Botany & MEDICINAL PLANTS
Transcript of Botany & MEDICINAL PLANTS
Pharmacognosy
Sherif S. Ebada, Ph.D.
Contact information:
Assoc. Prof. Dr. Sherif S. Ebada
Pharmaceutical Chemistry Dept.
Office hours:
Tuesdays and Thuresdays: 10:00 am–12:00 pm
E-mail: [email protected]
Lecture 2AB
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Lecture Outline
Introduction to Medicinal Leaves.
Senna.
Digitalis.
Solanaceous Leaves.
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What is a Leaf?
An aerial lateral outgrowth on the stem.
Function of the Leaf:
Photosynthesis.
Food exchange.
Protection of the floral parts & buds.
Leaf composed of three Parts:
Leaf Base.
Leaf Stalk “Petiole”.
Leaf Blade “Lamina”.
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Leaf Insertion on Stem:
Radical, e.g. carrot.
Cauline.
Phyllotaxis:
a. Alternate.
b. Opposite:
I. Decussate.
II. Superposed.
c. Whorled.
a b.I. b.II. c
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Leaf Base.
Stipulate or Ex-stipulate.
Leaf Stalk “Petiole”.
Petiolate or Sessile.
Leaf Blade “Lamina”.
According to the continuity divided into Three types:
Simple.
Lobed: either pinnate (midrib) or palmate (base).
Compound: divided into leaflets arranged on both sides
of leaf stalk named “Rachis”, i.e. continuation of midrib.
It can be either compound pinnate or palmate.
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Simple Leaf Pinnate Leaf Palmate Leaf
Compound paripinnate Leaf Compound imparipinnate Leaf
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Leaf Blade “Lamina”.
According to its margin divided into:
Serrate Crenate Incised Dentate
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Leaf Blade “Lamina”.
According to its surface divided into:
Glabrous “Smooth”.
Pubescent “Hairy”.
Leaf Blade “Lamina”.
According to its texture divided into:
Brittle: when very thin easy to break (dry).
Fleshy or “Succulent”: thick, juicy and fleshy.
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Histology of Leaf.
I. Epidermis:
Shape of cells: single layer, tubular with no intercellular
spaces except for the stomata. Anticlinal wall is either:
Straight e.g. Senna.
Wavy e.g. Belladonna.
Beaded e.g. Digitalis.
Straight e.g. Senna Wavy e.g. Belladonna Beaded e.g. Digitalis
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Histology of Leaf.
I. Epidermis:
Cuticle: a protective film covering the epidermis, it
might be:
Smooth e.g. Senna.
Striated e.g. Jaborandi.
Smooth e.g. Senna Striated e.g. Jaborandi
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Histology of Leaf.
I. Epidermis:
Stomata: consists of two similar cells, “Guard cells”,
enclosing a small lenticular (oval) space “Osteole”.
Guard cells are smaller & containing chloroplast
and starch granules.
Epidermal cells surrounding the stomata are
Subsidiary cells which differ in size & shape from
the remaining epidermal cells.
Guard cells
Osteole
Subsidiary cells
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Histology of Leaf.
I. Epidermis:
Types of Stomata:
In Monocotyledons: In Dicotyledons:
Dumbbell-shaped A. Anomocytic e.g. Digitalis.
“Graminaceous type” B. Anisocytic e.g. Solanaceous leaves.
C. Paracytic e.g. Senna.
D. Diacytic e.g. Mentha.
A B C D
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Histology of Leaf.
I. Epidermis:
Types of Stomata:
Stomatal number: it is the average number of
stomata per 1mm2
Stomatal index: it is the percentage of number of
stomata (S) to sum of total number of epidermal cells
(E) and Stomata together in the same unit area i.e.
= S x 100 / E + S N.B.: It is a constant value for a given
species.
Trichomes “Hairs”:
Extensions of the epidermdal cells divided into:
Non-glandular.
Glandular.
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Histology of Leaf.
I. Epidermis:
Trichomes “Hairs”:
Extensions of the epidermdal cells divided into: Non-glandular: might be either:
A. Unicellular: covered with warty cuticle e.g. Senna.
B. Multicellular: can be further divided into:
Unbranched: Branched:
Uniseriate e.g. Digitalis, Pyrethrum Simple e.g. Hyoscyamus
Biseriate e.g. Calendula flower Stellate e.g. Boldo leaf
Pluriseriate e.g. Cumin
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Histology of Leaf.
I. Epidermis:
Trichomes “Hairs”:
Extensions of the epidermdal cells divided into: Glandular: might be either:
A. Uniseriate stalk: can be either:
Unicellular head unicellular stalk e.g. Digitalis.
Unicellular head multicellular stalk e.g. Belladonna & Lavander.
Multicellular head unicellular stalk “Clavate” e.g. Solanaceous leaves.
Multicellular head unicellular stalk “Labiaceous” e.g. Mentha.
B. Biserate stalk:
Biseriate head biseriate stalk “Compositae” e.g. Compositae.
Multicellular head pluriseriate stalk e.g. Cannabis.
Labiaceous hairCompositae hair
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Histology of Leaf.
I. Epidermis:
Cell content: Mucilage: with methylene blue gives Blue.
Volatile oils: with sudan III gives Red.
Calcium Oxalate Crystals:
a) Prisms e.g. Senna; Styliod e.g. Quillaia.
b) Clusters e.g. Rhubarb.
c) Rosette e.g. Argel.
d) Raphides e.g. Squill.
e) Microsphenoidal crystals e.g. Stramonium & Belladonna.
Prism Styloid Cluster Rosette Raphides Microsphen-
oidal crystal
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Histology of Leaf.
II. Mesophyll:
Vascular system “ Stellar System”:
It consists of network structure.
It appears in transverse section (T.S.) as an arc opens above with the
phloem towards the lower surface of the leaf and the xylem towards the
upper surface.
Phloem: formed of small thin-walled elements.
Xylem: consists of radial rows of vessels with the protoxylem
towards the upper surface and separated by rows of wood
parenchyma.
Medullary rays may be visible, traversing the xylem and
phloem in the form of radiating lines.
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Histology of Leaf.
II. Mesophyll:
Vascular system “ Stelar System”:Types of Vascular Bundles:
A. Radial: when xylem & phloem form separate bundles which lie on different
alternating radii with each other, as in roots.
B. Conjoint: when xylem & phloem combine in one bundle there are three types:
1. Collateral: when xylem & phloem lie together on the same radius
When it has cambium it is an Opened V.B.
When it has no cambium it is a Closed V.B.
N.B. cambium is difficult to be differentiated
2. Bicollateral: both cambium & phloem occur twice; (above & below the xylem).
3. Concentric:
i. Vasocentric:
When xylem lies in the center & is surrounded by phloem as in ferns.
ii. Amphivasal:
When phloem lies in the center & is surrounded by xylem as in sweet flag. N.B.:
concentric bundle is always closed bundle.
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Diagnostic Elements of Powder
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Uses:
It is a cardio tonic drug. It increases the
contractibility and improves the tone of the
cardiac muscle, both reactions resulting in a
slower but much stronger heart beat, thus it is
used in most forms of cardiac failure, as
auricular fibrillation & ascitis.
N.B.: Digitoxin is cumulative drug, thus thedose
used must be monitored.
SOLANACEOUS LEAVES
General Characters of Solanaceous Leaves:
1. The leaves show adnation phenomenon; the leaves grow fused for a certain distance with the petiole thus, the leaves appear arise to from the stem “i.e. as if it is sessile”.
2. All solanaceous leaves contain alkaloids; atropine, hyoscine & hyoscyamine, which are mydriatics “dilate eye pupil”, thus used for eye examination.
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3. All Solanaceous leaves contain:
anisocytic type of stomata.
non glandular hairs (uniseriate from 3-5 cells).
glandular hairs; Clavate hairs (ovoid multi-cellular bi-serriate head & uni-
cellular stalk).
Uni-cellular head with uni-serriate or branched stalk.
Ca Ox crystals (clusters, prisms or sandy).
starch sheath.
pre-medullary or intra-xyllary phloem (batches of phloem cells above the xylem vessels).
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“Egyptian & European Henbane”
Origin: It is the dried leaves with or without the flowering fruiting tops of Hyoscyamus muticus &
Hyoscyamus nigra, Family Solanaceae
Hyoscyamus Leaves وراق السكرانأ
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Leaf insertion: cauline; alternate.
Leaf base: exstipulate.
Leaf petiole: very short cylindrical petiole “adnate” .
Lamina type: simple.
Shape: oval lanceolate.
Apex: acuminate.
Margin: repand “sinuate”.
Base: assymetric, decurrent “adnate with the petiole”.
Surface: pubescent; Clothed with hairs.
Texture: thick fleshy leaf.
Venation: reticulate pinnate.
Morphology:
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Egyptian
Henbane leafEuropean
Henbane leaf
Egyptian Henbane
“surface preparation”
European Henbane
“surface preparation”
Clavate Hair
with long stalkCrystal of CaOx
Clusters
Twin
prismsSandy
prisms
with short stalk
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Therapeutic Uses:
It has parasympatholytic “Sympathomimetic” action thus;
• It inhibits the contraction of iris eye muscle causes mydriasis
“dilatation of eye pupil” ; thus it is used in eye examination.
• It relaxes the intestinal smooth muscles “antispasmodic action”;
thus it is used with strong laxatives to prevent the gripping.
• It has sedative effect, on central nervous system; thus it is used
in insomnia as hypnotic.
It is also used as a source of hyoscyamine alkaloid.
Active constituents:
Alkaloids of tropane group; Hyoscyamine & Atropine
N.B.: 1.7% present in the Egyptian leaves, while 0.14%
present in the European leaves.
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Identifying Chemical Tests:
“tests for tropane - group alkaloids”:
Powdered plant + 10ml dil HCl., boil for 2 min., filter,
Vitali - Morin Color Reaction:
evaporate the filtrate (in a porcelain dish) till dryness then add drops of conc.
HNO3 yellow solution, evaporate to dryness, add drops of alc. KOH
purple colorless
Mayer’s Reagent:
Filtrate + drops of K2HgI creamy white ppt.
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• Parts of branched glandular hair.
• Parts of leaf epidermis showing anisocytic stomata, striated cuticle & hair cicatrix.
• Clusters of CaOx crystals.
• Sclerides of the testa & of the pericarp “in surface view”.
• Parenchyma of the stem showing Idioblast containing CaOx microsphenoidal crystals.
• Pollen grains.
Diagnostic Elements of Hyoscyamus
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Origin:
It is the dried leaves with or without the flowering tops of Atropa belladonna ,
Family Solanaceae
Belladonna Leaves وراق ست الحسنأ
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Active constituents:
Hyoscyamine, Hyoscine & Belladonine
alkaloids
Therapeutic Uses:
1. as anodyne i.e. analgesic for tooth ach (it has
local anesthetic effect).
2. as sedative.
3. as antispasmodic.
Identifying Chemical Tests: as for all Solanaceous1. Vitali - Morin Color Reaction
2. Mayer’s Reagent
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• Parts of leaf epidermis showing anisocytic stomata & striated cuticle; 1, 2 & 4
• Parts of the lamina in sectional view showing Idioblast in the spongy mesophyll & idioblast of CaOxmicrosphenoidal crystals; 5 & 9
• Parts of glandular & non- glandular hairs; 6, 10 &11
• Fragments of the inner tissues of the stem in S.V. showing reticulate thickened vessels & xylem parenchyma; 8
• Pollen grains; 3
Diagnostic Elements of Atropa belladonna
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Origin:
It is the dried leaves with or without the flowering tops of Datura stramonium ,
Family Solanaceae
Datura Leaves وراق داتورة أ
سترامونيوم
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Therapeutic Uses:
Sedative
Spasmodic cough
Identifying Chemical Tests:as for all Solanaceous Leaves:1. Vitali - Morin Color Reaction
2. Mayer’s Reagent
Active constituents:
Hyoscyamine & Atropine
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• Parts of leaf epidermis showing strong wavy walled-cells, anisocytic stomata, smooth cuticle; 1 & 2
• Fragments of the crystal layer in surface view showing cluster of CaOx crystals; 4 & 9
• Parts of glandular & non- glandular hairs; 7 & 8
• Parenchyma of the midrib in longitudinal view showing prisms & sandy CaOx crystals; 5
• Pollen grains; 10
Diagnostic Elements of Datura stramonium
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