MPharm Master of Pharmacy Pharmacognosy and Natural Products 2 — Questions and Answers
Question 1: What is the mechanism of action of colchicine, a plant-derived drug used for gout?
- Inhibits xanthine oxidase to reduce uric acid production
- Binds tubulin and inhibits microtubule polymerization to reduce neutrophil migration (Correct answer)
- Blocks urate reabsorption in the renal tubules
- Inhibits COX-2 to reduce prostaglandin synthesis
Correct answer: Binds tubulin and inhibits microtubule polymerization to reduce neutrophil migration
Colchicine binds to tubulin heterodimers, disrupting microtubule formation and inhibiting neutrophil chemotaxis and inflammation in acute gout attacks.
Question 2: Which botanical dietary supplement is contraindicated with anticoagulants due to its platelet-inhibiting properties?
- Echinacea
- Ginkgo biloba (Correct answer)
- Valerian
- Peppermint
Correct answer: Ginkgo biloba
Ginkgo biloba contains ginkgolides that inhibit platelet-activating factor (PAF), increasing bleeding risk when combined with anticoagulants like warfarin.
Question 3: The bitter acids in hops (Humulus lupulus) contribute to sedative effects primarily through which mechanism?
- Opioid receptor agonism
- GABA-A receptor positive modulation (Correct answer)
- Serotonin reuptake inhibition
- Histamine H1 receptor blockade
Correct answer: GABA-A receptor positive modulation
Hop bitter acids and methylbutenol metabolites have been shown to positively modulate GABA-A receptors, contributing to sedative and anxiolytic effects.
Question 4: In pharmacognosy, what is the difference between a primary and secondary metabolite?
- Primary metabolites are toxic; secondary metabolites are therapeutic
- Primary metabolites are essential for basic cell functions; secondary metabolites are not directly required but serve ecological or protective roles (Correct answer)
- Primary metabolites come from roots; secondary metabolites from leaves
- Primary metabolites are water-soluble; secondary metabolites are fat-soluble
Correct answer: Primary metabolites are essential for basic cell functions; secondary metabolites are not directly required but serve ecological or protective roles
Primary metabolites (carbohydrates, proteins, lipids) are essential for cell growth and survival, while secondary metabolites (alkaloids, terpenes, phenolics) serve defense, attraction, or competition functions.
Question 5: Curcumin, the active compound in turmeric, exhibits anti-inflammatory effects primarily by inhibiting which pathway?
- COX-2 and NF-κB signaling pathways (Correct answer)
- HMG-CoA reductase
- ACE enzyme
- 5-alpha reductase
Correct answer: COX-2 and NF-κB signaling pathways
Curcumin suppresses inflammatory gene expression by inhibiting NF-κB activation and downregulating COX-2 and LOX enzyme pathways.
Question 6: Which standardization method is most appropriate for herbal extracts to ensure consistent pharmacological activity?
- Standardization to a marker compound with known activity (Correct answer)
- Color standardization only
- Standardization to total plant weight
- Standardization to water content
Correct answer: Standardization to a marker compound with known activity
Standardizing herbal extracts to a pharmacologically relevant marker compound ensures consistent potency, therapeutic efficacy, and quality across batches.
MPharm Master of Pharmacy Pharmacognosy and Natural Products 2
What is the mechanism of action of colchicine, a plant-derived drug used for gout?