Q.28. - Organic Chemistry

Question

Crocin, which occurs naturally in crocus and gardenia flowers, is primarily responsible for the color of saffron. 

(a) What lipid and monosaccharides are formed by the hydrolysis of crocin? 

(b) Classify the lipid as a monoterpenoid, diperpenoid, etc., and locate the isoprene units.

Step-by-Step Solution

Answer

Answer

(a) The hydrolysis of crocin is as shown below:

It forms D-glucose (monosaccharide) and the lipid crocetin.

 

(b) The lipid present in it is crocetin. It is an example of a diterpenoid.

The isoprene units in it are as shown below:

Step 1: Crocin

The color of saffron is due to crocin. Chemically, crocin is an example of a diester. The carboxylic acid that forms crocin is crocetin and the gentiobiose carbohydrate.

Step 2: Hydrolysis of crocin

The hydrolysis of crocin forms the carbohydrate D-glucose and the dicarboxylic acid crocetin. The products of hydrolysis of crocin are as shown below:

Step 3: The type of lipid present in crocin

The lipid molecule that makes crocin is crocetin. The isoprene units will make the terpenoids. Based on the number of isoprene units, the terpenoid can be classified. In crocin, there are two terpenoids $\left(C_5{H}_8\right)$ units in it. They are as shown below:

This crocetin is an example of a diterpenoid.