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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