Question

Which of the following alkaloids are found as salts of meconic acid?

• A. $ \text{Rauwolfia Alkaloid} $
• B. $ \text{Tropane Alkaloid} $
• C. $ \text{Ergot Alkaloid} $
• D. $ \text{Opium Alkaloid} $

Hint:

Meconic acid is a key marker of natural opium — forming stable salts with its alkaloids.

Answer 1

The Correct Option is D

- Opium alkaloids, such as morphine, codeine, and thebaine, are typically found in nature as salts of meconic acid.
- Meconic acid is a non-nitrogenous organic acid unique to opium (Papaver somniferum).
- The presence of meconic acid is used to identify opium alkaloids using Ferric chloride test, which gives a deep red color.

Answer 2

This question asks which class of alkaloids occurs naturally combined with meconic acid, a characteristic organic acid found in one specific source plant. Each option can be checked against the source plant and chemistry of that alkaloid group.

1. Rauwolfia Alkaloid: Rauwolfia alkaloids such as reserpine and ajmaline are indole alkaloids obtained from Rauwolfia serpentina, and they are not associated with meconic acid; they occur as simple bases or combined with common plant acids.
2. Tropane Alkaloid: Tropane alkaloids like atropine and hyoscyamine, found in plants such as Atropa belladonna and Datura, are esters of tropic acid with tropine, not salts of meconic acid.
3. Ergot Alkaloid: Ergot alkaloids such as ergotamine and ergometrine are derivatives of lysergic acid produced by the fungus Claviceps purpurea, and they have no link to meconic acid either.
4. Opium Alkaloid: Opium alkaloids, including morphine, codeine, narcotine and papaverine, occur in the latex of Papaver somniferum together with meconic acid, and in the dried latex a large part of these alkaloids exists as their meconate salts.

Only opium alkaloids are naturally paired with meconic acid in this way, which is also the basis of a colour test for opium using ferric chloride.

Therefore, the correct answer is Opium Alkaloid.