mL-1. The essential oil of Ocimum basilicum (basil) containing
62.60% of eugenol also showed antibacterial activity against B. subtilis
with the low MIC of 0.625 μL mL-1 (Lv et
al., 2011). Cinnamaldehyde revealed a prominent antibacterial activity
against B. subtilis by disc diffusion method and it showed a higher activity
than benzoic acid at the same concentration (Wei et al.,
2011). Moreover, cinnamaldehyde and eugenol revealed a potent antimicrobial
activity to Streptococcus agalactiae, Streptococcus dysgalactiae,
Streptococcus uberis, Staphylococcus aureus, Helicobacter pylori
and Escherichia coli (Ali et al., 2005;
Baskaran et al., 2009; Pei
et al., 2009). Matan (2007) also found that
cinnamaldehyde and eugenol possessed antifungal activity against Aspergillus
niger by disc diffusion assay. In addition, when using various skin sensitization
potency assay methods, cinnamaldehyde was classified as a mild to moderate contact
allergen while eugenol was classified as a mild allergen (Kimber
et al., 2003). Therefore, the low concentration of 9.375 μL
mL-1 of cinnamon oil added to the deodorant gel in the present study
translates into a safe non-irritant concentration of cinnamaldehyde and eugenol.
Cinnamon oil foot deodorant gel stored at both accelerated conditions showed
less B. subtilis reduction than pure cinnamon oil. A time killing
assay of pure cinnamon oil revealed that the oil was able to reduce B. subtilis
population rapidly, at least 6 log of the initial population, within 1 h. By
contrast, the B. subtilis reduction ability of cinnamon oil foot deodorant
gel ranged between 1-4 log of the initial population after 1 h exposure. This
diminution in the ability of the cinnamon oil deodorant gel to reduce the B.
subtilis population might be attributed to the cinnamon oil deodorant gels
exposure to natural light and high temperature. The same phenomenon was occurred
with citronella oil oleogel, an anti-acne preparation, performed in our previous
researches. The oleogel containing 6.5% v/w of citronella oil which kept at
40°C for 120 days, could reduce less than 1.5 log of the initial Propionibacterium
acnes population after 12 h exposure (Lertsatitthanakorn
et al., 2008). By contrast, 5% v/v citronella oil could decrease
about 6.5 log of the initial P. acnes population within 6 h (Lertsatitthanakorn
et al., 2010). In addition, the retard effect of the gel base might
lead to a slow release of cinnamon oil from the gel even before it is exposed
to bacteria. Nevertheless, cinnamon oil foot deodorant gel still possesses satisfactory
biological stability due to its ability to decrease at least 1 log (90%) of
B. subtilis population over a 90 days storage period. To prove a foot
malodor relief efficacy of the developed gel, clinical trial should be studied
in people who possessing strong foot odor in the future.
CONCLUSION
Cinnamon oil demonstrated the highest antibacterial activity to B. subtilis,
the skin bacteria involved in strong foot odor. Therefore, cinnamon oil was
suitable to use as an antibacterial agent in foot deodorant preparations. The
developed cinnamon oil foot deodorant gel possessed a good ability to decrease
B. subtilis population throughout the gels
90 days storage period at accelerated conditions. To extend its shelf-life and
bacterial reduction ability, cinnamon oil gel should be protected from light
and exposure to high temperature. The cinnamon oil foot deodorant gel can be
developed as an alternative cosmetic for people who have strong foot odor.
ACKNOWLEDGMENTS
One of the authors (Pilanthana Lertsatitthanakorn) would like to kindly thank
Mahasarakham University Development Fund and Faculty of Pharmacy, Mahasarakham
University for financial support in presenting a part of this research as a
poster at the 1st International Conference on Antimicrobial Research, Valladolid,
Spain during 3-5 November 2010. In addition, we would like to thank Mahasarakham
University for providing a research grant, fiscal year 2009, to this project.
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REFERENCES |
1: Ali, S.M., A.A. Khan, I. Ahmed, M. Musaddiq and K.S. Ahmed et al., 2005. Antimicrobial activities of eugenol and cinnamaldehyde against the human gastric pathogen Helicobacter pylori. Ann. Clin. Microbiol. Antimicrob., Vol. 4 10.1186/1476-0711-4-20
2: Ara, K., M. Hama, S. Akiba, K. Koike and K. Okisaka et al., 2006. Foot odor due to microbial metabolism and its control. Can. J. Microbiol., 52: 357-364. PubMed | Direct Link |
3: Baskaran, S.A., G.W. Kazmer, L. Hinckley, S.M. Andrew and K. Venkitanarayanan, 2009. Antibacterial effect of plant-derived antimicrobials on major bacterial mastitis pathogens in vitro. J. Dairy Sci., 92: 1423-1429. CrossRef |
4: Caroprese, A., S. Gabbanini, C. Beltramini, E. Lucchi and L. Valgimigli, 2009. HS-SPME-GC-MS analysis of body odor to test the efficacy of foot deodorant formulations. Skin Res. Technol., 15: 503-510. PubMed | Direct Link |
5: Chimmalee, K. and P. Lertsatitthanakorn, 2010. Development of antibacterial liquid soap containing the selected spice essential oil. Proceeding of the 2nd Annual International Conference of Northeast Pharmacy Research, February 13-14, 2010, Maha Sarakham, Thailand pp: 10-.
6: Cottell, A., S.P. Denyer, G.W. Hanlon, D. Ochs and J.Y. Maillard, 2009. Triclosan-tolerant bacteria: Changes in susceptibility to antibiotics. J. Hosp. Infect., 72: 71-76. Direct Link |
7: Lu, F., Y.C. Ding, X.Q. Ye and Y.T. Ding, 2011. Antibacterial effect of cinnamon oil combined with thyme or clove oil. Agric. Sci. China, 10: 1482-1487. CrossRef | Direct Link |
8: Inouye, S., T. Takizawa and H. Yamaguchi, 2001. Antibacterial activity of essential oils and their major constituents against respiratory tract pathogens by gaseous contact. J. Antimicrobiol. Chemother., 47: 565-573. CrossRef | PubMed | Direct Link |
9: Kalavala, M., T.M. Hughes, R.G. Goodwin, A.V. Anstey and N.M. Stone, 2007. Allergic contact dermatitis to peppermint foot spray. Contact Dermatitis, 57: 57-58. PubMed | Direct Link |
10: Kimber, I., D.A. Basketter, M. Butler, A. Gamer and J.L. Garrigue et al., 2003. Classification of contact allergens according to potency: Proposals. Food Chem. Toxicol., 41: 1799-1809. CrossRef | Direct Link |
11: Lertsatitthanakorn, P., S. Taweechaisupapong, C. Aromdee and W. Khunkitti, 2006. In vitro bioactivities of essential oils used for acne control. Int. J. Aromather., 16: 43-49.
12: Lertsatitthanakorn, P., S. Taweechaisupapong, C. Aromdee and W. Khunkitti, 2008. Antibacterial activity of citronella oil solid lipid particles in oleogel against Int. J. Essent. Oil Ther., 2: 167-171. Direct Link |
13: Lertsatitthanakorn, P., S. Taweechaisupapong, C. Arunyanart, C. Aromdee and W. Khunkitti, 2010. Effect of citronella cil on time kill profile, leakage and morphological changes of Propionibacterium acnes. J. Essent. Oil Res., 22: 270-274. Direct Link |
14: Luangnarumitchai, S., S. Lamlertthon and W. Tiyaboonchai, 2007. Antimicrobial activity of essential oils against five strains of Propionibacterium acnes. Mahidol Univ. J. Pharm. Sci., 34: 61-64. Direct Link |
15: Lv, F., H. Liang, Q. Yuan and C. Li, 2011. In vitro antimicrobial effects and mechanism of action of selected plant essential oil combinations against four food-related microorganisms. Food Res. Int., 44: 3057-3064. CrossRef | Direct Link |
16: Matan, N., 2007. Growth inhibition of Aspergillus niger by cinnamaldehyde and eugenol. Walailak J. Sci. Tech., 4: 41-51. Direct Link |
17: Pei, R.S., F. Zhou, B.P. Ji and J. Xu, 2009. Evaluation of combined antibacterial effects of eugenol, cinnamaldehyde, thymol, and carvacrol against E. coli with an improved method. J. Food Sci., 74: M379-M383. CrossRef | PubMed | Direct Link |
18: Prabuseenivasan, S., M. Jayakumar and S. Ignacimuthu, 2006. In vitro antibacterial activity of some plant essential oil. BMC Complement. Altern. Med., Vol. 6. 10.1186/1472-6882-6-39
19: Rath, P.M., M. Knippschild and R. Ansorg, 2001. Diversity and persistence of Staphylococcus epidermidis strains that colonize the skin of healthy individuals. Eur. J. Clin. Microbiol. Infect. Dis., 20: 517-519. CrossRef | PubMed |
20: Chanthaphon, S., S. Chanthachum and T. Hongpattarakere, 2008. Antimicrobial activity of essential oils and crude extract from tropical Citrus spp. against food-related microorganisms. Songklanakarin J. Sci. Technol., 30: 125-131. Direct Link |
21: Singh, G., S. Maurya, M.P. de Lampasona and C.A.N. Catalan, 2007. A comparison of chemical, antioxidant and antimicrobial studies of cinnamon leaf and bark volatile oils, oleoresins and their constituents. Food Chem. Toxicol., 45: 1650-1661. CrossRef | Direct Link |
22: Tarawneh, K.A., F. Irshaid, A.S. Jaran, M. Ezealarab and K.M. Khleifat, 2010. Evaluation of antibacterial and antioxidant activities of methanolic extracts of some medicinal plants in northern part of Jordan. J. Biol. Sci., 10: 325-332. CrossRef | Direct Link |
23: Troccaz, M., G. Borchard, C. Vuilleumier, S. Raviot-Derrien, Y. Niclass, S. Beccucci and C. Starkenmann, 2009. Gender-specific differences between the concentrations of nonvolatile (R)/(S)-3-methyl-3-sulfanylhexan-1-ol and (R)/(S)-3-hydroxy-3-methyl-hexanoic acid odor precursors in axillary secretions. Chem. Senses, 34: 203-210. CrossRef |
24: Wannissorn, B., P. Maneesin, S. Tubtimted and G. Wangchanachai, 2009. Antimicrobial activity of essential oils extracted from Thai herbs and spices. Asian J. Food Agro Ind., 2: 677-689. Direct Link |
25: Wei, Q.Y., J.J. Xiong, H., Jiang, C. Zhang and W. Ye, 2011. The antimicrobial activities of the cinnamaldehyde adducts with amino acids. Int. J. Food Microbiol., 150: 164-170. PubMed |
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