Condensed tannin

Condensed Tannin

Schematic representation of condensed tannins

Condensed tannins, also known as proanthocyanidins, are a class of polyphenolic compounds found in a variety of plants. These compounds are known for their ability to bind and precipitate proteins, which contributes to their astringent taste. Condensed tannins are oligomers or polymers of flavan-3-ols, such as catechin and epicatechin.

Structure

Condensed tannins are composed of flavan-3-ol units linked together by carbon-carbon bonds. The most common linkage is the C4-C8 bond, but C4-C6 linkages can also occur. The degree of polymerization can vary, leading to a wide range of molecular weights and properties. The basic building block of condensed tannins is the flavan-3-ol unit, which can exist in different stereochemical forms, contributing to the diversity of these compounds.

Occurrence

Condensed tannins are widely distributed in the plant kingdom. They are found in high concentrations in the bark, wood, leaves, and seeds of many plants. Common sources include grapes, cocoa, tea, and various berries. In the plant, condensed tannins serve as a defense mechanism against herbivores and pathogens due to their ability to bind proteins and other macromolecules.

Biological Activity

Condensed tannins have been studied for their potential health benefits. They exhibit antioxidant properties, which can help in reducing oxidative stress in the body. Additionally, they have been shown to have anti-inflammatory, antimicrobial, and anticancer activities. The ability of condensed tannins to bind proteins also makes them useful in the treatment of diarrhea and other gastrointestinal disorders.

Uses

In addition to their health benefits, condensed tannins are used in various industrial applications. They are employed in the leather tanning industry due to their ability to cross-link collagen fibers, enhancing the durability and water resistance of leather. They are also used in the production of adhesives, inks, and as natural dyes.

Related Pages

• Tannin
• Polyphenol
• Flavonoid
• Antioxidant