Chapter 4 Notes – Phytoconstituents (ER20)
By Arvind Sharma, B.Pharm, M.Pharm, Assistant Professor, MUIT
Pharmacognosy Chapter 4 Notes – Phytoconstituents (ER20)
These notes cover phytoconstituents according to PCI ER20 syllabus for D.Pharm 1st Year.
Topics Covered
- Alkaloids
- Terpenoids
- Glycosides
- Volatile Oils
- Tannins
- Resins
- Occurrence of Phytoconstituents
- Isolation Methods
- Identification Tests
- Therapeutic Uses
- Pharmaceutical Applications
Definition of Phytoconstituents
Phytoconstituents are naturally occurring chemical substances present in medicinal plants which are responsible for therapeutic activity.
They are obtained from crude drugs and used in treatment of diseases.
Very important for exams.
Phytoconstituents: The Active Principles
Phytoconstituents are chemical substances present in medicinal plants which are responsible for their therapeutic activity. They are obtained from crude drugs and form the backbone of natural medicine.
Major Phytoconstituents Include:
- Alkaloids
- Glycosides
- Terpenoids
- Volatile oils
- Tannins
- Resins
Major Phytoconstituents and Examples
| Phytoconstituent | Examples |
|---|---|
| Alkaloids | Morphine, Quinine |
| Glycosides | Digitalis, Senna |
| Volatile Oils | Clove oil, Peppermint oil |
| Tannins | Catechu, Tea |
| Resins | Benzoin, Myrrh |
Alkaloids
Alkaloids are nitrogen-containing organic compounds obtained from plants, often exhibiting significant physiological activity.
Properties:
- Bitter taste
- Basic in nature
- Physiologically active
Examples:
- Morphine
- Quinine
- Atropine
Uses:
- Pain relief
- Antimalarial drugs
- Antispasmodic drugs
Terpenoids
Terpenoids are organic compounds derived from isoprene units, widely distributed in the plant kingdom.
Sources:
- Essential oils
- Resins
Examples:
- Menthol
- Camphor
Uses:
- Flavoring agents
- Medicinal uses
Glycosides
Glycosides are compounds which contain a sugar part (glycone) and a non-sugar part (aglycone), linked by a glycosidic bond.
Examples:
- Digitalis glycosides
- Senna glycosides
Uses:
- Cardiotonic drugs
- Laxatives
Volatile Oils
Volatile oils, also known as essential oils, are aromatic oils obtained from plants, characterized by their strong odor and volatility.
Properties:
- Pleasant odor
- Volatile in nature
Examples:
- Clove oil
- Peppermint oil
Uses:
- Flavoring agents
- Carminatives
Tannins
Tannins are a group of astringent plant constituents, known for their ability to precipitate proteins.
Properties:
- Bitter taste
- Astringent action
Sources:
- Catechu
- Tea leaves
Uses:
- Treatment of diarrhea
- Astringents
Resins
Resins are amorphous solid substances obtained from plants, often secreted in ducts or cavities.
Properties:
- Sticky nature
- Insoluble in water
Examples:
- Benzoin
- Myrrh
Uses:
- Antiseptic preparations
Occurrence of Phytoconstituents
Phytoconstituents occur naturally in various parts of medicinal plants.
- Leaves
- Roots
- Barks
- Seeds
- Fruits
Isolation of Phytoconstituents
Isolation involves the separation of active chemical constituents from crude drugs using various techniques.
Methods:
- Extraction
- Distillation
- Solvent extraction
Identification Tests
Specific tests are employed to detect and confirm the presence of different classes of phytoconstituents.
Examples:
- Alkaloid tests (e.g., Mayer's, Dragendorff's)
- Glycoside tests (e.g., Keller-Kiliani for cardiac glycosides)
- Tannin tests (e.g., Ferric chloride test)
Therapeutic Uses
Phytoconstituents are widely utilized in medicine for the treatment and prevention of various diseases.
Examples:
- Alkaloids for pain relief (e.g., Morphine)
- Glycosides for heart diseases (e.g., Digoxin)
- Volatile oils for digestion (e.g., Peppermint oil as carminative)
Pharmaceutical Applications
The applications of phytoconstituents extend beyond direct therapeutic use into various pharmaceutical domains.
- Used in preparation of modern medicines and formulations.
- Integral components of herbal formulations and traditional remedies.
- Crucial in drug discovery and development of new therapeutic agents.
Important Points for Exams
- Phytoconstituents are the active chemical constituents responsible for therapeutic activity.
- Alkaloids contain nitrogen and are basic in nature.
- Glycosides contain a sugar part and a non-sugar part.
- Volatile oils are aromatic and volatile.
- Tannins are known for their astringent property.
- Resins are insoluble in water and have a sticky nature.
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Other Chapters
- Chapter 1 – Introduction to Pharmacognosy
- Chapter 2 – Classification of Crude Drugs
- Chapter 3 – Quality Control of Crude Drugs
- Chapter 4 – Phytoconstituents
- Chapter 5 – Medicinal Crude Drugs
- Chapter 6 – Surgical Dressings
- Chapter 7 – Traditional Systems
- Chapter 8 – Medicinal Plants Economy
- Chapter 9 – Herbs as Health Foods
- Chapter 10 – Herbal Formulations
- Chapter 11 – Herbal Cosmetics
- Chapter 12 – Phytochemical Investigation
Complete Pharmacognosy Notes
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Keywords
- Pharmacognosy Chapter 4 Notes
- Phytoconstituents Notes
- D Pharm Pharmacognosy ER20
Exam Tip
Questions on alkaloids, glycosides and volatile oils are frequently asked in D.Pharm exams.