This presentation provides information on different types of volatile oils and their medicinal values. Volatile oils are also known as ethereal or essential oils, and evaporate at ordinary temperatures. They provide scents to plants and protect them from animals. There are various classifications of volatile oils including hydrocarbons, alcohols, aldehydes, ketones, phenols, and esters. Methods to obtain volatile oils include distillation, solvent extraction, and mechanical expression. Volatile oils have many medicinal uses such as for aromatherapy, as antiseptics, and to treat conditions like spasms. The presentation examines properties, chemical constituents, extraction methods, and applications of these important plant-derived oils
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Volatile oil
1. In The Name of ALLAH ,
The Most Beneficent and
Merciful
5. Contents
1.Volatile oils
2.Significance
3.Role in plants
4.Properties
5.Classification
6. Chemical constituents
7. Methods of obtaining
8. Volatile oil Vs. Fixed oil
9.Medicinal values
10. How it use
6. They evaporate when exposed to the air
at ordinary temperatures so they are
called volatile oils, ethereal oils or
essential oils.
They are called essential oil because
volatile oil represent the essences of
plants.
Volatile oils
7. Significance of volatile oil
As spices and condiments
Flavoring agents
As carminative
Manufacture of perfumes, soaps, cosmetics
etc.
8. Role of volatile oils in plants
Due to disagreeable taste and odor, they
protect the plants from grazing animals
In flowers, they attract the insects for
pollination.
9. Properties of volatile oils
• Characteristic odors
• High refractive index
• Optically active
• Immiscible with water
• Soluble in ethers, alcohol and
most organic solvents
11. 1.Hydrocarbon volatile oils
It has been observed that terpene
hydrocarbons usually occur in most of the
volatile oils obtained from natural sources. They
may be further classified into three categories,
namely:
(a) Unsaturated acyclic hydrocarbons,
(b) Aromatic hydrocarbons, and
(c) Alicyclic hydrocarbons.
Ex: Turpentine – pinene , carene , limonene
12. 2.Alcoholic volatile oils
A good number of alcohols occur abundantly in a
plethora of volatile oils, which may be judiciously
classified into the following heads, namely:
(a) Acyclic (aliphatic) alcohols,
(b) Monocyclic (aromatic) alcohols,
(c) Alicyclic (terpene and sesquiterpene) alcohols.
Ex: 1. Peppermint- Menthol
2. Cardamom- Borneol
3. Coriander- Coriandrol (Linalool)
4. Rose- Nerol
5. Sandalwood- Santola
13. 3.Aldehydic volatile oils
Aldehydes provide a soapy-waxy-lemony-
floral effect to the formula and are used to
classify a fragrance as "aldehydic".
Ex:
1. Cinnamon - Cinnamic aldehyde
2. Lemon peel - Citral
3. Orange peel - Citral
4. Citronella - Citronellal
5. Lemon grass - Citronellal
14. 4.Ketonic volatile oils
The ketones that invariably occur in volatile oils may
be classified
in the following two categories, namely:
(i) Aliphatic ketones, and
(ii) Aromatic Ketones.
Ex: Caraway- Carvone , Spearmint- Carvone ,
Vetiver- Vetivone , Fennel- Fenchone
15. 5.Phenolic volatile oils
The important drugs containing phenol volatile
oils are, namely: Clove oil, Myrcia oil (Bay oil),
Organum oil, Pinetar, Thyme etc. In fact, they
essentially owe their value in the pharmaceutical
domain almost exclusively by virtue of their
antiseptic and germicidal properties of
their phenolic constituents. A good many of
them are employed as popular flavouring
agents.
The phenols are classified into the following
categories, namely:
(i) Monohydric phenols and
(ii) Dihydric phenols.
Ex: Clove – Eugenol , Ajwon – Thymol
16. 6.Phenolic ether volatile oils
Phenolic ether occurs in volatile oils such as
anethol from anise and fennel, Safrole from
sassafras etc.
Ex: Anise , Fennel – Anethol , Nutmeg -
Myristicin
17. 7. Oxide volatile oils
It contains colourless or pale yellow oil which is
about 6%, having an aromatic odour, spicy
cooling taste, containing 70% of cineole
C10H18O, d- pinene and other terpenes,
resins, a bitter principle and tannin, eucalyptic
acid, Ca-oxalate etc.
Ex: Eucalyptus – Cinole (eucalyptol)
18. 8. Ester volatile oils
A wide variety of ester occurs in volatile oils. The
most common are the acetates of terpineol
borneol and geranial. Other examples of esters in
volatile oils are allyl isothiocyanate in mustard oil
and methyl salicylate in wintergreen oil.
Ex: Gaultheria(Wintergreen) – Methyl salicylate
20. a. Terpenes
Natural products whose structures may be divided into
isoprene units.
These units arise from acetate via mevalonic acid.
These are branched chain 5 carbon units containing 2
unsaturated bonds.
Made up of head to tail condensation of isoprene units.
If
i. 1 isoprene unit present= hemiterpene (C5H8)
ii. 2 isoprene unit present= monoterpenes (C10H16)
iii. 3 isoprene unit present= sesquiterpene (C15H24)
iv. 4 isoprene unit present= diterpene (C20H32)
v. 6 isoprene unit present= triterpene (C25H48)
Majority of the terpenes are monoterpenes in volatile
oils.
21. b. Phenylpropanoids
They are formed via shikimic acid
phenylpropanoid route.
These compounds contain phenyl ring with an
attached propane side chain.
Many of the Phenylpropanoids found in
volatile oils are phenols or phenol ethers.
22. Methods of obtaining volatile oils
The method of obtaining volatile oils depends
upon the condition of plant materials.
Oil production can be divided into three major
ways
i. Distillation
ii. Solvent extraction
iii. Mechanical expression
Specialized methods are:
i. Ecuelle Method
ii. Enfleurage
iii. Destructive distillation
23. Difference between volatile oil
and fixed oil
Evaporate from source when
exposed to room temperature.
Color less liquid, or crystalline
or amorphous solid.
Do not form permanent stains
on paper.
Do not rancidify.
Having distinct odor.
Can be distilled from natural
sources.
On exposure to air and light,
they oxidize and resins are
formed.
Remain fixed on the source
when exposed to room
temperature.
Some of these oils possess
colors i.e. castor oil, shark liver
oil.
Form permanent stain on paper.
Rancidified on exposure to air.
May or may not possess odor.
Can not be distilled.
On exposure to air or light, it
becomes rancid developing a
disagreeable odor.
24. Can not be saponified.
Mixture of mono
sesquiterpenes.
Immiscible in water but
soluble in alcohol.
Can be saponified.
They are esters of glycerol
with long fatty acid chain.
Soluble in water, sparingly
soluble in cold alcohol.
Difference between volatile oil
and fixed oil
28. USES OF VOLATILE OILS
Therapeutically (Oil of
Eucalyptus)
Flavouring (Oil of Lemon)
Perfumery (Oil of Rose)
Starting materials to
synthesize other compounds
(Oil of Turpentine)
Anti-septic – due to high
phenols (Oil of Thyme). Also
as a preservative (oils interfere
with bacterial respiration)
Anti-spasmodic (Ginger,
Lemon balm, Rosemary,
Peppermint, Chamomile,
Fennel, Caraway)
Aromatherapy