Introduction: This concise guide on Nature and source of drugs MCQs With Answer helps B. Pharm students master pharmacognosy and drug origin concepts. It covers chemical and biological classification, natural product biosynthesis, microbial and marine drug sources, extraction and isolation techniques, phytochemical screening, analytical methods (TLC, HPTLC, NMR, MS), and modern drug discovery approaches like semi-synthesis and combinatorial chemistry. Emphasis on clinical examples (e.g., morphine, paclitaxel, artemisinin, penicillin), quality control, and chemotaxonomy strengthens applied understanding. Ideal for exam prep and conceptual clarity, these questions probe deeper into mechanisms, sourcing, and analytical validation required for pharmaceutical practice. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary difference between primary and secondary metabolites in drug-producing organisms?
- Primary metabolites are involved in growth and are ubiquitous; secondary metabolites are non-essential, species-specific and often bioactive
- Primary metabolites are always toxic; secondary metabolites are always therapeutic
- Primary metabolites are only produced by microbes; secondary metabolites are only produced by plants
- Primary metabolites have higher molecular weight than secondary metabolites
Correct Answer: Primary metabolites are involved in growth and are ubiquitous; secondary metabolites are non-essential, species-specific and often bioactive
Q2. Which class of natural products does paclitaxel (taxol) belong to?
- Alkaloids
- Terpenoids (diterpenes)
- Flavonoids
- Polyketides
Correct Answer: Terpenoids (diterpenes)
Q3. Artemisinin is derived from which plant and which biosynthetic pathway primarily forms it?
- Cinchona officinalis; shikimate pathway
- Digitalis lanata; mevalonate pathway
- Artemisia annua; terpenoid (mevalonate/non-mevalonate) pathway
- Catharanthus roseus; polyketide pathway
Correct Answer: Artemisia annua; terpenoid (mevalonate/non-mevalonate) pathway
Q4. Which reagent is commonly used for preliminary detection of alkaloids in crude plant extracts?
- Liebermann-Burchard reagent
- Dragendorff’s reagent
- Benedict’s reagent
- Folin-Ciocalteu reagent
Correct Answer: Dragendorff’s reagent
Q5. Which method is most suitable for separating thermolabile plant constituents without continuous heating?
- Soxhlet extraction
- Maceration at room temperature
- Hydrodistillation
- Reflux extraction at high temperature
Correct Answer: Maceration at room temperature
Q6. Penicillin is an example of a drug obtained from which source?
- Plant alkaloid
- Fungal (mold) secondary metabolite produced by Penicillium species
- Marine sponge peptide
- Synthetic combinatorial chemistry product
Correct Answer: Fungal (mold) secondary metabolite produced by Penicillium species
Q7. Which chromatographic technique is preferred for rapid fingerprinting and standardization of herbal extracts in B.Pharm labs?
- Gas chromatography (GC)
- High-performance thin-layer chromatography (HPTLC)
- Gel permeation chromatography
- Paper chromatography
Correct Answer: High-performance thin-layer chromatography (HPTLC)
Q8. Digoxin is classified chemically as which type of natural product?
- Cardiac glycoside (steroidal glycoside)
- Alkaloid
- Saponin
- Flavonoid
Correct Answer: Cardiac glycoside (steroidal glycoside)
Q9. Which spectral technique gives direct information about molecular weight and fragmentation pattern useful in natural product elucidation?
- Infrared (IR) spectroscopy
- Mass spectrometry (MS)
- Ultraviolet-visible (UV-Vis) spectroscopy
- Optical rotation
Correct Answer: Mass spectrometry (MS)
Q10. Semi-synthetic drugs are best described as:
- Entirely synthesized from petrochemical precursors
- Natural products chemically modified to improve activity or pharmacokinetics
- Isolated natural products used unchanged
- Combinatorial library members
Correct Answer: Natural products chemically modified to improve activity or pharmacokinetics
Q11. Which plant-derived drug is a classic example of an alkaloid used as an analgesic?
- Atropine
- Morphine
- Digitoxin
- Aspirin
Correct Answer: Morphine
Q12. In bioassay-guided fractionation, what is the primary objective?
- To maximize extract dye content
- To isolate and identify active compounds based on biological activity testing of fractions
- To remove water from extracts
- To perform large-scale fermentation
Correct Answer: To isolate and identify active compounds based on biological activity testing of fractions
Q13. Which of the following is a polyketide antibiotic produced by Streptomyces species?
- Penicillin
- Streptomycin
- Erythromycin
- Nicotine
Correct Answer: Erythromycin
Q14. Chemotaxonomy in drug discovery is primarily used to:
- Classify drugs by therapeutic use
- Use chemical constituents to help classify plants and predict presence of drug-like compounds
- Standardize chromatographic conditions
- Determine LD50 values
Correct Answer: Use chemical constituents to help classify plants and predict presence of drug-like compounds
Q15. Which solvent system property is most important when performing partition extraction of phytochemicals?
- Equal polarity of both phases
- Appropriate polarity difference to selectively partition target compounds
- Use of only aqueous solvents
- High viscosity of solvents
Correct Answer: Appropriate polarity difference to selectively partition target compounds
Q16. Which enzyme class is often targeted or inhibited by many plant-derived alkaloids and used as a lead in drug design?
- Polymerases
- Proteases
- Acetylcholinesterase
- Kinases
Correct Answer: Acetylcholinesterase
Q17. Which analytical test is most specific for identifying unsaturation and certain functional groups like carbonyls in natural compounds?
- Thin-layer chromatography (TLC)
- Infrared (IR) spectroscopy
- Microscopy
- Flame test
Correct Answer: Infrared (IR) spectroscopy
Q18. Which of the following is a marine-derived anticancer agent?
- Paclitaxel
- Eribulin (derived from halichondrin B analog)
- Lidocaine
- Atropine
Correct Answer: Eribulin (derived from halichondrin B analog)
Q19. Which term describes the genetic clusters in microbes that encode pathways for secondary metabolite biosynthesis?
- Operons only found in plants
- Biosynthetic gene clusters (BGCs)
- Ribosomal binding sites
- Transposons
Correct Answer: Biosynthetic gene clusters (BGCs)
Q20. Which phytochemical group typically gives a positive Liebermann-Burchard test?
- Alkaloids
- Saponins
- Steroidal/triterpenoid compounds (e.g., cardiac glycosides aglycones)
- Flavonoids
Correct Answer: Steroidal/triterpenoid compounds (e.g., cardiac glycosides aglycones)
Q21. In herbal standardization, the purpose of marker compounds is to:
- Provide flavor only
- Serve as chemical indicators for identity, quality, and consistency of the herbal material
- Increase toxicity intentionally
- Replace all bioassays
Correct Answer: Serve as chemical indicators for identity, quality, and consistency of the herbal material
Q22. Which factor most influences the yield and profile of secondary metabolites in medicinal plants?
- Geographical origin, soil, climate, harvest time and plant part
- Only the extraction solvent
- Type of glassware used
- Color of the flower
Correct Answer: Geographical origin, soil, climate, harvest time and plant part
Q23. Lovastatin, used as a cholesterol-lowering agent, is produced by which source?
- Plant leaf extract
- Fungal fermentation (Aspergillus terreus)
- Synthetic petroleum chemistry only
- Marine algae only
Correct Answer: Fungal fermentation (Aspergillus terreus)
Q24. Which isolation technique is based on differences in polarity and is widely used for fractionation of plant extracts?
- Distillation
- Column chromatography (e.g., silica gel, reversed-phase)
- Centrifugation only
- Gel electrophoresis
Correct Answer: Column chromatography (e.g., silica gel, reversed-phase)
Q25. Which of the following is a common problem when translating a natural product lead into a drug candidate?
- Excessive water solubility only
- Poor pharmacokinetics, supply issues, complexity of synthesis and toxicity
- Always easy scale-up
- No regulatory requirements
Correct Answer: Poor pharmacokinetics, supply issues, complexity of synthesis and toxicity
Q26. Which phytochemical class typically contains conjugated aromatic rings and shows strong antioxidant activity?
- Terpenoids
- Phenolics and flavonoids
- Alkaloids only
- Steroids only
Correct Answer: Phenolics and flavonoids
Q27. Which process describes converting a natural compound into a more drug-like, orally bioavailable form via chemical modification?
- Bioprospecting
- Semi-synthesis or lead optimization
- Taxonomic classification
- Hydrodistillation
Correct Answer: Semi-synthesis or lead optimization
Q28. Which assay would you choose for quantitative estimation of a specific marker compound in a herbal formulation?
- Qualitative color test
- Validated HPLC or HPTLC assay
- Random solvent evaporation
- Simple organoleptic test
Correct Answer: Validated HPLC or HPTLC assay
Q29. Which example correctly pairs a drug with its biological source?
- Morphine — Penicillium species
- Streptomycin — Streptomyces griseus (actinomycete)
- Paclitaxel — Digitalis species
- Quinine — Artemisia annua
Correct Answer: Streptomycin — Streptomyces griseus (actinomycete)
Q30. Modern strategies to discover natural product drugs increasingly rely on which combination?
- Only traditional knowledge without analytics
- Metabolomics, genomics (BGC mining), high-throughput screening and synthetic biology
- Only random plant collection
- Only increasing extraction temperature
Correct Answer: Metabolomics, genomics (BGC mining), high-throughput screening and synthetic biology
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.
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