essential oil - جامعة نزوى · mustard and almond oils, which are produced by ... all...
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3-Jul-17 1
Essential oil
Definition
Difference from fixed oils
Distribution, localization and function
Uses
Physical characters
Methods of preparation
Quality control
Storage
Chemistry
Classification
Essential oils containing drugs from medicinal plants
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Learning Objectives
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The student should be able to describe Definition and classification of essential oils
Distribution, localization and function of essential oils drugs.
Physical properties and chemical composition of essential oils drugs.
Methods of production of essential oils.
Quality control of essential oils and drugs containing them.
Pharmacology, uses, toxicity and storage of essential oils drugs.
Names, synonyms and biological origins of drugs containing essential oils.
Active constituents, effects and indications of drugs containing essential
oils.
Precautions, adverse reactions and toxicity of drugs containing essential
oils.
Learning Outcomes
4
Pharmacognosy by W.C. Evans. Trease and Evan’s, 12th edition.
London. Page Number 23-153; 170-205; 250-289.
Pharmacognosy Phytochemistry by Jean Bruneton, Medicinal Plants
(1999) Page Number 5-73; 91-256; 312-345
Pharmacognosy and Pharmacobiotechnology (1996) by Page
Number 1-40; 59-121.
Phytochemical Methods, J. Harborne PDR for Herbal Medicines
2nd edition 30-75; 77-156.
Organic Chemistry by IL Finar Page Number 368-473; 170-205;
250-289
References
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VOLATILE OILS
Products generally of rather complex composition
Volatile principles contained in the plants, and more or less
modified during the preparation process
They are volatile in steam and also evaporate
when exposed to air and /or at ordinary temperature
Volatile oils represent the essences or odorous principles
found in various plant parts.
Exception: Some oils such as oils winter green,
mustard and almond oils, which are produced by
the enzymatic hydrolysis of the corresponding glycoside.
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What is Essential oils?
Oily liquids, which are entirely or almost entirely
volatile without decomposition
Plant products, giving the odors and tastes
characteristic of the particular plant, thus
possessing the essence.
Ether like in their volatility.
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Characteristic properties
All official volatile oils are
of vegetable origin.
Normally pre-exist in the
plant–stored in a special
secretory tissue.
Exception: Almond oil is
formed by hydrolysis of the
glycosides.
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VOLATILE OILS
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Air freshening
Bathing/amount of essential oils to use in bath
Foot and hand baths
Hair care/amount of essential oils to use in shampoo
Jacuzzis
Massage
Saunas
Showers
Sitz bath
Skin care/Bathing/amount of essential oils to use in creams
Steam inhalations
Vaporization
General Uses of volatile oils
Flavouring (Oil of Lemon)
Perfumery (Oil of Rose)
Starting materials to synthesize
other compounds (Oil of Turpentine)
Antiseptic activity–Due to high
phenols (Oil of Thyme). Also as a
preservative (oils interfere with
bacterial respiration)
Antispasmodic activity (Ginger,
Lemon balm, Rosemary, Peppermint,
Chamomile, Fennel, Caraway)
Aromatherapy 3-Jul-17 10
Therapeutic uses of volatile oils
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Four main types of volatile oils
Concretes
Pomades
Resinoids
Absolutes
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Types of volatile oils
CONCRETES
Prepared from raw materials of vegetable origin (bark, flowers, leafs, roots etc.)
Extracted by HC type solvents, rather than distillation or expression – Becomes necessary when the essential oil is adversely affected by hot water or steam (e.g. jasmine).
Produces a more true-to-nature fragrance.
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CONCRETES
Concretes contain about 50 % wax and 50 % essential oil (jasmine).
Ylang ylang (concrete volatile) contains 80 % essential oil and 20 % wax.
Advantages of concretes: they are more stable and concentrated than pure essential oils.
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POMADES
True pomades are (volatile oil) products of a process known as enfleurage (hot or cold).
Enfleurage is used for obtaining aromatic materials from flowers containing volatile oils to produce perfume long after they were cut.
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ENFLEURAGE: METHOD
A glass plate is covered with a thin coating of especially prepared and odourless fat (called a chassis).
The freshly cut flowers are
individually laid on to the fat which in time becomes saturated with their essential oils. The flowers are renewed with fresh material.
Eventually the fragrance-saturated
fat, known as pomade, may be treated with alcohol to extract the oil from the fat.
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RESINOIDS
Prepared from natural resinous material (dried material) by extraction with a non-aqueous solvent, e.g. Petroleum ether or hexane.
E.g. Balsams – Peru balsam or benzoin; resins (amber or mastic); Oleoresin (copaiba balsam and turpentine); Oleogum resins (frankincense and myrrh)
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RESINOIDS
Can be viscous liquids, semi-solid or solid.
Usually homogeneous mass of non-crystalline character.
Uses: in perfumery as fixatives to prolong the effect of a fragrance.
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ABSOLUTES
Obtained from a concrete, pomade, or a resinoid by alcoholic extraction.
The extraction process may be repeated.
The ethanol solution is cooled & filtered to eliminate waxes.
The ethanol is then removed by distillation.
They are usually highly concentrated viscous liquids.
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Extracting oil from the plants
The way in which oils are extracted from plants is important because
some processes use solvents that can destroy the therapeutic
properties. The usual method of extraction is through steam
distillation. After extraction, the properties of a good quality essential oil
should be as close as possible to the "essence" of the original plant. The
key to a 'good' essential oil is through low pressure and low temperature
processing. High temperatures, rapid processing and the use of solvents
alter the molecular structure, will destroy the therapeutic value and alter
the fragrance.
Early efforts at extraction used alcohol and a fermentation
process. Nowadays, a reputable distiller will try to preserve the original
qualities of the plant, but the final therapeutic result is often not formed
until after the extraction process. During extraction, the qualities of the oil
change to give it more value - for example, chamazulene (characteristic of
the pure blue colour of German Chamomile) is formed during the steam
distillation process.
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Essential oils are extracted from plant material. Each oil has many
chemical compounds within it which vary according to climate,
location, soil, methods of cultivating and harvesting.
Essential oils are extracted from plant material by 4 main methods:
1. Steam distillation
2. Solvent extraction
3. Expression
4. Enfleurage
EXTRACTION PROCEDURE
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Steam distillation
A process where steam is passed over the plant material. The steam is then condensed
again, the liquid is collected, and the essential oil separated from the liquid. The most
pure essential oils are collected in this way.
Solvent extraction
Where solvents and alcohol are mixed with the plant material in order to produce an
absolute, or very high quality flower water. True essential oils are not produced in this
way and there is some dispute as to their use in aromatherapy.
Expression Used with citrus oils to make 'essences'. The oils are extracted from the fruit by
machinery which mechanically squeezes the oil from the peel, a process called
scarification.
Enfleurage
An intensive and traditional way of extracting oil from flowers. The process involves
layering fat over the flower petals. After the fat has absorbed the essential oils, alcohol
is used to separate and extract the oils from the fat. The alcohol is then evaporated and
the essential oil collected. 3-Jul-17 22
Essential Oil Steam Distiller Flow sheet of Steam Distillation
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Types of Distillation Process
Distillation process can be divided into the following
Water distillation
Steam distillation
Hydro diffusion
Other specialized distillation
Cohobation
Rectification
Water and steam distillation
Fractional distillation
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Solvent extraction Process
Maceration
Enfleurage
Solvent
Expression Process
Sponge expression
ecuelle a piquer
Machine abrasion
Supercritical carbon dioxide CO2
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Water distillation
In water distillation, the botanical material is completely immersed in
water and then is boiled. This method protects the oil to be extracted till
a certain degree since surrounding water prevents it from overheating.
Then it is condensed and cooled down. The oil is then separated out, as it
layers on the top of the water. The water separated out in this process is
termed as floral waters (also called hydrosol or sweet water) such as rose
water, orange water and lavender water.
Water distillation can be operated at low pressures to reduce boiling
temperature. This helps in protecting the botanical material and essential
oil as well.
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Steam distillation apparatus.
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Hydro Diffusion
Hydro Diffusion method for extraction of oils is a type of steam distillation and is only
different in the way in which steam is enters the container of the still. In hydro
diffusion, steam is fed in from the top onto the botanical material while in the case of
steam distillation, steam is fed from the bottom. In this way the steam can saturate
the plants more evenly and in less time than with steam distillation. The condensation of the oil containing steam mixture occurs below the area in which
the botanical material is held. The main advantage of this method over steam
distillation is that less steam is used hence shorter processing time and therefore a
higher oil yield. This method is also less harsh on the botanical material.
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Fractional distillation
When we say fractional distillation, it only refers to normal distillation
process. In this only difference is that the oil is not collected continuously,
but is collected in parts i.e. fractions and oil normally so extracted is Ylang-
Ylang oil.
Rectification
When an essential oil contains any impurities, it can be purified by re-distillation,
either in steam or in vacuum and this purification of oil by re-distillation is referred to
as rectification.
This process is used to make oils of standard quality. An example of rectification is
eucalyptus oil.
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Cohobation Method
In some essential oil extractions, some chemical or part of the essential oil gets dissolved in
water and therefore gets removed from the oil. So to get the whole oil, we add the deficient
chemical to the deficient oil and re-distillation is done until we get the complete oil. An example
of this is rose oil.
Sponge Expression Method Most citrus essences are extracted by means of expression, and in the past were done by hand
where the fruit pulp was removed, with the rind and pith then soaked in warm water to make
the rind more pliable, since the pith of the fruit absorbed the water.
After the fruit has absorbed the water and become more elastic, it was inverted which helped to
rupture the oil cells and a sponge placed next to the rind. It was then squeezed to release the
volatile oil, which was then collected directly into the sponge.
As soon as the sponge became saturated with oil, it was squeezed and the essential oil collected
in a vessel and then decanted. 3-Jul-17 30
Machine Abrasion Method Machine Abrasion is very much same as coldpressed expression method and is mainly used in
extraction of citrus essential oils.
In machine abrasion, a machine strips off the outer peel of the botanical material, which is
then removed by running water and left over is then fed into a centrifugal separator.
The centrifugal separation is done extremely fast. But, it should be noted that due to the
fact that the essential oil is combined with other cell content for some time, some alteration
could occur in the oil due to enzymatic action.
Maceration Method Maceration actually creates more of an "infused oil" rather than an "essential oil" and is most
often used for creating extracts and resins.
The botanical material is soaked in vegetable oil, water, or another solvent. If it's soaked in
vegetable oil, and then heated and strained, it can be used for massage and if soaked in
water or another solvent such as alcohol, will create a much thicker extract or resin.
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Enfleurage Method
Enfleurage is a very labour-intensive way of extraction and an expensive process.
Therefore it is rarely used today. In some cases where flowers, such as jasmine or
tuberose, have very low contents of essential oil and are extremely delicate,
heating them would destroy them before releasing the essential oils, enfleurage is
used to remove the essential oils.
Flower petals are placed on solid sheets of warm fat, which will absorb the
essential oil from the flowers. When all the fragrance is transferred from the
flowers to the fat they are removed and replaced with fresh ones. This process is
repeated several times until the fat becomes saturated with the essential oil.
A solvent, usually alcohol, is then added to the saturated fat which separates the
essential oil from the fat. The remaining fat is then used to make soaps.
Enfleurage has the advantage that even the most delicate components of the
flower oils are preserved.
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Gulsen Rose Oil Factory, Senir Kasabasi, Isparta, Turkey
This is steam distillation system of Gulsen Rose Oil Factory.
Pale yellow portion is rose essential oil obtained by steam distillation.
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Distribution and localization
Distribution
Essential oils (volatile oils) occur in higher plants in all types of vegetable organs
(flowers, leaves, barks, wood, roots, rhizomes, fruits and seeds). All organs of a given
species may contain volatile oils but of variable composition.
Quantitatively, the levels of volatile oils are low with some exeptions like the flower bud
of clove.
Localization
Volatile oils are generally present in specialized histological structures often located on
or near the surface of the plant.
.
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Function
• Attracting (help polination) or repelling insects
• Protection from heat or cold
• As antibacterial agents
• Uses
• Pharmacy, aromatherapy
• Perfumery
• Food technology
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Physical properties
Possess characteristic odors
Liquids and volatile at ambient temp.
Soluble in common organic solvents. Sparingly soluble in water,
however sufficient to produce aromatic water.
Specific gravity (0.8-1.17), mostly lighter than water (clove and
cinnamon are heavier).
Have high refractive index and most of them rotate the plane of
polarized light.
Essential oil and volatile oils have low molecular weight
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Chemical composition
Terpenoids
Volatile oils terpenes of molecular weight which is not too high (mono and
sesquiterpenes). The molecular weight not more than 200 amu.
Monoterpenes
They may be acyclic, monocyclic or bicyclic and are of various classes:
Hydrocarbons
Alcohols
Aldehydes
Ketones
Esters
Ethers
Peroxides
Phenols 3-Jul-17 37
Sesquitertpenes
They are also of various classes:
Hydrocarbons
Alcohols
Aldehydes
Ketones
Esters
Aromatic compounds:
They are phenylpropanoids less common than terpenes.
Miscellaneous compounds: low molecular weight compounds that
are extracted during steam distillation like: hydrocarbons, acids, alcohols,
aldehydes, acyclic esters, N and S containing compounds.
Chemical composition
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Quality control of volatile oils and drugs containing
them
For drugs containing volatile oils: The quantitation is carried out with steam distillation
after removal of residual water. The oil is visualized with lipophilic dye.
Quality control of essential oils:
1. Evaluation of miscibility with ethanol
2. Physical measurement
3. Determination of various indexes
4. Analysis by chromatographic techniques
5. GC and TLC for quality control
6. Detection by UV and variable spraying reagents
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Pharmacological properties of essential oils
Antiseptic activity: against several bacteria, fungi and yeast. The required doses
are determined by in vitro experiments. Some are used as preservatives.
Spasmolytic and sedative properties: decrease gastrointestinal spasms,
stimulate gastric secretions and used as digestives or stomachic.They also improve
insomnia and nervousness.
Irritating properties: e.g turpentine oil causes increase in capillary blood flow,
sensation of heat and anesthetic activity. It is used externally to relieve sprains,
strains, joint and muscle spasms.
Eucaluptus oil, internally, stimulates mucous cells and increases motility of ciliated
epithelium in bronchi. Other oils may increase renal secretion
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Toxicity of essential oils
In high doses, thujone containing oils cause neurotoxicity. Camphor and
menthol are also toxic in high doses.
Uses of drugs containing volatile oils
1. In pharmacy: Drugs are used crude or in formulations. They are used for
aromatization of pharmaceutical preparations and to prepare eseential oils.
2. Perfumery and cosmetic industry.
3. Food technology
Storage
Due to their physical and chemical instability, essential oils are stored in
aluminum, stainless steel or brown glass containers, completely filled, tightly
closed, at low temperature and under inert nitrogen. Antioxidants may be added.
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Volatile oils containing drugs
Drug name : Lavendulae Flos Plant source : Lavendula angustifolia
Other name : Lavander
Family : Lamiaceae
Constituents: • Volatile oil composed mainly of Linalool and Linalyl acetate.
• Hydroxycoumarins
• Tannins
• Caffeic acid derivatives
Effects: It has cholegogic antimicrobial and neurodepressive effects.
Indications and usage:
1. Loss of appetite
2. Nervousness and insomnia
3. Circulatory disorders
4. Dyspeptic complains
Precautions and adverse reactions: No health hazards with therapeutic doses. The
oil may have a weak potential for sensitization. 3-Jul-17 42
Drug name : Melissae Folium
Plant source : Melissa officinalis
Other name : Melissa, Lemon, Folia citronelle
Family : Lamiaceae
Constituents:
• Volatile oil composed mainly of geraniol and neral.
• Iridoide
• Flavonoids
Effects: It has antispasmodic, febrifuge and sedative effects.
Indications and usage:
1. Digestive disorders
2. Agitation and insomnia
3. Treatment of febrile hemorrhoids, varicose veins and impure skin
4. Chills and constipation
Precautions and adverse reactions: No health hazards with therapeutic doses. 3-Jul-17 43
Drug name : Salviae Folium
Plant source : Salvia officinalis
Other name : Garden or Broad-leafed sage, Sage
Family : Lamiaceae
Constituents: 1. Volatile oil composed mainly of :
α-thujone and β-thujone,1, 8 cineole,Camphor, Broneol,
camphene, linalool, α- and β- pinene, α- and β- caryophyllene.
2. Caffeic acid derivatives
3. Diterpenes, triterpenes
4. Flavonoids
Effects: Antibacterial, fungistatic, virostatic, astringent, secretolytic, antiperispirant,
antihypertensive, spasmolytic, acts on CNS.
Indications and usage:
1. Loss of appetite
2. Inflammation of mouth and pharynx
3. Excessive perispiration
Precautions and adverse reactions: No health hazards with therapeutic doses. Sage
preparations should not be taken during pregnancy.
Contraindications: Sage preparations should not be taken during pregnancy.
Overdosage: a sence of heat, tachycardia, vertigo and convulsions may occur following
extended intake of alcohol extract of the drug or through overdosage. 3-Jul-17 44
Drug name : Thymi Herba Plant source : Thymus vulgaris
Other name : Thyme
Family : Lamiaceae
Constituents:
1. Volatile oil composed mainly of :
Thymol, P-cymene, Carvacrol, γterpinene,
Broneol and linalool
2. Caffeic acid derivatives
3. Triterpenes
4. Flavonoids
Effects: Bronchial antispasmodic, antibacterial, expectorant.
Indications and usage: Cough and bronchitis
Precautions and adverse reactions: No health hazards with therapeutic doses. The
oil may have a weak potential for sensitization.
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Drug name : Oleum Anisi Plant source : Pimpinella anisum
Other name : Anise
Family : Apiaceae
Constituents:
1. Volatile oil composed mainly of :
Trans-anethole, Estragole, Anisaldehyde,
2. Caffeic acid derivatives
3. Fatty acids
4. Flavonoids
5. Protein substances
Effects: The drug has expectorant, spasmolytic and antibacterial effects. The oil has
expectorant, spasmolytic and antibacterial, antiviral, insect repellent and estrogenic
effects.
Indications and usage:
1. Common cold
2. Cough and bronchitis
3. Fevers and colds
4. Inflammation of mouth and pharynx
5. Dyspeptic complains
6. Loss of appetite
Precautions and adverse reactions: No health hazards with therapeutic doses.
Sensitization has been observed very rarely.
Contraindications: It is contraindicated in patients allergic to anise and anethole. 3-Jul-17 46
Drug name : Foeniculi fructus Plant source : Foeniculum vulgare
Other name : Fennel
Family : Apiaceae
Constituents: 1. Volatile oil composed mainly of :
Trans-anethole, Estragole, Fenchone
2. Hydroxycoumarins
3. Pyranocoumarins
4. Flavonoids
5. Fatty oils
Effects: Antispasmodic, secretolytic action of respiratory tract, antimicrobial effects
Indications and usage:
-Cough and bronchitis
-Dyspeptic complains
Precautions and adverse reactions: No health hazards with therapeutic
doses. Allergic reactions have been observed very rarely.
Contraindications: Preparetions, excluding the drug itself and tea infusions are
not to be administered to small children or during pregnancy. 3-Jul-17 47
Drug name : Caryophylli Flos Plant source : Syzygium aromaticum, Caryophyllus aromaticus, Jambosa
caryophyllus, Eugenia caryophyllus
Other name : Caryophyllum, Clove
Family : Myrtaceae
Constituents: 1. Volatile oil composed mainly of :
Eugenol, Eugenyl acetate, β-Caryophyllene
2. Steroids
3. Tannins
4. Flavonoids
5. Triterpenes
Effects: Antiseptic, antibacterial, antifungal, antiviral, spsmolytic and local
anesthetic effects.
Indications and usage:
-Dental analgesic
-Inflammation of the mouth and pharynx
Precautions and adverse reactions: No health hazards with therapeutic doses.
Allergic reactions have been observed rarely. In concentrated form, oil may cause
irritation to mucosa. 3-Jul-17 48
Drug name : Menthae piperitae Folium Plant source : Mentha piperita
Other name : Peppermint
Family : Lamiaceae
Constituents:
1. Volatile oil composed mainly of :
Menthol, Menthyl acetate, Menthone, Isomenthone, Neomenthol, Menthofurane
2. Caffeic acid
3. Flavonoids
Effects: Antiseptic, antibacterial, antifungal, antiviral, spsmolytic and local anesthetic
effects.
Indications and usage:
Dental analgesic
Inflammation of the mouth and pharynx
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1. Peppermint oil: Obtained from Mentha piperita
2. Spearmint oil: Obtained by steam distillation of the aerial parts recently
harvested from Mentha spicata. The essential oil is obtained from Mentha
cardiaca also.
3. Cornmint oil: It is the partially dementholated form of Mentha arvensis by
freezing.
4. Pennyroyal oil: It is a non-official oil obtained from Mentha pulegium.
There are four different oils of different composition
obtained from different species of Mentha:
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Effects:
Peppermint leaves: spasmolytic effect on smooth muscles of digestive tract. It
also has antiviral, antimicrobial, diuretic, colagogic, carminative and mild sedative
effects.
Peppermint oil: spasmolytic effect on smooth muscles of digestive tract. It also
has antimibacterial, colagogic, carminative, insecticidal, secretolytic effects and
cooling effect on the skin.
Indications and usage:
Peppermint leaves:
1. Liver and gall bladder complains
2. Dyspeptic complains
Peppermint oil:
1. Common cold
2. Cough and bronchitis
3. Inflammation of mouth and pharynx
4. Liver and gall bladder complains
5. Tendency to infection 3-Jul-17 51
Contraindications:
Peppermint leaves: Contraindicated in cases of gallstones
Peppermint oil: internal administration is contraindicated in cases of occlusion of
the biliary ducts, gall bladder inflammation, severe liver damage and gallstones.
Precautions and adverse reactions:
Peppermint leaves: No health hazards with therapeutic doses. Colic may occurin
cases of gallstones carriers due to cholagocic effect.
Peppermint oil:
General: No health hazards with therapeutic doses. Gastric complains may occur
in susceptible persons. It should not be administered in cases of tendency to
gastrooesophogeal reflux. The oil has weak potential for sensitization due to
menthol contents.
Overdosage: No records of poisoning cases. 3-Jul-17 52
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