Carotenoids as nutraceuticals – α-carotene, β-carotene, Lycopene, Xanthophylls, Lutein MCQs With Answer

Carotenoids as nutraceuticals – α-carotene, β-carotene, Lycopene, Xanthophylls, Lutein MCQs With Answer

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Carotenoids as nutraceuticals – α-carotene, β-carotene, Lycopene, Xanthophylls, Lutein MCQs With Answer

Carotenoids are lipid‑soluble pigments with a conjugated polyene chain that function as antioxidants and some as provitamin A. Important nutraceuticals for B. Pharm students include α‑carotene and β‑carotene (provitamin A), lycopene (non‑provitamin A, potent singlet‑oxygen quencher), and xanthophylls such as lutein and zeaxanthin (oxygenated carotenoids vital for macular health). Key concepts: chemical structure, bioavailability, dietary sources, formulation strategies, metabolism by BCMO1, transport by lipoproteins, stability, clinical evidence for eye and prostate health, safety (carotenodermia, smoker interaction), and analytical HPLC assays. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which structural feature is characteristic of carotenoids?

  • A long conjugated polyene chain of alternating double bonds
  • A benzene ring with hydroxyl groups
  • A single saturated carbon chain without double bonds
  • A peptide backbone containing amino acids

Correct Answer: A long conjugated polyene chain of alternating double bonds

Q2. Which carotenoids exhibit provitamin A activity?

  • α‑carotene and β‑carotene
  • Lycopene and lutein
  • Zeaxanthin and lycopene
  • Lutein and zeaxanthin only

Correct Answer: α‑carotene and β‑carotene

Q3. What distinguishes lycopene from β‑carotene structurally and functionally?

  • Lycopene is acyclic and lacks provitamin A activity
  • Lycopene contains oxygen and is highly polar
  • Lycopene has a single ring and functions as provitamin A
  • Lycopene is a peptide derivative of β‑carotene

Correct Answer: Lycopene is acyclic and lacks provitamin A activity

Q4. Xanthophylls are best defined as:

  • Oxygenated carotenoids such as lutein and zeaxanthin
  • Carotenoids composed only of carbon and hydrogen
  • Synthetic carotenoid analogs used in supplements
  • Carotenoids exclusively found in animal tissues

Correct Answer: Oxygenated carotenoids such as lutein and zeaxanthin

Q5. The primary nutraceutical role of lutein in humans is:

  • Accumulating in the macula to filter blue light and protect the retina
  • Serving as a major circulating form of vitamin A
  • Acting as a calcium chelator in bone tissue
  • Being the main carotenoid stored in muscle

Correct Answer: Accumulating in the macula to filter blue light and protect the retina

Q6. Which dietary source is richest in lycopene?

  • Tomatoes and processed tomato products
  • Spinach and kale
  • Carrots and sweet potatoes
  • Egg yolk and dairy

Correct Answer: Tomatoes and processed tomato products

Q7. Carotenoid intestinal absorption is most enhanced by which dietary factor?

  • Co‑ingestion with dietary fat to promote micelle formation
  • High dietary fiber intake at the same meal
  • Simultaneous ingestion of large amounts of vitamin C
  • Fasting and taking carotenoids on an empty stomach

Correct Answer: Co‑ingestion with dietary fat to promote micelle formation

Q8. Which enzyme catalyzes central cleavage of β‑carotene to produce retinal?

  • β‑carotene 15,15′‑monooxygenase (BCMO1)
  • Cytochrome P450 3A4
  • Alcohol dehydrogenase
  • Glutathione S‑transferase

Correct Answer: β‑carotene 15,15′‑monooxygenase (BCMO1)

Q9. After intestinal absorption, carotenoids are initially transported in the circulation by:

  • Chylomicrons, then redistributed on LDL and HDL
  • Free diffusion bound to albumin only
  • Direct transport as water‑soluble micelles in plasma
  • Exosomal vesicles exclusively

Correct Answer: Chylomicrons, then redistributed on LDL and HDL

Q10. The preferred analytical method for separating and quantifying carotenoids in plasma and foods is:

  • High‑performance liquid chromatography (HPLC) with photodiode array detection
  • Gas chromatography without derivatization
  • Enzyme‑linked immunosorbent assay (ELISA)
  • Light microscopy

Correct Answer: High‑performance liquid chromatography (HPLC) with photodiode array detection

Q11. Which factors commonly cause trans‑to‑cis isomerization of carotenoids?

  • Heat, light and acidic conditions
  • Cold temperature and freezing only
  • Binding to albumin and low pH exclusively
  • Ultrasonic agitation without heat

Correct Answer: Heat, light and acidic conditions

Q12. Long‑term high‑dose β‑carotene supplementation was associated with which outcome in smokers?

  • An increased risk of lung cancer in randomized trials
  • A marked decrease in blood pressure
  • Complete prevention of age‑related macular degeneration
  • No biological effect observed in any study

Correct Answer: An increased risk of lung cancer in randomized trials

Q13. According to retinol activity equivalents (RAE), approximately how much dietary β‑carotene is equivalent to 1 µg retinol?

  • 12 µg of dietary β‑carotene
  • 2 µg of dietary β‑carotene
  • 100 µg of dietary β‑carotene
  • 0.5 µg of dietary β‑carotene

Correct Answer: 12 µg of dietary β‑carotene

Q14. Lutein and zeaxanthin differ primarily as:

  • Stereoisomers/structural isomers that both form macular pigment
  • One being a protein and the other a carbohydrate
  • One being water‑soluble and the other lipid‑soluble
  • Completely unrelated molecules with different elemental composition

Correct Answer: Stereoisomers/structural isomers that both form macular pigment

Q15. Compared with carotenes, xanthophylls are generally:

  • More polar due to oxygen functional groups
  • Less effective at quenching singlet oxygen
  • Completely insoluble in lipids
  • Composed only of saturated carbon atoms

Correct Answer: More polar due to oxygen functional groups

Q16. Carotenodermia is best described as:

  • Benign yellowish skin discoloration from high carotenoid intake
  • An acute allergic reaction to β‑carotene supplements
  • A genetic deficiency of BCMO1 causing blindness
  • A severe liver toxicity caused by lycopene

Correct Answer: Benign yellowish skin discoloration from high carotenoid intake

Q17. Epidemiological studies suggest dietary lycopene intake is associated with which clinical outcome?

  • Lower risk of prostate cancer in some observational studies
  • Increased incidence of skin infections
  • Rapid onset of scurvy
  • Guaranteed prevention of cardiovascular disease

Correct Answer: Lower risk of prostate cancer in some observational studies

Q18. In many commercial lutein supplements, lutein is commonly present as:

  • Fatty‑acid esters derived from marigold petals
  • Free water‑soluble monosaccharides
  • Inorganic lutein salts such as lutein chloride
  • Covalently bound to albumin peptides

Correct Answer: Fatty‑acid esters derived from marigold petals

Q19. Which formulation strategy most reliably improves carotenoid oral bioavailability?

  • Lipid‑based formulations such as emulsions, micelles or self‑emulsifying systems
  • Dry‑powder tablets without lipids
  • Immediate release aqueous syrups
  • High‑fiber capsules taken with no fat

Correct Answer: Lipid‑based formulations such as emulsions, micelles or self‑emulsifying systems

Q20. Which sample type is most commonly measured to assess human carotenoid status?

  • Serum or plasma carotenoid concentrations
  • Urine carotenoid excretion levels
  • Hair carotenoid content only
  • Cerebrospinal fluid carotenoid concentration

Correct Answer: Serum or plasma carotenoid concentrations

Q21. Which common carotenoid does NOT contain cyclic end groups?

  • Lycopene (acyclic structure)
  • α‑carotene
  • β‑carotene
  • γ‑carotene

Correct Answer: Lycopene (acyclic structure)

Q22. The principal antioxidant mechanism of carotenoids involves:

  • Quenching singlet oxygen and scavenging peroxyl radicals
  • Directly donating phosphate groups to ATP
  • Acting as metal chelators to remove iron from hemoglobin
  • Hydrolyzing peroxides enzymatically

Correct Answer: Quenching singlet oxygen and scavenging peroxyl radicals

Q23. Carotenoids are best described as soluble in which medium?

  • Lipids and nonpolar organic solvents (fat‑soluble)
  • Pure water at room temperature
  • Polar solvents like saline only
  • Alcohol‑free aqueous beverages exclusively

Correct Answer: Lipids and nonpolar organic solvents (fat‑soluble)

Q24. Which storage/processing condition accelerates carotenoid degradation?

  • Exposure to oxygen, light and heat
  • Freezing under nitrogen and darkness
  • Storage in opaque, sealed containers at low temperature
  • Vacuum packaging at −80°C

Correct Answer: Exposure to oxygen, light and heat

Q25. In the intestinal lumen, carotenoids are incorporated into mixed micelles with:

  • Bile salts, fatty acids and monoacylglycerols
  • Free amino acids and peptides only
  • Glucose and fructose to form glycosides
  • Pure water molecules without lipids

Correct Answer: Bile salts, fatty acids and monoacylglycerols

Q26. Which genetic factor can reduce conversion efficiency of β‑carotene to retinol?

  • Polymorphisms in the BCMO1 gene leading to lower enzyme activity
  • A polymorphism in amylase gene increasing starch digestion
  • Mutations in hemoglobin unrelated to carotenoid metabolism
  • Overexpression of collagen genes in skin

Correct Answer: Polymorphisms in the BCMO1 gene leading to lower enzyme activity

Q27. What is the regulatory Recommended Daily Allowance (RDA) for lutein?

  • There is no established RDA; studies commonly use 6–20 mg/day
  • 0.5 µg/day as an essential micronutrient
  • 1000 mg/day as an upper limit
  • 50 IU/day standardized internationally

Correct Answer: There is no established RDA; studies commonly use 6–20 mg/day

Q28. Which pair correctly represents xanthophyll carotenoids commonly found in the macula?

  • Lutein and zeaxanthin
  • β‑carotene and lycopene
  • α‑carotene and γ‑carotene
  • Astaxanthin and canthaxanthin only found in humans

Correct Answer: Lutein and zeaxanthin

Q29. The major human tissue sites for long‑term carotenoid storage are:

  • Adipose tissue and liver
  • Bone marrow and cartilage
  • Salivary glands exclusively
  • Urinary bladder epithelium only

Correct Answer: Adipose tissue and liver

Q30. Among common dietary carotenoids, which has the highest reported singlet oxygen quenching capacity?

  • Lycopene
  • β‑carotene
  • Lutein
  • α‑carotene

Correct Answer: Lycopene

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