BP105T Pharmacognosy Unit 1 Notes: Sources of Drugs, Pharmacopoeias, Crude Drug Classification
By Arvind Sharma, B.Pharm, M.Pharm, Assistant Professor, MUIT
BP105T: Introduction to Pharmacognosy — Unit 1
Fundamentals of Pharmacognosy
Unit Overview
This unit introduces you to Pharmacognosy — the science of medicines derived from natural sources. You will learn where drugs come from (plants, animals, microbes, marine life, minerals), explore landmark drug discoveries that changed medicine forever, understand official pharmacopoeias that set quality standards, and master different ways to classify crude drugs. This foundation is essential because every pharmacist must know the origin, quality, and classification of natural medicines before they reach patients.
Learning Objectives
By the end of this unit, you will be able to:
- Define pharmacognosy and explain its scope, history, and current relevance in modern pharmacy.
- Identify and describe the various sources of drugs — plant, animal, microbial, marine, mineral, and plant tissue culture.
- Recall the historical milestones in drug discovery (morphine, quinine, aspirin, warfarin, penicillin, cephalosporin, taxol, artemisinin) and their significance.
- Compare different pharmacopoeias (Indian, British, USP, Ayurvedic, Unani, American Herbal) and understand their importance in drug standardization.
- Distinguish between official, non-official, codified, and non-codified drugs with appropriate examples.
- Apply different classification systems (alphabetical, morphological, taxonomical, chemical, pharmacological, chemotaxonomic) to crude drugs and evaluate their merits and limitations.
Topic-by-Topic Notes
(a) Definition, History, Present Status, Scope & Development of Pharmacognosy
Definition
Pharmacognosy is the branch of pharmacy that deals with the study of crude drugs (medicines in their natural, unprocessed form) obtained from natural sources — mainly plants, animals, and minerals. It covers their identification, collection, preparation, preservation, and quality control.
Plain language: It's the science of understanding where our natural medicines come from, how to identify them, and how to ensure they are safe and effective.
History & Development
| Era | Key Developments |
|---|---|
| Ancient (Before 500 AD) | Use of herbs in Ayurveda (India), Traditional Chinese Medicine, and Egyptian medicine. |
| Medieval (500–1500 AD) | Arab scholars preserved Greek knowledge; "Materia Medica" compiled by Dioscorides. |
| Renaissance (1500–1800) | Exploration led to discovery of new plants; isolation of active compounds began. |
| 19th Century | Birth of modern pharmacognosy; isolation of morphine (1804), quinine (1820), cocaine (1860). |
| 20th Century | Discovery of penicillin (1928), cephalosporin (1945), taxol (1960s); shift from whole drugs to pure compounds. |
| 21st Century (Present) | Focus on herbal medicines, nutraceuticals, plant tissue culture, marine pharmacognosy, and biotechnology in drug discovery. |
Present Status & Scope
1. Quality control of herbal drugs — ensuring purity and potency.
2. Standardization of traditional medicines — Ayurvedic, Unani, Siddha.
3. Drug discovery from natural sources — marine organisms, microbes, plants.
4. Plant tissue culture — producing rare medicinal compounds artificially.
5. Forensic pharmacognosy — identifying adulterated or fake drugs.
6. Regulatory affairs — herbal drug registration and pharmacopoeial standards.
Clinical/Practical Relevance
A pharmacist must verify the authenticity and quality of crude drugs before dispensing. Poor-quality herbal medicines can be ineffective or toxic.
(b) Sources of Drugs
Definition
Drugs can be obtained from six major natural sources. Each source has unique advantages and challenges in terms of availability, sustainability, and yield.
Classification Table
| Source | Description | Key Examples |
|---|---|---|
| Plants | Most common source; leaves, roots, bark, seeds, flowers used | Digitalis (heart), Senna (laxative), Opium (pain relief) |
| Animals | Glands, organs, or whole animals used | Insulin (pancreas), Heparin (liver), Cod liver oil |
| Microbial | Bacteria, fungi, actinomycetes produce antibiotics | Penicillin (Penicillium), Streptomycin (Streptomyces) |
| Marine | Ocean organisms — algae, sponges, corals, fish | Taxol (originally from Pacific yew, now marine analogs), Cytarabine (sponge) |
| Mineral | Inorganic substances from earth | Kaolin (diarrhea), Talc (dusting powder), Calamine (skin) |
| Plant Tissue Culture | Growing plant cells in lab to produce rare compounds | Shikonin (wound healing), Taxol production in bioreactors |
Mechanism/Process: Plant Tissue Culture (Step-by-Step)
1. Selection of Explant — Choose a small piece of plant tissue (leaf, stem, root tip).
2. Surface Sterilization — Clean with disinfectants to remove microbes.
3. Inoculation — Place the explant on a nutrient medium (agar + hormones + nutrients).
4. Callus Formation — Undifferentiated mass of cells forms.
5. Organogenesis / Embryogenesis — Callus develops into shoots or roots.
6. Multiplication — Sub-culture to produce large numbers of plantlets.
7. Acclimatization — Transfer plantlets from lab to soil.
8. Extraction of Active Compounds — Harvest and extract medicinal compounds.
Key Drugs/Examples Table
| Drug Name | Source Type | Original Source | Use | Important Point |
|---|---|---|---|---|
| Morphine | Plant | Opium poppy (Papaver somniferum) | Severe pain | First isolated alkaloid (1804) |
| Penicillin | Microbial | Penicillium notatum | Bacterial infections | First antibiotic; discovered by Fleming |
| Insulin | Animal | Pig pancreas (now recombinant) | Diabetes | Replaced by human recombinant insulin |
| Heparin | Animal | Pig intestine | Blood thinner | Natural anticoagulant |
| Taxol | Plant/Marine | Pacific Yew tree | Cancer (ovarian, breast) | Now produced by semi-synthesis |
| Artemisinin | Plant | Artemisia annua (Sweet wormwood) | Malaria | Nobel Prize 2015 (Tu Youyou) |
| Shikonin | Plant Tissue Culture | Lithospermum erythrorhizon | Wound healing | First commercial tissue-culture product |
Clinical/Practical Relevance
Knowing the source helps pharmacists ensure sustainable supply, detect adulteration, and counsel patients about vegetarian vs. non-vegetarian drug sources.
(c) Historical Milestones in Drug Discovery
Definition
These are breakthrough moments when scientists isolated or discovered drugs from natural sources that transformed medicine.
Step-by-Step Discovery Stories
1. Morphine (1804) — Friedrich Sertürner
- Isolated from opium poppy latex.
- First pure plant alkaloid ever isolated.
- Proved that plants contain specific chemical compounds responsible for effects.
2. Quinine (1820) — Pelletier & Caventou
- Isolated from Cinchona bark.
- First effective treatment for malaria.
- Led to development of synthetic antimalarials.
3. Aspirin (1897) — Felix Hoffmann (Bayer)
- Synthesized from salicylic acid (found in willow bark).
- First synthetic drug based on a natural product.
- Revolutionized pain relief and anti-inflammatory therapy.
4. Warfarin (1940s) — Karl Link
- Discovered from spoiled sweet clover hay causing cattle bleeding.
- Isolated dicoumarol → developed into warfarin.
- Most widely used oral anticoagulant worldwide.
5. Penicillin (1928) — Alexander Fleming
- Accidental discovery from mold Penicillium notatum contaminating a bacterial plate.
- First antibiotic; saved millions during WWII.
- Led to the entire antibiotic era.
6. Cephalosporin (1945) — Giuseppe Brotzu
- Isolated from sewage water fungus Cephalosporium acremonium in Sardinia.
- Broader spectrum than penicillin; backbone of modern antibiotics.
7. Taxol (1962–1993) — Monroe Wall & Mansukh Wani
- Isolated from Pacific Yew tree bark (Taxus brevifolia).
- Potent anticancer drug for ovarian and breast cancer.
- Supply crisis led to semi-synthesis and tissue culture methods.
8. Artemisinin (1971) — Tu Youyou
- Isolated from sweet wormwood (Artemisia annua).
- Used in Traditional Chinese Medicine for fevers.
- Saved millions from malaria; Nobel Prize 2015.
Key Drugs Table
| Drug | Year | Discoverer | Source | Significance |
|---|---|---|---|---|
| Morphine | 1804 | Sertürner | Opium poppy | First pure alkaloid |
| Quinine | 1820 | Pelletier & Caventou | Cinchona bark | First antimalarial |
| Aspirin | 1897 | Hoffmann | Willow bark derivative | First synthetic from natural |
| Warfarin | 1940 | Link | Sweet clover | First oral anticoagulant |
| Penicillin | 1928 | Fleming | Penicillium mold | First antibiotic |
| Cephalosporin | 1945 | Brotzu | Cephalosporium fungus | Broad-spectrum antibiotic |
| Taxol | 1962 | Wall & Wani | Pacific Yew | Breakthrough anticancer |
| Artemisinin | 1971 | Tu Youyou | Artemisia annua | Nobel-winning antimalarial |
Clinical/Practical Relevance
A pharmacist must respect traditional knowledge while applying scientific methods to validate and standardize natural medicines.
(d) Introduction to Different Herbal/Traditional Pharmacopoeias
Definition
A Pharmacopoeia is an official book containing standards for drugs — their identity, purity, strength, and testing methods. It ensures that medicines are safe, effective, and consistent across manufacturers.
Classification Table
| Pharmacopoeia | Country/Region | Focus | Key Features |
|---|---|---|---|
| Indian Pharmacopoeia (IP) | India | All drugs (synthetic + herbal) | Published by IPC; mandatory for drug manufacturing in India |
| British Herbal Pharmacopoeia (BHP) | UK | Herbal medicines only | Monographs on British herbs; quality standards |
| United States Pharmacopeia (USP) — Herbal Medicines & Dietary Supplements | USA | All drugs + dietary supplements | USP-NF; legally enforceable in USA |
| Ayurvedic Pharmacopoeia of India (API) | India | Ayurvedic drugs | Standards for Ayurvedic single drugs and formulations |
| Unani Pharmacopoeia of India (UPI) | India | Unani (Greco-Arabic) medicines | Standards for Unani drugs |
| American Herbal Pharmacopoeia (AHP) | USA | Herbal medicines | Monographs with therapeutic and safety data |
Official vs. Non-Official; Codified vs. Non-Codified
| Term | Definition | Examples |
|---|---|---|
| Official Drugs | Drugs listed in official pharmacopoeias | Aspirin (IP), Digitalis (IP), Ashwagandha (API) |
| Non-Official Drugs | Drugs NOT in pharmacopoeias but used in practice | Many folk remedies, newly discovered herbs |
| Codified Drugs | Drugs with written standards in recognized systems (Ayurveda, Unani, Siddha) | Triphala (API), Safoof (UPI) |
| Non-Codified Drugs | Drugs used traditionally but without written standards | Many tribal/folk medicines |
Memory tip: Official = "On the list" (pharmacopoeia). Codified = "Written down" (traditional system books).
Diagram/Flowchart Description
Draw a hierarchy tree: At top — "Pharmacopoeias". Branch into "Modern" (IP, USP, BHP) and "Traditional" (API, UPI). Under each, list 2–3 example drugs. Add a side box: "Non-Official/Codified → Folk Medicine".
Clinical/Practical Relevance
Pharmacists must check the pharmacopoeial status of any drug before dispensing. Official drugs have guaranteed quality; non-official drugs require extra verification.
(e) Classification of Crude Drugs
Definition
Crude drugs are natural substances used for medicine in their unprocessed or minimally processed form. They need to be organized (classified) for easy study, identification, and use.
Classification Systems — Table with Merits & Limitations
| Classification | Basis | Merits (Advantages) | Limitations (Disadvantages) |
|---|---|---|---|
| Alphabetical | Name (A–Z) | Easy to locate; no prior knowledge needed | No relationship between drugs; no learning of properties |
| Morphological | External appearance (leaves, roots, barks, etc.) | Easy visual identification; useful in market | Similar-looking drugs may differ chemically |
| Taxonomical | Botanical family/genus/species | Scientific; shows relationships | Requires botanical knowledge; not useful for non-botanists |
| Chemical | Active constituent (alkaloids, glycosides, oils, etc.) | Direct link to pharmacological action | One drug may have multiple constituents |
| Pharmacological | Therapeutic use (cardiac, laxative, analgesic, etc.) | Clinically useful; easy for prescribers | Same drug may have multiple uses |
| Chemotaxonomic | Chemical + Taxonomic (chemical markers in plant families) | Modern; helps in drug discovery and quality control | Complex; requires advanced analytical skills |
Diagram/Flowchart Description
Draw a wheel diagram: Center = "Crude Drug". Six spokes going out to each classification system. Label each spoke with one example drug classified under that system.
Key Drugs/Examples Table
| Drug | Alphabetical | Morphological | Taxonomical | Chemical | Pharmacological | Chemotaxonomic |
|---|---|---|---|---|---|---|
| Digitalis | D | Leaf | Plantaginaceae | Cardiac glycoside | Cardiotonic | Steroidal glycosides in family |
| Senna | S | Leaf | Fabaceae | Anthraquinone glycoside | Laxative | Anthraquinones in Fabaceae |
| Opium | O | Dried latex | Papaveraceae | Alkaloid (morphine) | Analgesic | Benzylisoquinoline alkaloids |
| Cinchona | C | Bark | Rubiaceae | Alkaloid (quinine) | Antimalarial | Quinoline alkaloids in Rubiaceae |
| Castor oil | C | Fixed oil | Euphorbiaceae | Triglyceride | Laxative | Ricinoleic acid marker |
Clinical/Practical Relevance
A pharmacist uses morphological classification for quick market identification, chemical classification to understand drug action, and pharmacological classification to counsel patients on use.
Memory Tricks & Mnemonics
| Topic | Mnemonic | Explanation |
|---|---|---|
| Sources of Drugs | "PAM-M-MP" | Plants, Animals, Microbes, Marine, Minerals, Plant Tissue Culture |
| Sources of Drugs | "Every Pharmacist Must Value Plant & Micro Sources" | First letters: Earth (Mineral), Plants, Microbes, Value (Marine), Plant Tissue, Micro — wait, better: "PAM-MMP" = Plants, Animals, Microbes, Marine, Minerals, Plant Tissue Culture |
| Historical Milestones | "My Quiet Aunt Wore Pink Clothes To Art Class" | Morphine, Quinine, Aspirin, Warfarin, Penicillin, Cephalosporin, Taxol, Artemisinin |
| Pharmacopoeias | "I Bought US Apples Unani" | IP, BHP, USP, AHP, Unani (UPI), plus API (Ayurvedic) |
| Classification Systems | "A Man Took Chemistry, Pharmacology, and Taxonomy" | Alphabetical, Morphological, Taxonomical, Chemical, Pharmacological, Chemotaxonomic |
| Official vs. Codified | "Official = On Paper; Codified = Culture Book" | Official = in pharmacopoeia (official paper). Codified = in traditional system books (cultural texts). |
Quick Revision Table
| Topic | Key Point | Trick/Mnemonic |
|---|---|---|
| Definition of Pharmacognosy | Study of crude drugs from natural sources | "Pharma" = drug, "Gnosy" = knowledge |
| History | 1804: Morphine (first alkaloid) → 1928: Penicillin (first antibiotic) → 1971: Artemisinin (Nobel) | Timeline: 1804 → 1820 → 1897 → 1928 → 1945 → 1962 → 1971 |
| Sources of Drugs | 6 sources: Plant, Animal, Microbial, Marine, Mineral, Tissue Culture | PAM-MMP |
| Plant Tissue Culture Steps | Explant → Sterilize → Medium → Callus → Organ → Plantlet → Extract | "ESMCOPE" |
| Historical Milestones | 8 landmark drugs | "My Quiet Aunt Wore Pink Clothes To Art Class" |
| Pharmacopoeias | IP, USP, BHP, API, UPI, AHP | "I Bought US Apples Unani" |
| Official vs. Non-Official | Official = in pharmacopoeia; Non-official = not listed | "On the list = Official" |
| Codified vs. Non-Codified | Codified = in traditional books; Non-codified = folk use only | "Written down = Codified" |
| Classification Systems | 6 systems: Alphabetical, Morphological, Taxonomical, Chemical, Pharmacological, Chemotaxonomic | "A Man Took Chemistry, Pharmacology, and Taxonomy" |
| Alphabetical Classification | A–Z order; easy lookup | Phonebook style |
| Morphological Classification | By plant part (leaf, root, bark) | "What does it look like?" |
| Taxonomical Classification | By botanical family | "Who are its relatives?" |
| Chemical Classification | By active constituent (alkaloid, glycoside) | "What chemical is inside?" |
| Pharmacological Classification | By therapeutic use (laxative, cardiac) | "What does it treat?" |
| Chemotaxonomic Classification | Chemical + family relationship | "Modern fingerprinting" |
Important Exam Questions
Short-Answer Questions (2–5 Marks)
1. Define Pharmacognosy and explain its scope. (Most Repeated)
2. Describe the different sources of drugs with two examples each. (High-Weightage)
3. Write a short note on Plant Tissue Culture as a source of drugs.
4. What are pharmacopoeias? Name any four pharmacopoeias and their countries.
5. Distinguish between official and non-official drugs with examples. (Most Repeated)
Long-Answer/Essay Questions (10 Marks)
1. Describe the historical milestones in drug discovery with special reference to morphine, penicillin, and artemisinin. (Most Repeated — High-Weightage)
2. Explain the different systems of classification of crude drugs. Discuss the merits and limitations of each. (High-Weightage)
3. Write a detailed note on different pharmacopoeias (modern and traditional) and their importance in pharmacy practice.
Practice MCQs
1. Who is known as the "Father of Pharmacognosy"?
- A) Alexander Fleming
- B) Friedrich Sertürner
- C) Seydler
- D) Tu Youyou
- Answer: C) Seydler — Carl Friedrich Seydler first used the term "Pharmacognosy" in 1815.
2. The first pure alkaloid isolated from a plant was:
- A) Quinine
- B) Morphine
- C) Cocaine
- D) Atropine
- Answer: B) Morphine — Isolated by Sertürner in 1804 from opium.
3. Which of the following is NOT a source of drugs?
- A) Plants
- B) Animals
- C) Synthetic chemicals only
- D) Marine organisms
- Answer: C) Synthetic chemicals only — Synthetic drugs are not natural sources; the question asks for natural sources.
4. Penicillin was discovered from:
- A) Streptomyces
- B) Penicillium notatum
- C) Cephalosporium
- D) Aspergillus
- Answer: B) Penicillium notatum — Discovered by Alexander Fleming in 1928.
5. The Ayurvedic Pharmacopoeia of India (API) contains standards for:
- A) Allopathic drugs
- B) Ayurvedic drugs
- C) Unani drugs
- D) Homeopathic drugs
- Answer: B) Ayurvedic drugs — API specifically standardizes Ayurvedic medicines.
6. Which classification system arranges drugs based on their external appearance?
- A) Chemical
- B) Morphological
- C) Pharmacological
- D) Taxonomical
- Answer: B) Morphological — Based on plant parts (leaf, root, bark, etc.).
7. Artemisinin, used for malaria, was discovered by:
- A) Alexander Fleming
- B) Tu Youyou
- C) Felix Hoffmann
- D) Karl Link
- Answer: B) Tu Youyou — Chinese scientist; Nobel Prize 2015.
8. Codified drugs are those that:
- A) Are listed in the Indian Pharmacopoeia
- B) Have written standards in traditional systems like Ayurveda/Unani
- C) Are newly discovered
- D) Are synthetic only
- Answer: B) Have written standards in traditional systems — Codified = documented in traditional texts.
9. Plant tissue culture is important because:
- A) It replaces all synthetic drugs
- B) It can produce rare medicinal compounds without destroying wild plants
- C) It is cheaper than farming
- D) It only works for food crops
- Answer: B) It can produce rare medicinal compounds without destroying wild plants — Sustainable and protects endangered species.
10. The chemotaxonomic classification of crude drugs is based on:
- A) Color of the drug
- B) Chemical constituents + taxonomic relationships
- C) Market price
- D) Country of origin
- Answer: B) Chemical constituents + taxonomic relationships — Modern approach linking chemistry and botany.
Common Mistakes Students Make
| Mistake | Correction |
|---|---|
| Confusing "Official" with "Codified" | Official = in pharmacopoeia (IP, USP). Codified = in traditional system books (API, UPI). A drug can be both or neither. |
| Forgetting that Taxol comes from a plant | Taxol was originally isolated from the Pacific Yew tree bark, not synthetic. Semi-synthesis and tissue culture came later. |
| Mixing up Penicillin and Cephalosporin sources | Penicillin = Penicillium mold. Cephalosporin = Cephalosporium fungus. Both are fungal but from different genera. |
| Thinking all herbal drugs are "safe" because natural | Natural ≠ Safe. Many natural drugs (morphine, digitalis) are highly toxic if misused. Pharmacognosy includes toxicity study too. |
One-Line Summary Box
If you remember nothing else, remember this:
Pharmacognosy = Study of natural medicines. Drugs come from 6 sources (PAM-MMP). 8 landmark drugs changed medicine forever. Pharmacopoeias ensure quality. Drugs are classified by name, look, family, chemistry, use, or both chemistry+family. Always check if a drug is official (in pharmacopoeia) and codified (in traditional books).
Motivational Closing Line
"Every great medicine started as a leaf, a mold, or a bark. As a pharmacist, you are the bridge between nature's pharmacy and the patient's relief. Master these fundamentals, and you master the origin of healing itself."
| Prepared for A2GSmart.com | BP105T — Introduction to Pharmacognosy | Unit 1: Fundamentals of Pharmacognosy | PCI Syllabus, India |
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