Pharmacognosy Exam Answers
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### Pharmacognosy Basics - **Pharmacognosy:** Study of crude drugs from natural sources (plants, animals, minerals). - **Chemotaxonomy:** Plant classification based on chemical constituents (secondary metabolites like alkaloids, glycosides, flavonoids, terpenoids). Helps in identifying plant relationships, adulteration detection, and drug discovery. - *Example:* Solanaceae plants contain alkaloids like atropine. - **Crude Drugs:** - **Organized Drugs:** Possess cellular structure, obtained from definite plant parts (roots, stems, leaves). - **Unorganized Drugs:** Lack cellular structure, obtained as exudates or secretions (gums, resins, latex). ### Drug Adulteration - **Definition:** Debasement of crude drugs by mixing inferior, spurious, or harmful substances. - **Types:** - **Intentional Adulteration:** Deliberate mixing. - **Unintentional Adulteration:** Accidental mixing. - **Substitution:** Replacing with a different substance. - **Deterioration:** Due to improper storage. ### Evaluation of Crude Drugs - **Purpose:** Ensures quality and purity of crude drugs. - **Methods:** - **Organoleptic:** Sensory evaluation (taste, smell, appearance). - **Microscopic:** Examination under a microscope for cellular structure, palisade ratio. - **Palisade Ratio:** Average number of palisade cells beneath one epidermal cell. - **Lycopodium Spore Method:** Quantitative microscopic method for powdered drugs. - **Physical:** Determination of physical constants (e.g., specific gravity, melting point). - **Chemical:** Identification tests, assays for active constituents. - **Biological:** In vivo or in vitro tests to assess pharmacological activity. ### Key Compounds - **Glycosides:** Organic compounds that yield sugar and aglycone upon hydrolysis. - **Classification:** Cardiac, anthraquinone, saponin, cyanogenetic glycosides. - **Identification Tests:** Borntrager's test, Keller-Killiani test. - **Uses:** Cardiac tonics, laxatives, expectorants. - **Alkaloids:** Nitrogen-containing organic compounds, often basic. - **Isolation:** 1. Powder crude drug. 2. Extract with dilute acid. 3. Filter the extract and make it alkaline. 4. Extract alkaloids using organic solvents (chloroform, ether). 5. Recover by evaporation. - **Volatile Oil:** Aromatic oils that evaporate at room temperature. - **Resin:** Amorphous plant products, insoluble in water but soluble in alcohol. ### Scope of Pharmacognosy - **Deals with:** Identification, evaluation, cultivation, collection, and standardization of crude drugs. - **Role:** Important in drug discovery and quality control of herbal medicines.
