Question

Which of the following pigments does NOT have pro-vitamin A activity?

• A. \(\beta\)-Carotene
• B. \(\beta\)-Cryptoxanthin
• C. Lycopene
• D. \(\alpha\)-Carotene

Hint:

Carotenoids with a \(\beta\)-ionone ring → pro-vitamin A (e.g., \(\beta\)-carotene, \(\alpha\)-carotene, \(\beta\)-cryptoxanthin). Carotenoids without the ring (e.g., lycopene, lutein, zeaxanthin) → NO pro-vitamin A activity.

Answer 1

The Correct Option is C

Step 1: Recall meaning of pro-vitamin A activity.
- Compounds that can be enzymatically converted into retinol (vitamin A) are considered to have pro-vitamin A activity. - Structural requirement: Must contain a \(\beta\)-ionone ring.

Step 2: Analyze each pigment.
- (A) \(\beta\)-Carotene → classic pro-vitamin A carotenoid, most efficient source.
- (B) \(\beta\)-Cryptoxanthin → contains \(\beta\)-ionone ring, has vitamin A activity.
- (C) Lycopene → does not contain any cyclic end groups (\(\beta\)-ionone ring absent), so NO vitamin A activity.
- (D) \(\alpha\)-Carotene → has one \(\beta\)-ionone ring, hence shows partial vitamin A activity.

Step 3: Conclude.
Among the given, only Lycopene lacks pro-vitamin A activity. Final Answer: \[ \boxed{\text{(C) Lycopene}} \]