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The antimicrobial activity of Lavandula angustifolia essential oil was assessed in combination with 45 other oils to establish possible interactive properties. The composition of the selected essential oils was confirmed using GC-MS with a flame ionization detector. The microdilution minimum inhibitory concentration (MIC) assay was undertaken, whereby the fractional inhibitory concentration (ΣFIC) was calculated for the oil combinations. When lavender oil was assayed in 1 : 1 ratios with other oils, synergistic (26.7%), additive (48.9%), non-interactive (23.7%), and antagonistic (0.7%) interactions were observed. When investigating different ratios of the two oils in combination, the most favourable interactions were when L. angustifolia was combined with Cinnamomum zeylanicum or with Citrus sinensis, against C. albicans and S. aureus, respectively. In 1 : 1 ratios, 75.6% of the essential oils investigated showed either synergistic or additive results, lending in vitro credibility to the use of essential oil blends in aroma-therapeutic practices. Within the field of aromatherapy, essential oils are commonly employed in mixtures for the treatment of infectious diseases; however, very little evidence exists to support the use in combination. This study lends some credence to the concomitant use of essential oils blended with lavender.
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Evidence-Based Complementary and Alternative Medicine
Volume , Article ID ,  pages.//
Research Article
The In Vitro Antimicrobial Activity of
Lavandula angustifolia Essential Oil in Combination with
Other Aroma-Therapeutic Oils
Stephanie de Rapper,1Guy Kamatou,2Alvaro Viljoen,2and Sandy van Vuuren1
1Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Parktown,
Johannesburg 2193, South Africa
2Department of Pharmaceutical Sciences, Faculty of Science, Tshwane University of Technology, Pretoria 0001, South Africa
Correspondence should be addressed to Sandy van Vuuren;
Received  February ; Accepted  April 
Academic Editor: Jenny M. Wilkinson
Copyright ©  Stephanie de Rapper et al. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
e antimicrobial activity of Lavandula angustifolia essentialoilwasassessedincombinationwithotheroilstoestablish
possible interactive properties. e composition of the selected essential oils was conrmed using GC-MS with a ame ionization
detector. e microdilution minimum inhibitory concentration (MIC) assay was undertaken, whereby the fractional inhibitory
concentration (ΣFIC) was calculated for the oil combinations. When lavenderoilwasassayedin:ratioswithotheroils,synergistic
(.%), additive (.%), non-interactive (.%), and antagonistic (.%) interactions were observed. When investigating
dierent ratios of the two oils in combination, the most favourable interactions were when L. angustifolia was combined with
Cinnamomum zeylanicum or with Citrus sinensis, against C. albicans and S. aureus, respectively. In :  ratios, .% of the essential
oils investigated showed either synergistic or additive results, lending in vitro credibility to the use of essential oil blends in aroma-
therapeutic practices. Within the eld of aromatherapy, essential oils are commonly employed in mixtures for the treatment of
infectious diseases; however, very little evidence exists to support the use in combination. is study lends some credence to the
concomitant use of essential oils blended with lavender.
1. Introduction
Essential oils, which form part of naturopathic therapy, are
widely known for their antimicrobial properties. ey have
been found to be benecial in the elds of dermatology,
gastritis, respiratory complaints, wound healing, and gen-
ital infections. Of all the essential oils used commercially,
lavender (Lavandula angustifolia)oilappearstobeoneofthe
most popular. e earliest therapeutic use of L. angustifolia
e signicance of which, with respect to antimicrobial
applications, has been further emphasised in a number of
studies [,]. Within aromatherapy and wellness industries,
the oil has been indicated for the treatment of a plethora of
conditions, such as rhinitis, wet coughs, minor burns, and in
the emergency treatment of wounds [].
Essential oils are not only used in monotherapy but have
been used in combination for many years []. ey are used
to bring about healing in a holistic manner by stimulating the
mind, body, and senses, where the combination is believed
to act synergistically to further enhance these eects. Aer
examining the literature on the application of various essen-
tial oils for their use in treating microbial infections, more
than  possible essential oil combinations were identied,
of which the majority included the use of L. angustifolia in
combination for the treatment of infections []. According
to the general literature, L. angustifolia hasbeenusedasan
antibiotic or antiseptic in combination with a number of
other oils (bitter orange, caraway, cederwood, chamomile,
geranium, grapefruit, lemon, marjoram, patchouli, rosemary,
sage, sweet orange, and ylang-ylang) []. In spite of the
numerous references to L. angustifolia in combination with
Evidence-Based Complementary and Alternative Medicine
other essential oils, supporting evidence is lacking. Only two
scientic papers were found where L. angustifolia was studied
in combination with commercially available essential oils.
Melaleuca alternifolia (tea tree oil) in combination with L.
ocinalis was investigated against Trichophyton rubrum and
T. ment a g r o p hy t e s var. interdigitale.edataconrmedthat
synergistic activity was evident when these oils were placed
in combination []. Another study conducted by Edwards-
Jones et al.[]placedL. ocinalis in combination with M.
alternifolia,Pogostemon cablin, Pelargonium graveolens,and
Citricidal (a grapefruit seed extract, commercially available
as an antibacterial agent). e antibacterial ecacy was
tested using the inhibition zone method, in which direct
and vapour contact of the essential oils were tested. When
placed in combination with P. g r a v e o l e n s and M. alternifolia,
L. ocinalis demonstrated an increased inhibitory eect
against Staphylococcus aureus. Antagonism was noted for
the combination of L. ocinalis and M. alternifolia against
methicillin-resistant S.aureus (MRSA). While these two
studies provide conrmation of improved ecacy in some
cases when the oils are used in combination, the overall
interactive potential with other essential oils has not been
fully explored. In aromatherapy practices, essential oils are
rarely used individually but rather applied as blends to
achieve a superior therapeutic eect. With this in mind, the
aim of this study was to evaluate the interactive in vitro
antimicrobial properties of L. angustifolia andaselectionof
essential oils commonly used in therapeutic combinations.
2. Materials and Methods
2.1. Essential Oil Selection and Chemical Composition Anal-
ysis. Forty-ve essential oil samples were obtained as a
gi from commercial fragrance and avour suppliers. e
composition of the selected essential oils was conrmed
using gas chromatography coupled to a mass spectrome-
ter and ame ionization detector (GC-MS-FID). e GC-
MS-FID (Agilent  N GC system and  MS) was
equipped with a HP-Innowax polyethylene glycol column
( m × 𝜇mi.d.×. 𝜇mlmthickness).Avolumeof
𝜇L of the essential oil was injected (using a split ratio
of  : ) with an autosampler at .psi and an inlet
temperature of C. e GC oven temperature was set
at C for  min, then Catarateof
C/min for
 min and followed by a temperature of Catarateof
. mL/min. Spectra was obtained on electron impact at  eV,
scanning from  to m/z. e percentage composition
of the individual components was quantied by integra-
tion measurements, using ame ionization detection (FID,
C). Component identications were made by comparing
mass spectra from the total ion chromatogram, and retention
indices using NIST and Mass Finder GC-MS libraries and
major compounds given in Tab l e  [].
2.2. Antimicrobial Assays. Seven laboratory cultured bacte-
rial strains, three laboratory cultured fungal strains, and four
clinical bacterial strains were selected for the study (Tab l e ).
is was undertaken to provide a broad-spectrum prole
of the antimicrobial activity for L. angustifolia. In order
to evaluate combined ecacies, three microorganisms were
selected (Staphylococcus aureus, ATC C  ; Pseudomonas
aeruginosa, ATCC  and Candida albicans, ATCC  ),
whereby the oils were evaluated for antimicrobial activity
using the microdilution minimum inhibitory concentration
(MIC) assay [].Essentialoilsaretypicallyusedtotreat
topical and respiratory infections, and these microorganisms
were selected on the basis of this pathogenesis. Furthermore,
selection was based on the criteria to include a Gram-
positive, a Gram-negative, and a yeast strain. e Clinical
and Laboratory Standards Institute guidelines (CLSI) []
were used to ensure that accurate microbiological assay
and transfer techniques were followed. Stock cultures were
retained at C,subculturedontoTryptoneSoya(TSA)
agar, and incubated at optimum temperatures (Cfor
 h for bacteria, and C for  h for the yeast). Isolated
pure colonies were selected and transferred onto TSA and
thereaer kept viable by subculturing weekly for stock culture
Essential oils were diluted to a concentration of  mg/mL
using acetone as the diluent. e microtitre plates were
prepared by adding  𝜇L of sterile, distilled water into each
of the wells. ereaer, the oils were added at a volume
of  𝜇L (when tested individually) and  :  𝜇L(when
tested in combination).e essential oils were serially diluted
. mg/mL. e microorganisms for testing were diluted
using sterile TSB at a  :  dilution in order to achieve an
approximate concentration of ×6colony forming units
(CFU)/mL. Cultures were added to all the wells of their
respective microtitre plates, at a volume of  𝜇L. e
microtitre plates were then sealed with a sterile adhesive
sealing lm, to prevent any essential oil loss due to their
inherent volatility. e microtitre plates were incubated
under optimal conditions (Cforhforbacteriaand
C for  h for yeasts). Aer incubation, . mg/mL of p-
iodonitrotetrazolium violet solution (INT) was added to each
well ( 𝜇L). Viable micro-organisms interact with INT to
create a colour change from clear to a red-purple colour. us
the lowest dilution with no colour change was considered as
the MIC for that oil [].
For the  :  combinations, the fractional inhibitory con-
centration index (ΣFIC) was used to determine the interac-
tion of the oils. e ΣFIC was calculated by dividing the MIC
value of the combined essential oils with the MIC value of
each essential oil placed in the combination. e ΣFIC was
then calculated by adding these two values. e ΣFIC for each
combination was interpreted as antagonistic where a ΣFIC
value of greater than . is observed. Indierence was noted
for ΣFIC values greater than . but less than or equal to
.. Additive properties for ΣFIC values more than . but
less than or equal to ., with synergistic properties noted
for ΣFIC values less than or equal to . [].
Isobolograms were constructed to determine what
antimicrobial interactions could be apparent if variable
concentrations of selection of oils (Daucus carota,Juniperus
Evidence-Based Complementary and Alternative Medicine
T : e chemical composition (major compounds only) of the essential oils under investigation.
Essential oil Major constituent % Abundance
Abies balsamea
𝛽-pinene .
bornyl acetate .
𝛿--carene .
Andropogon muricatus
𝛽-vetirenene .
zizanol .
𝜆-vetivenene .
isoeremophilene .
𝛽-vetispirene .
vetivenic acid .
Angelica archangelica root
𝛼-phellandrene .
𝛼-pinene .
𝛽-phellandrene .
𝛿--carene .
Angelica archangelica seed 𝛽-phellandrene .
Anthemis nobilis
-methylbutyl--methyl propanoic acid .
limonene .
-methylpentyl--butenoic acid .
isobutyl isobutyrate .
Artemisia dracunculus estragole .
Canarium luzonicum
limonene .
elemol .
𝛼-phellandrene .
Cananga odorata heads
benzyl acetate .
linalool .
methyl benzoate .
Cananga odorata bicyclosesquiphellandrene .
𝛽-farnesene .
Carum carvi limonene .
carvone .
Cinnamomum zeylanicum eugenol .
Citrus aurantium linalyl acetate .
linalool .
Citrus grandis limonene .
Citrus sinensis limonene .
Commiphora myrrha furanoeusdema-,-diene .
lindestrene .
Cupressus sempervirens 𝛼-pinene .
𝛿--carene .
Cymbopogon citratus geranial .
Cymbopogon nardus
citronellal .
geraniol .
citronellol .
Daucus carota
carotol .
𝛽-caryophyllene .
𝛽-bisabolene .
Eucalyptus globulus ,-cineole .
𝛼-terpineol .
Evidence-Based Complementary and Alternative Medicine
T : Continu ed .
Essential oil Major constituent % Abundance
Foeniculum dulce E-anethole .
Hyssopu s ocinali s isopinocamphone .
pinocamphone .
Juniperus virginiana
thujopsene .
cedrol .
𝛼-cedrene .
Juniperus virginiana berries
𝛼-pinene .
myrcene .
bicyclosesquiphellandrene .
Laurus nobilis
eugenol .
myrcene .
chavicol .
Lavandula angustifolia
linalyl acetate .
linalool .
terpinen--ol .
Litsea cubeba geranial .
nerol .
Matricaria chamomilla bisabolene oxide A .
𝛽-farnesene .
Melaleuca alternifolia terpinen--ol .
𝛾-terpinene .
Melaleuca viridiora ,-cineole .
𝛼-terpinene .
Mentha piperita menthol .
menthone .
Myrtus communis
myrtenyl acetate .
,-cineole .
𝛼-pinene .
Ocimum basilicum linalool .
Origanum majorana ,-cineole .
linalool .
Pelargonium odoratissimum citronellol .
geraniol .
Pinus sylvestris
bornyl acetate .
camphene .
𝛼-pinene .
Piper nigrum 𝛽-caryophyllene .
limonene .
Pogostemon patchouli
patchouli alcohol .
𝛼-bulnesene .
𝛼-guaiene .
Rosmarinus ocinalis ,-cineole .
Salvia sclarea linalyl acetate .
linalool .
Santalum album 𝛼-santalol .
Styrax benzoin cinnamyl alcohol .
benzene propanol .
Syzygium aromaticum eugenol .
eugenol acetate .
Evidence-Based Complementary and Alternative Medicine
T : Continu ed .
Essential oil Major constituent % Abundance
Tag et e s p a t u l a
(E)-𝛽-ocimene .
E-tagetone .
verbenone .
ymus vulgaris
p-cymene .
thymol .
𝛾-terpinene .
T : e antimicrobial eects of L. angustifolia essential oil against  test pathogens.
Microorganism Reference strain no. MIC
Methicillin-resistant Staphylococcus aureus (MRSA) ATCC  .
Methicillin-resistant Staphylococcus aureus Clinical strain .
Methicillin-gentamicin resistant Staphylococcus aureus (MGRSA) ATCC  .
Staphylococcus aureus ATC C  .
Staphylococcus aureus Clinical strain .
Staphylococcus epidermidis ATCC  .
Staphylococcus epidermidis Clinical strain .
Vancomycin-resistant Enterococcus faecalis ATC C  .
Enterococcus faecalis Clinical strain .
Klebsiella pneumoniae ATCC  .
Pseudomonas aeruginosa ATC C  .
Cryptococcus neoformans ATC C  .
Candida tropicalis ATCC  .
Candida albicans ATC C  .
Ciprooxacin Positive control . ×to . ×
Amphotericin B Positive control . ×
MIC given in mg/mL.
virginiana,Cinnamomum zeylanicum,andCitrus sinensis)
were combined with L. angustifolia. Selection was based
on promising synergistic interactions observed in the  :
ΣFIC analysis. Nine ratios, that is, : ;  : ;  : ;  : ;  : ;
:;:; :;and : ofthe oilsweremixed andthereaer
the MIC values were determined for these combinations,
as well as for the essential oils independently. Isobolograms
were plotted using GraphPad Prism, version ve soware to
present the mean MIC values of the combinations as ratios
[]. e isobolograms were interpreted by examining the
data points for each ratio in relation to the MIC values for
the oils independently. All points between the . : . line
and . : . line were classied as non-interactive. Points
between the . : . and . : . line were interpreted as
additive and points below or on the . : . line on the
isobologram were interpreted as synergistic. Antagonism
was identied as data points above the . : . line [].
Positive and negative controls were included in all assays,
with . mg/mL ciprooxacin used as a positive control
for bacteria, and . mg/mL amphotericin B for the yeast.
e negative control was a water/acetone solution at a
concentration of  mg/mL, to determine any antimicrobial
activity of the diluent. Media and culture controls, such as
Tryptone Soya broth (TSB), were included to conrm sterility
and viability, respectively. Assays were done in triplicate and
further repetitions conducted where necessary.
3. Results
3.1. Chemical Composition. e chemical composition of the
essential oils were analysed in order to conrm the specic
chemotypes (Table ).Althoughafullchemicalprolewas
established for each essential oil, only the major constituents
previously published proles.
3.2. Antimicrobial Analysis. e antimicrobial ecacy for L.
angustifolia essential oil was investigated against  pathogens
whereby MIC values of . mg/mL were predominantly
observed against the tested pathogens. A few exceptions
(Klebsiella pneumoniae with an MIC of . mg/mL, Candida
tropicalis with an MIC of . mg/mL, and C. albicans with an
MIC of . mg/mL) were noted (Tab l e  ). When examining
the entire panel of oils tested, Santalum album showed the
greatest antimicrobial eect, with the lowest MIC values for
Evidence-Based Complementary and Alternative Medicine
S. aureus (MIC value of . mg/mL) and P. a e r u g i n o s a (MIC
value of . mg/mL).
When the  essential oil samples were placed in com-
bination with L. angustifolia in equal ratios, .% of the
combinations exhibited either synergistic or additive antimi-
crobial activity (Tab le  ). e most noteworthy synergistic
interactions were evident for C. albicans, particularly the
combination of L. angustifolia with Cupressus sempervirens
(ΣFIC value of .) and L. angustifolia with Litsea cubeba
(ΣFIC value of .). For all combinations studied, antag-
onism was only noted once, where Cymbopogon citratus
was investigated in combination with L. angustifolia (ΣFIC
value of .). Some  :  combinations (L. angustifolia with
either D. carota or J. virginiana or C. zeylanicum or C.
sinensis) demonstrated synergistic interactions against both
C. albicans and S. aureus. ese combinations were analysed
further against these microorganisms to determine if varied
ratios of the two essential oils in the combination would
yield varied interactions (Figure ). e combination where
L. angustifolia was combined with C. zeylanicum in various
ratios against C. albicans displayed the greatest synergistic
4. Discussion
Although a number of in vitro studies have been conducted
on the antimicrobial activity of L. angustifolia essential oil
against a wide variety of microorganisms, many studies have
used disc diusion assays to quantify antimicrobial activity,
]. e MIC method used for antimicrobial analysis of the
essential oils is considered to be the preferred method, and
as such, is the only one considered for comparative purposes
here [].
L. angustifolia has been extensively studied for antimi-
crobial eects against a variety of test microorganisms [
]. ese previous studies have demonstrated the ecacy of
this essential oil as an antimicrobial agent as well as augment
the ndings of this study. e essential oil from S. album
has demonstrated notable activity in past studies. Superior
antimicrobial activity (MIC value of .% v/v) of S. album
was observed when tested with a selection of  essential
oils []. A later study by the same authors demonstrated
activity for an Australian based S. album against C. albicans
(MIC value of .% v/v), P. a e r u g i n o s a (MIC value of
>. mg/mL), and S. aureus (MIC value of . mg/mL) [].
e data from these studies are congruent with that reported
here and demonstrate the antimicrobial potential of S. album.
e combination of L. angustifolia with D. carota against
C. albicans in various ratios displayed a predominantly syn-
ergistic eect for eight of the ratios studied. For S. aureus,the
tested ratios indicated mostly additive interactions. Where a
higher concentration of D. carota essential oil was present
in the oil mixture, a more favourable antimicrobial eect
was noted. Lavandula angustifolia has been associated with
the treatment of fungal infections and is also used in the
treatment of Staphylococcal-related infections, such as boils
and abscesses [,]. No information could be obtained to
support the use of D. carota for Staphylococcal and Candidal
related infections, yet when the two essential oils are com-
bined, the ratios where D. carota is in higher concentrations
demonstrated a more favourable eect. is suggests that
the presence of D. carota plays a role in the additive and
synergistic ndings observed against these microorganisms
e combination of L. angustifolia and J. virginiana
against C. albicans in various ratios indicated a synergistic
eect for all nine of the ratios analysed. Against S. aureus,
the ratios displayed a predominantly additive eect. Juniperus
virginiana in combination with L. angustifolia essential oil
infections [], while the combination was also noted for
its use in the treatment of Candidal-type infections such
as thrush []. Where the two essential oils are combined,
regardless of ratio, the essential oils display synergistic eects
for C. albicans.
e combination where L. angustifolia was combined
with C. zeylanicum in various ratios against C. albicans
displayed the greatest synergistic eect of all oils studied.
It was also interesting to note that for these combinations,
the higher the concentration of L. angustifolia, the more
favourable (additive or synergistic) the interaction.Against S.
aureus, the converse was true. Most of the ratios indicated an
additive eect with one ratio (L. angustifolia:C. zeylanicum,
 : ) indicating synerg y. e combination of C. zeylanicum
and L. angustifolia has been associated with the treatment
of topical infections and as a general antimicrobial agent
[]. is combination has demonstrated a greater antifungal
eect when placed in various ratios as ve of the nine ratios
were synergistic against C. albicans.eratioswhereL.
angustifolia is in higher concentrations demonstrated a more
favourable eect and this suggests that the presence of L.
angustifolia playsagreaterroleinthesynergyobserved.
When L. angustifolia was combined with C. sinensis
in various ratios, a predominantly synergistic eect was
recorded for both microorganisms tested. e use of C.
sinensis essential oil in combination with L. angustifolia for
the treatment of respiratory infections has been documented
[]. Even though C. sinensis demonstrated poor activity when
tested singularly [,], when combined with L. angustifolia,
ecacy was enhanced.
5. Conclusion
In summary, the analysis of the combination of L. angustifolia
with a selection of other aroma-therapeutic essential oils
has largely demonstrated noteworthy activity against the
pathogens tested. e ΣFIC analysis indicated that these oils
have favourable antimicrobial interactions when placed in
combination, that is, .% synergistic and .% additive
eects for selected oils. Only one combination (C. citratus in
combination with L. angustifolia with a ΣFIC value of .)
demonstrated antagonistic eects. When placed in various
ratios the combination of L. angustifolia and C. sinensis
essential oil demonstrated the best antimicrobial eect with
synergy identied for all ratios against the microorganisms
Evidence-Based Complementary and Alternative Medicine
T : e antimicrobial eects of the essential oils studied individually and in combination with L. angustifolia essential oil.
Essential oil
Oils examined individually  :  Combinations
C. albicans S. aureus P. aeruginosa C. albicans S. aureus P. aeruginosa
(AT CC   ) (AT CC  ) (ATC C   ) (AT CC   ) (AT CC  ) (ATC C   )
Abies balsamea . . . . . . . . .
Andropogon muricatus . . . . 0.45 . . . .
Angelica archangelica (seed) . . . . . . . . .
Angelica archangelica (root) . . . . 0.42 . . . .
Anthemis nobilis . . . . 0.33 . . . .
Artemisia dracunculus . . . . 0.42 . . . .
Canarium luzonicum . . . . 0.25 . . . .
Cananga odorata (heads) . . . . . . . . .
Cananga odorata . . . . . . . . .
Carum carvi . . . . 0.42 . . . .
Cinnamomum zeylanicum . . . . 0.40 . 0.50 . .
Citrus aurantium . . . . 0.42 . . . .
Citrus grandis . . . . 0.42 . . . .
Citrus medica limonum . . . . 0.42 . . . .
Citrus sinensis . . . . 0.42 . 0.38 . .
Commiphora myrrha . . . . 0.29 . . . .
Cupressus sempervirens . . . .0.15 . . . .
Cymbopogon citratus . . . . . . . . .
Cymbopogon nardus . . . . 0.42 . . . .
Daucus carota . . . . 0.50 . 0.50 . .
Eucalyptus globulus . . . . 0.38 . . . .
Foeniculum dulce . . . . 0.45 . . . .
Hyssopu s ocinali s . . . . 0.33 . . . .
Juniperus virginiana . . . . 0.50 . 0.50 . .
Juniperus virginiana (berries) . . . . 0.21 . . . .
Laurus nobilis . . . . . . . . .
Litsea cubeba . . . . 0.19 . . . .
Matricaria chamomilla . . . . . . . . .
Melaleuca viridiora . . . . . . . . .
Melaleuca alternifolia . . . . 0.50 . . . .
Mentha piperita . . . . . . . . .
Myrtus communis . . . . 0.50 . . . .
Ocimum basilicum . . . . . . . . .
Origanum majorana . . . . 0.42 . . . .
Pelargonium odoratissimum . . . . . . . . .
Pinus sylvestris . . . . 0.50 . . . .
Piper nigrum . . . . 0.42 . . . .
Pogostemon patchouli . . . . 0.50 . . . .
Rosmarinus ocinalis . . . . 0.42 . . . .
Salvia sclarea . . . . . . . . .
Santalum album . . . . 0.42 . . . .
Styrax benzoin . . . . 0.42 . . . .
Syzygium aromaticum . . . . . . . . .
Tag et e s p a t u l a . . . . 0.42 . . . .
ymus vulgaris . . . . . . 0.40 . .
Ciprooxacin control NR0.45 × 10−3 0.45 × 10−3 NR0.45 × 10−3 0.45 × 10−3
Amphotericin B control 0.60 × 10−3 NRNR0.60 × 10−3 NRNR
NR indicates not relevant; bold indicates synergy; MIC given in mg/mL.
Evidence-Based Complementary and Alternative Medicine
C.albicans (ATCC 10231)
C.albicans (ATCC 10231)
C.albicans (ATCC 10231)
00.5 1 1.5
00.5 1 1.5
00.5 1 1.5
MIC Daucus carota in combination/MIC
of Lavandula angustifolia independently
00.5 1 1.5
MIC Daucus carota in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
S.aureus (ATCC 6538)
S.aureus (ATCC 6538)
S.aureus (ATCC 6538)
MIC Juniperus virginiana in combination/MIC
of Lavandula angustifolia independently
00.5 1 1.5
MIC Juniperus virginiana in combination/MIC
of Lavandula angustifolia independently
MIC Cinnamomum zeylanicum in combination/MIC
of Lavandula angustifolia independently
00.5 1 1.5
MIC Cinnamomum zeylanicum in combination/MIC
of Lavandula angustifolia independently
F : Continued.
Evidence-Based Complementary and Alternative Medicine
MIC Citrus sinensis in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
MIC Lavandula angustifolia in combination/MIC
of Lavandula angustifolia independently
00.5 1 1.5
MIC Citrus sinensis in combination/MIC
of Lavandula angustifolia independently
00.5 1 1.5
C.albicans (ATCC 10231) S.aureus (ATCC 6538)
F : Isobolograms constructed for the synergistic essential oil combinations against the pathogens C. albicans and S. aureus. 󳵳indicates
L. angustifolia essential oil in majority concentration, indicates other essential oils (D. carota or J. virginiana or C. zeylanicum or C. sinensis)
in majority concentration, and indicates equal ratios of essential oil in combination.
tested. Essential oils blends have been used for many years
for their curative properties and this study lends credibility
to the frequent use of combining oils to achieve a superior
therapeutic outcome.
No competing interests exist for the data obtained in this
paper. e authors have not submitted the data for any other
nancial gain or secondary interest. is work has been
generated for academic purposes only.
e authors are grateful to Robertet (France), Givaudan
(Switzerland), and Clive Teubes cc (South Africa) for supply-
ing the essential oils used in this study. e National Research
Foundation is thanked for nancial support.
[] T. Eveleigh, Lavender,LorenzBooks,Sydney,Australia,.
[]C.J.ChuandK.J.Kemper,“Lavender(Lavandula spp.),
[] H. M. A. Cavanagh and J. M. Wilkinson, “Biological activities
of lavender essential oil,Phytotherapy Research,vol.,no.,
[] T. Dunning, “Caring for the wounded healer-nurturing the self,
Journal of Bodywork and Movement erapies,vol.,no.,pp.
–, .
[] J. Lawless, eIllustratedEncyclopediaofEssentialOils:e
ism, Element Books Limited, Rockport, Mass, USA, .
[] W. Sellar, e Directory of Essential Oils,C.W.DanielCompany
Limited, London, UK, .
[] S. Curtis, Essential Oils, Aurum Press, London, UK, .
[] C.N.Shealy,e Illustrated Encyclopedia of Healing Remedies,
Element Books, Rockport, Mass, USA, .
[] P. Hili, e Antimicrobial Properties of Essential Oils, Winter
Press, Kent, UK, .
[] J. Buckle, Clinical Aromatherapy: Essential oils in Practice,
Churchill Livingstone, London, UK, nd edition, .
[] B. M. Lawrence, Antimicrobial Biological Activity of Essential
Oils, Allured, Aurora, Ill, USA, .
[] S. Cassella, J. P. Cassella, and I. Smith, “Synergistic antifungal
activity of tea tree (Melaleuca alternifolia) and lavender (Lavan-
dula angustifolia) essential oils against dermatophyte infection,
International Journal of Aromatherapy,vol.,no.,pp.,
[] V. Edwards-Jones, R. Buck, S. G. Shawcross, M. M. Dawson, and
K. Dunn, “e eect of essential oils on methicillin-resistant
Staphylococcus aureus using a dressing model,Burns,vol.,
no. , pp. –, .
[] S. F. Van Vuuren, G. P. P. Kamatou, and A. M. Viljoen, “Volatile
composition and antimicrobial activity of twenty commercial
frankincense essential oil samples,South African Journal of
[ ] S . D e R a pp e r, S . F. Va n Vu u re n , G . P. P. K a m a to u e t a l . , “ e
additive and synergistic antimicrobial eects of select frank-
incense and myrrh oils—a combination from the pharaonic
pharmacopoeia,Letters in Applied Microbiology,vol.,pp.
–, .
[] CLSI and Clinical and Laboratory Standards Institute, Meth-
ods for Dilution Antimicrobial Susceptibility Tests for Bacteria
that Grow Aerobically, Approved Standard M-A, National
Committee for Clinical Laboratory Standards, Fort Wayne, Ind,
USA, th edition, .
 Evidence-Based Complementary and Alternative Medicine
[] J. E. Angeh, Biological characterization of isolated compounds
[Ph.D. thesis], University of Pretoria, Pretoria, South Africa,
[] S. F. Van Vuuren and A. M. Viljoen, “Plant-based antimicro-
bial studies methods and approaches to study the interaction
between natural products,Planta Medica,vol.,no.,pp.
–, .
[] S. Suliman, S. F. Van Vuuren, and A. M. Viljoen, “Validating the
in vitro antimicrobial activity of Artemisia afra in polyherbal
combinations to treat respiratory infections,South African
Journal of Botany,vol.,no.,pp.,.
[] J. L. R´
ıos and M. C. Recio, “Medicinal plants and antimicrobial
activity,Journal of Ethnopharmacology,vol.,no.-,pp.
, .
[] P. Cos, A. J. Vlietinck, D. Van den Berg et al., “Anti-infective
potential of natural products: how to develop a stronger in vitro
‘proof-of-concept’,Journal of Ethnopharmacology,vol.,pp.
–, .
[] D. Kalemba and A. Kunicka, “Antibacterial and antifungal
properties of essential oils,Current Medicinal Chemistry,vol.
, no. , pp. –, .
[] R. R. S. Nelson, “In-vitro activities of ve plant essential
oils against methicillin-resistant Staphylococcus aureus and
vancomycin-resistant Enterococcus faecium,” Journal of Antimi-
crobial Chemotherapy, vol. , no. , pp. –, .
Arsenakis, “Antifungal activities of origanum vulgare subsp.
hirtum, Mentha spicata,Lavandula angustifolia,andSalvia
fruticosa essential oils against human pathogenic fungi,Journal
of Agricultural and Food Chemistry,vol.,no.,pp.,
[] K.A.Hammer,C.F.Carson,andT.V.Riley,“In-vitro activity
of essential oils, in particular Melaleuca alternifolia (tea tree)
oil and tea tree oil products, against Candida spp.,Journal of
Antimicrobial Chemotherapy,vol.,no.,pp.,.
[] K. A. Hammer, C. F. Carson, and T. V. Riley, “Antimicrobial
activity of essential oils and other plant extracts,Journal of
Applied Microbiology,vol.,no.,pp.,.
[] S. Shin and S. Lim, “Antifungal eects of herbal essential oils
alone and in combination with ketoconazole against Tri chop hy-
ton spp.,Journal of Applied Microbiolo gy,vol.,no.,pp.
, .
[] L. Mayaud, A. Carricajo, A. Zhiri, and G. Aubert, “Comparison
of bacteriostatic and bactericidal activity of  essential oils
against strains with varying sensitivity to antibiotics,” Letters in
Applied Microbiology,vol.,no.,pp.,.
[] M.H.Lodhia,K.R.Bhatt,andV.S.aker,“Antibacterialactiv-
ity of essential oils from palmarosa, evening primrose, lavender
and tuberose,” Indian Journal of Pharmaceutical Sciences,vol.,
no. , pp. –, .
[] V. Agarwal, P. Lal, and V. Pruthi, “Eect of plant oils on Candida
albicans,” Journal of Microbiology, Immunology and Infection,
vol. , no. , pp. –, .
[] M. Sokovi´
c, J. Glamoˇ
clija, P. D. Marin et al., “Antibacterial
eects of the essential oils of commonly consumed medicinal
herbs using an in vitro model,Molecules, vol. , pp. –,
[] T.H.Tsai,T.H.Tsai,W.H.Wu,J.T.P.Tseng,andP.J.Tsai,
In vitro antimicrobial and anti-inammatory eects of herbs
against Propionibacterium acnes,” Food Chemistry,vol.,no.
, pp. –, .
[] A. Alexopoulos, A. C. Kimbaris, S. Plessas et al., “Antibacterial
activities of essential oils from eight Greek aromatic plants
against clinical strains of Staphylococcus aureus,” Anaerobe,vol.
, pp. –, .
[] S.Chao,G.Young,C.Oberg,andK.Nakaoka,“Inhibitionof
methicillin-resistant Staphylococcus aureus (MRSA) by essential
oils,Flavour and Fragrance Journal,vol.,no.,pp.,
[] C. A. O’Bryan, P. G. Crandall, V. I. Chalova, and S. C.
Ricke, “Orange essential oils antimicrobial activities against
Salmonella spp.,Journal of Food Science,vol.,no.,pp.
M–M, .
... In the L. angustifolia oil examined, the main components are linalyl acetate and linalool, according to the composition of this oil as reported by other authors [32]. The same authors attributed to these two components, and especially to the monoterpene linalool, the antifungal activity against C. albicans, though the antimicrobial effects of the oil may be the result of the synergistic action of its major and minor components [33]. ...
... Quantification of the biofilm biomass was performed by crystal violet staining, as previously described [33]. To quantify the biofilm formation, the optical density cut off value (ODc) was calculated as the three standard deviations above the mean OD of the negative. ...
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The high virulence of Candida auris, a pathogen fungus considered as a global threat for public health, is due to its peculiar traits such as its intrinsic resistance to conventional antifungals. Its biofilm lifestyle certainly promotes the prolonged survival of C. auris after disinfection or antifungal treatments. In this work, for the first time, we detected persister cells in a biofilm of C. auris in a microwell plate model, following caspofungin treatment. Furthermore, we showed how persisters can progressively develop a new biofilm in situ, mimicking the re-colonization of a surface which may be responsible for recalcitrant infections. Plant-derived compounds, such as essential oils, may represent a valid alternative to combat fungal infections. Here, Lavandula angustifolia essential oil, as free or encapsulated in liposomes, was used to eradicate primary and persister-derived biofilms of C. auris, confirming the great potential of alternative compounds against emergent fungal pathogens. As in other Candida species, the action of essential oils against C. auris involves ROS production and affects the expression of some biofilm-related genes.
... The aroma-therapeutic literature notes extensively the use of essential oils in combination for improved antimicrobial, anti-oxidative, anti-inflammatory, as well as antihistaminic effects [15]. Previous studies have demonstrated the therapeutic potential of some commercial and indigenous essential oils when tested in combination [16][17][18][19][20]. However, a lack of data still exists for the antimicrobial efficacy of a large number of commonly applied commercial essential oils used in combination. ...
... The broth microdilution method described by de Rapper et al. [18] was used to quantify the antimicrobial inhibitory activity of the selected essential oils. The antimicrobial activities of the essential oils independently have been previously investigated [33]. ...
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This study investigated the potential efficacy of 369 commercial essential oil combinations for antimicrobial, anti-toxic and anti-inflammatory activity with the aim of identifying synergy among essential oils commonly used in combination by aromatherapists for respiratory purposes. Essential oil combinations were assessed for their antimicrobial activities using a panel of Gram-positive, Gram-negative, and yeast strains associated with respiratory tract infections. The antimicrobial activity was measured by determining the minimal inhibitory concentration (MIC) of microbial growth. The fractional inhibitory concentration index (ΣFIC) was calculated to determine the antimicrobial interactions between the essential oils in the combination. The toxicity of the essential oil combinations was tested in vitro using the brine shrimp lethality assay, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on RAW 264.7 mouse macrophage cells and A549 lung cancer cell lines. In addition, an inflammatory response was evaluated measuring nitric oxide production. The essential oils, when in combination, demonstrated an increased antimicrobial effect, a reduction in toxicity and provided improved anti-inflammatory outcomes. Five distinct combinations [Cupressus sempervirens (cypress) in combination with Melaleuca alternifolia (tea tree), Hyssopus officinalis (hyssop) in combination with Rosmarinus officinalis (rosemary), Origanum marjorana (marjoram) in combination with M. alternifolia, Myrtus communis (myrtle) in combination with M. alternifolia and Origanum vulgare (origanum) in combination with M. alternifolia] were found to be the most promising, demonstrating antimicrobial activity, reduced cytotoxicity and improved anti-inflammatory effects. With the increased prevalence of respiratory tract infections and the growing antimicrobial resistance development associated with antimicrobial treatments, this study provides a promising complementary alternative for the appropriate use of a selection of essential oil combinations for use in the respiratory tract.
... Treatment by using plant extracts or essential oils is widely accepted and increasingly acknowledged by the peoples of both developed as well as developing countries 4 . Essential oil is supposed to work synergistically in healing the body, senses and mind 11 . ...
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Respiratory tract infection (RTI) is among one of the common infections in human beings with life-threatening complications. Respiratory tract infection causes approximately 50 million deaths globally. The present study aimed to analyze two essential oils' anti-proliferative and antimicrobial activities against some common respiratory tract infection-causing microbes. The antibacterial activity of two essential oils including thyme and cinnamon oil, against the six RTI bacterial species, namely, Streptococcus pneumonia, Streptococcus pyogenes, Pseudomonas aeruginosa, Haemophilus influenza, Moraxella catarrhalis and Staphylococcus aureus, was assessed by cut well diffusion method. Cytotoxicity/anti-proliferative activity of essential oil (thyme and cinnamon) was investigated by using the SW480 cell line. The antibacterial activity of the oils was calculated by measuring the inhibitory zone and the maximum zone of 40.33 mm of cinnamon oil against H. influenza followed by a 40 mm zone of thyme oil against S. aureus and a minimum zone of 16.33 mm of cinnamon was observed against the S. pneumonia. The MIC value of the oils ranges from 0.10-0.60 mg/ml. The SW480 epithelial cells treated with the oils show an increase in cytotoxicity in a concentration-dependent manner. The in vitro cytotoxicity and antimicrobial activity results show that both the essential oils possess antimicrobial activity. The evidence shows that thyme oil has shown a little higher activity against respiratory tract infection. So, it can be used as an alternative to treat upper and lower respiratory infection-causing bacteria.
... To overcome antimicrobial resistance, the mechanism of action must be elucidated when diverse combinations of EOs mixtures are used [59]. Furthermore, the synergistic effects of LEO in combination with other EOs have been demonstrated in previous studies [60]. Associating specific oils generates synergism due to the combined action of some EOs elements, especially by their major compounds, the minor compounds also influencing the favorable interactions noticed [20]. ...
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Chemical composition, antioxidant capacity, and antimicrobial activity of lavender es-25 sential oils (LEOs) extracted from three different varieties of Lavandula angustifolia Mill. (1-26 Moldoveanca 4, 2-Vis Magic, and 3-Alba 7) have been determined. These plants previously pa-27 tented in the Republic of Moldova were cultivated in organic agriculture system in the Northeast-28 ern part of Romania and then harvested in three consecutive years (2017-2019) to obtain the essen-29 tial oils. From the inflorescences in the complete flowering stage, the LEOs were extracted by 30 hydro distillation. Then their composition was analyzed by gas chromatography coupled with 31 mass spectrometry (GC-MS) and by Fourier Transformed Infrared spectroscopy (FT-IR). The 32 major identified constituents are as follows: linalool (). The antioxidant capacity as determined by ABTS and 35 DPPH assays indicates inhibition with the highest activity obtained for LEO var. Alba 7 from 2019. 36 The in vitro antimicrobial activities of the LEOs and combinations were investigated as well, by 37 using disk diffusion method and minimum inhibitory concentration (MIC) against the Gram-38 positive bacterial strain Staphylococcus aureus (ATCC 6538), and Gram-negative Pseudomonas aeru-39 ginosa (ATCC 27858), Escherichia coli (ATCC 25922), and the yest Candida albicans (ATCC 10231), 40 and also clinical isolates. Our results have shown that LEOs obtained from the three studied varie-41 ties of L. angustifolia manifest significant bactericidal effects against tested microorganisms 42 (Staphylococcus aureus and Escherichia coli), and antifungal effect against Candida albicans. The mix-43 ture of LEOs (Var. Alba 7) and geranium, respectively tea tree EOs, in different ratios, showed a 44 significant enhancement of the antibacterial effect against all the studied strains, except Pseudomo-45 nas aeruginosa.
... Hence, the study of the antimicrobial effectiveness of essential oils against pathogens is in high demand. Several studies show that the combination of essential oils can lead to the optimization of the medical activities (De Rapper et al., 2013). It has been shown that formulations containing lavender essential oil act to a greater extent against S. aureus (Hossain et al., 2017;Thosar et al., 2013). ...
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Abstract Increasing the rates of drug resistant bacteria, having adverse effects and also high costs of antibiotics lead to essential oils (EOs) with antibacterial properties have gained importance. The present study was predicted to evaluate antibacterial activity of cinnamon, lavender, tea tree, lemon, coconut, oregano, mint, laurel and eucalyptus EOs alone and in combination. Chemical components of effective EOs were examined through gas chromatography/mass spectrometry (GC/MS). Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays were used to identify antibacterial effects of EOs against bacterial strains. The Fractional Inhibitory Concentration index (FICI) of the binary combinations of EOs was determined by checkerboard method. Carvacrol, linalool, linalyl acetate, 1,8-cineole, cinnamaldehyde, terpinen-4-ol and p-cymene were found main components of EOs. Oregano, cinnamon and tea tree EOs exhibited the strongest antibacterial activity with the MIC range between 0.03125-1.00% (v/v). Tea tree/lavender and cinnamon/lavender mixtures showed a synergistic effect against Streptococcus pyogenes and Streptococcus agalactiae. Oregano with tea tree and laurel exhibited a synergistic effect against Staphylococcus aureus. Oregano showed a synergistic effect when combined with cinnamon, lavender and tea tree against S.agalactiae. Our findings indicated that EOs either alone or in combination against pathogens should be preferred as potential antibacterial agents.
Skin diseases contribute significantly to worldwide morbidity and mortality. It is the most common of all human diseases which can affect people of any age group. Most importantly, it is seen that the COVID-19 pandemic have further detrimentally contributed to dermatological manifestations. Due to the enormous socioeconomic burden created by skin disorders, the dermatological treatments have been added in the WHO List of Essential Medicines. Some of the major predominant diseases are acne, psoriasis, eczema, fungal infections and skin carcinoma. As a matter of fact, focus on treatment of skin diseases should be arguably considered as a matter of global urgency. Although treatments are available, they face numerous challenges which limit patient acceptability. Essential oils have a long history of pharmacological use; however their role in the treatment of dermatological disorders is vague. Therefore, in this review, the potential and mechanism of different essential oils obtained from various sources in the treatment of major dermal disorders has been summarized. This will help the formulation scientists and the clinicians to develop suitable formulation strategies for the prevention and cure of skin diseases.
The antimicrobial effects of essential oils are commonly cited within aromatherapeutic texts for use in respiratory tract infections. These essential oils are inhaled or applied to the skin to treat infections and manage symptoms associated with these conditions. A limited number of these essential oils have been scientifically studied to support these claims, specifically, against respiratory pathogens. This study reports on the minimum inhibitory concentration (MIC) of 49 commercial essential oils recommended for respiratory tract infections, and identifies putative biomarkers responsible for the determined antimicrobial effect following a biochemometric workflow. Essential oils were investigated against nine pathogens. Three essential oils, Amyris balsamifera (amyris), Coriandrum sativum (coriander) and Santalum austrocaledonicum (sandalwood) were identified as having greater activity (MIC = 0.03–0.13 mg/ml) compared to the other essential oils investigated. The essential oil composition of all 49 oils were determined using Gas Chromatography coupled to Mass Spectroscopy (GC-MS) analysis and the GC-MS data analysed together with the antimicrobial data using chemometric tools. Eugenol was identified as the main biomarker responsible for antimicrobial activity in the majority of the essential oils. The ability of a chemometric model to accurately predict the active and inactive biomarkers of the investigated essential oils against pathogens of the respiratory tract was 80.33%.
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Natural products have been studied aiming to understand their biological properties. Thus, this study aimed to investigate the antimicrobial activity of twenty-seven essential oils (EOs) used in aromatherapy procedures, a natural therapy with great emphasis currently used against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa strains. The agar dilution method was carried out and minimal inhibitory concentration against 50% and 90% of strains (MIC50% and MIC90% values) were reported. The S. aureus strains were highly susceptible with MIC90% from 0.21 mg/mL to black pepper (Piper nigrum) and tea tree (Melaleuca alternifolia) to 26.52 mg/mL with copaiba (Copaifera officinalis) EO. Cinnamon (Cinnamomum cassia) and clove (Syzygium aromaticum) EOs were effective against E. coli (2.0 mg/mL) while the S. aromaticum EO was against P. aeruginosa (8.29 mg/mL). Thus, the higher susceptibility of Gram-positive bacteria when compared with Gram-negative strains was found, and a large variability in the potential antibacterial has also been observed.
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Artemisia afra is one of the most widely used medicinal plants in African traditional medicine and is commonly administered in polyherbal combinations to treat respiratory infections. Focussing on plant volatiles, the aim of this study was to provide scientific evidence for the antimicrobial activity of A. afra (principle plant) in combination with essential oils from three medicinal aromatic plants; Agathosma betulina, Eucalyptus globulus and Osmitopsis asteriscoides. In vitro minimum inhibitory concentration (MIC) assays were undertaken on four pathogens (Enterococcus faecalis ATCC 29212, Moraxella catarrhalis ATCC 23246, Klebsiella pneumoniae NCTC 9633 and Cryptococcus neoformans ATCC 90112) to determine antimicrobial efficacy of the oils and their combinations. The fractional inhibitory concentration (FIC) and isobolograms were used to interpret pharmacodynamic interactions such as synergy, antagonism or additive profiles. The antimicrobial activity of the individual oils mostly displayed moderate activity. Predominantly, additive interactions were noted. The most prominent synergistic interaction (FIC value of 0.5) was observed when A. afra was combined with O. asteriscoides in the 8:2 ratio (eight parts A. afra with two parts O. asteriscoides) against C. neoformans. No antagonistic interactions were evident.
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Trees from the genus Boswellia (Burseraceae) are traditionally used as a medicine, a fumigant, in various cosmetic formulations and in aromatherapy in several countries around the world. This plant produces a commercial oil known as frankincense which has a woody, spicy and haunting smell. Frankincense oil has several pharmacological properties, of which many elude to the anti-infective potential. Variation in the chemical composition of this oil has been reported in literature. These factors prompted an investigation to study the commercial frankincense oils from various international suppliers. Twenty essential oils were analyzed by gas chromatography coupled to mass spectrometry. Considering the major constituents, the oils were found to be qualitatively similar. However, there was immense quantitative variation for certain oil constituents. The components identified and their range in the oils include α-pinene (2.0–64.7%); α-thujene (0.3–52.4%); β-pinene (0.3–13.1%); myrcene (1.1–22.4%); sabinene (0.5–7.0%); limonene (1.3–20.4%); p-cymene (2.7–16.9%) and β-caryophyllene (0.1–10.5%). The antimicrobial activity (minimum inhibition concentration assay) of the oils was investigated against five reference test organisms and the activity ranged from 4–16 mg/ml (Staphylococcus aureus); 1.5–8.3 mg/ml (Bacillus cereus); 4.0–12.0 mg/ml (Escherichia coli); 2.0–12.8 mg/ml (Proteus vulgaris) and 5.3–12.0 mg/ml (Candida albicans).Research Highlights► This is the first scientific comparison of the antimicrobial andessential oil composition of a number of commercial frankincense oils. ► The publication highlights differences in constituents and antimicrobial efficacies between samples, thus providing a standard with which to compare quality.
Aromatherapy is one of the main complementary therapies to be practiced by nurses and other health care professionals in hospital, hospice, and community settings. Written by a nurse, this clinical text highlights how aromatherapy can enhance care and the role health care professionals play in its practice. It examines key facts and issues in aromatherapy practice, and applies these within a variety of contexts and conditions, taking a carefully holistic approach in dealing with the patient.
The antimicrobial effects of many herbs and spices have been well known for centuries and are used to increase the shelf-life of foods. These antimicrobial properties are attributed to the essential oil fraction. Essentials oils have a broad spectrum of activity, with inhibition observed against bacteria, yeasts and fungi. As natural products already used as food flavours, essentials oils are currently being studied to acquire a better understanding of their natural food preservative potential. The methods for testing the antimicrobial properties of essential oils and aroma compounds are reviewed, with a focus on micro-atmosphere, and direct contact in liquid or solid media. Hydrophobic compound dispersion is the main problem encountered by authors, although the use of colloïdal agar-agar mixtures seems to offer a valuable solution. Essential oils and aroma compounds have a negative effect on the growth (e.g. Escherichia coli 0157:H7, Listeria monocytogenes), sporulation (e.g. Clostridium botulinum) and toxinogenesis (e.g. Staphylococcus aureus) of bacteria. Concerning yeasts, the compounds show some influence on growth and pseudomycelium production. In fungi, spore germination may be inhibited, as well as mycelium elongation (e.g. Aspergillus flavus), sporulation and toxinogenesis (e.g. Aspergillus ochraceus). Usually, the results obtained on synthetic culture media are confirmed in food assays, but only if a higher amount of essential oil is added, leading to concern over potential alteration of the organoleptic quality of foods.
Health professionals have to deal with a “wounded society”, for example, violence, natural disasters and displaced people. Shortage of health professional groups and the high use of complementary therapies may reflect professional wounds, such as stress and burnout. Self-care is an important aspect of health professionals’ lives, given modern-day work stressors that can affect an individual's physical, mental and spiritual health. Often people become healers through personal suffering. Each person wounded or not, needs to understand his or her own need to be nurtured, and develop and implement a self-care health programme. Personal and professional reflection are important to understanding the nature of events that lead to “wounds” and how they can be transcended and the experiences used in holistic care. Aromatherapy can be a useful addition to self-care especially in managing stress and minor self-limiting conditions.
The essential oils of Origanum vulgare subsp. hirtum, Mentha spicata, Lavandula angustifolia, and Salvia fruticosa exhibited antifungal properties against the human pathogens Malassezia furfur, Trichophyton rubrum, and Trichosporon beigelii. Of the four oils, O. vulgare subsp. hirtum oil showed the highest fungicidal activity and at a dilution of 1/50000 caused a 95% reduction in the number of metabolically active cells within 6 h of exposure. Among the main components of the four oils, carvacrol and thymol exhibited the highest levels of antifungal activity. The therapeutic efficacy of the O. vulgare subsp. hirtum essential oil was tested in rats experimentally infected with T. rubrum and yielded promising results. Furthermore, the above essential oils were tested with the Ames test and did not exhibit any mutagenic activity. Keywords: Essential oils; Origanum vulgare; Mentha spicata; Lavandula angustifolia; Salvia fruticosa; Malassezia furfur; Trichophyton rubrum; Trichosporon beigelii; Dermatophytosis; antifungal; mutagenic; in vivo studies
The antifungal potential of tea tree and lavender essential oils alone and in combination, against common causes of tinea infection in humans was investigated via in-vitro investigations, in order to determine a suitable dosage for use in clinical trials. The concept of synergy was considered, in the microbiological environment, and as a chemical phenomenon. Trichophyton rubrum and T. mentagrophytes var. interdigitale were studied, as the most prevalent causes of tinea and onychomycosis. Possible chemical interactions between essential oils were examined using gas chromatography-mass spectrometry (GC-MS) infra-red (IR) spectroscopy and polarimetry. There was a clear antifungal action by both tea tree and lavender essential oils on these organisms grown in culture. In combination, appropriate blends demonstrated synergistic action. No changes in retention times or identified compounds were observed by GC-MS. Alterat ions were found using IR spectroscopy in some combinations of the essential oils. The inconsistency in findings between the two analytical techniques may in part be due to a difference in sensitivities of the techniques or the conditions used in the G C-MS equipment; different column parameters have yet to be trialled. These were time dependent and affected by changing temperature. The measurement of optical rotation was determined to be an inappropriate technique for the study of synergy in essentia l oil mixtures. The data from this study confirm that synergistic action does occur between these two commonly used essential oils in effecting antifungal activity. GC-MS analysis demonstrated that there was no chemical interaction resulting in a new c ompound that could be identified using the analytical equipment in this study. IR analysis supports the suggestion that synergistic action may be dependent upon reaction involving the numerous organic substances present in essential oils. These changes m ay be due to as yet unidentified transient chemical interactions between functional groups within the essential oil mixtures.
Ninety-one essential oils, each distilled from a single plant source, and 64 blended essential oils obtained from a commercial source were screened using the disc diffusion assay for inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA). Of the 91 single essential oils, 78 exhibited zones of inhibition against MRSA, with lemongrass, lemon myrtle, mountain savory, cinnamon and melissa essential oils having the highest levels of inhibition. Of 64 blended essential oils, 52 exhibited inhibitory activity against MRSA, with R.C. (a combination of myrtle, Eucalyptus globulus, Eucalyptus australiana, Eucalyptus radiata, marjoram, pine, cypress, lavender, spruce, peppermint and Eucalyptus citriodora oils), Motivation (a combination of Roman chamomile, ylang ylang, spruce and lavender oils) and Longevity (a combination of frankincense, clove, orange and thyme oils) blended essential oils having the highest inhibitory activity. These results indicate that essential oils alone and in combination can inhibit MRSA in vitro. Application of these results may include the potential use of essential oils as an alternative therapy for various diseases sustained by S. aureus MRSA. Copyright © 2008 John Wiley & Sons, Ltd.
Propionibacterium acnes play an important role in the pathogenesis of acne by inducing certain inflammatory mediators and comedogenesis. The objective of this study was to evaluate the antimicrobial and anti-inflammatory effects of herbal extracts against P. acnes. Among the ten tested herbs, methanolic extracts of rose (Rosa damascene), duzhong (Eucommia ulmoides Oliv.), and yerba mate (Ilex paraguariensis) were found to inhibit the growth of P. acnes with respective minimum inhibitory concentrations of 2, 0.5, and 1 mg/ml. In addition, duzhong and yerba mate extracts reduced the secretion of pro-inflammatory cytokines such as tumour necrosis factor-α, interleukin (IL)-8, and IL-1β by human monocytic THP-1 cells pretreated with heat-killed P. acnes at a concentration of 0.1 mg/ml. Our results suggested that duzhong and yerba mate extracts possess both antimicrobial and anti-inflammatory effects against P. acnes and can possibly be used as therapeutic agents for acne.