Lavender essential oil: A review

Abstract

Lavender essential oil is popular as a complementary medicine in its own right and as an additive to many over the counter complementary medicine and cosmetic products¹⁻³. Indeed, products derived from the popular garden herb Lavender (Lavandula spp.) have been used for centuries as a therapeutic agent, with the more ’recent’ addition, the essential oils derived from these plants, being widely used as an antibacterial in World War I1,4. The oil is traditionally believed to have sedative, carminative, anti-depressive and antiinflammatory properties, in addition to its recognised antimicrobial effects.
Many of the activities attributed to lavender oil have not, however, been substantiated in the scientific literature. This is further complicated by the fact that the majority of research into lavender essential oils has been based on oil derived from English lavender (Lavandula angustifolia), with little or no differentiation being made between this and other lavender essential oils. The therapeutic potential of essential oils produced from other varieties, such as L. x intermedia (lavandin), L. stoechas (French lavender) and L. x allardii, have largely been ignored. Although the ethnobotanical uses and major chemical constituents are similar between various lavenders, some differences do occur in both oil composition and in the reported therapeutic uses for different species3,5. The significant scientific interest in recent years into the validity/veracity of the traditional beliefs surrounding lavender oil and their scientific basis, if any, was recently reviewed by Cavanagh & Wilkinson³. In this paper we provide an overview of the use of lavender oil in infectious disease and an update on recent research on alternative uses of lavender oil.

Full text

Australian Infection Control
Lavender essential oil: a review
Heather
MA
Cavanagh
BSc(Hons) Microbiology
Jenny
M
Wilkinson
BSc(Hons)(Qld), GradDip FET(SQld),
(University of Glasgow), PhD(Macq)
PhD Molecular Virology (University of Glasgow), School of Biomedical Sciences, Charles Sturt University, NSW
PGCE (Strathclyde University)
School of Biomedical Sciences, Charles Sturt University, NSW
Abstract
Lavender essential oil is popular as a complementary medicine in its own right and as an additive to many over the counter
complementary medicine and cosmetic products
'
\
Indeed, products derived from the popular garden herb Lavender (Lavandula spp.)
have been used for centuries as a therapeutic agent, with the more 'recent
'
addition, the essential oils derived from these plants, being
widely used as an antibacterial in World War
I],!
The oil is traditionally believed to have sedative, carminative, anti-depressive and anti-
inflammatory properties, in addition to its recognised antimicrobial effects.
Many of the activities attributed to lavender oil have not, however, been substantiated in the scientific literature. This is further
complicated by the fact that the majority of research into lavender essential oils has been based on oil derived from English lavender
(Lavandula angustifolia), with little or no differentiation being made between this and other lavender essential oils. The therapeutic
potential of essential oils produced from other varieties, such as L.
x
intermedia (lavandin), L. stoechas (French lavender) and L.
x
allardii,
have largely been ignored. Although the ethnobotanical uses and major chemical constituents are similar between various lavenders,
some differences do occur in both oil composition and in the reported therapeutic uses for different ~pecies~,~. The significant scientific
interest in recent years into the validity/veracity of the traditional beliefs surrounding lavender oil and their scientific basis, if any, was
recently reviewed by Cavanagh
&
Wilkinson? In this paper we provide an overview of the use of lavender oil in infectious disease and
an update on recent research on alternative uses of lavender oil.
Lavender oil (primarily L. angustifolia) has been found to be
active against many species of bacteria, including those resistant
to antibiotics such as methicillin-resistant Staphylococcus aureus
(MRSA) and vancomycin-resistant Enterococcus (VRE)
b~R.
Recent
investigations into the antibacterial properties of a range of
Lavandula oils (L. angustifolia, L. allardii, L.
x
intermedia 'Grosso',
L.
x
intermedia 'Seal', L.
x
intermedia 'Miss Donnington', L.
x
heterophylla and
L.
stoechas 'Avonview') support the anecdotal use
of lavender oils as antibacterial agents and demonstrated that
Despite the known antibacterial activity, questions remain about
the clinical utility of lavender oil. The MIC (minimum inhibitory
concentration) values of lavender oil (L. angustifolia and
L.
latifolia) have been reported as being comparable to that of tea
tree oil (0.16% against Haemophilus influenzae, 0.32% against S.
pyogenes and S. aureus and greater than 0.32% against
E.
~oli)'~.
These figures would appear to support the use of lavender oils as
a prophylactic or for use in topical application for surface
infection rather than for use against deep-seated infections.
some oils which had previously not been investigated (e.g. L. Lavender oil has also been reported to be an effective antifungal
heterophylla) displayed good antibacterial activity against a range agent against fungi of both medical and agricultural importance,
of bacteria including Streptococcus pyogenes, Enterobacter aerogenes, especially in inhibition of germ-tube growth
".
A recent study
S. aureus, MRSA, Pseudomonas aeruginosa, Citrobacter freundii, demonstrated that all Lavandula essential oils examined to date
Proteus vulgaris, Escherichia coli, VRE, Shigella sonnei and displayed some antifungal activity, with oils derived from
L.
Propionibacterium acnes
9.
an~ustifolia and L.
x
intermedia demonstrating the greatest effect
-.
Interestingly, there was considerable variability in the activity of against Aspergillus nidulans and Trichophyton mentagrophytes.
the essential oils, with L. angustifolia and
L.
x
intermedia oils In contrast, oil derived from L, stoechas was particularly effective
showing the highest activity against several bacteria. However, against the agricultural fungi Leptosphaeria maculans and Sclerotinia
no one oil produced the highest level of antibacterial activity sclerotiorum, demonstrating that Lavandula oils have activity
against all bacteria tested, suggesting that differences in chemical against fungi of both medical and agricultural importance, and
composition make some oils more effective against particular suggesting that essential oils from various lavender varieties may
bacteria. No strong correlation has been observed between be useful in the treatment of fungal infections
''.
percentage of major chemical components and antibacterial
activity, and
P
aeruginosa was not susceptible to any Lavandula oil The recent interest in the therapeutic use of hydrosols, however,
tested9. These results support the anecdotal use of lavender oils appears unlikely to have scientific merit as no antimicrobial
as antibacterial agents and demonstrate that some oils which had activity has been found to be associated with any Lavandtlla
previously not been investigated have good antibacterial activity. hydrosols examined by this group to date
12.
Hydrosols or
Vol10 Issue
1
March 2005

Australian Infection Control
distillate waters are a by-product of steam distillation and
contain variable amounts of essential oil and other plant derived
components. The variation found in the activity of the different
oils suggests that different oils should be targeted for different
therapeutic uses. Further work is required to determine whether
the
in uitro
results are realised in a clinical environment, but it is
clear that not all lavenders are equal in terms of their
antimicrobial properties.
Interestingly, the volatile components of Lavandula essential oils
have also been found to display potent antifungal activity;
however, no significant differences in activity have been reported
between different
Lauandula
oil volatiles
l2I5.
Vapour treatment
would appear to have an advantage over solution treatment in
that the microbial growth could be inhibited by a smaller amount
of essential oil, while potentially also acting as a potent inhibitor
of sporulation, assuming that suitable vapour concentration and
treatment times can be determined. Initial studies suggest that
the gaseous contact activity of the essential oils was determined
mainly by the maximum vapour concentration at an early stage
of incubation and that maintaining high vapour concentration for
long periods of time was not necessary
15.
It should be noted,
however, that the effective vapour concentrations in a clinical
setting have not yet been directly related to the concentrations
used routinely in aromatherapy.
The use of essential oil volatiles for therapeutic benefit is not new.
Indeed, lavender oil today is used predominantly in
aromatherapy or massage, and many benefits are claimed for its
use in this way, including relief of the symptoms of stress and
depression, in improving 'mood' and relieving anxiety
3.
Aromatherapy is thought to be therapeutically effective due to
both the psychological effect of the odour and the physiological
effects of the inhaled volatile compounds, where the latter effects
are believed to act via the limbic system, particularly the
amygdala and hippocampus. However, although inhalation of
lavender oil volatiles has been reported to be capable of altering
patient mood and improving sleep patterns, the true therapeutic
benefit of inhalation of lavender oil remains controversial
',
16, 17.
This may be related to the fact that many studies combine both
massage and lavender oil and are unable to determine whether
the benefits seen are as a result of massage or of lavender oil
inhalation/absorption.
For example, a recent study investigating the use of lavender oil
aromatherapy in dementia patients found no evidence that a
purely olfactory form of aromatherapy led to decreased agitation
in severely demented patients and suggested that cutaneous
application of the essential oil may be necessary to achieve the
optimum effect 18. Similarly, although percutaneous
administration of one of the main ingredients of lavender oil,
(-)-
linalool, led to a decrease in systolic blood pressure and skin
temperature, compared to a corresponding control group
receiving a placebo, no effect on subjective evaluation of well-
being was noted
19.
In another study, although massages with lavender essential oil
and an inert carrier oil were unable to demonstrate any
significant long-term benefits in improving pain control, but
anxiety or quality of life (compared to those patients who
received the inert carrier oil only or no massage) and sleep scores
improved significantly in both the massage and the combined
massage (aromatherapy and massage) groups. These findings
were accompanied by a statistically significant reduction in
depression scores in the massage group, whether lavender oil
was used or not 20. Inhalation of lavender aromatherapy during
radiotherapy was also found to reduce anxiety
21.
Conversely, several authors have noted an association between
lavender odour, positive emotional states and therapeutic
benefit
22~25.
For example, Diego
et al.
26
found that individuals
receiving lavender oil (10%) odour for
3
minutes were
significantly more relaxed, had decreased anxiety scores, better
moods and showed increased alpha power in their EEGs (an
indication of increased drowsiness). Similarly, in a pilot study by
Walsh
&
Wilson 27, long-stay neurology in-patients also showed
increased mood scores and reduced psychological distress
following aromatherapy (tea tree, rosemary and
L. angustifolia
oils), suggesting that lavender aromatherapy can improve
patients' experiences in intensive care with no detrimental
physical or behavioural outcomes.
Inhalation of lavender oil is also reported to be of benefit in pain
relief. Lavender oil has been shown to be an effective short-term
treatment for lower back pain when acupoint stimulation was
followed by acupressure with aromatic lavender oilZR. In an other
recent (animal) study, it was shown that inhalation of lavender oil
(L.
x
intermedia
'Grosso') for
1
hour resulted in significant
analgesic activity at doses that did not produce a sedative side-
effect, with the oil appearing to significantly reduce the acetic
acid-writhing response in a naloxone-sensitive manner.
A
similar
effect was found with oral (100mg/kg) administration2'.
It has been suggested, however, that, rather than having a direct
analgesic effect, inhalation of lavender oil may simply elicit a
more positive appraisal and subsequent positive retrospective
evaluation of treatment-related pain from the patient when they
report on lavender aromatherapy associated pain relief
".
Interestingly, Barocelli
et al.
z'
also reported that oral
administration of lavender oil, or its major constituents linalool
or linalyl acetate, could protect animals against acute ethanol-
induced gastric ulcers.
Extensive research is now being carried out worldwide to
identify and isolate the chemical components of lavender oil,
which will allow the identification of biologically active
constituents of the oil and determination of any synergistic
effects of the 'mixed' components. While it is known that the
main constituents play a major role in the biological activity of
lavender oil, it has also been reported that the antimicrobial
activity of different types of lavender oil are not all related to
these major constituents.
For example, studies investigating the relationship between
biological activity and chemical composition of lavender have
found no correlation between linalool or linalyl acetate content
Vol
10
Issue
1
March
2005

Australian Infection Control
and antibacterial or antifungal activity
7.
In addition, very little is
known of any synergistic relationships which occur between the
oil constituents.
There is no doubt that identification of the biologically active
components of lavender oil and determination of their mechanisms
of action,
in
isolation and in combination, will help to clarify many
of the inconsistencies currently found in lavender oil research and
may lead to identification of novel, effective therapeutic
compounds. Indeed, one constituent of lavender oil, perillyl
alcohol
(POH)
has recently been identified as a potential anticancer
agent, which may be useful in both treatment and prevention3l.".
Lavender is traditionally regarded as a 'safe' oil and, although it
was recently reported that lavender oil, and its major constituent
linalyl acetate, are toxic to human skin cells
in
vitro,
contact
dermatitis to lavender oil appears to occur at only a very low
frequency
3z
34. The relevance of this
in
vitro
toxicity to
dermatological application of
Lavandula
oils remains unclear.
Despite the apparent safety of lavender oil as a topical agent, oral
administration is not recommended.
In conclusion, many more claims are made for therapeutic benefit
derived from lavender oil than are reviewed in this paper;
however, controversy surrounds many aspects (reviewed in
Cavanagh
&
Wilkinson
9).
Further research is required to
determine the true bioactivity of lavender oil and its constituents.
Despite this lack of evidence for many claims, lavender continues
to be used by the general public and clinical staff, perhaps
because any potential therapeutic benefit is seen as a possible
'bonus' to the simple love of lavender.
References
1. Gattefosse R-M. Gattefosse's Aromatherapy. Saffron Walden,
England, 1937.
2. Evelegh T. Lavender. Lorenz Books, Sydney, 1996.
3. Cavanagh HMA
&
Wilkinson
JM.
Biological activities of lavender
essential oil.
J
Phyto Res 2002; 16:301-308.
4. Grieve M. A Modem Herbal. Harcourt, Brace
&
Co, New York, 1931.
5. Agricultural Research Service. Dr Duke's Phytochemical and
ethnobotanical databases.
http://www.ars-grin.gov/duke/
2000.
6. Nelson
RRS.
In-vitro activities of five plant essential oils against
methacilh-resistant
Staphylococcus aureus
and vancomycin-resistant
Enferococcus faecium.
J
Antimicrob Chemother 1997; 40:305-306.
7. Lis-Balchin M, Deans SG
&
Eaglesham E. Relationship between
bioactivity and chemical composition of commercial essential oils.
Flavour Fragr J 1998; 13:98-104.
8. Hammer K, Carson C
&
Riley T. Antimicrobial activity of essential
oils and other plant extracts. J Appl Microbiol1999; 86985.990.
9. Moon T, Cavanagh HMA
&
Wilkinson JM. Lavender as an
antibacterial essential oil
-
are all lavenders equal? AICA National
Conference, 2004, abstracts p46.
10. Inouye S, Yamaguchi H
&
Taluzawa T. Screening of the antibacterial
effects of a variety of essential oils on respiratory tract pathogens,
using the modified dilution assay method. J Infect Chemother 2001;
7251-254.
11. Daferera DJ, Ziogas BN,
&
Polissiou MG. GC-MS analysis of essential
oils from some Greek aromatic plants and their fungitoxicity on
Penicillium digitatum.
J
Agric Food Chem 2000; 48:2576-2581.
12. Moon T, Chan YF, Wilkinson
JM
&
Cavanagh HMA. Antifungal
activity of
Lava~zdula
essential oil and oil volatiles. AICA National
Conference, 2004; abstracts p46.
Inouye
S,
Watanabe M, Nishiyama Y, Takeo K, Akao M
&
Yamaguchi
H. Antisporulating and respiration-inhibitory effects of essential oils
on filamentous fungi. Mycoses 1998; 41:403-410.
Inouye S, Tsuruoka T, Watanabe M, Takeo K, Akao M, Nishiyama Y
&
Yamaguch H. Idubitory effect of essential oils on apical growth of
Aspergillusfumigatus.
Mycoses 2000; 4317-23.
Inouye
S,
Tsuruoka T, Uchida
K
&
Yamaguchi H. Effect of sealing and
Tween 80 on the antifungal susceptibility testing of essential oils.
Microbiol Immunol2001; 45:201-208.
Bumett
KM,
Solterbeck LA
&
Strapp CM. Scent and mood state
following an anxiety-provoking task. Psychol Rep 2004; 95:707-722.
Camped CE, Crawley EJ
&
Meier ME. Role of suggestion in odor-
induced mood change. Psychol Rep 2004; 94(3:2):1127-1136.
Snow LA, Hovanec
L
&
Brandt J. A controlled trial of aromatherapy
for agitation in nursing home patients with dementia. J Altern
Complement Med 2004; 10:431-437.
Heuberger E, Redhammer S
&
Buchbauer G. Transdermal absorption
of (-)-linalool induces autonomic deactivation but has no impact on
ratings of well-being in humans.
Neuropsycho-pharmacology
2004;
29:1925-1932.
Soden K, Vincent
K,
Craske S, Lucas C
&
Ashley S. A randomized
controlled trial of aromatherapy massage in a hospice setting. Palliat
Med 2004; 18:87-92.
Graham PH, Browne
L,
Cox H
&
Graham J. Inhalation aromatherapy
during radiotherapy: results of a placebo-controlled double-blind
randomized trial.
J
Clin Oncol2003; 21:2372-2376.
Alaoui-Ismaili
0,
Vernet-Maury E, Dittrnar A, Delhomme G
&
Chanel
J. Odor hedonics: connection with emotional response estimated by
autonomic parameters. Chem Senses 1997; 22:237-248.
Tysoe P. The effect on staff of essential oil burners in extended care
settings. Int J Nurs Pract 2000; 6:110-112.
Masago R, Matsuda T, IOkuchi Y, Miyazaki Y, Iwanaga K, Harada H
&
Katsuura T. Effects of inhalation of essential oils on EEG activity
and sensory evaluation. J Physiol Anthropol Appl Human Sci 2000;
1935-42.
Millot J-L
&
Brand G. Effects of pleasant and unpleasant ambient
odors on human voice pitch. Neurosci Lett 2001; 29:61-63.
Diego MA, Jones NA, Field T, Hernandez-Reif M, Schanberg S, Kuhn
C, McAdam V, Galamaga R
&
Galamaga M. Aromatherapy positively
affects mood, EEG patterns or alertness and math computations. Int J
Neurosci 1998; 96:217-224.
Walsh E
&
Wilson C. Complementary therapies in long-stay
neurology in-patients settings. Nurs Stand 1999; 13:32-35.
Yip YB
&
Tse SH. The effectiveness of relaxation acupoint stimulation
and acupressure with aromatic lavender essential oil for non-specific
low back pain in Hong Kong: a randomised controlled trial.
Complement Ther Med 2004; 12:28-37.
Barocelli E, Calcina F, Chiavarini M, Impicciatore M, Bruni R, Bianchi
A
&
Ballabeni V. Antinociceptive and gastroprotective effects of
inhaled and orally administered
Lavandula hybrida
Reverchon
"Grosso" essential oil. Life Sci 2004; 76:213-223.
Gedney JJ, Glover TL
&
Fillingim RB. Sensory and affective pain
discrimination after inhalation of essential oils. Psychosom Med 2004;
66:599-606.
Samaila D, Ezekwudo DE, Yimam
KK
&
Elegbede JA. Bioactive plant
compounds Inhibited the proliferation and induced apoptosis in
human cancer cell lines, in vitro. Transactions of the Integrated
Biomedical Informatics
&
Enabling Technologies Symposium Journal
2004; 1:34-42.
Liston BW, Nines R, Carlton
PS,
Gupta A, Aziz R, Frankel W
&
Stoner
GD. Perillyl alcohol as a chemopreventive agent in N-
nitrosomethylbenzylamine-induced
rat esophageal tumorigenesis.
Cancer Res 2003; 63:2399-2403.
Prashar A, Locke IC
&
Evans CS. Cytotoxicity of lavender oil and its
major components to human skin cells. Cell Prolif 2004; 37221-229.
Matthieu L, Meuleman L, Van Hecke E, Blondeel A, Dezfoulian 8,
Constandt L
&
Goossens A. Contact and photocontact allergy to
ketoprofen: the Belgan experience. Contact Dermatitis 2004; 50:238-
241.
Vol10 Issue
1
March 2005