Ellagitannins in foods

Ellagitannins belong to the class of hydrolysable tannins, they are esters of hexahydroxydiphenoic acid and monosaccharide (most commonly glucose) and are classified under hydrolyzable tannins. The tannin family of bioactive molecules includes ellagitannins, proanthocyanidins (condensed tannins), gallic acid, and gallotannins.

Ellagitannins are recognized as the largest group of tannins, with over 500 compounds and they are a family of bioactive polyphenols in fruits and nuts such as pomegranates, black raspberries, raspberries, strawberries, walnuts, and almonds.

The main ellagitannins identified in foods (specially in fruits, nuts, and seeds) are punicalagin, sanguiin H6, lambertianin C, pedunculagin, vescalagin, castalagin, casuarictin and potentillin.

Epidemiological evidence indicates that intake of ellagitannins and ellagic acid-rich foods may be protective against certain chronic diseases. Ellagitannins exhibit a wide range of biological activity, reflected in their anti-atherogenic, antithrombotic, anti-inflammatory and anti-angiogenic properties. Studies have confirmed a correlation between the consumption of foods rich in ellagitannins (walnuts, pomegranates) and improved cardiovascular health.

Ellagitannins are hydrolyzed to ellagic acid under physiological conditions in vivo and ellagic acid is then gradually metabolized by the intestinal microbiota to produce different types of urolithins. Urolithins are the dibenzopyran-6-one secondary metabolites.
Ellagitannins in foods