Review Article Commercial Essential Oils as Potential Antimicrobials to Treat ... - Semantic Scholar

92 Pages·2017·2.31 MB·English

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Evidence-Based Complementary and Alternative Medicine
Volume 2017, Article ID 4517971, 92 pages
https://doi.org/10.1155/2017/4517971
Review Article
Commercial Essential Oils as Potential
Antimicrobials to Treat Skin Diseases
AnéOrchardandSandyvanVuuren
DepartmentofPharmacyandPharmacology,FacultyofHealthSciences,UniversityoftheWitwatersrand,
7YorkRoad,Parktown2193,SouthAfrica
CorrespondenceshouldbeaddressedtoSandyvanVuuren;[email protected]
Received 21 July 2016; Accepted 9 October 2016; Published 4 May 2017
AcademicEditor:PinarosaAvato
Copyright©2017Ane´OrchardandSandyvanVuuren. This is an open access article distributedunder theCreative Commons
AttributionLicense,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkis
properlycited.
Essentialoilsare oneofthe mostnotorious naturalproducts usedfor medical purposes.Combinedwith theirpopular usein
dermatology,theiravailability,andthedevelopmentofantimicrobialresistance,commercialessentialoilsareoftenanoptionfor
therapy.Atleast90essentialoilscanbeidentifiedasbeingrecommendedfordermatologicaluse,withatleast1500combinations.
This review explores the fundamental knowledge available on the antimicrobial properties against pathogens responsible for
dermatologicalinfectionsandcomparesthescientificevidencetowhatisrecommendedforuseincommonlayman’sliterature.Also
includedisareviewofcombinationswithotheressentialoilsandantimicrobials.Theminimuminhibitoryconcentrationdilution
methodisthepreferredmeansofdeterminingantimicrobialactivity.WhiledermatologicalskinpathogenssuchasStaphylococcus
aureushavebeenwellstudied,otherpathogenssuchasStreptococcuspyogenes,Propionibacteriumacnes,Haemophilusinfluenzae,
andBrevibacteriumspecieshavebeensorelyneglected.Combinationstudiesincorporatingoilblends,aswellasinteractionswith
conventionalantimicrobials,haveshownthatmostlysynergyisreported.Veryfewviralstudiesofrelevancetotheskinhavebeen
made.Encouragementismadeforfurtherresearchintoessentialoilcombinationswithotheressentialoils,antimicrobials,and
carrieroils.
1.Introduction Intheeventofskintraumafrominjuriessuchasburns,
skin thinning, ulcers, scratches, skin defects, trauma, or
Theskinisthebody’slargestmechanicalbarrieragainstthe wounds, the skin’s defence may be compromised, allowing
external environment and invasion by microorganisms. It formicrobialinvasionoftheepidermisresultinginanything
is responsible for numerous functions such as heat regu- from mild to serious infections of the skin. Common skin
lation and protecting the underlying organs and tissue [1, infections caused by microorganisms include carbuncles,
2]. The uppermost epidermal layer is covered by a pro- furuncles, cellulitis, impetigo, boils (Staphylococcus aureus),
tective keratinous surface which allows for the removal of folliculitis (S. aureus, Pseudomonas aeruginosa), ringworm
microorganismsviasloughingoffofkeratinocytesandacidic (Microsporum spp., Epidermophytonspp. , and Trichophyton
sebaceoussecretions.Thisproducesahostileenvironmentfor spp.), acne (P. acnes), and foot odour (Brevibacteriumspp.)
microorganisms.Inadditiontothesedefences,theskinalso [3,8–11].Environmentalexposure,forexample,inhospitals
consistsofnaturalmicroflorawhichoffersadditionalprotec- where nosocomial infections are prominent and invasive
tionbycompetitivelyinhibitingpathogenicbacterialgrowth proceduresmakethepatientvulnerable,mayalsocreate an
bycompetingfornutrientsandattachmentsitesandbypro- opportunity for microbial infection. For example, with the
ducingmetabolicproductsthatinhibitmicrobialgrowth.The addition of intensive therapy and intravascular cannulae, S.
skin’snaturalmicrofloraincludesspeciesofCorynebacterium, epidermidiscanenterthecannulaandbehaveasapathogen
staphylococci,streptococci,Brevibacterium,andCandidaas causing bloodborne infections. Noninfective skin diseases
wellasPropionibacterium[3–8]. such as eczema can also result in pathogenic infections by
2 Evidence-BasedComplementaryandAlternativeMedicine
damaging the skin, thus increasing the risk of secondary
infectionbyherpessimplexvirusand/orS.aureus[5,8,12].
Skin infectionsconstituteone of the five most common
reasons for people to seek medical intervention and are
consideredthemostfrequentlyencounteredofallinfections.
Atleastsixmillionpeopleworldwideareaffectedbychronic
woundsandupto17%ofclinicalvisitsarearesultofbacterial
skininfectionsandthesewoundsareafrequentdiagnosisfor
hospitalisedpatients.Theseareexperienceddailyandevery
doctor will probably diagnose at least one case per patient.
Furthermore, skin diseases are a major cause of death and
morbidity [8, 13, 14]. The healing rate of chronic wounds is
affectedbybacterialinfections(suchasS.aureus,E.coli,and
P.aeruginosa),pain,inflammation,andbloodflow,andthus
infectionandinflammationcontrolmayassistinaccelerating
healing[15–17].
Topicalskininfectionstypicallyrequiretopicaltreatment;
however,duetotheabilityofmicrobestoevolveanddueto
theoveruseandincorrectprescribingofthecurrentavailable
conventional antimicrobials, there has been emergence of Acne related conditions Odour related
resistanceincommonskinpathogenssuchasS.aureusresult- Bacterial infection (excl. acne) Fungal related
General skin maintenance Rosacea
ing as methicillin-resistant Staphylococcus aureus (MRSA)
Inflammatory conditions Viral related
and other such strains. Treatment has therefore become a
challenge and is often not successful [8, 18, 19]. In some Figure 1: Summary of categorised dermatological conditions in
regionsoftheworld,infectionsareunresponsivetoallknown whichessentialoilsareused.
antibiotics[20].Thisthreathasbecomesoseverethatsimple
ulcers now require treatment with systemic antibiotics [21].
A simple cut on the finger or a simple removal of an be used for treating dermatological conditions [1, 2, 26, 32,
appendixcouldresultindeathbyinfection.TheWorldHealth 36–43].Anoverviewoftheskinrelatedusescanbeseenin
Organization (WHO) has warned that common infections Figure 1. Essential oils are mostly used for the treatment of
may be left without a cure as we are headed for a future infections caused by bacteria, fungi, or viruses (total 62%).
without antibiotics [22]. Therefore, one of the solutions Thisisfollowedbyinflammatoryskinconditions(20%)such
availableistomakeuseofoneoftheoldestformsofmedicine, asdermatitis,eczema,andlupusandthengeneralskinmain-
natural products, to treat skin infections and wounds [18, tenance (18%) such as wrinkles, scars, and scabs, which are
23]. thethirdmostcommonuseofessentialoils.Otherapplica-
Complementary and alternative medicines (CAMs) are tionsincludeanti-inflammatoryandwoundhealingapplica-
used by 60–80% of developing countries as they are one tions(Figure1).Ofthe98essentialoilsrecommendedforder-
of the most prevalent sources of medicine worldwide [24– matologicaluse,88areendorsedfortreatingskininfections.
27]. Essential oils are also one of the most popular natural Ofthese,73areusedforbacterialinfections,49specifically
products,withoneoftheirmainapplicationsbeingfortheir foracne,34forfungalinfections,and16forviralinfections.
useindermatology[28–30].Infact,ofallCAMs,essentialoils
arethemostpopularchoicefortreatingfungalskininfections 2.MaterialsandMethods
[13,31].Theiruseindermatology,inthenursingprofession,
and in hospitals has been growing with great popularity 2.1. Searching Strategy/Selection of Papers. The aim of the
worldwide, especially in the United States and the United comparative review was to identify the acclaimed derma-
Kingdom[1,27,32–35].Furthermore,thearomatherapeutic tological commercial essential oils according to the aro-
literature [1, 2, 26, 32, 36–43] identifies numerous essential matherapeutic literature and then compare and analyse the
oils for dermatological use, the majority of which are rec- availablepublishedliterature.Thiswillserveasaguidelinein
ommended for infections. This brought forth the question selectingappropriateessentialoilsintreatingdermatological
as to the efficacy of commercial essential oils against the infections.Theanalysedpaperswereselectedfromthreedif-
pathogensresponsibleforinfections.Theaimofthisreview ferentelectronicdatabases:PubMed,ScienceDirect,andSco-
wastocollectandsummarisetheinvivo,invitro,andclinical pus, accessed during the period 2014–2016. The filters used
findings of commercial essential oils that have been tested includedeither“essentialoils”,“volatileoils”,or“aromather-
against infectious skin diseases and their pathogens and, in apy” or the scientific or common name for each individual
doingso,offeraromatherapistsanddermatologistsvaluable essentialoillistedinTable1andtheadditionalfilters“antimi-
information regarding the effectiveness of essential oils for crobial”, “antibacterial”, “skin”, “infection”, “dermatology”,
dermatologicalinfections. “acne”,“combinations”,“fungalinfections”,“dermatophytes”,
The readily available aromatherapeutic literature has “Brevibacteria”,“odour”,“antiviral”,“wounds”,“dermatitis”,
reportedover90(Table1)commercialessentialoilsthatmay “allergy”,“toxicity”,“sentitisation”,or“phototoxicity”.
Evidence-BasedComplementaryandAlternativeMedicine 3
Table1:Essentialoilsusedindermatology.
Scientificname Commonname Dermatologicaluse Reference
𝐵𝑢𝑟𝑛𝑠∗,cracks,cuts,eczema,rashes,sores,
Abiesbalsamea Balsam(Peru,Canadian) [32]
andwounds
Abiesbalsamea Fir Skintonic [36]
Antiseptic,generalcare,oilyconditions,
Acaciadealbata Mimosa [2,32]
andnourisher
Acacia
Cassie Dryorsensitiveconditions [32]
farnesiana
Acne,burns,chappedskin,cuts,
dermatitis,eczema,healingagent,
Achillea
Yarrow infections,inflammation,oilyconditions, [32,36,40,42]
millefolium
pruritus,rashes,scars,toner,sores,ulcers,
andwounds
Acne,antiseptic,fungalinfections
Alliumsativum Garlic (ringworm),lupus,septicwounds,and [32,36]
ulcers
Amyris
Amyris Inflammation [36]
balsamifera
Anethum
Dill Woundhealingencouragement [36]
graveolens
Congestedanddullconditions,fungal
Angelica
Angelica infections,inflammation,psoriasis,and [32,36]
archangelica
tonic
Acne,congestedconditions,cuts,
damagedskin,dermatitis,generalcare,
Aniba
Rosewood greasyandoilyconditions,inflammation, [2,32,36,37,39,41,42]
rosaeodora
psoriasis,scars,regeneration,sores,
wounds,andwrinkles
Abscesses,acne,allergies,antiseptic,
blisters,boils,burns,cleanser,cuts,
dermatitis,eczema,footblisters,general
care,herpes,inflammation,insectbites
Anthemisnobilis Romanchamomile [2,26,32,36–43]
andstings,nappyrash,nourisher,
problematicskin,pruritus,psoriasis,
rashes,rosacea,sores,sunburn,ulcers,and
wounds
Apium
Celery Reducingpuffinessandredness [36]
graveolens
Artemisia
Tarragon Infectiouswounds [36]
dracunculus
Congestedconditions,dermatitis,
Betulaalba Birch(white) [32,36]
eczema,psoriasis,andulcers
Abscesses,acne,agedordryanddamaged
complexions,antiseptic,bacterial
infections,blemishes,carbuncles,
dermatitis,disinfectant,eczema,fungal
Boswelliacarteri Frankincense/olibanum andnailinfections,generalcare,healing [1,2,32,36–43]
agent,inflammation,oilyconditions,
psoriasis,problematicconditions,
regenerationorrejuvenation,scars,sores,
toner,tonic,ulcers,wounds,andwrinkles
Bursera Acne,conditioning,cuts,dermatitis,
Linaloe(copal) [32,40]
glabrifolia sores,andwounds
4 Evidence-BasedComplementaryandAlternativeMedicine
Table1:Continued.
Scientificname Commonname Dermatologicaluse Reference
Athlete’sfoot,burns,cuts,diaperrash,
Calendula
Marigold eczema,fungalinfections,inflammation, [26,32,39]
officinalis
oilyandgreasyconditions,andwounds
Acne,balancingsebum,dermatitis,
Cananga
Ylang-ylang eczema,generalcare,greasyandoily [2,32,36–38,40,42,43]
odorata
conditions,insectbites,andtoner
Agedanddrycomplexions,bacterial
Canarium infections,balancingsebum,cuts,fungal
Elemi [32,36,40]
luzonicum infections,inflammation,sores,ulcers,
wounds,andwrinkles
Acne,boils,infectedwounds,oily
Carumcarvi Caraway [36]
conditions,andpruritus
Acne,antiseptic,∗𝑏𝑟𝑜𝑚𝑜𝑑𝑜𝑠𝑖𝑠,cellulite,
crackedskin,dandruff,dermatitis,
eczema,eruptions,fungalinfections,
Cedrusatlantica Cedarwood [1,2,32,36–39,41–43]
generalcare,genitalinfections,greasyand
oilyconditions,inflammation,insectbites
andstings,psoriasis,scabs,andulcers
Cinnamomum Acne,burns,inflammation,oily
Camphor(white) [32,36,42]
camphora conditions,spots,andulcers
Cinnamomum Antiseptic,gumandtoothcare,warts,and
Cinnamon [32,36,37,41,42]
zeylanicum waspstings
Agedcomplexion,bacterialinfections,
bedsores,blockedpores,eczema,oily
Cistusladanifer Rockrose/Cistus/labdanum [2,32,40]
conditions,sores,ulcers,varicoseulcers,
wounds,andwrinkles
Acne,bacterialinfections,boils,cellulite,
Citrus congestedorgreasyandoilyconditions,
Lime [2,32,36,40–43]
aurantifolia cuts,insectbites,pruritus,tonic,sores,
ulcers,warts,andwounds
Acne,agedanddrycomplexions,
antiseptic,brokencapillaries,cuts,
Citrus
dermatitis,eczema,generalcare,healing
aurantiumvar. Neroli [2,26,32,36–43]
agent,psoriasis,scars,stretchmarks,
amara
toner,tonic,threadveins,wounds,and
wrinkles
Acne,antiseptic,bacterialinfections,
Citrus balancingsebum,blemishes,greasyand
aurantiumvar. Petitgrain oilyconditions,∗∗hyperhidrosis,pimples, [1,2,32,36,37,39–42]
amara pressuresores,sensitivecomplexions,
toner,tonic,andwounds
Abscesses,acne,antiseptic,athlete’sfoot,
bacterialinfections,blisters,boils,cold
sores,deodorant,dermatitis,eczema,
fungalinfections,greasyandoily
Citrusbergamia Bergamot [2,26,32,36,37,40–43]
conditions,healingagent,inflammation,
insectbites,pruritus,psoriasis,shingles,
ulcers,viralinfections(chickenpox,
herpes,andshingles),andwounds
Abscesses,acne,antiseptic,athlete’sfoot,
blisters,boils,cellulite,corns,cuts,grazes,
greasyandoilyconditions,insectbites,
Citruslimon Lemon [1,2,26,32,36,37,39,41–43]
mouthulcers,rosacea,sores,ulcers,viral
infections(coldsores,herpes,verrucae,and
warts),andwounds
Evidence-BasedComplementaryandAlternativeMedicine 5
Table1:Continued.
Scientificname Commonname Dermatologicaluse Reference
Acne,antiseptic,celluliteimprovement,
cleanser,combinationandproblematic
Citrusparadisi Grapefruit [1,2,32,36,37,39–43]
skin,congestedandoilyconditions,
stretchmarks,andtoner
Acne,cellulite,congestedandoily
Citrusreticulata Mandarin conditions,generalcare,healingagent, [1,32,36–38,40,43]
scars,stretchmarks,andtoner
Acne,blockedpores,congestedandoily
conditions,dermatitis,dryanddull
Citrussinensis Orange [1,32,36–38,40–43]
complexions,problematicskin,ulcers,
andwrinkles
Acne,chappedskin,inflammation,oily
Citrustangerina Tangerine conditions,rashes,stretchmarks,and [36,40,42]
toner
Acne,antiseptic,athlete’sfoot,bacterial
infections,bedsores,boils,crackedskin,
Commiphora cuts,dermatitis,eczema,fungalinfections
Myrrh [1,2,26,32,36–43]
myrrha (athlete’sfoot,ringworm),healingagent,
inflammation,scars,sores,ulcers,weeping
wounds,andwrinkles
Coriandrum Usedtopreventthegrowthofodour
Coriander [37]
sativum causingbacteria
Acne,blockedpores,bromodosis,cellulite,
Cupressus
Cypress cellulitis,deodorant,hyperhidrosis,oily [1,2,32,36–38,40–43]
sempervirens
conditions,rashes,rosacea,andwounds
Curcumalonga Turmeric Cuts,sores,andwounds [40]
Acne,athlete’sfoot,bacterialinfections,
Cymbopogon blockedoropenpores,cellulite,fungal
Lemongrass [2,32,36,37,41,42]
citratus infections,hyperhidrosis,oilyconditions,
andtoner
Acne,bacterialinfections,balancing
sebum,damagedanddrycomplexions,
Cymbopogon
Palmarosa dermatitis,eczema,fungalinfections,oily [2,32,36–42]
martinii
conditions,pressuresores,psoriasis,scars,
toner,tonic,sores,wounds,andwrinkles
Cymbopogon Bromodosis,hyperhidrosis,oily
Citronella [32,36,42]
nardus conditions,andsoftener
Agedanddrycomplexions,carbuncles,
dermatitis,eczema,inflammation,oily
Daucuscarota Carrotseed conditions,pruritus,psoriasis,rashes, [2,32,36,40,42]
scarring,toner,ulcers,vitiligo,weeping
sores,wounds,andwrinkles
Dryobalanops
Borneol(BorneoCamphor) Cutsandsores [32]
aromatica
Abscesses,antiseptic,athlete’sfoot,
bacterialdermatitis,bacterialinfections,
blisters,boils,burns,chickenpox,cleanser,
Eucalyptus
Eucalyptus congestedconditions,cuts,fungal [1,26,32,36–39,41–43]
globulus
infections,generalinfections,herpes(cold
sores),inflammation,insectbites,shingles,
sores,ulcers,andwounds
Acne,antiseptic,athlete’sfoot,burns,cuts,
Syzygium
Clove coldsores,fungalinfections,lupus,sores, [32,36,37,41,42]
aromaticum
septiculcers,andwounds
6 Evidence-BasedComplementaryandAlternativeMedicine
Table1:Continued.
Scientificname Commonname Dermatologicaluse Reference
Abscesses,acne,blisters,boils,cuts,
Ferula
Galbanum inflammation,scartissueimprovement, [32,36]
galbaniflua
toner,andwounds
Agedandwrinkledcomplexions,
Foeniculum bromodosis,cellulite,cellulitis,congested,
Fennel [1,32,36,37,40–43]
dulce greasy,andoilyconditions,cleanser,and
tonic
Guaiacum
Guaiacwood Firmingortighteningtheskin [36]
officinale
Abscesses,acne,athlete’sfoot,bacterial
infections,boils,blisters,cellregeneration,
Helichrysum cuts,damagedskinconditions,
Immortelle/everlasting/Helichrysum [2,32,36,40,41]
italicum dermatitis,eczema,fungalinfections
(ringworm),inflammation,psoriasis,
rosacea,scars,sores,ulcers,andwounds
Humulus
Hops Dermatitis,ulcers,rashes,andnourisher [32]
lupulus
Hyssopus Cuts,dermatitis,eczema,healingagent,
Hyssop [32,36,41]
officinalis inflammation,scars,sores,andwounds
Agedanddrycomplexions,generalcare,
Jasminum
Jasmine inflammation,revitalization,oily [2,26,32,36,37,40]
officinale
conditions,andpsoriasis
Acne,antiseptic,blockedpores,cellulite,
congestedandoilyconditions,deodorant,
Juniperus
Juniper eczema,dermatitis,generalcare,general [1,2,32,36,37,39,41–43]
virginiana
infections,psoriasis,toner,ulcers,weeping
eczema,andwounds
Juniperus
Cade Cuts,dermatitis,eczema,sores,andspots [32]
oxycedrus
Kunzeaericoides Ka¯nuka Athlete’sfoot [40]
Acne,fungalinfections,inflammation,oily
Laurusnobilis Bay conditions,pressuresores,andvaricose [32,36,41]
ulcers
Abscesses,acne,antiseptic,bacterial
infections,blisters,boils,burns,carbuncles,
cellulite,congestedandoilyconditions,
cuts,deodorant,dermatitis,eczema,foot
blisters,fungalinfections(athlete’sfoot,
Lavandula
Lavender ringworm),generalcare,healingagent, [2,26,32,36–43]
angustifolia
inflammation,insectbitesandstings,
pressuresores,pruritus,psoriasis,rosacea,
scalds,scarring,sores,sunburn,
ulcers,viralinfections(chickenpox,cold
sores,shingles,andwarts),andwounds
Acne,abscesses,boils,blisters,congested
Lavandula conditions,cuts,eczema,healingagent,
Lavandin [32,36,41]
flagrans inflammation,insectbitesandstings,
pressuresores,scalds,sores,andwounds
Abscesses,acne,bacterialinfections,
blisters,boils,burns,congestedandoily
conditions,cuts,dermatitis,eczema,
Lavandulaspica Lavenderspike [32,36,41]
inflammation,fungalinfections(athlete’s
foot,ringworm),pressuresores,psoriasis,
sores,ulcers,andwounds
Leptospermum Acne,cuts,fungalinfections(athlete’sfoot,
Manuka [2,40]
scoparium ringworm),ulcers,andwounds
Evidence-BasedComplementaryandAlternativeMedicine 7
Table1:Continued.
Scientificname Commonname Dermatologicaluse Reference
Verbena
Verbena Congestedconditionsandnourisher [36]
officinalis
Liquidambar
Sweetgum Cuts,ringworm,sores,andwounds [32]
orientalis
Acne,dermatitis,greasyandoily
Litseacubeba MayChang [32,36]
conditions,andhyperhidrosis
Abrasions,abscesses,acne,antiseptic,
bacterialinfections,blemishes,blisters,
boils,burns,carbuncles,cuts,dandruff,
fungalinfections(athlete’sfoot,nails,
Melaleuca
Teatree ringworm,andtinea),inflammation, [1,2,26,32,36–43]
alternifolia
insectbites,oilyconditions,rashes,sores,
spots,sunburn,ulcers,viralinfections
(coldsores,chickenpox,herpes,
shingles,andwarts),andwounds
Melaleuca Acne,insectbites,oilyconditions,
Cajuput [32,36,42]
cajuputi psoriasis,andspots
Abscesses,acne,antiseptic,bacterial
infections,blisters,boils,burns,chicken
Melaleuca
Niaouli/Gomenol pox,congestedandoilyconditions,cuts, [2,32,36,39–42]
viridiflora
eruptions,healingagent,insectbites,
psoriasis,sores,ulcers,andwounds
Allergicreactions,coldsores,eczema,
Melissa
Melissa/lemonbalm fungalinfections,inflammation,insect [1,26,32,36,41,42]
officinalis
stings,ulcers,andwounds
Acne,antiseptic,blackheads,chickenpox,
congestedandgreasyconditions,
Menthapiperita Peppermint dermatitis,inflammation,pruritus, [1,2,32,36,37,41–43]
ringworm,scabies,softener,toner,and
sunburn
Acne,congestedconditions,dermatitis,
Menthaspicata Spearmint [32,36,39,42]
pruritus,scabs,andsores
Myristica
Nutmeg Hairconditioner [36]
fragrans
Myrocarpus
Cabreuva Cuts,scars,andwounds [32]
fastigiatus
Acne,antiseptic,blemishes,blocked
Myrtus
Myrtle pores,bruises,congestedandoily [2,32,36,40]
communis
conditions,andpsoriasis
Nardostachys Eczema,inflammation,psoriasis,and
Spikenard [32,40]
jatamansi sores
Ocimum Acne,antiseptic,congestedconditions,
Basil [1,36,37,39,40,42]
basilicum insectbites,andwaspstings
Origanum
Marjoram Bruisesandfungalinfections [32,36]
majorana
Athlete’sfoot,bacterialinfections,cuts,
Origanum
Oregano eczema,fungalinfections,psoriasis,warts, [36,41]
vulgare
andwounds
Acne,agedanddrycomplexions,
bacterialinfections,balancingsebum,
burns,cellulite,chickenpox,congested
andoilyconditions,crackedskin,cuts,
Pelargonium dermatitis,deodorant,eczema,fungal
Geranium [2,26,32,36–43]
odoratissimum infections(athlete’sfoot,ringworm),
generalcare,healingagent,herpes,
impetigo,inflammation,measles,
psoriasis,rosacea,shingles,problematic
skin,sores,ulcers,andwounds
8 Evidence-BasedComplementaryandAlternativeMedicine
Table1:Continued.
Scientificname Commonname Dermatologicaluse Reference
Pelargonium
Rosegeranium Aginganddryorwrinkledskin [40]
roseum
Petroselinum
Parsley Bruises,scalpconditioning,andwounds [36]
sativum
Pimpinella
Anise Infectiousdiseases [36]
anisum
Antiseptic,bromodosis,congested
Pinussylvestris Pine conditions,cuts,eczema,hyperhidrosis, [32,36,37,41–43]
pruritus,psoriasis,andsores
Pipernigrum Blackpepper Bruisesandfungalinfections [36,42]
Abscesses,blisters,boils,cuts,ringworm,
Pistacialentiscus Mastic [32]
andwounds
Pistacia Abscesses,blisters,boils,cuts,infectious
Terebinth [32,36]
palaestina wounds,ringworm,andsores
Abscesses,acne,chappedordamagedand
crackedskin,dermatitis,coldsores,
eczema,fungalinfections(athlete’sfoot),
Pogostemon
Patchouli generalcare,healingagent,impetigo, [1,2,32,36–43]
patchouli
inflammation,oilyconditions,pruritus,
scalpdisorders,scars,sores,tonic,stretch
marks,andwounds
Aginganddryconditions,bacterial
Rosadamascena Roseotto infections,eczema,inflammation,toner, [2,38–41]
tonic,andwounds
Brokencapillaries,cuts,dryandaging
conditions,burns,eczema,healingagent,
Rosagallica Rose inflammation,pruritus,psoriasis,scars, [26,32,36–38,42,43]
toner,tonic,stretchmarks,sunburn,
threadveins,andwrinkles
Acne,bacterialinfections,balancing
Rosmarinus sebum,cellulite,congestedandoily
Rosemary [1,32,36,37,39,41,42]
officinalis conditions,dandruff,dermatitis,dry
scalp,eczema,generalcare,androsacea
Acne,antiseptic,bacterialinfections,
Salvia cellulite,coldsores,cuts,dermatitis,
Spanishsage [32,36,37,41]
lavandulifolia deodorant,hyperhidrosis,oilyconditions,
psoriasis,sores,andulcers
Abscesses,acne,balancingsebum,blisters,
boils,cellregeneration,dandruff,
Salviasclarea Clarysage dermatitis,greasyandoilyconditions, [1,2,32,36,40,42]
hyperhidrosisofthefeet,inflammation,
ulcers,andwrinkles
Acne,antiseptic,bacterialinfections,boils,
burns,chappedordamagedanddry
conditions,eczema,fungalinfections,
Santalumalbum Sandalwood [1,2,26,32,36–39,41–43]
generalcare,greasyandoilyconditions,
inflammation,pruritus,sunburn,and
wounds
Santolina
Inflammation,pruritus,ringworm,scabs,
chamaecyparis- Santolina [36]
verrucae,andwarts
sus
Cracks,cuts,dermatitis,eczema,healing,
Styraxbenzoin Benzoin inflammation,injuredandirritated [1,2,32,36,40,42]
conditions,pruritus,sores,andwounds
Evidence-BasedComplementaryandAlternativeMedicine 9
Table1:Continued.
Scientificname Commonname Dermatologicaluse Reference
Bacterialinfections,fungalinfections,
Tagetesminuta Tagetes inflammation,andviralinfections [32,36,42]
(verrucaeandwarts)
Abscesses,acne,antiseptic,blisters,burns,
carbuncles,cellulitis,cuts,deodorant,
Thymusvulgaris Thyme [1,32,36,37,41,42]
dermatitis,eczema,fungalinfections,oily
conditions,sores,andwounds
Blemishes,burns,freckles,softener,tonic,
Tiliaeuropaea LindenBlossom [36]
andwrinkles
Acne,antiseptic,balancingsebum,cuts,
Vetiveria eczema,malnourishedandagingskin,
Vetiver [1,2,32,36,37,41,42]
zizanioides oilyconditions,weepingsores,and
wounds
Acne,bruises,congestedandoily
Violaodorata Violet conditions,eczema,inflammation, [2,32,36,40]
infections,ulcers,andwounds
Zingiber
Ginger Bruises,carbuncles,andsores [36]
officinale
∗
Conditionsinvolvedindermatologicalinfectionsareshowninitalics.
∗∗
Amedicalconditionthatcausesexcessivesweating.
2.2. Inclusion Criteria. In order to effectively understand was extrapolated and recorded and comments were made.
the possible implications and potential of essential oils, the Observations were made and new recommendations were
inclusion criteria were broad, especially with this being the madeastofuturestudies.
firstreviewtocollatethisamountofscientificevidencewith
the aromatherapeutic literature. Inclusion criteria included 3.Results
thefollowing:
3.1. Description of Studies. After the initial database search,
(i)Type of in vitro studies for bacterial and fungal
1113reportswerescreened.Duplicateswereremoved,which
pathogens by means of the microdilution assay,
brought the article count down to 513, after which the
macrodilutionassay,ortheagardilutionassay
abstracts were then read and additional reports removed
(ii)Invivostudies
basedonnotmeetingtheinclusioncriteria.Afinalnumber
(iii)Antiviralstudies of 349 articles were read and reviewed. Of these, 143 were
in vitro bacterial and fungal studies (individual oil and 45
(iv)Casereports
combinations), two in vivo studies, 15 antiviral studies, 19
(v)Animalstudies
clinical trials, and 32 toxicity studies. The process that was
(vi)Allclinicaltrials followedissummarisedinFigure2.
2.3.ExclusionCriteria. Papersorpiecesofinformationwere 3.2.ExperimentalApproaches
excludedforthefollowingreasons:
3.2.1. Chemical Analysis. Essential oils are complex organic
(i)Lackofaccessibilitytothepublication
(carbon containing) chemical entities, which are generally
(ii)If the incorrect in vitro technique (diffusion assays) made up of hundreds of organic chemical compounds in
wasemployed combinationthatareresponsiblefortheessentialoil’smany
(iii)Indigenous essential oils with no relevance to com- characteristic properties. These characteristics may include
mercialoils medicinal properties, such as anti-inflammatory, healing,
or antimicrobial activities, but may also be responsible for
(iv)If they were in a language not understood by the
negativequalitiessuchasphotosensitivityandtoxicity[37].
authorsofthereview
Even with the high quality grade that is strived for in
(v)Pathogensstudiednotrelevanttoskindisease thecommercialsectorofessentialoilproduction,itmustbe
notedthatitisstillpossibleforessentialoilqualitytodisplay
2.4.DataAnalysis. Thetwoauthors(Ane´OrchardandSandy discrepancies, changes in composition, or degradation. The
vanVuuren)conductedtheirowndataextractionindepen- essential oil composition may even vary between the same
dently,afterwhichcriticalanalysiswasapplied.Information species[1,44].Thismaybeduetoahostofdifferentfactors
10 Evidence-BasedComplementaryandAlternativeMedicine
Essential oils used in dermatology in the agar into which the essential oil is instilled. After
identified using layman’s literature incubation, antimicrobial activity is then interpreted from
(books and information leaflets) the zone of inhibition (measured in millimetres) using the
available to the public (n=13) following criteria: weak activity (inhibition zone ≤ 12mm),
moderate activity (12mm < inhibition zone < 20mm), and
strongactivity(inhibitionzone≤20mm)[24,60–62].
Although this used to be a popular method, it is more
Articles identified via database suitabletoantibioticsratherthanessentialoilsasitdoesnot
searching (n=1113) accountforthevolatilenatureoftheessentialoils.Essential
oilsalsodiffusepoorlythroughanaqueousmediumasthey
are hydrophobic. Thus, the results are less reliable as they
Articles after duplicates were removed are influenced by the ability of the essential oil to diffuse
(n=513) throughtheagarmedium,resultinginvariableresults,false
negatives, or a reduction in antimicrobial activity [24, 63].
Theresultshavebeenfoundtovarysignificantlywhentested
Abstracts read (n=513) this way and are also influenced by other factors such as
disc size, amount of compound applied to the disc, type
of agar, and the volume of agar [57, 59, 64–68]. It has
Articles included (n=349) thus been recommended that results are only considered
wheretheminimuminhibitoryconcentration(MIC)orcidal
Figure2:Flowdiagramofthereviewapproach. concentrationvalueshavebeenestablished[65].
3.3.2. Dilution Methods. The dilution assays are reliable,
suchastheenvironmentorlocationthattheplantsaregrown widely accepted, and promising methods for determining
in, the harvest season, which part of the plant was used, anorganism’ssusceptibilitytoinhibitors.Themicrodilution
the process of extracting the essential oil, light or oxygen methodisconsideredthe“goldstandard”[64,68–70].This
exposure,thestorageoftheoil,andthetemperaturetheoil is a quantitative method that makes it possible to calculate
wasexposedto[45–51]. the MIC and allows one to understand the potency of the
Gas chromatography in combination with mass spec- essential oil [68, 71]. With one of the most problematic
trometry (GCMS) is the preferred technique for analysis of characteristics of essential oils being their volatility, the
essentialoils[52].Thisisaqualitativeandquantitativechem- microdilution technique allows for an opportunity to work
ical analysis method which allows for the assurance of the aroundthisproblemasitallowsforlessevaporationdueto
essential oil quality through the identification of individual theessentialoilbeingmixedintothebroth[67].
compounds that make up an essential oil [1, 45, 53]. It has This microdilution method makes use of a 96-well
clearly been demonstrated that there is a strong correlation microtitreplateunderasepticconditionswheretheessential
betweenthechemicalcompositionandantimicrobialactivity oils (diluted in a solvent to a known concentration) are
[51,54,55].Understandingthechemistryofessentialoilsis seriallydiluted.Resultsareusuallyreadvisuallywiththeaid
essentialformonitoringessentialoilcomposition,whichthen of an indicator dye. The microdilution results can also be
further allows for a better understanding of the biological interpretedbyreadingtheopticaldensity[72,73];however,
properties of essential oils. It is recommended to always theshortcomingofthismethodisthatthecolourednatureof
include the chemical composition in antimicrobial studies someoilsmayinterferewithaccurateturbidimetricreadings
[56]. [74].
Activity is often classified differently according to the
3.3. Antimicrobial Investigations. Severalmethodsexistthat quantitative method followed. van Vuuren [56] recom-
maybeemployedforantimicrobialanalysis,withtwoofthe mended2.00mg/mLandlessforessentialoilstobeconsid-
most popular methods being the diffusion and the dilution ered as noteworthy, Agarwal et al. [75] regarded 1.00% and
methods[56–59]. less, and Hadad et al. [76] recommended ≤250.00𝜇g/mL.
On considering the collection of data and frequency of
3.3.1. Diffusion Method. There are two types of diffusion certainMICvalues,thisreviewrecommendsMICvaluesof
assays. Due to the ease of application, the disc diffusion ≤1.00mg/mLasnoteworthy.
method is one of the most commonly used methods [60]. Themacrodilutionmethodemploysasimilarmethodto
Thisisdonebyapplyingaknownconcentrationofessential thatofthemicrodilutionmethod,exceptthat,insteadofa96-
oilontoasterilefilterpaperdisc.Thisisthenplacedontoagar wellmicrotitreplatebeingused,multipleindividualtesttubes
whichhaspreviouslybeeninoculatedwiththemicroorgan- are used. Althoughthe results are still comparable, this is a
ism to be tested, or it is spread on the surface. If necessary, time-consumingandatediousmethod,whereasthe96-well
the essential oil may also be dissolved in an appropriate microtitreplateallowsformultiplesamplestobetestedper
solvent. The other diffusion method is the agar diffusion plate,allowingforspeed,anditmakesuseofsmallervolumes
method,where,insteadofdiscsbeingplaced,wellsaremade which adds to the ease of its application [77, 78]. The agar