detail and complete study on the topic of volatile oil extraction . the ppt is made by the student- teacher coordination for the well being for all

1. Volatile oils
Ravish Yadav

2. VOLATILE OILS
 Volatile or essential oils are volatile in steam.
 They differ entirely in both chemical and physical
properties from fixed oils.
 They are secreted in:
oil cells e.g. Cinnamon
Oil glands e.g. Clove
Secretion ducts (vittae) e.g. Anise
Glandular hairs e. g. Chamomile
 They are frequently associated with other
substances such as gums ( oleo gum) and resins
(oleoresin) or both (oleo gum resin)

3. Production and Uses of Volatile Oils
There are about 100 commercially valuable volatile
oils directly derived from plants.
 Volatile oils are used:
1- For their therapeutic action: antiseptic e.g.
thyme and clove, carminative e.g. Mentha
2- Flavoring (e.g. oil of lemon),
3- in perfumery (e.g. oil of rose)
4- starting materials for the synthesis of other
compounds (e.g. oil of turpentine).

4.  For therapeutic purposes they are administered
as inhalations (e.g. eucalyptus oil), orally (e.g.
peppermint oil), as gargles and mouthwashes
(e.g. thymol) and transdermally (many essential
oils including those of lavender, rosemary and
bergamot are employed in the practice of
aromatherapy).
 Those oils with a high phenol content, e.g. clove
and thyme have antiseptic properties, whereas
others are used as carminatives.
 Oils showing antispasmodic activity, and much
used in popular medicine. e.g. fennel, mentha,
caraway, chamomile, anise, rosemary.

5. Composition of Volatile Oils
 Volatile oils are generally mixtures of
hydrocarbons and oxygenated
compounds derived from these
hydrocarbons.
 The odour and taste of volatile oils is
mainly determined by these oxygenated
constituents, which are to some extent
soluble in water but more soluble in
alcohol.

6.  Practically all volatile oils consist of chemical
mixtures that are often quite complex; they vary
widely in chemical composition.
 Almost any type of organic compound may be
found in volatile oils (hydrocarbons, alcohols,
ketones, aldehydes, ethers, oxides, esters, and
others).
 It is not uncommon for a volatile oil to contain
over 200 components, and often the trace
constituents are essential to the odor and flavor.
The absence of even one component may
change the aroma.

7. Determination of the structure of terpenes
Chemical constituents of volatile oils may be divided
into 2 broad classes based on their biosynthetic origin:
2- Terpene derivatives formed via acetate mevalonic pathway.
1- Aromatic compounds formed via shikimic acid. These contain C6
phenyl ring with an attached C3 propane side chain.

8. Classification of constituents of volatile oil:
1- Hydrocarbons
- Unsaturated acyclic hydrocarbon eg. myrcene
-Aromatic hydrocarbon eg. p-cymene

9. Monocyclic eg. limonene which occur in citrus fruit,
mint, thyme.
Bicyclic eg. α-pinene found in lemon, anise, eucalyptus,
thyme, fennel.
* Limonene and α-pinene are biosynthesised from terpene pathway.
- Sesquiterpene eg. Chamazulene

10. 2- Alcohols:
-Eg. Linalool, Citronellol
Aromatic alcohol eg. benzyl alcohol

11. 3- Ketones:
Camphor occurs in rosemary, lavender.
Uses: topical antipruritic, rubefacient, anti-infective.
LavenderRosemary

12. 4- Esters:
-Methyl salicylate
* Methyl salicylate also this oil is known as wintergreen oil.
Uses: methyl salicylate has local irritant, antiseptic,
antirheumatic properties.

13. 5- Phenols:
Eugenol, Thymol are the most important phenol present in volatile
oil.
Eugenol occur in clove oil and in cinnamon bark.
Uses: as dental analgesic, antiseptic,
counter irritant, carminative.
Eugenia caryophyllus
CH3
H3C CH3
OH
Thymol

14. Thymol occurs in Thyme oil.
Uses: antifungal, antibacterial agent.
Phenolic ether volatile oil
Safrole from myristica or nutmeg
uses: flavoring agent and carminative.
CH3
H3C CH3
OH
Thymol

15. Physical Properties
Although volatile oils differ greatly in their chemical
constitution, they have a number of physical
properties in common:
1. They possess characteristic odors.
2. They are characterized by high refractive indices.
3. Most of them are optically active.
4. Their density is generally lower than that of water (the
essential oils of sassafras, clove, or cinnamon are the
exceptions).
5. As a rule, volatile oils are immiscible with water, but
they are sufficiently soluble to impart their odor to
water. The aromatic waters are dependent on this
slight solubility.

16. Preparation of volatile oils
The principal methods used in the preparation
of volatile oils from plants depend on:
1. Distillation in water or steam.
2. Scarification and expression.
3. Extraction with solvents.
4. Enzymatic hydrolysis (for glycosidic volatile oils
e.g. mustard oil).
5. Enfleurage (extraction of oils used in perfumery).

17. I- Distillation Methods:
• There are two types of traps:
One for oils lighter than water and the other for oils heavier
than water.
• These two types differ only in the mechanism of the return
of the aqueous layer to the distillation flask, keeping the
volatile oil layer in its position.
Types of distillation used:
1-Water and steam distillation
2-Direct steam distillation

18. Clevenger apparatus for
volatile oil preparation

19. Points for consideration in the distillation method:
1- It is often necessary to subject the plant material to special
treatment prior to steam distillation e.g. cut or crushed.
Crushing or cutting facilitates penetration of water into
oil- containing structures in the plant.
eg. Oil cells, glandular hairs.
2- For removal of water or moisture which might be present in
the prepared volatile oil, anhydrous sodium sulfate is usually
used.

20. Because of the volatile nature of the
constituents of essential oils, the
composition of the product
obtained by steam distillation is
often different from the
constituents originally found in the
secretory organs of the plant.
During steam distillation, the water,
acidity and tempereature may
induce hydrolysis of the esters.
Rearrangements, isomerizations,
racemiazations, oxidations and
other reactions also occur, all of
which change the composition.

21. Some volatile oil can´t be distilled without
decomposition and are usually obtained by:
II- Expression method
Expression can be carried out by means of any of
the following three processes:
a) Sponge method:
- The citrus fruit (orange, lemon) is washed, cut into
halve and the juicy part removed.
- The rind is squeezed, when secretion glands rupture
and the oil collected by mean of the sponge, until the
sponge becomes saturated with water and oil.
- The sponge is then periodically squeezed in a vessel.
- The upper oily layer in the vessel is separated.

22. b) Scarification method:
- Citrus oil involve puncturing the oil glands by rolling the fruit over
a trough lined with sharp projection that are long enough to penetrate
the epidermis.
- By repeatedly rotating the instrument after placing lemons in the
bowel the oil glands are punctured (scarified) and discharge their
contents which collect in the handle.
- The liquid is poured off at interval into a large vessel, where it is
allowed to stand until the oil can be decanted and filtered.
c) Machine processes:
- These machine methods have now almost completely replaced the old
hand methods. A centrifuge may be used to separate the emulsion of
oil and water.

23. III- Extraction method
- This method is used for the preparation of those oils which
decompose by the action of steam or are present in extremely
small quantities in plant organs containing them.
- The minute quantities of oil actually distilling over, are lost
in the large volume of distillation water from which the oil
cannot be recovered.
- This is applied to flowers such as jasmine, gardenia, violet,
and few others.
- The method of extraction is carried out using:
a) Volatile solvents of low boiling point such as hexane.
b) Non-volatile solvents such as fat (lard).

24. a)Extraction with volatile solvents
- The material containing the volatile oil is extracted
with the volatile solvent with low boiling point by
percolation.
- The volatile oil solution obtained is evaporated
under reduced pressure, where the volatile solvent
will evaporate, leaving the volatile oil behind although
some of the volatile oil will be lost.

25. Advantage of extraction over distillation:
- Uniform temperatures (usually 50°C) can be maintained during most
of the process.
But the distillation method is a low-cost operation compared to the
extraction process.

26. Floral concrete:
- In preparing volatile oil with volatile solvents e.g. hexane, pet.ether
the completely concentrated and purified products represent the so called
floral concretes.
- These floral concretes contain the odoriferous principles of the natural
flower perfume plus a considerable amount of plant waxes and color
pigments.
- The concretes are solid and only partly soluble in alcohol 95%.
Absolute:
- By ppt. and eliminating the insoluble waxes from the floral concretes
with strong alcohol and concentrating the filtered alcoholic solutions.
a- Extraction with volatile solvents:

27. B- Extraction with non-volatile solvents:
This process is used for the preparation of:
* Natural flower oils, where the volatile oil content of the fresh
plant is so small, very expensive, for production of perfumes.

28. 1- Enfleurage method
- A mixture of melted lard is thickly smeared on both surfaces of
each of the glass plates which are enclosed in a wooden frame.
- Each glass plate is sprinkled with flowers to cover its top.
- The plates are left for 24 hours.
- The flowers are then removed and replaced by a fresh supply.
- This is repeated until after some weeks, the fats becomes saturated
with essential oil of the flowers.

29. - The flowers are then removed and then fat is separated off and is
stirred with absolute alcohol which will take the volatile oil and
leave the fat being insoluble in alcohol.
- The alcoholic extract is carefully cooled and filtered to remove any
traces of fat which might remain in solution.

30. 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.

31. 1- Clove (Caryophylli)
Origin: the dried flower buds of
Syzygium aromatica , Eugenia
aromaticum or Eugenia
caryophyllus F. Myrtaceae
Morphology: reddish brown, 16-21
mm long, the lower stalk like
portion (hypanthium
which is an extension of the
receptacle) is about 10-13 mm
long, terminating in 4 triangular
sepals and a dome- shaped
head of 4 unexpanded petals
enclosing other parts of the
flower.

32. Powder: dark brown, with strong
aromatic spicy agreeable
odour and warm spicy
agreeable taste followed by
numbness sensation in the
mouth
1. Epidermal cells of sepals,
petals and hypanthium
showing anomocytic
stomata.
2. Oil glands.
3. Parenchyma with cluster
crystals of calcium oxalate.
4. Xylem vessels and fibres.
5. Fibrous layer of anther and
elongated cells of the
filament.
6. Pollen grains: triangular with
truncate apices.

33. Active constituents:
1. Volatile oil (15 -20%) contains eugenol (85%).
2. Pyrogallol tannin.
Uses:
1. Local anesthetic for toothache.
2. Antispasmodic and carminative.
3. Spice.
4. In manufacture of vanillin.
Chemical test: 1- Test for oil using Sudan III →
red colour.
2- FeCl3 → blue colour.
3- KOH: needle crystals of K eugenate.

34. Adulteration of clove:
Mother clove (fruit): characterized by the presence
of starch.
Exhausted clove: lighter than water.
Clove stalk: presence of prisms of calcium oxalate
and pseudo crystal sheath.

35. 2- German chamomile
Origin: the dried expanded
flower heads of Matricaria
chamomilla F. Compositae
(Asteraceae).
Morphology: flower head
(capitulum) is hemispherical
with hollow receptacle
carrying two types of small
sessile flowers called florets:
Marginal or ray florets (white in
colour)
Central or disc florets (yellow in
colour)
Surrounded by an involucre.

36. Active constituents: 1- volatile oil contains
matricarin which converted to chamazulene
by heating.
2- flavonoid glycosides.
Uses: 1- carminative, antispasmodic.
2- tranquilizer.
3- local anti-inflammatory for sun burns and
diaper rashes.
Chemical test: sudan III : red colour

37. 3- Anise Fruit
(Fructus Anisi, Aniseed)
Origin: the dried ripe fruits of
Pimpinella Anisum F.
Umbelliferae
Morphology: cremocarp,
partly separated into its
mericarps, often entire
attached to a slender
pedicel, 2-12 mm long,
ovoid, enlarged at the
base and tapering at the
apex, grayish or greenish
grey in colour rough to
touch due to the presence
of hairs, each mericarp
with 5 raised ridges.

38. Powder: grey, greenish
brown or yellowish
brown, having strong
aromatic agreeable
characteristic taste and
sweet strongly aromatic
taste, showing fragments
of:
1. non-glandular,
unicellular warty hairs.
2. Branching vitta usually
crossed by the cells of
the endocarp.
3. Aleurone grains.
4. Microrosette crystals of
calcium oxalate.
5. Few fibres and pitted
parenchyma.

39. Active constituents: 1- volatile oil containing
anethol
2- fixed oil and protein.
Uses: stimulant, carminative and flavoring
agent.
Chemical test: Sudan III

40. 4- Cinnamon Bark
(Cortex Cinnamomi)
Origin: the dried bark of the
branches of the coppiced
trees of Cinnamomum
zylanicum F. Lauraceae.
deprived of most of its
cork and cortex and
known as Ceylon
Cinnamon.
Morphology: occurs in
long, slender sticks about
1 meter in length,
compound quills.

41. Powder: a reddish brown
powder with a
characteristic pleasant and
aromatic odour and taste,
showing fragments of:
1. Sclereids, isodiametric,
thick wall, lignified, the
outer wall is less thickened
than the others.
2. Fibres, thick walled
lignified, narrow lumen, slit-
shaped pits and pointed
apices.
3. Starch granules and
needle crystals of calcium
oxalate.
4. Oil cells.
5. Cork cells are rare.

42. Active constituents: 0.5-1% volatile oil
contains cinnamaldehyde and eugenol
Mucilage and tannins.
Uses: 1- carminative and flavoring agents
2- Antiseptic and mild astringent.
3- Emmenagogue.
Chemical test: Sudan III, Rhuthenium red,
FeCl3 and KOH for eugenol.

43. 5- Cassia Bark
(Chinese Cinnamon)
Origin: the dried stem
bark of Cinnamomum
cassia F. Lauraceae
Morphology: channeled
or single quills, up to 40
cm long, earthy brown
colour with patches of
the thin grayish cork.

44. Powder: differs than
cinnamon in:
1. Odour is less delicate,
taste as cinnamon but
slightly mucilaginous.
2. Numerous fragments
of cork cells, polygonal
with slightly thick wall,
contains reddish
brown content.
3. Fibres are shorter and
thicker.

45. Active constituents: volatile oil contains
cinnamaldehyde and no eugenol.
Uses: substitute for cinnamon.
Chemical test: all as cinnamon but negative test
for eugenol

46. 6- Cardamom Seed
(Semen Cardamomi)
Origin: the dried ripe or nearly ripe
seeds of Elettaria cardamomum
F. Zingiberaceae, recently
separated from the fruit.
Morphology: cardamom has a
strong aromatic odour and
agreeable aromatic pungent
taste. Fruit is ovoid or oblong
capsule, green to pale buff in
colour contains many seeds.
Seed is oblong, ovoid pale ornge
to dark reddish brown usually
enveloped by a thin colourless
membranous arillus.

47. Active constituents: 1- volatile oil contains terpinyl
acetate and cineole.
2- starch, fixed oil and calcium oxalate
Uses: 1- flavoring agent in pharmaceutical industry.
2- spice
Chemical test: Sudan III
Adulterants:
1. Loose seeds: they yield less volatile oil than those
which stored in the pericarp until required for use.
2. Cardamom husk: characterized by the presence
of fibres, sclereids and large vessels which are
absent in the seeds.

48. 7- Mentha Herb (Peppermint)
(Herba Mentha Piperitae)
Origin: the dried leaves
and flowering tops of
Mentha piperita F.
Labiatae

49. Powder: green to light olive green, with
an aromatic characteristic odour
and an aromatic taste followed by a
sensation of cold in the mouth. It is
characterized microscopically by
the presence of fragments of:
1. Epidermal cells with wavy walls
and diacytic stomata.
2. Non-glandular hairs.
3. Glandular labiaceous hair,
unicellular stalk multicellular head
consists of 8-16 cells radiating from
a common center.
4. Different types of xylem vessels,
fibres and wood parenchyma.
5. Smooth spherical pollen grains.
6. NO CALCIUM OXALATE.

50. Active constituents: 1- volatile oil contains menthol
2- tannin.
Uses:
1. carminative, flavoring agent and aromatic
stimulant.
2. Menthol is used in pharmaceutical preparations
as local antipruritic, counter irritant and
antiseptic.
3. Used in tooth paste, mouth wash and similar oral
preparations.
4. Recently the oil is used for treatment of colitis.
Chemical test: Sudan III

51. 8- Ginger, Zingiber, Zanjabeel
(Rhizoma Zingiberis)
Origin: the dried rhizome of
Zingiber officinale F.
Zingiberaceae, deprived of
the dark outer tissues and
known as unbleached
Jamaica ginger.
Morphology: ginger occurs in
horizontal laterally flattened
branching pieces, 4-16 cm
long,1.5-6.5 cm wide and up
to 2 cm thick, pale buff or
light brown, longitudinally
striated. It has an agreeable
aromatic odour and an
agreeable pungent aromatic
taste.

52. Powder: powdered ginger is
yellowish white having an
agreeable aromatic odour and an
agreeable aromatic pungent
taste. Microscopically, it is
characterized by the presence of:
1. thin walled parenchyma
containing starch granules.
2. Starch granules: simple, flat, oval,
oblong with terminal
protruberance in which eccentric
hilum is situated with transverse
striations.
3. Thin walled septate fibres.
4. Non-lignified xylem vessels.
5. Yellowish brown oleo-resin
masses, free or in cells.
6. Absence of scleried cells or

53. Active constituents:
1. volatile oil contains monoterpenes
(phellandrene, camphene, cineole, citral
and borneol) and sesquiterpenes
(zingiberene and bisabolene).
2. Resin, starch and mucilage.
Uses:
1. carminative and stimulant.
2. Antiemetic.
3. Antirheumatic.
4. Condiment.