Diosgenin is a steroidal sapogenin extracted mainly from Dioscorea (wild yam) tubers and serves as a key industrial precursor for semi-synthesis of steroid drugs such as progesterone and corticosteroids. Industrial production involves solvent extraction, acid or enzymatic hydrolysis to liberate the sapogenin, purification, and analytical quality control (HPLC, GC‑MS, NMR). Modern processes emphasize sustainable sourcing, greener hydrolysis or microbial biotransformation, and strict purity testing. Understanding diosgenin’s chemistry, extraction parameters, regulatory context, and analytical methods is essential for B. Pharm students focused on natural product–based pharmaceutical manufacture. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which plant genus is the primary industrial source of diosgenin?
- Dioscorea
- Digitalis
- Atropa
- Ginkgo
Correct Answer: Dioscorea
Q2. Diosgenin is classified chemically as which of the following?
- Alkaloid
- Steroidal sapogenin
- Flavonoid
- Polyketide
Correct Answer: Steroidal sapogenin
Q3. The main industrial use of diosgenin is as a precursor for the semi-synthesis of which class of drugs?
- Antibiotics
- Antivirals
- Steroid hormones
- Antihistamines
Correct Answer: Steroid hormones
Q4. Which structural feature characterizes diosgenin?
- Benzene ring with nitro group
- Spirostane (spiroketal) steroid nucleus
- Linear diterpene chain
- Porphyrin macrocycle
Correct Answer: Spirostane (spiroketal) steroid nucleus
Q5. In industrial extraction, diosgenin is typically liberated from steroidal saponins by which process?
- Base-catalyzed oxidation
- Acid hydrolysis
- Photolysis
- Salt precipitation
Correct Answer: Acid hydrolysis
Q6. Which solvent is commonly used in large-scale extraction of diosgenin from plant material due to safety and efficiency?
- Chloroform
- Hexane
- Ethanol
- Carbon tetrachloride
Correct Answer: Ethanol
Q7. An enzymatic alternative to acid hydrolysis for releasing diosgenin involves which enzyme activity?
- Protease
- β-glucosidase
- Lipase
- Amylase
Correct Answer: β-glucosidase
Q8. Which analytical technique is most commonly used for routine quantification of diosgenin in extracts and formulations?
- Atomic absorption spectroscopy
- HPLC with UV detection
- Polarimetry
- Gel electrophoresis
Correct Answer: HPLC with UV detection
Q9. For GC‑MS analysis of diosgenin, what preparative step is usually required?
- Lipidation
- Formation of trimethylsilyl (TMS) derivatives
- Protein precipitation with acetone
- Direct injection without derivatization
Correct Answer: Formation of trimethylsilyl (TMS) derivatives
Q10. The historic Marker degradation process is associated with conversion of diosgenin into which steroidal compound?
- Testosterone
- Progesterone
- Insulin
- Penicillin
Correct Answer: Progesterone
Q11. Which industrial factor most strongly affects diosgenin yield from tubers?
- Altitude of processing plant
- Plant variety and tuber age
- Color of foliage
- Time of day of harvest
Correct Answer: Plant variety and tuber age
Q12. One environmental concern linked to diosgenin production is:
- Overharvesting of wild Dioscorea species
- Heavy metal contamination from catalysts
- CFC emissions from solvents
- Excessive use of genetically modified organisms
Correct Answer: Overharvesting of wild Dioscorea species
Q13. Which green alternative is being developed to reduce chemical steps in diosgenin-based steroid production?
- Use of mercury catalysts
- Microbial biotransformation and enzymatic methods
- Incineration of crop waste
- Replacing diosgenin with petroleum feedstocks exclusively
Correct Answer: Microbial biotransformation and enzymatic methods
Q14. In quality control of diosgenin, which of the following is a key purity test?
- pH paper test
- HPLC assay for percent diosgenin
- Klucel viscosity measurement
- Colorimetric starch test
Correct Answer: HPLC assay for percent diosgenin
Q15. Which functional group in diosgenin gives a characteristic IR absorption around 3400 cm−1?
- Carbonyl (C=O)
- Hydroxyl (O–H)
- Nitro (NO2)
- Alkyne (C≡C)
Correct Answer: Hydroxyl (O–H)
Q16. Which spectroscopy technique is essential for confirming the detailed carbon skeleton and stereochemistry of diosgenin?
- 1H and 13C NMR spectroscopy
- UV–Vis spectroscopy only
- Fluorescence spectroscopy
- Raman mapping of powders
Correct Answer: 1H and 13C NMR spectroscopy
Q17. During purification, a common chromatographic method to separate diosgenin from related sapogenins is:
- Ion-exchange chromatography
- Normal- or reverse-phase liquid chromatography
- Size-exclusion for proteins
- Paper chromatography only
Correct Answer: Normal- or reverse-phase liquid chromatography
Q18. Which co-extracted plant components often complicate diosgenin purification from tuber material?
- Starch and storage proteins (dioscorin)
- Alkaloids and glycosides of Digitalis
- Volatile essential oils exclusively
- Cellulose nitrates
Correct Answer: Starch and storage proteins (dioscorin)
Q19. The pharmacological activity of diosgenin itself in humans is best described as:
- Highly estrogenic and used directly as a hormone
- Primarily an intermediate; limited direct steroid activity
- A potent antibiotic
- A cardiac glycoside
Correct Answer: Primarily an intermediate; limited direct steroid activity
Q20. A safety concern related to crude saponin-containing extracts is:
- Hemolytic activity on red blood cells
- Radioactivity
- High fluoride content
- Strong basic corrosivity
Correct Answer: Hemolytic activity on red blood cells
Q21. Which storage condition is recommended for purified diosgenin to maintain stability?
- Warm and humid environment
- Cool, dry, and dark storage
- Frozen in aqueous solution
- Exposed to direct sunlight
Correct Answer: Cool, dry, and dark storage
Q22. Which industrial operation is essential after solvent extraction and before final purification to remove sugars and polar impurities?
- Liquid–liquid partitioning and washing
- Direct crystallization without washing
- Nitrogen sparging only
- Electroplating
Correct Answer: Liquid–liquid partitioning and washing
Q23. In large-scale diosgenin production, regulatory scrutiny increases when diosgenin is used to produce:
- Food preservatives
- Steroidal pharmaceuticals (e.g., contraceptives)
- Fertilizers
- Textile dyes
Correct Answer: Steroidal pharmaceuticals (e.g., contraceptives)
Q24. Which impurity class is commonly monitored as a degradation product during storage and processing?
- Polyhalogenated dioxins
- Oxidation products and partially hydrolyzed saponins
- Transition metal salts
- Synthetic polymer residues
Correct Answer: Oxidation products and partially hydrolyzed saponins
Q25. Which assay is directly used to evaluate haemolytic potential of saponin-rich extracts during safety testing?
- MTT cell viability assay
- Red blood cell (RBC) hemolysis assay
- ELISA for antibodies
- Chromogenic limulus amebocyte lysate test
Correct Answer: Red blood cell (RBC) hemolysis assay
Q26. Which plant part generally contains the highest concentration of diosgenin for commercial extraction?
- Leaves
- Flowers
- Tubers/rhizomes
- Seeds
Correct Answer: Tubers/rhizomes
Q27. The critical chemical change needed to convert diosgenin into a progesterone-like skeleton is:
- Side-chain cleavage at C-22 to C-27
- Addition of a sugar moiety
- Nitration of the steroid nucleus
- Formation of an ether linkage at C-3
Correct Answer: Side-chain cleavage at C-22 to C-27
Q28. Diosgenin is more specifically classified as a:
- Furostanol sapogenin
- Spirostanol sapogenin
- Cardenolide
- Monoterpene
Correct Answer: Spirostanol sapogenin
Q29. A practical chromatographic detection reagent for visualizing sapogenins on TLC plates is:
- Dragendorff’s reagent
- Anisaldehyde–sulfuric acid spray
- Biuret reagent
- Bromothymol blue
Correct Answer: Anisaldehyde–sulfuric acid spray
Q30. To reduce reliance on wild plant harvesting, industry may adopt which policy relevant to diosgenin supply?
- Developing cultivated Dioscorea plantations and sustainable sourcing
- Importing fossil steroid precursors only
- Banning all herbal raw materials
- Switching to illicit synthetic routes
Correct Answer: Developing cultivated Dioscorea plantations and sustainable sourcing
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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