Coumarin Glycosides

2.5.1 Coumarin Glycosides

These are reported to be present in about 150 different species spreading over to nearly 30 different families, of which a few important ones are, namely: Caprifoliaceae, Leguminosae, Oleaceae, Rubiaeeae, Solaneceae, and Umbelliferae.

This basic nucleus of coumarin is considered to be derived from o-hydroxy cinnamic acid (or o-coumarin acid) by its dehydration to yield the fused lactone ring as shown below:

It has been observed that invariably most naturally occurring coumarins essentially bear an oxygen atom either as hydroxyl (OH) or alkoxyl (—OCH₃ or —OC₂H₅) at C-7 position.

A few important naturally occurring coumarin glycosides along with their respective biological sources have been summarised in Table 4.3.

2.5.1.1 Coumarin Coumarin is abundantly found in a variety of natural products which are used profusely as a flavouring agent in pharmaceutical preparations.

Synonyms Tonka bean camphor; Cumarin; Coumarimic anhydride.

 

Biological Source It is found in the tonka seed, also known as tonquin beans or tonco seed i.e., Dipteryx odorata Wild, and Dipteryx oppositifolia L., belonging to family Leguminosae. It is also

obtained from Woodruff (Asperula species) and in sweet clover i.e.; Melilotus alba Dess., family : Leguminosae.

Geographical Source These plants are found in Europe, India and in the African continent.

Description

Colour : Colourless

Odour : Pleasant and fragrant odour resembling that of vanilla beans.

Taste : Burning Taste

Shape : Orthorhombic, rectangular plates.

Chemical Structures Coumarin has the following structure:

Uses It is mostly employed as a pharmaceutical aid.

Source: Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar