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1- Cloves القرنفل

Botanical Source:

Clove is the dried flower buds of Eugenia caryophyllus,

family Myrtaceae. Dried until they turn red- brown in colour.

Geographical source: Zanaibar, Madegashcar and Molucca

islands.

Commercial clove should contain not more than 5% of its stalk

and fruits, and yields not loss than 15% of Volatile Oil.

Morphology of the buds: The buds are bright reddish brown in colour , 15-20 m.m.long.

the hypanthium is flattened-cylinderical or somewhat four-

sided. It is surmounted by four, spreading thick acute sepals and

dome shaped closed corolla which are formed of four petals.

The stamens are numerous, tetradelphous i.e., united through

their filaments, and opposite the petals. The stamens surround

an erect style in the centre, with nectary disc at its base. The

ovary is inferior, bilocular and situated in the upper part of the

hypanthium.

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Plate 37

Each locule contains about 20 ovules with axile placentation.

Clove has characteristic strong spicy aromatic odour, while its

taste is agreeable aromatic, warm which is followed by slight

numbness.

Histology of the bud:

1- A transverse section at the hypathium region, shows a

central cylinder of parenchyma (the columella ) with

several small vascular bundles, surrounded by an area of

aerenchma , with large spaces, beyond which is a circle of

vascular strands, followed by a layer of collenchymatous

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parenchyma---- containing circles of schizolysigenous oil

glands in the outer region. The epidermal cells are made of

tabular, polygonal cells with straight walls and thick

cuticle and showing anomocytic stomata

II) the ovary region , the area of columella and aerenchyma is

replaced by a bilocular ovary showing several ovules in each

locule attached by an axile plcentation. Cluster crystals of

calcium oxalate are scattered especially in the collumella.

III) The sepals, show epidermis similar to that of the

hypanthium, oil glands in the undifferentiated mesophyll

and clusters of calcium oxalate.

IV) the petals show similar structre, but is thinner and the

epidermis with no stomata.

V) The stamens, show a typical fibrous layer of the anther and

some occasional oil glands in the filament and in the

connective.

VI) The pallen grains are biconvex with rounded edges,

appearing triangular in surface view with truncate apices

and three pores measuring about 15 µ in diameter.

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Plate 38

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Plate 39

Powder clove :

It is brown in colour with strong characteristic aromatic odour

and agreeable warm taste, it shows the following.

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I) Numerous fragments of hypanthium with rows of

schizolysigenous oil glands .

II) Fragments of fiberous layer of anther with lignified bar

like thickening.

III) Yellow pollen grains appearing oval or triangular in

shape with oval or truncate edges.

IV) Fragments of epidermis of polygonal cells, showing

anomocytic stomata.

V) Framents of parenchyma of the hypanthium with cluster

crystals of calcium oxalate.

VI) Fragments of vascular strands showing spiral vessels

and lignified thick walled fibers.

VII) Calcium axalate prisms, starch and lignified sclereids

from the stalk should be absent.

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Plate 40

Active constituent of cloves:

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Cloves contain about 15-20% Volatile oil. The oil is composed

chiefly of the aromatic phenol eugenol ( 85%) and little

acetyleugenol. It also contain about 13% of galotannic acid and

a colorless, odorless crystalline, substance called Caryophylline

Test for identity : mix a little powdered clove with few drops of

ferric chloride solution, a deep blue colour is produced in all

elements except in the fibres which remain colourless.

Uses

Clove is widely used as carminative and flavouring agent,

agreeable aromatic stimulant and antispasmodic. Clove oil is

used in dentistry as local analgesic and antiseptic. Eugenol the

main constituent of clove oil is used in the preparation of

vanillin.

Adultration of cloves:

(1) Clove- stalk :

This is the selender stem of the in florescence axis and

shows opposite decussate branching. It is brownish, rough and

irregularly wrinkled longitudinally, with less pleasant odour.

It can be detected in powder cloves microscopically by:

(a) Presence of isodiametric thick-walled

sclereids.

(b) Phloem fibers with crystal sheath.

(c) Presence of prisms of calcium oxalate from

cortex and pith.

(d) Presence of starch granules.

(2) Mother Clove:

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It is the unripe fruits of cloves. They contain much less

volatile oil. They contain much starch from the seed, while

powder clove is free from starch.

(3) Exhausted cloves :

It is clove deprived from all or most of the volatile oil

which has been removed by steam distillation. Exhausted cloves

is darker in colour, much shrunken and float on water surface.