Sulfides as nutraceuticals – Diallyl sulfides, Allyl trisulfide MCQs With Answer

Sulfides as nutraceuticals are organosulfur compounds primarily derived from garlic (Allium sativum), including diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS or allyl trisulfide). These bioactive molecules show antioxidant, anti-inflammatory, antimicrobial and anticancer potential through mechanisms such as enzyme modulation, phase II enzyme induction, NF-κB inhibition, H2S donation and thiol modification. For B. Pharm students, understanding chemical structure, pharmacology, metabolism, analytical methods (GC‑MS/HPLC), formulation challenges and safety is essential to evaluate their nutraceutical roles. This concise overview emphasizes diallyl sulfides, DATS pharmacodynamics and formulation strategies. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which chemical class do diallyl sulfide and diallyl trisulfide belong to?

• Alkaloids
• Organosulfur compounds
• Flavonoids
• Terpenoids

Correct Answer: Organosulfur compounds

Q2. What is the primary natural source of diallyl sulfides studied as nutraceuticals?

• Citrus fruits
• Green tea
• Allium sativum (garlic)
• Soybean

Correct Answer: Allium sativum (garlic)

Q3. Which functional group characterizes diallyl sulfide compounds?

• Ester
• Thioether (sulfide)
• Amide
• Phenol

Correct Answer: Thioether (sulfide)

Q4. What does the abbreviation DATS commonly denote in garlic phytochemistry?

• Diallyl sulfoxide
• Diallyl disulfide
• Diallyl trisulfide
• Diallyl thioester

Correct Answer: Diallyl trisulfide

Q5. Which pharmacological effect is most consistently reported for diallyl trisulfide in preclinical studies?

• Pro‑inflammatory cytokine upregulation
• Anticancer activity via apoptosis induction
• Direct insulin secretion stimulation
• Selective beta‑adrenergic blockade

Correct Answer: Anticancer activity via apoptosis induction

Q6. Which gaseous signaling molecule can be released from allyl polysulfides in biological systems?

• Nitric oxide (NO)
• Carbon monoxide (CO)
• Hydrogen sulfide (H2S)
• Methane (CH4)

Correct Answer: Hydrogen sulfide (H2S)

Q7. Which hepatic enzyme is inhibited by diallyl sulfide, affecting xenobiotic metabolism?

• CYP3A4
• CYP2E1
• CYP1A2
• UDP‑glucuronosyltransferase

Correct Answer: CYP2E1

Q8. Diallyl sulfides are known to induce which phase II detoxification enzyme commonly measured in chemoprevention studies?

• Aromatic hydroxylase
• Glutathione S‑transferase (GST)
• Acetylcholinesterase
• Monoamine oxidase

Correct Answer: Glutathione S‑transferase (GST)

Q9. Which cell cycle phase arrest is frequently observed after treatment with diallyl trisulfide in cancer cells?

• G0 phase
• G1 phase
• S phase
• G2/M phase

Correct Answer: G2/M phase

Q10. What is the primary route of metabolic transformation for diallyl sulfides in vivo?

• Renal excretion unchanged
• P450‑mediated hepatic oxidation and conjugation
• Direct microbial fermentation to glucose
• Nonenzymatic photodegradation

Correct Answer: P450‑mediated hepatic oxidation and conjugation

Q11. Which analytical technique is most commonly used to separate and quantify volatile diallyl sulfides in garlic oil?

• UV‑Visible spectrophotometry
• Gas chromatography–mass spectrometry (GC‑MS)
• Capillary electrophoresis
• Nuclear magnetic resonance (NMR) for routine QC

Correct Answer: Gas chromatography–mass spectrometry (GC‑MS)

Q12. Which physicochemical property presents a formulation challenge for diallyl sulfide supplements?

• High aqueous solubility
• High melting point
• Volatility and strong odor
• Extreme acidity (pKa < 1)

Correct Answer: Volatility and strong odor

Q13. Which clinically relevant interaction is associated with garlic-derived sulfide supplements?

• Reduced absorption of calcium supplements
• Potentiation of anticoagulant/antiplatelet effects, increasing bleeding risk
• Strong inhibition of insulin action causing hyperglycemia
• Marked increase in digoxin plasma levels

Correct Answer: Potentiation of anticoagulant/antiplatelet effects, increasing bleeding risk

Q14. Which pharmaceutical strategy helps mask odor and improve stability of diallyl sulfide nutraceuticals?

• Immediate‑release tablets without coating
• Microencapsulation or enteric coating
• Packaging in paper sachets
• Formulation as a highly hygroscopic syrup

Correct Answer: Microencapsulation or enteric coating

Q15. What structural difference distinguishes DAS, DADS and DATS?

• Type of alkyl chain saturation
• Number of sulfur atoms linking allyl groups
• Presence of an aromatic ring
• Different carbohydrate conjugates

Correct Answer: Number of sulfur atoms linking allyl groups

Q16. Which trend is commonly observed in biological potency among DAS, DADS and DATS?

• DAS > DADS > DATS in anticancer potency
• DATS > DADS > DAS, with higher polysulfide content often showing stronger activity
• All three have identical potency
• Only DAS shows bioactivity; others are inert

Correct Answer: DATS > DADS > DAS, with higher polysulfide content often showing stronger activity

Q17. Which pro‑survival transcription factor pathway is inhibited by diallyl sulfides contributing to anti‑inflammatory and anticancer effects?

• Wnt/β‑catenin
• NF‑κB
• Notch
• Hedgehog

Correct Answer: NF‑κB

Q18. What antimicrobial mechanism is attributed to allyl polysulfides?

• Selective inhibition of DNA gyrase only
• Thiol modification of microbial proteins and membrane disruption
• Competitive inhibition of folate synthesis identical to sulfonamides
• Chelation of essential metals like calcium

Correct Answer: Thiol modification of microbial proteins and membrane disruption

Q19. Why are diallyl sulfides considered nutraceutical rather than conventional drugs in most contexts?

• They are synthetic pharmaceutical agents
• They are used as clinical parenteral therapies only
• They are dietary constituents with potential health benefits, used in functional foods/supplements
• They are regulated as controlled substances

Correct Answer: They are dietary constituents with potential health benefits, used in functional foods/supplements

Q20. Which in vitro assay is commonly used to assess cytotoxicity of diallyl sulfides on cancer cell lines?

• MTT or MTS cell viability assay
• ELISA for hemoglobin
• Platelet aggregation test
• Thrombin time assay

Correct Answer: MTT or MTS cell viability assay

Q21. Regarding standardized therapeutic dosing of diallyl sulfide supplements, which statement is accurate?

• There is a universally accepted clinical dose for cancer prevention
• Standardized dosing is lacking and varies across products and studies
• The FDA prescribes a fixed daily dose for all garlic extracts
• Oral doses >10 g/day are routinely recommended

Correct Answer: Standardized dosing is lacking and varies across products and studies

Q22. How does diallyl sulfide inhibit CYP2E1—what type of inhibition is typically described?

• Competitive inhibition reversible by substrate
• Mechanism‑based (suicide) inhibition leading to enzyme inactivation
• Allosteric activation of CYP2E1
• No interaction with CYP enzymes

Correct Answer: Mechanism‑based (suicide) inhibition leading to enzyme inactivation

Q23. Which mitochondrial event is commonly implicated in DATS‑induced apoptosis in tumor cells?

• Stabilization of mitochondrial membrane potential
• Release of cytochrome c and caspase activation
• Inhibition of caspase cascade
• Complete preservation of ATP levels

Correct Answer: Release of cytochrome c and caspase activation

Q24. Which isolation technique is typically employed to obtain volatile allyl sulfides from garlic for analysis?

• Steam distillation or hydrodistillation
• Supercritical CO2 extraction only for proteins
• Crystallization from water
• Electrochemical deposition

Correct Answer: Steam distillation or hydrodistillation

Q25. Which statement best describes oral bioavailability of diallyl sulfides?

• They are hydrophilic and show complete oral bioavailability
• They are lipophilic with variable oral bioavailability due to first‑pass metabolism
• They are not absorbed and remain in the gut lumen unchanged
• They are exclusively absorbed via sublingual mucosa

Correct Answer: They are lipophilic with variable oral bioavailability due to first‑pass metabolism

Q26. How does glutathione (GSH) participate in the biological activity of diallyl trisulfide?

• GSH oxidizes DATS to inactive polymers
• GSH reacts with DATS to release H2S and form GSH conjugates
• GSH prevents any interaction between DATS and proteins
• GSH transports DATS across the blood‑brain barrier intact

Correct Answer: GSH reacts with DATS to release H2S and form GSH conjugates

Q27. Which cardiovascular effect has been associated with garlic sulfide supplementation in clinical studies?

• Uniform and large increase in heart rate by 50 bpm
• Modest reduction in blood pressure in some hypertensive subjects
• Immediate reversal of heart failure
• Complete blockade of beta‑adrenergic receptors

Correct Answer: Modest reduction in blood pressure in some hypertensive subjects

Q28. Which adverse effect is most commonly reported with high doses of garlic sulfide supplements?

• Severe nephrotoxicity requiring dialysis
• Gastrointestinal irritation and strong body/halitosis odor
• Permanent hearing loss
• Profound and irreversible hypoglycemia

Correct Answer: Gastrointestinal irritation and strong body/halitosis odor

Q29. What is the chemical structure of an allyl group commonly present in diallyl sulfides?

• –CH2–CH2–CH3 (propyl)
• –CH=CH–CH3 (1‑propene without methylene link)
• –CH2–CH=CH2 (allyl, CH2=CH–CH2– when attached)
• –C≡CH (ethynyl)

Correct Answer: –CH2–CH=CH2 (allyl, CH2=CH–CH2– when attached)

Q30. Which compound is commonly quantified as a quality marker in garlic oil and related preparations by routine GC analysis?

• Allicin (stable marker for long‑term storage)
• Diallyl disulfide (DADS)
• Glucose
• Cholesterol

Correct Answer: Diallyl disulfide (DADS)

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