Saponins and steroidal constituents: shatavarins, withanolides MCQs With Answer

Introduction

This quiz collection focuses on saponins and steroidal constituents—specifically shatavarins and withanolides—aligned with the M.Pharm Advanced Pharmacognosy I curriculum. It highlights chemical nature, biosynthetic origin, pharmacological profiles, analytical and isolation techniques, and characteristic pharmacognostic tests. Questions emphasize mechanistic and structural distinctions between steroidal and triterpenoid saponins, practical extraction and chromatographic approaches, spectroscopic markers for lactones and sapogenins, and biologically relevant activities such as adaptogenic, galactagogue and anticancer effects. The set is designed to deepen conceptual understanding and support practical lab work and exam preparation for postgraduate students studying medicinal plant steroidal constituents.

Q1. Which of the following best describes shatavarins chemically?

• Steroidal saponin glycosides
• Triterpenoid aglycones
• Alkaloid nitrogenous bases
• Flavonoid glycosides

Correct Answer: Steroidal saponin glycosides

Q2. The primary botanical source of shatavarins is which plant?

• Withania somnifera
• Asparagus racemosus
• Dioscorea opposita
• Glycyrrhiza glabra

Correct Answer: Asparagus racemosus

Q3. Many steroidal saponins occur as which aglycone skeleton types?

• Spirostanol/furostanol type aglycones
• Lupane pentacyclic skeletons
• Flavone nucleus

Correct Answer: Spirostanol/furostanol type aglycones

Q4. Which statement correctly describes withanolides?

• Polyketide-derived macrolides
• Steroidal lactones with an α,β‑unsaturated lactone side chain
• Triterpenoid saponins with oligosaccharide chains
• Amino acid conjugates derived from shikimate

Correct Answer: Steroidal lactones with an α,β‑unsaturated lactone side chain

Q5. Traditionally, Asparagus racemosus extracts rich in shatavarins are most commonly used as:

• Antihypertensive agents
• Galactagogues (promote lactation)
• Topical antiseptics
• Anticoagulants

Correct Answer: Galactagogues (promote lactation)

Q6. Which structural feature is characteristic of the well-known withanolide withaferin A?

• An epoxy ring and an α,β‑unsaturated lactone moiety
• A glycosidic sugar chain at C-3
• A long aliphatic fatty acid ester at C-17
• A flavonoid C-ring opening

Correct Answer: An epoxy ring and an α,β‑unsaturated lactone moiety

Q7. Which extraction strategy is most appropriate for isolating steroidal saponins such as shatavarins from plant roots?

• Cold hexane maceration alone
• Hydroalcoholic extraction (methanol/ethanol) followed by n‑butanol partition
• Steam distillation
• Supercritical CO2 without polar co-solvent

Correct Answer: Hydroalcoholic extraction (methanol/ethanol) followed by n‑butanol partition

Q8. The classical pharmacognostic foam test for saponins is positive because saponins are:

• Strong acids that liberate gas
• Surface-active agents that reduce surface tension and form stable foam
• Volatile oils that vaporize and foam
• Polyphenols that complex with proteins forming froth

Correct Answer: Surface-active agents that reduce surface tension and form stable foam

Q9. For analytical quantification of withanolides in a drug extract, which technique and detector combination is most appropriate?

• Reverse‑phase HPLC with UV detection (photodiode array)
• Thin layer chromatography with iodine vapour only
• Gravimetric analysis after precipitation
• Direct GC without derivatization

Correct Answer: Reverse‑phase HPLC with UV detection (photodiode array)

Q10. Acid hydrolysis of steroidal saponins is used to yield which products for further identification?

• Proteins and peptides
• Aglycone (sapogenin) and carbohydrate residues
• Unsaponifiable lipids only
• Volatile monoterpenes

Correct Answer: Aglycone (sapogenin) and carbohydrate residues

Q11. In IR spectroscopy, the carbonyl absorption of a lactone ring in withanolides typically appears near which wavenumber?

• 1700–1750 cm⁻¹
• 1600–1620 cm⁻¹
• 1400–1450 cm⁻¹
• 1200–1250 cm⁻¹

Correct Answer: 1700–1750 cm⁻¹

Q12. Biosynthetically, withanolides are derived from which primary metabolic pathway?

• Shikimate pathway leading to aromatic amino acids
• Mevalonate (isoprenoid) pathway via sterol intermediates
• Polyketide synthase pathway producing macrolides
• Non‑ribosomal peptide synthetase pathway

Correct Answer: Mevalonate (isoprenoid) pathway via sterol intermediates

Q13. Common sugar moieties attached to steroidal saponins include which of the following?

• Glucose, rhamnose, and galactose residues
• Fructose, sucrose and lactose exclusively
• Maltose, cellobiose and trehalose only
• Peptidoglycan fragments

Correct Answer: Glucose, rhamnose, and galactose residues

Q14. A key chemical distinction between steroidal and triterpenoid saponins is the usual carbon number of their aglycone; steroidal sapogenins are typically:

• Derived from C27 sterol-like aglycones
• Always C30 pentacyclic triterpenes
• Composed of aromatic 15-carbon skeletons
• Oligopeptides of variable length

Correct Answer: Derived from C27 sterol-like aglycones

Q15. Which colorimetric reagent is commonly used for the quantification of total steroidal saponins or sapogenins after appropriate hydrolysis?

• Vanillin–sulfuric acid reagent (colorimetric assay)
• Ninhydrin reagent
• Biuret reagent
• Folin–Ciocalteu reagent only for proteins

Correct Answer: Vanillin–sulfuric acid reagent (colorimetric assay)

Q16. Which withanolide has been most widely investigated for its anticancer and apoptotic activities?

• Withaferin A
• Shatavarin I
• Diosgenin
• Ginsenoside Rg1

Correct Answer: Withaferin A

Q17. A commonly used TLC solvent system for separating steroidal saponins is which of the following?

• n‑Butanol : acetic acid : water (4:1:5) or its upper phase
• Pure hexane
• Ethyl acetate : methanol (1:1) without modifiers for sugars
• Acetone : chloroform : ammonia (9:1:0.1)

Correct Answer: n‑Butanol : acetic acid : water (4:1:5) or its upper phase

Q18. Acid treatment of furostanol glycosides often leads to which chemical change in the sapogenin portion?

• Conversion of furostanol type to spirostanol aglycone via ring closure
• Oxidative cleavage to simple ketones only
• Polymerization into high molecular weight tannins
• Complete loss of steroidal nucleus yielding terpenes

Correct Answer: Conversion of furostanol type to spirostanol aglycone via ring closure

Q19. A significant toxicological concern with saponin-rich extracts is their ability to cause what effect in red blood cells?

• Hemolysis through membrane disruption and cholesterol complexation
• Methemoglobin formation exclusively
• Permanent crystallization of hemoglobin
• Irreversible DNA adduct formation in erythrocytes

Correct Answer: Hemolysis through membrane disruption and cholesterol complexation

Q20. On TLC, which spray reagent is frequently used as a confirmatory developer for detecting withanolides and other steroidal constituents producing diagnostic colored spots?

• Anisaldehyde–sulfuric acid spray reagent followed by heating
• Ninhydrin spray without heating
• Dragendorff reagent for alkaloids only
• Iodine vapour as the sole confirmatory test

Correct Answer: Anisaldehyde–sulfuric acid spray reagent followed by heating

Download