Introduction To Pharmacognosy And Phytochemistry Flashcards
Pharmacognosy
Definition: Derived from Greek pharmakon (remedy) and gignosco (knowledge). It is the science of biogenic or nature-derived pharmaceuticals and poisons.
Focus of Pharmacognosy
Medicinal plants
Crude herbs (herbal substance) or extracts (phytotherapy)
Pure compounds like morphine
Foods with additional health benefits, known as nutraceuticals
Examples of Crude Drugs
Ginkgo biloba:
Use: Cognitive deficiencies
Senna (Cassia spp.):
Use: Constipation
St John’s Wort (Hypericum perforatum):
Use: Treatment of mild to moderate depression
Pure compounds derived from plants
Morphine from opium poppy (Papaver somniferum) used as an analgesic
Digoxin and other digitalis glycosides from foxglove (Digitalis spp.) used to treat heart failure
Taxol from the Pacific yew (Taxus brevifolia) used as an anticancer treatment
Nutraceuticals or ‘Functional Foods’
Garlic, ginger, turmeric, and many other herbs and spices
Carotenoid-containing plants such as tomatoes, carrots, and many other vegetables
Role of natural drug substances in medicine
Serve as extremely useful natural drugs
Provide basic compounds affording less toxic and more effective drug molecules
Exploration of biological-active-prototypes towards newer and better synthetic drugs
Modification of inactive natural products by suitable biological/chemical means into potent drugs
How many medicinal plants are extensively used, and what percentage of them possess well-established active constituents?
• Around 20,000 medicinal plants used, 1.4% with well-established active constituents.
• Example: Artemisinin from Artemisia Annua Linne for cerebral malaria.
What role do naturally occurring plant products play in drug synthesis?
Naturally occurring plant products serve as prototypes for synthesizing potent compounds.
How are better synthetic drugs developed based on biologically active prototypes?
Example: Procaine from cocaine with improved therapeutic index.
Constituents
Definition: Chemical substances present in the plant and animal kingdom are termed as ‘constituents.’
Active Constituent vs. Inert Constituent
Active Constituent:
Definition: Entities solely responsible for pharmacological, microbial, or therapeutic activities.
Examples: Alkaloids, glycosides, steroids.
Inert Constituent:
Definition: Compounds in plants and animals without definite therapeutic values but useful in drug formulation or surgery.
Provide examples of active constituents
Examples: Alkaloids, glycosides, steroids
Provide examples of inert constituents
Examples: Cellulose, lignin, cutin.
Drug Biosynthesis (Biogenesis)
Definition: Exclusive study of biochemical pathways leading to the formulation of active constituents, mainly employed as drugs
What does drug biosynthesis focus on, and what are active constituents?
- Focuses on biochemical pathways that lead to formation of active constituents
- Active constituents are defined as compound with pharmacological properties
