Terpenoids – Artemisinin MCQs With Answer: Artemisinin is a sesquiterpene lactone terpenoid from Artemisia annua that transformed antimalarial therapy. This focused MCQ set for B.Pharm students covers artemisinin chemistry, biosynthesis, the vital endoperoxide (1,2,4-trioxane) pharmacophore, activation by heme/iron, structure–activity relationships, major derivatives (artemether, artesunate, dihydroartemisinin), pharmacokinetics, formulation, semi-synthetic production, resistance mechanisms (K13 mutations), analytical methods (HPLC/LC-MS), and quality-control considerations. Questions blend mechanistic depth with clinical and pharmaceutical applications to reinforce exam readiness and practical understanding. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which terpenoid class does artemisinin belong to?
- Monoterpene
- Sesquiterpene lactone
- Diterpene
- Triterpene
Correct Answer: Sesquiterpene lactone
Q2. What is the primary plant source of naturally occurring artemisinin?
- Digitalis purpurea
- Cinchona officinalis
- Artemisia annua
- Taxus brevifolia
Correct Answer: Artemisia annua
Q3. Which structural feature is essential for artemisinin’s antimalarial activity?
- Lactone carbonyl
- Endoperoxide (1,2,4-trioxane) bridge
- Phenolic hydroxyl group
- Conjugated diene system
Correct Answer: Endoperoxide (1,2,4-trioxane) bridge
Q4. Activation of artemisinin in the parasite mainly requires which chemical species?
- Heme-derived ferrous iron (Fe2+)
- Molecular oxygen
- NADPH oxidase
- Glutathione
Correct Answer: Heme-derived ferrous iron (Fe2+)
Q5. What is the major active metabolite common to many artemisinin derivatives?
- Artemether
- Dihydroartemisinin
- Artemisinic acid
- Artesunate
Correct Answer: Dihydroartemisinin
Q6. Which artemisinin derivative is preferred for intravenous therapy in severe malaria?
- Artemether
- Artesunate
- Artemisinic acid
- Dihydroartemisinin suppository
Correct Answer: Artesunate
Q7. Why are artemisinins generally not recommended as monotherapy for falciparum malaria?
- They have no effect on ring stages
- Short half-life and risk of resistance development
- High oral bioavailability eliminates combination needs
- They cannot be combined with other drugs chemically
Correct Answer: Short half-life and risk of resistance development
Q8. Which genetic marker is most commonly associated with artemisinin resistance in Plasmodium falciparum?
- pfcrt mutations
- dhfr point mutations
- K13 propeller domain mutations
- mdr1 gene amplification
Correct Answer: K13 propeller domain mutations
Q9. Semi-synthetic production of artemisinin precursors has used engineered microbes to produce which intermediate?
- Artemisinin itself directly from yeast
- Artemisinic acid
- Dihydroartemisinin
- Artemether
Correct Answer: Artemisinic acid
Q10. Which analytical technique is most widely used for quantitative determination of artemisinin and its derivatives in formulations?
- UV spectrophotometry without separation
- HPLC with UV or MS detection (LC-MS)
- TLC visual inspection only
- Infrared spectroscopy
Correct Answer: HPLC with UV or MS detection (LC-MS)
Q11. The endoperoxide bond in artemisinin, upon activation, primarily leads to formation of:
- Peroxyl radicals stable in aqueous media
- Carbon-centered radicals that alkylate biomolecules
- Nitrogen-centered radicals targeting DNA
- Singlet oxygen without alkylation
Correct Answer: Carbon-centered radicals that alkylate biomolecules
Q12. Which property best describes the elimination half-life of artemisinin derivatives like artemether and artesunate?
- Very long (several days)
- Prolonged (12–24 hours)
- Short (1–3 hours)
- Variable but always >48 hours
Correct Answer: Short (1–3 hours)
Q13. Common early adverse effects associated with artemisinin therapy include:
- Profound renal failure
- Severe agranulocytosis
- Nausea, vomiting and dizziness
- Immediate anaphylaxis in all patients
Correct Answer: Nausea, vomiting and dizziness
Q14. Which formulation characteristic is critical for ensuring rapid absorption of intramuscular artemether preparations?
- High water solubility
- Use of oil-based vehicle prolonging absorption
- Presence of enteric coating
- Microencapsulation to prevent release
Correct Answer: Use of oil-based vehicle prolonging absorption
Q15. Why is artemisinin often administered in combination as an ACT (artemisinin-based combination therapy)?
- To reduce treatment cost only
- To enhance taste and palatability
- To combine rapid parasite clearance with a partner drug that eliminates residual parasites and reduces resistance
- Because artemisinin cannot be formulated alone
Correct Answer: To combine rapid parasite clearance with a partner drug that eliminates residual parasites and reduces resistance
Q16. Which statement about the photostability of artemisinin compounds is correct?
- They are highly photostable and do not degrade in light
- They are sensitive to light and should be protected from exposure
- Light exposure converts them into more active forms
- They require UV irradiation for activation before administration
Correct Answer: They are sensitive to light and should be protected from exposure
Q17. The artemisinin pharmacophore is best described as which ring system?
- 1,2,4-trioxane (endoperoxide) ring
- Alpha-lactam ring
- Porphyrin macrocycle
- Benzodiazepine scaffold
Correct Answer: 1,2,4-trioxane (endoperoxide) ring
Q18. In the parasite food vacuole hypothesis, artemisinin interacts primarily with which molecule to become activated?
- Hemozoin crystal
- Heme (ferriprotoporphyrin IX) or ferrous iron derived from hemoglobin digestion
- Host DNA
- Parasite ribosomal RNA
Correct Answer: Heme (ferriprotoporphyrin IX) or ferrous iron derived from hemoglobin digestion
Q19. Which pharmacokinetic interaction is characteristic of artemisinin derivatives?
- They are potent CYP450 inhibitors causing increased co-drug levels
- They are inducers of certain CYP enzymes reducing co-administered drug levels
- They have no effect on drug-metabolizing enzymes
- They block renal tubular secretion of all drugs
Correct Answer: They are inducers of certain CYP enzymes reducing co-administered drug levels
Q20. How many isoprene units constitute a sesquiterpene like artemisinin?
- One isoprene unit (C5)
- Two isoprene units (C10)
- Three isoprene units (C15)
- Four isoprene units (C20)
Correct Answer: Three isoprene units (C15)
Q21. Which derivative is more water-soluble and often used for oral or parenteral formulations after conversion?
- Artemether (highly water-soluble)
- Artesunate (water-soluble prodrug)
- Artemisinic acid (water-soluble antimalarial)
- Taxanes (related compounds)
Correct Answer: Artesunate (water-soluble prodrug)
Q22. For sensitive and specific measurement of artemisinin levels in plasma, the preferred method is:
- Colorimetric assay without separation
- LC-MS/MS (liquid chromatography–tandem mass spectrometry)
- Gravimetric analysis
- Titration with iodine
Correct Answer: LC-MS/MS (liquid chromatography–tandem mass spectrometry)
Q23. The primary biochemical consequence of artemisinin radical formation in parasites is:
- Inhibition of DNA gyrase exclusively
- Alkylation and damage to multiple parasite proteins and lipids
- Competitive antagonism at parasite neurotransmitter receptors
- Chelation of calcium in host cells only
Correct Answer: Alkylation and damage to multiple parasite proteins and lipids
Q24. Which clinical sign is most indicative of emerging artemisinin resistance in a patient treated appropriately with an ACT?
- Immediate clinical deterioration within hours
- Delayed parasite clearance (prolonged time to negative smear)
- Acute hypersensitivity reaction after first dose
- Excessive sedation unrelated to malaria
Correct Answer: Delayed parasite clearance (prolonged time to negative smear)
Q25. Which statement about production of artemisinin from plant material is correct?
- Artemisinin content in Artemisia annua is uniform across cultivars
- Harvest time and cultivation strongly influence artemisinin yield
- Extraction is unnecessary because the plant is administered whole
- Artemisinin is synthesized in high yields by all plants
Correct Answer: Harvest time and cultivation strongly influence artemisinin yield
Q26. Co-administration of rifampicin with artemisinin is likely to cause which effect?
- Increased artemisinin plasma levels due to CYP inhibition
- No interaction between the two drugs
- Reduced artemisinin exposure due to CYP induction by rifampicin
- Complete metabolic blockade increasing toxicity
Correct Answer: Reduced artemisinin exposure due to CYP induction by rifampicin
Q27. Which quality control parameter is particularly challenging for artemisinin oral solid dosage forms?
- Assay and dissolution due to low water solubility and short stability
- Uniformity of color only
- Melting point determination in tablets
- Sterility testing for non-sterile tablets
Correct Answer: Assay and dissolution due to low water solubility and short stability
Q28. Why is derivatization often performed before GC analysis of artemisinin?
- To reduce polarity and increase volatility for GC detection
- To make it fluorescent for UV detection
- To polymerize it for better chromatographic behavior
- Derivatization is never required for GC analysis
Correct Answer: To reduce polarity and increase volatility for GC detection
Q29. Which artemisinin derivative is primarily responsible for the rapid parasiticidal effect seen within hours of dosing?
- Artemisinic acid (slow-acting precursor)
- Dihydroartemisinin (rapidly active metabolite)
- Chloroquine (non-artemisinin comparator)
- Primaquine (gametocytocidal only)
Correct Answer: Dihydroartemisinin (rapidly active metabolite)
Q30. A major formulation consideration for maintaining artemisinin stability is to:
- Expose products to high humidity during storage
- Store formulations protected from heat, light, and moisture
- Always freeze oral tablets to prevent degradation
- Add strong oxidizing agents to packaging
Correct Answer: Store formulations protected from heat, light, and moisture
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