Pharmacognosy-I (PG202) Notes

Mansoura National University - Faculty of Pharmacy - Pharmacognosy Department

Course Overview

Pharmacognosy-I (PG202) is a Level 1, Second Semester course for the Clinical Pharmacy Pharm D Program. It covers drugs derived from different plant parts: leaves, barks, flowers, seeds, and woods.

Course Objectives

  • Learn the basics of pharmacognosy.
  • Differentiate between plant organs morphologically and microscopically.
  • Identify active constituents, medicinal uses, and side effects of plant drugs.

Key Elements

  • Macroscopical and microscopical characters of medicinal leaves, flowers, barks, woods, and seeds.
  • Geographical and botanical origin of studied medicinal plants.
  • Principles of physical, chemical, and microscopical characters in medicine preparation from plant organs.
  • Main active constituents of studied medicinal plants, their therapeutic effects, and safety.

Course Content

  • Leaves: Introduction, Senna, Bearberry, Henna, Witch-Hazel, Gingko, Digitalis, Squill, Coca, Jaborandi, Boldo, Tea, Solanaceous leaves, Mentha, Eucalyptus, Buchu, Rosemary, Thymus, Gujava.
  • Flowers: Introduction, Clove, Hibiscus, Chamomile, Pyrethrum, Santonica, Calendula, Lavender, Saffron, Safflower, Tilia, Red-rose, Arnica.
  • Seeds: Introduction, Linseed, Nux-vomica, Strophanthus, Fenugreek, Black mustard, Cardamon, Nutmeg, Colchicum, Psyllium, Unofficial seeds.
  • Bark: Introduction, Cassia, Cinnamon, Cinchona, Cascara, Frangula, Pomegranate, Quillaia, Salix, Witch-Hazel, Wild cherry, Aleppo Galls.
  • Wood: Introduction, Quassia, Guaiacum, Sandal (yellow/red), Log wood.

Teaching and Learning Methods

  • Computer-aided learning (lectures, online learning, interactive discussions).
  • Self-learning.
  • Practical sessions using chemicals and lab equipment.
  • Class activities (case studies, group discussions).
  • Problem-based learning and brainstorming.

Student Assessment

  • Written exam.
  • Practical exam.
  • Oral exam.
  • Periodical (Mid-term exam) / Course work.

Leaf Description

  • Condition: (dry/fresh/whole/broken/flat/twisted, etc.)
  • Color: (upper surface/lower surface).
  • Insertion: Radical or Cauline (stem) leaves.
  • Phyllotaxis: Arrangement of cauline leaves on the stem.
  • Leaf venation
  • Leaf lobing

Leaf Parts

  • Petiole: Present (petiolate) or absent (sessile).
  • Leaf base: Sheathing, Decurrent, or Winged petiole.
  • Lamina base: Symmetric or Asymmetric.
  • Lamina (leaf-blade) shape: Linear, Elliptical, Ovate, Oval, Oblong, Lanceolate, Cordate, Reniform, Acicular, Orbicular, Sagittate, Hastate, Lyrate, Spatulate, Rhomboid, Oblique, Cuneate.
  • Margin
  • Apex

Leaf Types

  • Simple Leaf: Single Lamina.
  • Compound Leaf: Separate leaflets attached to a common stalk.

Senna Leaf

  • Macroscopical Characters:

    • Petiole: very short
    • Lamina: lanceolate
    • Color: pale greyish green
    • Apex: acute
    • Base: asymmetric
    • Margin: entire

  • Chemical Tests:

    • General test: Powder + water, boiling, cool, filter, filtrate + 5% NaOH → red color (anthraquinone glycosides).
    • Bornträger's test: Boil with alc. KOH → acidifies with dil. HCl → extract with ether → add ammonia solution to ethereal layer → pink color (ammoniacal layer).

Digitalis Leaf

Digitalis purpurea
* Shape of lamina: Oval lanceolate
* Petiole: winged
* Margin: Irregular crenate
* Apex: Sub-acute
Digitalis lanata
* Shape of lamina: Linear lanceolate
* Petiole: sessile
* Margin: entire
* Apex: Acuminate

  • Chemical tests for cardiac glycosides
    • Baljit's test: orange-red colour indicates presence of cardenolides.
      Baljit's reagent (1\% picric acid in ethanol + 10\% alcoholic potassium hydroxide)
    • Keller-Killiani's test:(test for deoxy sugar)
      → reddish-brown layer slowly become → bluish green.

Solanaceous Leaves

  • Datura stramonium (Thorn-apple)

    • Ovate or triangular ovate
    • Margin: unequally dentate or irregularly serrate margin
    • Apex: acuminate

  • Atropa belladonna (deadly nightshade)

    • Oval lanceolate
    • Margin: entire
    • Apex: acute

  • Hyoscyamus muticus (Egyptian henbane)

    • Lamina: oval, rhomboidal
    • Margin: entire with 2-3 large teeth on each side and acuminate apex

  • Chemical tests for alkaloids

    • General test (mayer's test): Boil powdered drug with dil. HCl, then filter, filtrate with Mayer's reagent, gives white or yellowish white ppt.

Eucalyptus Leaf

  • Symmetric base.
  • Entire margin.
  • Acute apex.
  • Lamina: isobilateral palisade and punctate.
  • Strong camphoraceous odor.

Rosemary Leaf

  • Linear shape
  • Sessile
  • Obtuse apex
  • Entire margin
  • Dorsiventral leaf
  • Strong camphoraceous odor.

Guajava Leaf

  • Simple leaf
  • Fresh and complete leaf
  • Elliptical lamina, entire margin, symmetric base
  • Acute to rounded apex
  • Petiolate
  • Leathery fracture

Clove Flower

  • Dark brown color
  • Strong Spicy, aromatic odor
  • Pungent spicy taste, followed by slight numbness
  • Hypanthium is wrinkled externally and exudes volatile oils when scratched

Hibiscus Flower

  • Purplish red color
  • Mucilaginous acrid taste
  • Calyx: Petalloid, hard fleshy, with celiate apex
  • Epicalyx: extend below calyx
  • Tests: With HCl,
    • KOH: Blue color
    • Na acetate: violet color
    • conc. NH_4OH: green color
    • Lead acetate: blue ppt

German Chamomile

  • Greenish yellow to yellowish-brown color
  • Pleasant aromatic odor
  • Slightly bitter taste

Seeds

Linseed

  • Elongated-ovate, flattened with rounded end and other obliquely pointed one, type of ovule: anatropous.
  • Chemical Tests:
    • Guignard paper test: brick-red color (cyanogenetic glycosides).

Nux Vomica Seed

  • Disc shaped (button shaped)
  • Odorless, very bitter taste -Chemical Tests:
    • Test for strychnine: powder + solution of sulphovanidic acid, a violet color is produced.

Fenugreek Seed

  • Rhomboidal
  • yellowish brown
  • Chemical Tests:
    • Test for saponins (Froth test).

Black Mustard Seed

  • Spherical or nearly spherical
  • Seed: Exalbuminous

Cardamom

  • The seeds are irregularly angular, 3 to 4 sided, oblong, or ovoid.
    -seed: Albuminous.
  • outgrowth: Arillus

Barks

Cassia

  • Channel pieces or single quills, rarely double.
  • Thickness: 1-3 mm

Cinnamon

-  Rolled into a tubular form known as a quill or compound quills
- striations due to bundles of pericyclic fibers.

Cinchona

-Shape: Quill, double quill, chips, or curved pieces varying in size.

Chemical Tests

  • Cinnamon and cassia: FeCl_3 : greenish black color.
  • Cinnamon: KOH: needle shaped crystals of K.eugenate
  • Cinchona bark: Thalleioquine test: gives emerald green color

Galls

Macroscopical Characters:
Galls are hard sub-spherical, greenish. having small bluntly conical projections on the surface
Chemical tests:
Galls powder give ………..color with ferric chloride solution
Galls powder filtrate when treated with………… gives precipitation

Wood

Quassia : with phloroglucinol and Hydrochloric acid gives rose red color