Therapeutic uses of secondary metabolites MCQs With Answer

Therapeutic uses of secondary metabolites MCQs With Answer

Secondary metabolites are bioactive natural products from plants, microbes, and fungi that provide diverse therapeutic effects. This introduction for B. Pharm students outlines major classes—alkaloids, terpenoids, flavonoids, glycosides, and microbial antibiotics—their mechanisms of action, clinical uses (analgesic, anticancer, antimalarial, cardiotonic, antimicrobial), safety profiles, extraction and standardization methods, and relevance in drug discovery and phytopharmaceutical development. Emphasis is on pharmacology, structure–activity relationships, toxicities and regulatory aspects to build strong competency in pharmacognosy and drug development. Practical MCQs will solidify your understanding of mechanisms, examples, assays, and formulation challenges. ‘Now let’s test your knowledge with 30 MCQs on this topic.’

Q1. Which statement best defines secondary metabolites?

• Compounds essential for cellular respiration and immediate growth
• Molecules produced during primary metabolism like amino acids
• Bioactive compounds not directly required for growth but important for ecological interactions
• Inorganic cofactors required for enzyme activity

Correct Answer: Bioactive compounds not directly required for growth but important for ecological interactions

Q2. Which class of secondary metabolites commonly includes alkaloids like morphine and quinine?

• Terpenoids
• Alkaloids
• Flavonoids
• Glycosides

Correct Answer: Alkaloids

Q3. Paclitaxel, an anticancer drug, is derived from which type of secondary metabolite?

• Alkaloid
• Terpenoid (diterpene, taxane)
• Flavonoid
• Cardiac glycoside

Correct Answer: Terpenoid (diterpene, taxane)

Q4. Artemisinin used in malaria treatment is classified as which secondary metabolite?

• A steroidal glycoside
• An alkaloid
• A sesquiterpene lactone (terpenoid)
• A flavonoid

Correct Answer: A sesquiterpene lactone (terpenoid)

Q5. Which secondary metabolite class is most associated with antioxidant and anti-inflammatory properties?

• Flavonoids
• Alkaloids
• Polyketide antibiotics
• Cardiac glycosides

Correct Answer: Flavonoids

Q6. Which secondary metabolite is a well-known cardiac glycoside used for heart failure?

• Digoxin
• Penicillin
• Atropine
• Quinine

Correct Answer: Digoxin

Q7. Statins such as lovastatin are originally derived from which biological source?

• Higher plants
• Fungi (Aspergillus species)
• Marine algae
• Synthetic chemical modification only

Correct Answer: Fungi (Aspergillus species)

Q8. Which secondary metabolite mechanism is responsible for the analgesic effect of morphine?

• Inhibition of bacterial cell wall synthesis
• Agonism at mu-opioid receptors in the central nervous system
• Blockade of beta-adrenergic receptors
• Inhibition of HMG-CoA reductase

Correct Answer: Agonism at mu-opioid receptors in the central nervous system

Q9. Which extraction parameter is critical for preserving labile secondary metabolites during isolation?

• High-temperature prolonged reflux
• Use of non-volatile, nonpolar solvents only
• Low temperature and minimal exposure to light and oxygen
• Strong acidic hydrolysis in all cases

Correct Answer: Low temperature and minimal exposure to light and oxygen

Q10. Which assay is commonly used to quantify total phenolic content in plant extracts?

• Benedict’s test
• Folin–Ciocalteu assay
• Kirby–Bauer disk diffusion
• Kjeldahl nitrogen estimation

Correct Answer: Folin–Ciocalteu assay

Q11. Which secondary metabolite class includes erythromycin and tetracycline?

• Cardiac glycosides
• Alkaloids
• Polyketide antibiotics
• Terpenoids

Correct Answer: Polyketide antibiotics

Q12. Atropine, used as an antimuscarinic agent, is derived from which plant-derived secondary metabolite class?

• Flavonoid
• Cardiac glycoside
• Tropane alkaloid
• Saponin

Correct Answer: Tropane alkaloid

Q13. Which secondary metabolite is the primary active component of grapefruit that affects CYP3A4 and drug interactions?

• Quercetin (flavonoid)
• Furanocoumarins (e.g., bergamottin)
• Anthocyanins
• Terpenoidal sterols

Correct Answer: Furanocoumarins (e.g., bergamottin)

Q14. Which property is important when standardizing herbal extracts for therapeutic use?

• Only the color of the extract
• Quantification of marker compounds and batch-to-batch consistency
• Elimination of all secondary metabolites
• Maximizing solvent residues

Correct Answer: Quantification of marker compounds and batch-to-batch consistency

Q15. Which secondary metabolite mechanism underlies the anticancer activity of paclitaxel?

• DNA alkylation
• Microtubule stabilization inhibiting mitosis
• Topoisomerase II inhibition only
• Inhibition of bacterial protein synthesis

Correct Answer: Microtubule stabilization inhibiting mitosis

Q16. Which technique is commonly used for separation and identification of secondary metabolites in quality control?

• Thin-layer chromatography (TLC) and HPLC
• Gram staining
• Tissue histology only
• Direct visual inspection without instrumentation

Correct Answer: Thin-layer chromatography (TLC) and HPLC

Q17. Which microbial secondary metabolite class includes penicillin?

• Alkaloids
• Beta-lactam antibiotics (secondary metabolites of fungi)
• Cardiac glycosides
• Flavonoids

Correct Answer: Beta-lactam antibiotics (secondary metabolites of fungi)

Q18. Glycoside hydrolysis commonly releases which two components?

• An aglycone and a sugar
• Two amino acids
• A lipid and a steroid
• An inorganic salt and a vitamin

Correct Answer: An aglycone and a sugar

Q19. Which secondary metabolite is known for antimalarial activity from Cinchona tree?

• Atropine
• Quinine (an alkaloid)
• Paclitaxel
• Lovastatin

Correct Answer: Quinine (an alkaloid)

Q20. Which factor most influences biosynthesis of secondary metabolites in plants?

• Genotype, environmental stress, and developmental stage
• Only soil pH regardless of genetics
• Time of day exclusively
• Presence of antibiotics in the soil alone

Correct Answer: Genotype, environmental stress, and developmental stage

Q21. Which secondary metabolite group commonly interacts with enzymes by chelation of metal ions and free radical scavenging?

• Terpenoids
• Flavonoids
• Alkaloids
• Saponins

Correct Answer: Flavonoids

Q22. Which secondary metabolite is associated with hepatotoxic pyrrolizidine alkaloids found in some herbal products?

• Glycyrrhizin
• Pyrrolizidine alkaloids
• Taxanes
• Statins

Correct Answer: Pyrrolizidine alkaloids

Q23. Which regulatory document is important when developing phytopharmaceuticals for clinical use?

• ICH guidelines and national herbal drug regulations
• Only local compounding pharmacy notes
• Unverified internet sources
• Only ancient herbals without scientific validation

Correct Answer: ICH guidelines and national herbal drug regulations

Q24. Which analytical parameter assesses biological activity rather than chemical content of a secondary metabolite?

• Bioassay (e.g., antimicrobial or cytotoxicity assay)
• UV absorbance without correlation to activity
• Colorimetric observation only
• Moisture content measurement

Correct Answer: Bioassay (e.g., antimicrobial or cytotoxicity assay)

Q25. Which secondary metabolite is primarily responsible for the bitter taste and antimalarial property of Artemisia annua?

• Artemisinin
• Curcumin
• Resveratrol
• Ginsenoside

Correct Answer: Artemisinin

Q26. Which adverse effect is classically associated with cardiac glycosides like digoxin?

• Hypoglycemia
• Cardiac arrhythmias and visual disturbances
• Severe neutropenia only
• Hepatotoxicity as primary toxicity

Correct Answer: Cardiac arrhythmias and visual disturbances

Q27. In structure–activity relationship (SAR), what modification often increases lipophilicity of a secondary metabolite to improve membrane permeability?

• Addition of polar hydroxyl groups
• Introduction of nonpolar alkyl chains or esterification
• Cleavage of aromatic rings
• Addition of charged sulfate groups

Correct Answer: Introduction of nonpolar alkyl chains or esterification

Q28. Which technique is preferred for preparative isolation of a pure secondary metabolite from plant extract?

• Preparative HPLC
• Gram staining
• Light microscopy only
• Thin smear culture

Correct Answer: Preparative HPLC

Q29. Which secondary metabolite-target interaction explains antibacterial activity of beta-lactams?

• Inhibition of bacterial DNA gyrase
• Binding to penicillin-binding proteins inhibiting cell wall synthesis
• Blockade of eukaryotic ribosomes
• Antagonism of opioid receptors

Correct Answer: Binding to penicillin-binding proteins inhibiting cell wall synthesis

Q30. For safe clinical use of herbal products, which practice is most important?

• Assuming safety because natural origin
• Standardization, toxicity testing, documentation of interactions, and evidence-based dosing
• Using maximum possible dose without studies
• Avoiding any form of regulatory oversight

Correct Answer: Standardization, toxicity testing, documentation of interactions, and evidence-based dosing

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com