Novel medicinal agents from marine sources explore bioactive compounds isolated from sponges, tunicates, algae, marine bacteria, cyanobacteria and molluscs that have informed modern drug discovery and pharmacology. Key topics include marine natural products chemistry, polyketides, peptides, alkaloids and terpenes, bioassay‑guided fractionation, structure elucidation (NMR, LC‑MS), dereplication, genome mining and sustainable supply strategies such as synthesis and microbial fermentation. Understanding mechanisms of action—anticancer, antiviral, antibacterial and analgesic—and formulation and PK challenges is essential for B. Pharm students preparing for careers in drug development. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which marine organism is the original natural source of the drug ziconotide?
- Marine sponge (Tethya)
- Sea hare (Dolabella)
- Cone snail (Conus)
- Tunicate (Ecteinascidia)
Correct Answer: Cone snail (Conus)
Q2. Trabectedin, an anticancer agent, was originally isolated from which marine source?
- Marine cyanobacteria
- Tunicate (Ecteinascidia)
- Sponge (Halichondria)
- Cone snail (Conus)
Correct Answer: Tunicate (Ecteinascidia)
Q3. Which structural class is common among many marine natural products with potent bioactivity?
- Polyketides
- Synthetic benzodiazepines
- Polyethylene glycol polymers
- Monosaccharides only
Correct Answer: Polyketides
Q4. What is a primary challenge in developing drugs from marine organisms?
- Excessive ease of cultivating all marine microbes
- Sustainable supply and low natural abundance
- Complete lack of bioactive compounds in marine life
- Universal oral bioavailability of marine peptides
Correct Answer: Sustainable supply and low natural abundance
Q5. Which approved anticancer drug is a synthetic analogue of halichondrin B derived from marine sponge?
- Eribulin
- Paclitaxel
- Doxorubicin
- Imatinib
Correct Answer: Eribulin
Q6. Bioassay‑guided fractionation primarily refers to which process?
- Purifying compounds based on solubility only
- Using biological assays to guide fractionation and isolate active compounds
- Sequencing genomes of marine organisms without testing activity
- Computational docking without experimental testing
Correct Answer: Using biological assays to guide fractionation and isolate active compounds
Q7. Which analytical techniques are essential for structural elucidation of marine natural products?
- NMR and mass spectrometry (LC‑MS/MS)
- Simple pH testing only
- Gram staining and light microscopy
- Paper chromatography exclusively
Correct Answer: NMR and mass spectrometry (LC‑MS/MS)
Q8. Dereplication in marine drug discovery is used to:
- Intentionally rediscover known compounds early to avoid redundancy
- Increase redundancy in screening libraries
- Replace biological assays with pure chemistry
- Eliminate the need for structural elucidation
Correct Answer: Intentionally rediscover known compounds early to avoid redundancy
Q9. Which marine-derived drug is a peptide used intrathecally for severe chronic pain by blocking N‑type calcium channels?
- Cytarabine
- Ziconotide
- Trabectedin
- Eribulin
Correct Answer: Ziconotide
Q10. Cytarabine (Ara‑C), an antimetabolite used in leukemia, was originally isolated from:
- Terrestrial plant alkaloids
- Marine sponge (Tethya)
- Human gut microbiota
- Freshwater algae only
Correct Answer: Marine sponge (Tethya)
Q11. Which feature is common in many marine natural products and contributes to unique bioactivity?
- Extensive halogenation (bromine, chlorine)
- Absence of chiral centers
- Simple monosaccharide backbones only
- Identical to terrestrial metabolites in all cases
Correct Answer: Extensive halogenation (bromine, chlorine)
Q12. Genome mining and metagenomics help marine drug discovery by:
- Directly replacing bioassays with clinical trials
- Identifying biosynthetic gene clusters for novel natural products
- Only sequencing human DNA
- Providing no useful biosynthetic information
Correct Answer: Identifying biosynthetic gene clusters for novel natural products
Q13. Dolastatin 10, a potent cytotoxic from sea hare, contributed to cancer therapy development mainly as:
- A direct marketed chemotherapy agent unchanged
- An inspiration for synthetic analogues and ADC payloads (e.g., MMAE)
- A probiotic supplement
- An over‑the‑counter analgesic
Correct Answer: An inspiration for synthetic analogues and ADC payloads (e.g., MMAE)
Q14. Which screening assay is commonly used to assess cytotoxicity of marine extracts in vitro?
- MTT or resazurin cell viability assays
- Gram staining
- pH paper strip test
- Flame photometry for metals
Correct Answer: MTT or resazurin cell viability assays
Q15. A major sustainable supply strategy for scarce marine natural products is:
- Harvesting unlimited wild populations
- Total chemical synthesis and semisynthesis
- Stopping all drug development
- Relying solely on unregulated collection
Correct Answer: Total chemical synthesis and semisynthesis
Q16. Which phenomenon explains why many marine bioactives are produced by symbiotic microbes rather than the host animal?
- Horizontal gene transfer and microbial biosynthetic capacity within host microbiomes
- Host animals perform all biosynthesis without microbes
- Marine hosts lack any associated microbes
- Symbionts only consume host metabolites and never produce compounds
Correct Answer: Horizontal gene transfer and microbial biosynthetic capacity within host microbiomes
Q17. Which technique helps rapidly identify known compounds in crude extracts to avoid rediscovery?
- Dereplication using LC‑MS libraries and databases
- Random guessing
- Only thin‑layer chromatography without detection
- Visual color inspection of extracts
Correct Answer: Dereplication using LC‑MS libraries and databases
Q18. Which pharmacokinetic challenge is especially relevant for marine peptides used as drugs?
- High oral bioavailability by default
- Rapid enzymatic degradation and poor membrane permeability
- Infinite half‑life in plasma
- No need for formulation improvements
Correct Answer: Rapid enzymatic degradation and poor membrane permeability
Q19. Which formulation strategy can improve stability and delivery of marine-derived peptides?
- PEGylation or nanoparticle encapsulation
- Administering as raw sea water
- Giving only as a dry powder with no excipients
- Avoiding any modification to improve PK
Correct Answer: PEGylation or nanoparticle encapsulation
Q20. Which method increases the chance of cultivating previously unculturable marine microbes?
- Axenic culturing in high‑nutrient artificial media only
- Co‑culture with helper strains and diffusion chambers
- Immediate autoclaving of samples
- Exclusive reliance on long stationary incubations without environmental cues
Correct Answer: Co‑culture with helper strains and diffusion chambers
Q21. Eribulin’s mechanism of anticancer action primarily involves:
- DNA alkylation exclusively
- Microtubule dynamics inhibition leading to mitotic blockade
- Inhibiting bacterial cell wall synthesis
- Acting as an opioid receptor agonist
Correct Answer: Microtubule dynamics inhibition leading to mitotic blockade
Q22. Which database or resource is commonly used for natural product dereplication and identification?
- AntiBase (and similar natural product libraries)
- PubMed abstracts only
- Social media posts
- Generic web search without spectral data
Correct Answer: AntiBase (and similar natural product libraries)
Q23. Which statement about marine alkaloids is true?
- They never affect the central nervous system
- Many marine alkaloids modulate CNS targets and ion channels
- They are structurally identical to all plant alkaloids
- They are always non‑chiral and simple
Correct Answer: Many marine alkaloids modulate CNS targets and ion channels
Q24. High‑throughput screening (HTS) in marine drug discovery provides which main advantage?
- Ability to test thousands of extracts or fractions rapidly for activity
- Guaranteed clinical approval of hits
- Replacing all confirmatory secondary assays
- Avoiding the need for dereplication
Correct Answer: Ability to test thousands of extracts or fractions rapidly for activity
Q25. Which is an example of a marine-derived nucleoside analogue used in antiviral or anticancer therapy?
- Cytarabine (Ara‑C)
- Ibuprofen
- Penicillin
- Metformin
Correct Answer: Cytarabine (Ara‑C)
Q26. Semisynthesis in marine drug development is best described as:
- Altering a natural product’s structure chemically to improve properties
- Extracting and using crude extract without modification
- Cloning the host organism for direct marketing
- Ignoring natural product structure and designing unrelated drugs
Correct Answer: Altering a natural product’s structure chemically to improve properties
Q27. Which regulatory body approves marine‑derived drugs for clinical use in the United States?
- World Health Organization (WHO)
- US Food and Drug Administration (FDA)
- Federal Communications Commission (FCC)
- International Maritime Organization (IMO)
Correct Answer: US Food and Drug Administration (FDA)
Q28. Monomethyl auristatin E (MMAE) used in antibody‑drug conjugates is derived conceptually from which marine product?
- Dolastatin 10 from sea hare
- Caffeine from marine algae
- Cholesterol from fish oils
- Penicillin from fungi
Correct Answer: Dolastatin 10 from sea hare
Q29. Which approach helps link a bioactive compound to its biosynthetic genes when the producer is uncultured?
- Metagenomic library screening and heterologous expression
- Only observing color change in crude extract
- Discarding genetic approaches entirely
- Direct oral administration of crude seawater
Correct Answer: Metagenomic library screening and heterologous expression
Q30. Which characteristic often makes marine secondary metabolites attractive as drug leads?
- High chemical diversity and novel scaffolds distinct from terrestrial compounds
- Complete lack of stereochemistry
- Guaranteed absence of toxicity in humans
- Simple low‑diversity structures identical to common dietary molecules
Correct Answer: High chemical diversity and novel scaffolds distinct from terrestrial compounds
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