Botany and Medicinal Plants (201)
First year Students
Seventh Practical Session
Pharmacognosy Department
2016/2017
Digitalis Leaf
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2
Digitalis leaves
Digitalis purpurea
Digitalis lanata
(Due to the purple color of the flower)
The official drug
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non-official drug
3
Digitalis lanata
I-Morphology
• Name : Digitalis Leaf.
• Origin: The dried leaves of Digitalis lanata,
family Scrophulariaceae, collected and rapidly
dried at 55-60°C. Why?!!
The main active constituents are Cardiac
glycosides which are sensitive to:
high temperature and moisture
, so it should be rapidly and at temperature not exceed 55-60 ̊C to avoid
breakdown of the glycosides and loss of activity.
• Colour : Green.
• Condition: dried, broken pieces and
moistened.
• Insertion: ??
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Radical Insertion
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I-Morphology
Acute
• Leaf petiole:
apex
1. Occurrence: sessile
Broadly
2. Characters: ------dentate
3. Pulvinous : ------margin
Lamina:
1. Composition :simple.
2. Incision: ------3. Shape : oblanceolate, linear,
lanceolate.
Symmetric base
4. Apex : acute.
5. Margin : broadly dentate margin.
6. Base : symmetric.
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Entire ,ciliate at
the base. 5
7. Venation: pinnate reticulate venation,
veins leave midrib at narrow acute angle.
(appears as parallel venation)
8. Size: as shown (length in cm. x width in cm.)
9. Surface:
• upper: green, glabrous to the naked
eye.
• lower: pale green, glabrous to the
midrib
naked eye.
-midrib is prominent to the lower surface
Pinnate reticulate
and depressed on the upper.
venation
• Texture : papery.
• Odor : slight tea-like odor.
• Taste : persistent bitter taste.
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II-Surface Preparation.
Upper surface
Lower surface
Beaded
wall
Anomocytic
stomata
1- Shape
2-Anticlinal
walls
3- Cuticle
4- Stomata
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Anisocytic
stomata
polygonal isodiametric to axially elongated
nealry Straight
,beaded
smooth
Straight to slightly
wavy , beaded
smooth
anomocytic , few anisocytic
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Upper surface
5-Hairs
Lower surface
-Glandular hair with unicellular stalk and unicellular or bicellular head.
-Glandular hair with multicellular -Non glandular multicellular
uniseriate stalk and unicellular unbranched uniseriate hair.
head.
6-Content
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------8
III-T.S.
Lamina region
Midrib region
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Upper epidermis
Lamina Region
mesophyll
Palisade
mesophyll
Spongy tissue
Differentiated
(palisade and
spongy tissue)
undifferentiated
(spongy tissue)
lower epidermis
Type of mesophyll ?!!!
Undifferentiated
(homogenous)
mesophyll
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Chlorenchyma
(parenchyma cells
containing chloroplast)
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Midrib Region
Vascular bundle
Pericycle
Cortex
1- Vascular bundle
Xylem
Vascular
bundle
phloem
One crescent shape and collateral vascular bundle.
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Midrib Region
2- Pericycle
Collenchymatous pericycle
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Midrib Region
3- Cortex
Parenchyma
Lower Collenchyma
The cortex is parenchymatous with lower
collenchyma.
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III-T.S.
Undifferentiated Lamina
(homogenous)
Crescent Collateral Vascular Bundle
Collenchymatous Pericycle
Parenchymatous Cortex
Lower Collenchyma
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III-T.S.
Description:
• Leaf lamina is undifferentiated (homogenous).
• it may be differentiated into upper palisade and spongy tissue.
• If differentiated, the leaf is dorsiventral.
• The palisade (if differentiated )is discontinuous on the upper
surface.
• The midrib is strongly prominent to the lower surface and
depressed on the upper surface.
• The midrib region:
-Vascular bundle: crescent in shape, collateral in type.
-Pericycle: collenchymatous.
• The cortex is parenchymatous with lower collenchyma.
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IV-Powder of Digitalis Leaf
Color: green.
Odor: Slight tea-like odour.
Taste: Persistant bitter taste.
Microscopically characterized by :
1.Fragment of Upper surface
Beaded
Anticlinal Wall
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2.Fragment of Lower surface
3-Fragments of Glandular hair with short multicellular
or unicellular stalk and unicellular or bicellular head.
4.Xylem vessels
N.B.:
No Ca-oxalate
No fibers
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