Useful for B.Pharma students

1. MORPHOLOGY AND
MICROSCOPY OF VOLATILE OIL
DRUGS
Dr.U.Srinivasa, M. Pharm., M.Phil., Ph.D.
Professor and Head, Dept. of Pharmacognosy
Srinivas college of pharmacy, Mangalore.
Email. usreenivas1966@rediffmail.com

2. CASSIA
Biological source: Cassia consists of the dried stem bark
of Cinnamomum cassia , Family - Lauraceae
Morphology:

3. Condition - Dried stem bark
Colour - Dark reddish brown on both surfaces
Odour - Aromatic, sweet
Taste - Aromatic, sweet, mucilagenous
Shape - Channelled, single quills
Size - Length upto 40 cm ; width 1 to 2 cm,
thickness 1 to 5 mm
Fracture - Short, granular in outer part and slightly
fibrous in inner part
Extra
feature
- Outer - Surface - Rough and grayish.
Inner- surface- Brownish with fine
striations.

4. Active constituents:
It contains 1-2% of volatile oils. The main
constituent of volatile oil is cinnamic aldehyde
(75 - 90%). It also contains tannins, starch,
mucilage etc.
Uses:
Flavouring agent, as a mild astringent, powerful
germicide (oil).

5. MICROSCOY

6. Cork:
It consists of both thin walled and thick walled cells.
Thick walled cells are lignified.
Phellogen and Phelloderm:
Cannot be distinguished either from each other or from
the cork.
Cortex:
It is parenchymatous (10-15 layers) and contains
sclereids thickened on three sides either single or in
small groups. Highly lignified with pitted walls. Also
contains starch grains and minute acicular raphides.
Pericycle: It consists of sclerenchymatous zone of 3- 4
layers of stone cells with small groups of fibres at
interval.

7. Secondary phloem:
It consists of phloem parenchyma, phloem fibres and
medullary rays.
Phloem parenchyma contains volatile oil and mucilage
and some cells contains starch and calcium oxalate.
Phloem fibres are lignified, slender, either isolated or in
group arranged tangentially.
Medullary rays are usually two cells wide on inner side
and widen as they proceed outwards.

8. CLOVE
 Biological sources: Clove is the dried flower
bud of Eugenia caryophyllus
 Family - Myrtaceae.
 It contains less than 15% of clove oil.

9. MORPHOLOGY

10. Condition - Dried flower buds
Colour - Dark brown or crimson red
Odour - Aromatic, spicy
Taste - Strong, spicy, aromatic and pungent
followed by numbness
Shape - Sub- cylindrical, slightly flattened
Size - Length varies from 10 - 17 mm,
Width varies from 5 – 6 mm
Thickness 2 mm

11.  Extra features –
 Hypanthium - Sub-cylindrical, slightly tapering
at the lower end
 Crown - It consists of calyx, corolla, stamens
and style
 Calyx - It consists of 4 hard and thick sepals
with oil glands
 Corolla - Is dome shaped, yellow coloured
immature membrane petals
 Androecium - Numerous stamens,

12.  Gynoecium –
 Bilocular, inferior ovary with ovules (many)
placentatioaxile.
Style - Single and erect about 3 mm long
 The volatile oil is situated in the oil glands or
ducts which are present in all parts of the flower
bud.

14.  T.S. Through hypanthium: Following are the
important tissues. Epidermis, cortex and
columella.
 Epidermis: Single layer, straight walled cells
and has a very thick cuticle with anomocytic or
ranunculaceous (irregular celled) type of
stomata.

15.  Cortex: It is divided into three distinct zones.
 (a) The peripheral region containing 2 to 3
layers of big, ellipsoidal, schizo-lysigenous oil
glands embedded in the radially elongated
parenchymatous cells.
 (b) .The middle region containing 1 or 2 rings of
bicollateral vascular bundles associated
with a few pericyclic fibres embedded in thick
walled parenchyma and
 (c) The inner region made of loosely arranged
parenchyma.

16.  Columella: Forms, the central cylinder
containing thick walled parenchyma with a ring
of bicollateral vascular bundles towards the
periphery of the cylinder. Numerous cluster
crystals ( Sphaeraphides) are seen scattered
throughout the columella.
 T.S through the ovary region shows identical
structure as that a hypanthium but here central
region is occupied by a bilocular ovary with
several ovules showing an axile placentation.

17.  Active constituents: It contains 15- 20% of
volatile oils. The chief constituents of volatile oil
are eugenol (80- 88%), acetyl eugenol (10 –
15%), humulen (5-12%), α and β-
Caryophyllene, tannins – (10 – 13%)
 Uses: Cloves are used as a carminative, as
natural anthelmintic, as a dental analgesic,
antiseptic, stimulant and aromatic.

18. FENNEL
Biological source: Fennel consists of the
dried ripe fruits of Foeniculum vulgare
Family - Umbelliferae
 It contains not less than 1.4% v/w of
volatile oil.

19. MORPHOLOGY:

20. Type - Cremocarp with two one-seeded
mericarps
Condition - Dried fruits
Colour - Greenish or yellowish brown
Odour - Strongly aromatic and sweet
Taste - Strongly aromatic and sweet
Shape - Straight or slightly curved, oblong, oval,
each is bearing five ridges.
Size - 5 to 10 mm in length
2 to 4 mm in broad

21.  Extra features –
 Fruits are glabrous with 5 straight, prominent
primary ridges. Prominent yellow coloured
primary ridges and a bifid stylopod at the top.
Entire cremocarps usually with pedicels.

22. MICROSCOPY

23.  Fennel is a typical umbelliferous fruit called
cremocarp. Each cremocarp consists of two
mericarps connected by central stalk called
carpophores. T.S. of mericarp shows two
prominent surfaces. Commissural and dorsal.
Commissural surface is flat with two ridges are
present in the dorsal surface.

24. The cremocarp is divided into two mericarps and
each mericarp consists of the following
structures.
 Epicarp: It is composed of single layer of
polygonal to quadrangular with smooth cuticle.
 Mesocarp: Five bicollateral vascular bundles
with lateral phloem are present below each
primary ridge and lignified reticulate parenchyma
present above and below the vascular bundle.
Four vittae are present on dorsal surface and
two vittae on ventral surface

25.  Endocarp or inner epidermis: Shows
frequently arrangement; a group of 4-5 cells
parallel are placed at acute angles with groups
of cellular cells appear tangentially elongated in
transaction.
 Testa: Single layered and yellowish color.
 Endosperm: Consists of wide polyhedral thick
walled cells contain fixed oil and aleurone
grains with oil globules.
 Raphe: A single of vascular strands appear in
the middle of commissural surface.

26. CORIANDER
Biological source:
Coriander consists of the dried ripe fruits of the plant
known as Coriandrum sativum
Family - Umbelliferae.
It contains not less than 0.3% v/w of volatile oil.

27. MORPHOLOGY

28. Type of fruit - Cremocarp
Condition Dried fruits
Colour Straw yellow or brownish yellow
Odour Aromatic
Taste Spicy, aromatic and agreeable
Shape Globular or subspherical
Size 2.3 to 4.3 mm diameter
Extra
features
These fruits usually occur as entire cremocarps. A
short stylopod with 5 small calyx teeth present at
the apex.
10 wavy inconspicuous primary ridges alternating
with 8 prominent straight secondary ridges

29. MICROSCOPY

30.  Epicarp: Single layer, thickened, polygonal
cells, few cells contain calcium oxalate covered
with smooth cuticle.
 Mesocarp: Divided into three layers.
 Outer layer: Outer loosely arranged tangentially
elongated parenchyma.
 Middle layer: (Middle compact sclerenchyma)
 Outer region of this sclerenchmatous band is
represented by longitudinally running fibres
below the primary ridges where as the inner
region is made of tangentially running fibres
corresponding to secondary ridges.

31.  Five vascular bundles at dorsal side present
above longitudinally elongated sclerenchyma.
Two vittae at ventral side. Inner layer: large
irregular, polygonal and lignified parenchyma.
 Endocarp: It shows parquetry arrangement of
cells.
 Testa: Single layered and yellowish in colour.
 Endosperm: It consists of polygonal, thick
walled colourless parenchyma containing fixed
oil and aleurone grains.