Indican

Indican is a naturally occurring glucoside found in various plants, most notably in species of the genus Indigofera. It is a precursor to the dye indigo, which has been used for centuries to produce blue dye for textiles.

Chemical Structure and Properties

Indican is chemically classified as a glycoside, specifically a glucoside of indoxyl. Its chemical formula is C₁₄H₁₇NO₆. In its pure form, indican is a colorless, crystalline substance that is soluble in water.

Biosynthesis

Indican is synthesized in plants through the shikimate pathway, which is a common route for the biosynthesis of aromatic compounds. The process involves the conversion of tryptophan to indoxyl, which is then glycosylated to form indican.

Role in Plants

In plants, indican serves as a storage form of indoxyl. When the plant tissue is damaged, enzymes hydrolyze indican to release indoxyl, which then oxidizes to form the blue dye indigo. This process is a defense mechanism against herbivores and pathogens.

Historical and Industrial Significance

Indican has been historically significant due to its role in the production of indigo dye. The extraction and processing of indigo from plants like Indigofera tinctoria were important industries in ancient civilizations, including those in India, Egypt, and Greece.

Extraction and Processing

The traditional method of extracting indigo dye from plants involves fermenting the plant material to hydrolyze indican into indoxyl. The indoxyl is then oxidized to form indigo, which precipitates out of solution and can be collected and processed into dye.

Applications

While the primary historical use of indican has been in dye production, modern research has explored its potential applications in biotechnology and medicine. For example, indican and its derivatives are being studied for their potential use in antimicrobial treatments and as indicators in various biochemical assays.

Related Compounds

Indican is related to other naturally occurring glycosides and indole derivatives, such as indoxyl sulfate and indole-3-acetic acid.

See Also

• Indigo dye
• Indigofera
• Glycoside
• Shikimate pathway
• Indoxyl