Question

Which is the active form of vitamin E?

• A. 1,25‐dihydroxycholecalciferol
• B. \(\alpha\)‐tocopherol
• C. Menadione
• D. Retinol

Hint:

The antioxidant activity of Vitamin E relies on the chromanol ring of \(\alpha\)-tocopherol, which donates a hydrogen atom to neutralize free radicals, protecting membrane lipids from peroxidation.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Vitamins are essential organic compounds that function as vital micronutrients in various biochemical processes.
Many vitamins exist in several related chemical forms (vitamers), but only specific forms exhibit high biological activity inside animal tissues.

Step 2: Detailed Explanation:
Vitamin E is a group of fat-soluble compounds composed of four tocopherols (\(\alpha, \beta, \gamma, \delta\)) and four tocotrienols (\(\alpha, \beta, \gamma, \delta\)).
Among these, \(\alpha\)-tocopherol is the most biologically active form in animals.
It is preferentially recognized, bound, and distributed by the hepatic \(\alpha\)-tocopherol transfer protein (\(\alpha\)-TTP), allowing it to accumulate in tissues and act as a membrane-bound lipid antioxidant.
Let us identify the other options to confirm this:
- 1,25-dihydroxycholecalciferol: The active hormonal form of Vitamin D (calcitriol).
- Menadione: A synthetic precursor form of Vitamin K (Vitamin \(\text{K}_3\)).
- Retinol: The primary transport and storage form of Vitamin A.
Therefore, \(\alpha\)-tocopherol is the active form of Vitamin E.

Step 3: Final Answer:
The active form of Vitamin E is \(\alpha\)-tocopherol.