MPharm Master of Pharmacy Pharmacognosy and Natural Products 1 — Questions and Answers
Question 1: Which class of secondary metabolites includes morphine, quinine, and vincristine?
- Terpenoids
- Alkaloids (Correct answer)
- Flavonoids
- Glycosides
Correct answer: Alkaloids
Alkaloids are nitrogen-containing secondary metabolites derived from amino acids and include many pharmacologically significant compounds like morphine and quinine.
Question 2: What is the pharmacologically active component of the foxglove plant (Digitalis purpurea) used in cardiac therapy?
- Atropine
- Digoxin and digitoxin (cardiac glycosides) (Correct answer)
- Quinine
- Reserpine
Correct answer: Digoxin and digitoxin (cardiac glycosides)
Digitalis contains cardiac glycosides (digoxin, digitoxin) that inhibit Na+/K+ ATPase, increasing cardiac contractility used in heart failure treatment.
Question 3: Which extraction technique is most commonly used to isolate essential oils from plant material in pharmacognosy?
- Soxhlet extraction
- Steam distillation (Correct answer)
- Cold maceration
- Ultrasound-assisted extraction
Correct answer: Steam distillation
Steam distillation is the classical method for isolating volatile essential oils; steam carries the volatiles, which are then condensed and separated.
Question 4: Artemisinin, the antimalarial compound derived from Artemisia annua, belongs to which chemical class?
- Alkaloid
- Sesquiterpene lactone endoperoxide (Correct answer)
- Flavonoid glycoside
- Triterpene saponin
Correct answer: Sesquiterpene lactone endoperoxide
Artemisinin is a sesquiterpene lactone containing a unique 1,2,4-trioxane endoperoxide bridge essential for its antimalarial activity.
Question 5: Which test is used to detect the presence of tannins in plant extracts?
- Molisch's test
- Ferric chloride test (Correct answer)
- Biuret test
- Benedict's test
Correct answer: Ferric chloride test
Tannins form blue-black or green complexes with ferric chloride (FeCl₃) due to their phenolic hydroxyl groups chelating iron.
Question 6: Which plant is the natural source of taxol (paclitaxel), an important anticancer agent?
- Vinca rosea
- Taxus brevifolia (Pacific yew) (Correct answer)
- Catharanthus roseus
- Podophyllum peltatum
Correct answer: Taxus brevifolia (Pacific yew)
Paclitaxel was originally isolated from the bark of Taxus brevifolia (Pacific yew) and works by stabilizing microtubules to prevent cell division.
