This document provides information about volatile oils. It begins by defining volatile oils as odorous and volatile products produced by plants. Volatile oils are composed of terpenes and their derivatives and are found in secretory tissues of plants. They can be extracted through various methods including water, steam, solvent extraction and expression. Common sources of volatile oils include leaves, flowers, bark and seeds. Tests can identify volatile oils in plants using reagents like Sudan III. Volatile oils have many pharmaceutical applications as fragrances, flavors and medicines due to their antimicrobial and other therapeutic properties.
2. Definition
• Volatile oils are the odorous and volatile products of various plant.
As they have a tendency to undergo evaporation on being exposed
to the air even at an ambient temperature, they are invariably
termed as volatile oils, essential oil or ethereal oils.
• Chemically, they are composed of hydrocarbons of the general
formula (C5H8) and their oxygenated, hydrogenated and
dehydrogenated derivatives.
• All the volatile oils are of vegetable origin.
• These volatile oils are usually formed by two modes namely; first,
by hydrolysis of some glycosides; and secondly, by the
protoplasm directly.
3. • In most instances, the volatile oil preexists in the plant
and is usually contained in some special secretory
tissuesas glandular hairs, parenchyma cells, vittae or oil
tubes, in mesophyll (Eucalyptus leaves), sub-epidermal
tissues of Lemon and Orange. in lysigenous or
schizogenous passages, in all tissues (Conifers), In
petals (Orange. Rose), in bark and leaves (Cinnamon),
in pericarp (Umbelliferous fruits), in glandular hairs of
the stems and leaves (Mint), and in rind (Orange).
• These represent essence of active constituents of the plant
and hence also known as essential oils.
Why they are called Essential Oil?
4.
5. • They are evaporated at ordinary temperature
• Volatile oils are colourless liquids, but when exposed
to air and direct sunlight these become darker due to
oxidation.
To prevent this darkening, they should he stored in a cool,
dry place in tightly stoppered preferably amber glass
containers.
• They possess characteristic odors
• Characterized by high refractive indices
• Most of them are optically active [specific rotation
is often a valuable diagnostic properties]
Physical Properties
6. • Volatile oils are immiscible with water, but they are
sufficiently soluble to impart their odor to water
• Soluble in ether, alcohol, chloroform and most
organic solvents.
• Volatile oils neither leave permanent grease spot on
filter paper nor saponified with alkalis
• They are present in entire plants (Mint, Conifers) or
any part of the plant (Rose)
7. No Volatile oil Fixed oil
1.
Volatile oil can evaporate when placed
under room temperature
Fixed oils do not evaporate at room temperature
2.
Mixtures of cleoptenes & stearoptenes are
termed as volatile oils
Esters of higher fatty acids & glycerin are called
as fixed oils.
3
Their primary source is leaves, roots, in
petals and bark.
Their major source is seeds of the plant and
animal.
4. Possess high refractive index Possess low refractive index
5. These are optically active. These are optically inactive.
6.
There is no spot (no permanent stain) left
after evaporation
Some type of spot (permanent stain) left after
evaporation
7. They are unable to undergo saponification Fixed oils can be easily saponified.
8.
Essential oils do not go rancid, rather they
oxidize and lose their therapeutic benefit
Fixed oils can go rancid (stale) over time
9. Colorless Some possess colors (yellowish)
10. Have characteristic odor May or may not possess odor
11. Immiscible in water Soluble in water
12. Obtained by distillation Obtained by extraction
13. Low boiling point High boiling point
14. Soybean oil, castor oil Cinnamon oil, peppermint oil.
8. Chemical composition
• Many volatile oils consist largely of Terpenes. The term
‘terpene’ was given to the compounds isolated from
terpentine, a volatile liquid isolated from pine trees.
• But there is a tendency to use more general term ‘terpenoids’,
which includes hydrocarbons and their oxygenated
derivatives.
• Terpenoids are volatile substances which give plants and
flowers their fragrance
• ‘Terpenoids are the hydrocarbons of plant origin of the
general formula (C5H8)n as well as their oxygenated,
hydrogenated, and dehydrogenated derivatives.’
9. • Isoprene Rule
Isoprene rule states that the terpenoid
molecules are constructed from two or
more isoprene unit.
• Special Isoprene Rule
It states that the terpenoid molecules
are constructed of two or more
isoprene units joined in a ‘head to tail’
fashion.
• But this rule can only be used as
guiding principle and not as a fixed
rule
10. • Most natural terpenoid hydrocarbons have the general
formula (C5H8) n. They can be classified on the basis
of number of carbon atoms present in the structure.
1. Monoterpenoids, 2 isoprene units (C5H8) 2
2. Sesquiterpenoids, 3 isoprene units (C5H8) 3
3. Diterpenoids, 4 isoprene units (C5H8)4
4. Triterpenoids, 6 isoprene units (C5H8) 6
5. Tetraterpenoids, 8 isoprene units (C5H8) 8
6. Polyterpenoid with a larger number (>8) of
isoprene units (C5H8) >8
Classification of Terpinoids
12. • Each class can be further subdivided into subclasses
according to the number of rings present in the
structure.
1. Acyclic Terpenoids:
They contain open structure.
2. Monocyclic Terpenoids:
They contain one ring in the structure.
3. Bicyclic Terpenoids:
They contain two rings in the structure.
4. Tricyclic Terpenoids:
They contain three rings in the structure.
5. Tetracyclic Terpenoids:
They contain four rings in the structure.
17. Natural drugs containing volatile oils can be
tested by following chemical tests:
1. Thin section of drug on treatment with
alcoholic solution of Sudan III develops red
color in the presence of volatile oils.
2. Thin section of drug is treated with tincture
of alkana, which produces red color that
indicates the presence of volatile oils in natural
drugs.
CHEMICAL TESTS
18. Volatile oils are used as flavouring agent, perfuming agent in
pharmaceutical formulations, foods, beverages, and in
cosmetic industries. These are also used as important medicinal
agent for therapeutic purposes like:
1. Carminative (e.g. Umbilliferous fruits)
2. Anti-helminitic (e.g. Chenopodium oil)
3. Diuretics (e.g. Juniper)
4. Antiseptic (e.g. Eucalyptus)
5. Counter irritant (e.g. Oil of winter green)
6. Local anesthetic (e.g. Clove)
7. Sedative (e.g. Jatamansi)
8. Insect repellent (e.g. Citronella)
10. Source of vitamin A (e.g. Lemongrass)
PHARMACEUTICAL APPLICATIONS
Counter irritant:
An externally applied
substance that causes
irritation or mild
inflammation of the
skin for the purpose of
relieving pain in
muscles, joints and
viscera distal to the site
of application
19. PREPARATION OF VOLATILE OILS
Enzymatic
Hydrolysis
Distillation
Method
Expression/
Ecuelle Method
Extraction
Method
Destructive
Distillation
Water
Water +
Steam
Steam
Vacuum
CO2
Extraction
Enfleurage
20. • Volatile oils are usually obtained by distillation of the
plant part containing the oil
• The method depends on the condition of the plant
material.
DISTLLATION PROCESS
Steam Distillation
Water & Steam
Distillation
Water Distillation
21. Sample:
Which are not destroyed or injured by boiling up to 100oC
Dried plant sample
WATER DISTILLATION
22. A small piece of dried plant material is introduced into
the distilling chamber
Water is added
Heated up to 100oC
Vapor of volatile oil and water goes into the condenser
After being condensed, volatile oil is separated by
Florentine Flask
PROCEDURE
Florentine Flasks of the type FLW or FHW depending on whether the resulting oil is
lighter than water or heavier than water.
23.
24. • The distillation flask is heated initially to start the
process of steam distillation. Once the distillation
commences the heat of the steam entering the flask
not only maintains the high-temperature required but
also in removing the volatile components to the water
condenser for ultimate collection in the respective
Florentine Flask.
• Excess heat must be avoided
• Process must be air tight
• Full amount of the water must be vaporized.
CAUTIONS
25. • Sample:
▫ Fresh material
▫ Materials which may be injured by direct boiling
▫ Materials which may be hydrolyzed
▫ Example: Peppermint Oil
STEAM DISTILLATION
NO
MECERATION
26.
27.
28. The plant sample taken into a metal distillation chamber over the
perforated tray
The steam is forced to the fresh sample from below
Then the vapor of the volatile oil and steam is passed through the
condenser
The volatile oil is finally separated through Florentine flask
PROCEDURE
29. • Samples:
▫ Both fresh and dried samples
▫ Materials which may be injured by direct boiling
▫ Example: Clove Oil, Cinnamon Oil
WATER AND STEAM DISTILLATION
MECERATION
BEFORE STEAM
DISTILLATION
30. The sample is put into a flask with water so that the
sample is well mecerated
Steam is generated else where to prevent the impairing
of drug due to direct heat is passed through the
mecerated mixture
The vapor of volatile oil and liquid pass through the
condenser
Two layer is formed – one is oleaginous layer and
another is aqueous layer
Finally the volatile oil is separated through Florentine
flask.
PROCEDURE
31. • Performed under reduced pressure
• This technique separates compounds based on
differences in boiling points
difficult to achieve or will cause the compound to
decompose
pressure boiling point of compounds
• Fresh plant parts
• Heat sensitive materials
• Prevent the oxidation of volatile oils.
VACUUM DISTILLATION
32. Sample with water is introduced into the distilling
chamber
Hg-pump is added to remove gas and create the vacuum
Heat is applied and the steam of oil and water are passed
through the condenser
Finally the volatile oil is separated through Florentine
flask
PROCEDURE
34. • There are some glycosides which contain volatile oil.
To separate these types of volatile oils, we need
Enzymatic Hydrolysis process.
ENZYMATIC HYDROLYSIS
Gylcosides
Glycone Aglycone (volatile oil)
37. • Often referred to as “cold pressing.”
• The term expression refers to any physical process in which
the essential oil glands in the peel are crushed or broken to
release the oil.
• Sample: citrus essential oils, such as tangerine, lemon,
bergamot, sweet orange, and lime,
• This method involves the rind portion of the fruit, or the
outermost waxy layer of the fruit’s peel
• This method is most useful with plant materials that lose
their fragrance and beneficial properties when exposed to
the temperatures required for steam distillation
• Oil is forced from the material under high mechanical
pressure and generally produces a good quality oil
EXPRESSION
38. SPONGE EXTRACTION PROCESS
The fruit pulp was removed.
The remaining rind and pith were soaked in warm water to make
the rind more pliable, because the pith of the fruit absorbed the
water.
The operator takes a sponge in one hand and with the other presses
the softener peel against the sponge, so that the oil glands burst open
and the sponge absorbs the exuded oil
As the sponge became saturated with oil, it was squeezed and the
essential oil collected in a vessel and then decanted.
39. • The whole of the above process is carried out in cool,
darkened rooms to minimize the harmful effects of
heat and light on the oil
41. • In this process, the rinds are ruptured
mechanically using numerous pointed
projections with a rotary movement and
the oil is collected.
• Ecuelle a piquer is a specially designed
apparatus is nothing but a large bowl
meant for pricking the outer surface of
citrus fruits.
• It is more or less a large funnel made of
copper having its inner layer tinned
properly. The inner layer has numerous
pointed metal needles just long enough to
penetrate the epidermis.
• The lower stem of the apparatus serve two
purposes; first, as a receiver for the oil;
and secondly, as a handle.
ECUELLE EXTRACTION PROCESS
42. The fruit is placed in a device with spikes and rotated repeatedly on
the side puncturing the oil cells in the skin of the fruit.
This causes the oil cells to rupture and the essential oil, and pigment,
to run down to the collection area in the center.
The liquid is separated and the oil is removed from the water-based
parts of the mixture and decanted.
PROCESS
44. • The plant material containing
the volatile oil is usually
extracted with a low boiling
volatile solvent, such as n-
hexane, benzene, petroleum
ether etc., either by adopting
the method of hot continuous
extraction (Soxhlet
extraction) or by percolation
• Process depends on the
nature of volatile oil
Extraction Method
45. Carbondioxide Extraction
CO2 gas at low temperature and high pressure
Turns into liquid
Rupture the plant material
This fluid enters into the cell
Volatile oil extracted into the media (liq CO2)
Volatile oil is collected by fractional distillation
46. Enfleurage method
Glass plates are covered with a thin layer of fixed oil or fat those are
securedly placed in a covered wooden frame
Each glass plate is liberally sprinkled with fresh flower petals to
cover its top surface only.
loaded plates are allowed to remain for 24hours
flowers are then removed and recharged with fresh lots
This very process is repeated religiously for several weeks till the
fatty layers appear to be fully saturated with the essential oils of the
flowers
47. The flowers are subsequently removed
the fat is separated carefully and stirred with absolute alcohol
alcohol will dissolve the volatile oil portion thereby leaving the fat
undissolved in alcohol
The alcoholic extract is reasonably chilled and filtered to get rid off
any traces of residual fat.
Three successive extraction procedures are repeated so as to affect
the complete recovery of volatile oil
the resulting solution is employed as such in the perfume industry
and is commonly termed as the ‘Tripple Extract’
48. The volatile oil may be recovered from the ‘Triple Extract’ by
anyone of the following methods, namely:
first, fractional distillation under vacuum at 0oC;
secondly, evaporation under vacuum at 0o
C;
thirdly, the alcoholic extract is diluted with water and
saturated with NaCl, when the oil will seaparate with the
retention of fresh natural ordour
49. Destructive distillation
• Destructive distillation is the chemical process of the
decomposition of unprocessed material by heating it to
a high temperature
• Empyreumatic oils: being or having an odor of
burnt organic matter as a result of decomposition at
high temperatures
• Destructive distillation is a means of obtaining
Empyreumatic oils
50. The wood or resin of members of the Pinaceae or Cupressaceae is
heated without access of air,
decomposition takes place, and a number of volatile compounds are
driven off.
The resultant mass is charcoal.
The condensed volatile matter usually separates into 2 layers:
1. an aqueous layer containing wood naphtha (methyl alcohol)
and pyroligneous acid crude acetic),
2. a tarry liquid in the form of pine tar, juniper tar, or other
tars, depending on the wood introduced.
53. • Obtained from the dried flower buds of Syzygium
aromaticum (Eugenia caryophyllus)
• Family : Myrtaceae
• Obtained by Steam distillation process.
Clove oil
• Physical properties:
Colorless or pale yellow liquid
Spicy order and pungent taste
It becomes darker and thicker on exposure to air and by
aging.
56. 1. Flavoring agent
2. Commercially producing vanillin
3. Antioxidant
4. In throat infection
5. Remove fatigue
6. Toothache remedy
7. Antiseptic
8. Counterirritant
9. Carminative
10. Mouthwash
11. Dental preperation (eugenol)
12. Antimicrobial (diarrhea, intestinal worms, and other
digestive ailments)
13. Eugenol is also used as local anaesthetic in small doses.
14. The oil stimulates peristalsis; it is a strong germicide, also
a stimulating expectorant in bronchial problems.
15. Antiemetic
Uses
85% volatile oil
Phenolic type
Eugenol
57. Cinnamon oil
• Obtained from the leaves and barks of Cinnamonum
cassia
• Family : Lauraceae
• Obtained by Steam distillation process.
• Also known as cassia oil
• Physical properties:
Yellowish or brownish color
Sweet in taste
Spicy delicate fragrance.
60. Uses
1. Mild antiseptic
2. Carminative
3. Astringent
4. Flavoring agent
5. Anti-diarrhoeal
6. Increase the action of insulin
61. • Source: Peppermint consists of dried leaves and
flowering tops of Mentha pipenta
• Family : Labiatae.
• Distilled with steam from the fresh overground parts
Peppermint oil
• Physical properties:
Colourless, pale yellow or greenish yellow liquid
Strong agreeable odour and a powerful aromatic
taste, followed by a cooling sensation when air is
drawn into the mouth
64. Uses
1. Flavoring agent
2. Carminative
3. Stimulant
4. Counterirritant
5. Reducing gastralgia, nausea, flatulence and vomiting
6. Mild antiseptic and local anaesthetic properties
7. Externally in rheumatism, neuralgia, headache and
toothache.
8. Peppermint oil is used for flavoring in pharmaceuticals.
dental preparation, mouth washes, cough, drops, soaps,
chewing gums, candles, confectionery and alcoholic liquers
chewing gum 55%; toothpaste, mouthwash, and
pharmaceuticals 34%; confectionary products, 10%; and
other products 1%.
65. • Sources: dried, scythe-shaped the fresh leaves of various
species of Eucalyptus such as E. globulus Labill. E.
polybractea. E. smithii, E. vimino.lis, and E.
australlana.
• Family : Myrtaceae
• Obtained by Steam distillation.
Physical properties:
• The oil is a colorless or pale yellow liquid that has
a characteristic, aromatic, camphoraceous odor and a
pungent, spicy, cooling taste
Eucalyptus oil
68. Uses
1. Stimulant,
2. Antiseptic,
3. Flavoring agent,
4. Aroma therapy,
5. Deodorant,
6. Expectorant,
7. Antimicrobial,
8. Febrifuge,
9. Diuretic,
10. Antispasmodic.
11. Used in the treatment of lung diseases, sore throat, cold
12. A vapour bath for asthma and various respiratory ailments and in bronchitis
13. Burns and as mosquito repellant.
14. Eucalyptus Increases the flow of saliva, gastric and intestinal juices and thus
increases appetite and digestion.
15. It increases the rate of heart beats, lowers the arterial tension and quickens
respiration.
16. Toxic doses it is a narcotic poison. It paralyses the respiratory center in the
medulla
It is taken internally in
the form of mixtures,
inhalations, lozenges
and
pastilles and applied
externally as ointments
and liniments.
69. • The star-anise oil is obtained from Illicium verum
• Family: Illiciaceae
• Chemical constituents:
Anise seed oil
Anise seed
oil
1. Anethole (87–94%)
2. Estragole (0.5–5.0%)
3. Anisaldehyde (0.1–0.5%)
4. Foeniculin (0.1–3.0%);
5. Anisic acid,
6. Anise ketone,
7. Β-caryophylline,
8. Linalool;
9. Polymers of anethole,
dianethole, and
photoanethole.
10. Coumarins
11. Flavonoid glycosides (rutin,
isovitexin and quercetin),
12. Phenylpropanoids.
70.
71. Uses
1. Flavouring agents
2. Carminatives
3. Expectorant
4. Used in the treatment of bronchitis, asthma,
5. Antimicrobial
6. Antispasmodic.
7. Enhance the memory,
8. Increases lactation,
9. Relieves menopausal discomforts,
10. Whooping cough,
11. Externally in scabies,
12. Overcomes nausea, and as a digestive.
72. • Nutmeg is the kernel of the dried ripe seed of Myristica
fragrans
• Family : Myristicaceae.
• Obtained from distilled with steam
• The oil is a colorless or pale yellow liquid that has the
characteristic odor and taste of nutmeg.
Nutmeg oil
75. 1. Flavoring agent
2. Carminative,
3. Astringent,
4. Aphrodisiac,
5. Stomachic
6. Nausea and vomiting
7. Antibacterial activity.
8. Ingestion of large quantities causes drowsiness,
stupor and death.
9. It has narcotic action and peripherally it irritates
and produces anesthetics action, since it irritates
intestine and uterus it can cause abortion.
Uses
76. • Biological Source : Fennel oil is obtained from the
dried, ripe fruits of F'oeniculum vulgare.
• Family : Umbelliferae
• Chemical constituents:
Fennel seed oil
1. Anethole (55–75%)
2. Fenchone (12–25%)
3. Anisaldehyde (maximum
2.0%)
4. Anisic acid,
5. Estragole (methyl
chavicol) (maximum
5.0%).
6. Dipentene,
7. Limonene
8. Phelandrene
9. Β-pinene,
Fennel
77.
78. 1. Stomachic
2. Aromatic stimulant
3. Diuretic
4. Carminative
5. Diaphoretic
6. Digestive
7. Flavouring agent
8. Anethole may have estrogen-like activity and inhibit spasms
in smooth muscles.
9. Fennel can increase production of bile,
10. Used in the treatment of infant colic,
11. Reduce pain in dysmenorrhea,
12. Can increase lactation,
13. Act as antipyretic,
14. Emmenagogue
15. Antimicrobial and anti-inflammatory
16. Anethole is used in mouth and dental preparations.
17. Fennel is useful in diseases of the chest, spleen and kidney.
Uses
79. 1. linalool (65-70%)
2. pinene.
3. geranlol,
4. boineol.
5. p-cymene,
6. dipentene,
7. phellandrene,
8. terpinolene,
9. hydrocarbons such 3-terpinne,
10.geraniol,
11.n-decylic aldehyde
12.camphor,
13.malic acid,
14.esters of acetic and decylic acids,
tannins, and mucilage are also present.
15.Other constituents isolated from the
fruits include flavonoids, coumarins,
isocoumarins, phthalides and phenolic
acids.
Coriander
oil
# Obtained from the
dried, nearly ripe fruit of
Coriandrum sativum
Family : Umbelliferae
81. Uses
1. Flavouring agent
2. Carminative.
3. Aromatic stimulant,
4. Antispasmodic,
5. Diaphoretic
6. Appetizer,
7. Diuretic,
8. Aphrodisiac,
9. Stomachic.
10. Antibiliou
11. Coriander oil can be applied externally for rheumatism
and painful joints.
12. The infusion of decoction of dried fruit of cardamom is
useful for the treatment of sore-throat, indigestion,
vomiting, flatulence, and other intestinal disorders.