Ergot refers to a group of fungi, particularly Claviceps purpurea, which infects cereal grains like rye and produces a range of pharmacologically active compounds. The pharmacognostic features of ergot primarily pertain to its identification, preparation, and chemical composition, which are essential for understanding its therapeutic and toxicological properties.



Here are the systematic pharmacognostic features of ergot:

1. Biological Source:

  • Ergot is primarily derived from Claviceps purpurea, a parasitic fungus that infects the ovaries of cereals and grasses, particularly rye (Secale cereale).
  • It is collected from mature sclerotia, which are the hardened, fungal resting structures formed in place of the grain.

2. Geographical Source:

  • Ergot is found in temperate regions, particularly in Europe, North America, and parts of Asia where rye and other cereals are cultivated.

3. Morphological Features:

  • Sclerotia (the medicinally significant part) appear as dark purple or black, elongated, horn-like structures replacing the grain of the host plant.
  • Size: The sclerotia are 1-3 cm long and 2-5 mm in diameter.
  • Shape: Sclerotia are slightly curved, with a rough and wrinkled surface.
  • Color: Externally dark brown to black; internally white or pale brown.

4. Organoleptic Characteristics:

  • Color: Black or purplish-black externally.
  • Odor: Faint but characteristic when fresh; can develop a musty odor upon aging.
  • Taste: Bitter and unpleasant.
  • Texture: Hard and brittle when dry.

5. Microscopic Features:

  • Under microscopy, ergot sclerotia show a compact arrangement of fungal hyphae.
  • Hyphal cells: These are thin-walled and septate.
  • Oil cells: Contain minute oil globules.
  • Calcium oxalate crystals: May be present.

6. Chemical Constituents:

  • Ergot alkaloids: The main active compounds are ergoline derivatives. Major alkaloids include:
    • Ergotamine
    • Ergometrine (ergonovine)
    • Ergosine
    • Ergocristine
    • Ergocornine
  • Ergoline derivatives: These compounds can induce smooth muscle contraction and act on the central nervous system.
  • Ergosterol: A sterol precursor of vitamin D2 found in fungi.
  • Peptides: Derived from ergoline alkaloids.
  • Other minor components include fatty acids, triglycerides, and pigments.

7. Powder Characteristics:

  • The powdered form of ergot is dark brown to black.
  • Under the microscope, it shows fungal hyphae, oil globules, and calcium oxalate crystals.

8. Adulterants:

  • Ergot may be adulterated with other fungal structures or cereals.
  • Common adulterants include fragments of rye grains or other cereal sclerotia that mimic ergot.

9. Pharmacological Actions:

  • Ergot alkaloids exhibit vasoconstrictor properties and are potent uterine muscle stimulants.
  • They are used therapeutically to manage migraine headaches (via ergotamine), and postpartum hemorrhage (via ergometrine).
  • Some ergot derivatives are used for Parkinson’s disease due to their dopaminergic action.

10. Toxicity:

  • Prolonged or excessive ingestion of ergot-contaminated grains leads to ergotism, a condition historically known as St. Anthony’s Fire. Symptoms include:
    • Convulsive ergotism: Nervous system manifestations such as seizures and hallucinations.
    • Gangrenous ergotism: Vasoconstriction leading to gangrene of extremities due to restricted blood flow.

11. Uses in Medicine:

  • Ergotamine: For treating acute migraine attacks.
  • Ergometrine: For preventing and treating postpartum hemorrhage by stimulating uterine contraction.
  • Ergot alkaloid derivatives: In small doses, are used to manage certain cardiovascular and neurological disorders.

12. Storage:

  • Ergot should be stored in well-closed containers, protected from light, moisture, and air, as its active alkaloids are sensitive to environmental degradation.

13. Extraction and Preparation:

  • Alkaloids from ergot are extracted using alcohol or aqueous solutions, which are then purified for medicinal use.
  • Standardized extracts of ergot are used in pharmaceutical preparations for specific therapeutic applications.

These pharmacognostic features are crucial for identifying ergot, understanding its pharmacological uses, and preventing its toxic effects in therapeutic contexts.