Introduction
Pharmacognosy is the branch of pharmaceutical science that deals with natural drugs obtained from plants, animals and minerals. In early days, identification of drugs was done mainly through external appearance. With time, the subject expanded to include anatomical, chemical and biological study of crude drugs. The word Pharmacognosy comes from Greek: “Pharmakon” meaning drug and “Gnosis” meaning knowledge.
Definition
Pharmacognosy is the scientific study of crude drugs from natural sources. It includes their identification, classification, cultivation, collection, preparation, storage, evaluation and use. Crude drugs may be entire plants, plant parts, animal products or minerals used with minimum processing.
Crude Drugs and Their Sources
Crude drugs are natural substances used without extensive processing, except drying or size reduction. Examples:
- Plant sources: Senna leaves, digitalis leaf, clove flower bud, cinchona bark, Rauwolfia root.
- Animal sources: Beeswax, wool fat, gelatin, vitamins.
- Mineral sources: Talc, chalk, bentonite.
- Marine sources: Plants and animals with new pharmacological potential.
Introduction and Early Development
Pharmacognosy grew from early human experience with medicinal plants. Ancient civilizations like India, China, Egypt and Greece documented the use of herbs for healing. Later, the subject became a scientific discipline closely related to botany and pharmacy.
Historical Highlights
- Ancient India: Rigveda and Atharvaveda described many medicinal plants. Ayurveda classified herbs systematically.
- China: Shen Nung’s herbal text “Pentaso” is one of the oldest records.
- Greek contributions: Hippocrates is known as the father of medicine. Dioscorides wrote “De Materia Medica” describing 600 medicinal plants.
- Seydler (1815): First used the term Pharmacognosy in “Analecta Pharmacognostica”.
- Galen (131–200 AD): Developed methods of extraction, leading to Galenical Pharmacy.
Modern Pharmacognosy
Modern pharmacognosy integrates advanced biological and chemical sciences, including phytochemistry, biotechnology, chromatography techniques (TLC, HPLC, GC), mass spectrometry and molecular biology.
Important milestones include isolation of active compounds such as:
- Reserpine from Rauwolfia
- Vincristine and vinblastine from Vinca
- Digitoxin from Digitalis
- Morphine and codeine from opium poppy
- Ergotamine from ergot
Modern research also focuses on biosynthetic pathways, molecular docking, genetic studies and development of nutraceuticals and nanomedicines.
Functions of a Pharmacognosist
- Identify drug sources and authenticate plant materials.
- Study morphological and microscopic characters.
- Evaluate purity, potency and absence of adulterants.
- Plan cultivation and collection of medicinal plants.
- Understand extraction and isolation methods.
- Study phytochemicals and their therapeutic actions.
- Perform physical, chemical and biological evaluation of crude drugs.
Scope of Pharmacognosy
Pharmacognosy plays a major role in traditional and modern healthcare systems. India’s vast biodiversity supports Ayurvedic, Siddha and folk medicine practices, which use thousands of medicinal plants.
Key Areas in the Scope
- Drug discovery: Natural products continue to be a major source of new medicines.
- Quality control: Ensures identity, purity and safety of herbal drugs.
- Phytopharmaceuticals: Development of standardized plant-based medicines.
- Pharmacological research: Understanding the activity and mode of action of plant constituents.
- Industrial applications: Use of natural substances in pharmaceuticals, cosmetics and food.
Pharmacognosy is also linked with various other sciences such as botany, zoology, pharmacology, medicinal chemistry, molecular biology, marine science, nanotechnology and nutraceutical research.
Contribution to Natural and Physical Science
Pharmacognosy contributes to scientific progress through:
- Study of drug interactions (drug–drug and drug–food).
- Bioassay-guided extraction of active compounds.
- Use of herbal ingredients in pharmaceutical manufacturing.
- Ensuring safety, efficacy and quality of natural drugs.
Detailed Notes:
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