Essential Oils & Herbs: Treatment of Intestinal Dysbiosis

Essential Oils & Herbs: Treatment of Intestinal Dysbiosis
By Michelle Morgan
The human gut is the natural habitat for a large, diverse and
dynamic population of microorganisms, mainly bacteria. The
intestinal habitat of a human adult contains 300–500 different
species of bacteria. Thirty to 40 species comprise up to 99% of
the population. Some of the bacteria are pathogens or potential
pathogens when the integrity of the mucosal barrier is functionally
Major functions of the intestinal microflora include:1
metabolic activities that result in salvage of energy and
absorbable nutrients
protection against invasion by alien microbes (a barrier effect)
trophic effects on intestinal epithelia (eg the control of
the proliferation and differentiation of epithelial cells) and
on immune structure and function (eg assisting in the
development and homoeostasis of the immune system such
as via intestinal lymph tissue)
Dysbiosis is an imbalance of the intestinal ecosystem,2 usually a
breakdown in the balance between “protective” and “harmful”
intestinal bacteria.3 Changes in the composition or metabolic
functions of intestinal flora may be associated with pathological
conditions, including inflammatory bowel diseases and colon
cancer.1 There are several types of dysbiosis, more than one of
which can co-exist in an individual and cause poor health:
Helicobacter pylori presence in the stomach (although some
argue it is a commensal) can lead to peptic ulcer and stomach
small intestinal bacterial overgrowth
colonic flora imbalance – can include abnormal presence of
parasites (protozoa) or yeasts (Candida)
infections, spasmodic cough, tuberculosis and asthma. It
stimulates digestion and is effective for relieving intestinal gas
and for killing intestinal parasites.8,9 Essential oil of Origanum
vulgare is used in traditional Chinese medicine (TCM) to treat
dysentery and enteritis.10
Oregano oil has demonstrated growth inhibitory activity towards
human intestinal pathogens including Candida albicans when
tested in vitro. The phenolic compounds, carvacrol and thymol
are important for the activity.11-13 Oral administration of Oregano
oil for 30 days successfully treated 80% of mice with systemic
Clinical Trial
The antiparasitic effect of Oregano oil has been demonstrated
in an uncontrolled trial in the United States involving 14 adults
whose stools tested positive for enteric parasites (protozoa):
Blastocystis hominis, Entamoeba hartmanni and Endolimax
nana. For six weeks patients took emulsified oil of Origanum
vulgare (200 mg, three times per day) with meals. Thirteen
of the 14 patients completed the treatment and submitted
follow-up stool samples. Parasites could no longer be detected
in 10 patients, seven of these patients reported a reduction
of symptoms. Parasite scores decreased for the other three
Anise Oil
Anise (also known as Aniseed) essential oil is obtained by steam
distillation of the fruit of Pimpinella anisum. The main constituent
of Anise essential oil is trans-anethole.15
excessive antibiotics or a diet low in soluble fibre may create
a deficiency of healthy flora (linked to food intolerance and
irritable bowel syndrome)
Aniseed fruit is traditionally used as an expectorant, spasmolytic
and carminative, for bronchitis, tracheitis and flatulent colic.16 A
decoction of Aniseed fruit is traditionally used as a vermifuge by
the people of rural northern Argentina.17 Aniseed fruit is recorded
in the monastic scriptures of Cyprus written during the Ottoman
period (1571–1878). It reveals that, in addition to the many
familiar traditional applications (dyspepsia, to promote lactation,
cough), Aniseed was also recommended for prophylaxis of
cholera and plague.18
abnormal responses to normal flora or excessive presence of
pathogenic flora lead to deranged immune function (leading to
autoimmune disease or chronic skin disorders)
Anise oil has been used traditionally for colic, indigestion,
coughs, bronchitis,19 and as an antibacterial in cough mixtures
and lozenges.4
putrefaction due to high fat and meat and low fibre diets
(linked to colon and breast cancer)
carbohydrate intolerance due to excess fermentation by
normal bacteria in overgrowth or excessive yeasts (Candida)
Oregano Oil
Many species of plant with the common name ‘oregano’ are used
throughout the world as condiments or medicines. Most common
is European Oregano (Origanum vulgare) and Mexican Oregano
(Lippia graveolens).4,5 The composition of the essential oil of
European Oregano can vary. All widely used varieties show a
high content (>90%) of four major constituents: carvacrol,
gamma-terpinene, p-cymene and thymol.6,7
Oral administration of the essential oil of Oregano (Origanum
vulgare) is used in herbal medicine particularly in France and
Germany. It is a strong antimicrobial, useful in respiratory
Anise oil has demonstrated growth inhibitory activity towards
human intestinal pathogens including Candida albicans when
tested in vitro. Anethole has been found to be responsible for the
antifungal activity of Anise oil.20-22
Pau d’Arco
The bark of Pau d’Arco (Tabebuia avellanedae, T. impetiginosa)
is used in traditional South American medicine for dysentery,
fever, sore throat, intestinal inflammation, snake bites
and carcinomas.23 It is also regarded as a tonic.24 The
naphthoquinones (including lapachol and beta-lapachone) are
key active constituents.25
Tabebuia impetiginosa bark extracts exhibited growth inhibition
of the human intestinal pathogenic bacteria Clostridium
perfringens and C. paraputrificum in vitro.26 Tabebuia
avellanedae bark extracts demonstrated growth inhibitory
activity towards methicillin-resistant Staphylococcus aureus
strains in vitro. Several compounds in the ethanolic extract
appeared to be acting synergistically.27
The effect of each compound on the microbial growth of the test
organisms is outlined in Table 1 (below). A value of 0 means
there were no colonies left after three hours. Values over 100 are
possible because the organism may have grown faster over the
three hour time period than the controls. The emulsifier used in
the preparation of the essential oils made a small contribution to
their antimicrobial effect.
Lapachol has demonstrated activity against protozoa in vitro.28
Key findings were:
The aerial parts of Andrographis paniculata is used in many
traditional systems, with an emphasis on enhancing immune
function, treating fever and infections, including those of the
gastrointestinal tract.29-31 In Ayurveda and Indonesian traditional
medicine it is also regarded as a tonic.31,32 Key constituents of
Andrographis include diterpenoid lactones, collectively referred to
as andrographolides.33
Andrographis has been found to affect the cell surface
hydrophobicity of E. coli strains in vitro and hence possibly
interfere with this bacteria’s adhesion capability.34 Andrographis
also reduced the E. coli enterotoxin secretory response in
isolated intestinal tissue.35 However, with regard to infections and
intestinal dysbiosis, its value is mainly as an immune-enhancing
treatment and it is a useful part of any formulation on that
Pau d’Arco had a significant inhibitory effect on the growth of
Candida albicans, C. glabrata and Enterococcus faecalis, with
the greatest effect on the latter organism
Synergistic Formulation
These essential oils and herbs would complement each other in a
very potent formulation with the following actions:
A trial conducted in Thailand found that Andrographis decreased
the frequency and amount of discharge in patients with acute
diarrhoea and bacillary dysentery. In China, treatment with
Andrographis preparations was found to be beneficial for bacillary
dysentery and enteritis. Andrographolides were also of benefit in
the treatment of bacillary dysentery, but other constituents may
also be important for the therapeutic activity of Andrographis.33,36
The in vitro antimicrobial activity of Oregano and Anise essential
oils and extracts of Pau d’Arco and Andrographis was assessed
by an independent laboratory at Charles Sturt University in 2007.
The test microorganisms included two yeasts (Candida albicans,
Candida glabrata) and four bacteria (Enterococcus faecalis,
Escherichia coli (E. coli), Klebsiella pneumonia, Salmonella spp.
serotype Monschaui). All of these organisms are commonly
found in the human intestinal flora.
Anise essential oil significantly inhibited the growth of all
organisms, with the effect on Candida albicans less than
that for the other organisms which were almost completely
With the exception of Enterococcus faecalis no significant
antimicrobial effect was demonstrated for Andrographis, as
might be expected (results not shown)
Clinical Trials
In vitro Antimicrobial Activity by
Essential Oils & Herbs
Oregano essential oil and the combination of all compounds
completely inhibited the growth of all organisms
antimicrobial, antiparasitic
It is advantageous to use more than one antimicrobial and
antiparasitic agent to reduce the risk of organisms becoming
resistant. It is also best to have the combination presented with
enteric coating, to deliver the antimicrobial and antiparasitic
agents directly to the intestine where their action is needed.
The use of some essential oils by oral administration is part
of the tradition of herbal medicine, particularly in Europe, as
can be seen by their inclusion in old pharmacopoeial texts.
These essential oils can be used safely when administered
at the recommended dosage. Information from the British
Pharmaceutical Codex 1934 allows the following oral dosages to
be derived: Oregano essential oil (170–1150 mg/day), Aniseed
essential oil (177–788 mg/day).37
As part of a bowel flora protocol for intestinal dysbiosis
Adjunctive treatment for diarrhoea and candidiasis
The compounds were suitably prepared in broth to a
concentration of 0.1 w/v (weight per volume). A combination
containing equal amounts by weight of each of the compounds
was also tested. Broth was tested as a control. The test
organisms were prepared, added to a broth containing each
compound and allowed to incubate for a period of three hours.
Colony count was then performed after 48 hours for yeasts and
24 hours for bacteria. Assays were performed in triplicate.
Oregano (essential oil)
Candida albicans
Candida glabrata
Enterococcus faecalis
Escherichia coli
Klebsiella pneumonia
Salmonella spp. (serotype: Monschaui)
Table 1. Colony count as a percentage of controls.
References available at MediHerb’s Professional Library
Any health condition linked to intestinal dysbiosis such as
autoimmune disease, gut disorders (such as irritable bowel
syndrome, food sensitivities, gastrointestinal infections),
chronic skin disorders, poor immunity, fatigue, breast and
colon cancer
Cautions and Contraindications
Contraindicated in pregnancy and lactation.
Mean Growth (%)
Pau d’Arco stem bark
Anise (essential oil)
(powdered extract)
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