Ellagic acid is an organic heterotetracyclic compound resulting from the formal dimerisation of gallic acid by oxidative aromatic coupling with intramolecular lactonisation of both carboxylic acid groups of the resulting biaryl. It is found in many fruits and vegetables, including raspberries, strawberries, cranberries, and pomegranates. It has a role as an antioxidant, a food additive, a plant metabolite, an EC 5.99.1.2 (DNA topoisomerase) inhibitor, an EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor, an EC 1.14.18.1 (tyrosinase) inhibitor, an EC 2.3.1.5 (arylamine N-acetyltransferase) inhibitor, an EC 2.4.1.1 (glycogen phosphorylase) inhibitor, an EC 2.5.1.18 (glutathione transferase) inhibitor, an EC 2.7.1.127 (inositol-trisphosphate 3-kinase) inhibitor, an EC 2.7.1.151 (inositol-polyphosphate multikinase) inhibitor, an EC 2.7.4.6 (nucleoside-diphosphate kinase) inhibitor, a skin lightening agent, a fungal metabolite and an EC 2.7.7.7 (DNA-directed DNA polymerase) inhibitor. It is an organic heterotetracyclic compound, a cyclic ketone, a lactone, a member of catechols and a polyphenol. It derives from a gallic acid. Ellagic acid, also known as ellagate, belongs to the class of organic compounds known as hydrolyzable tannins. These are tannins with a structure characterized by either of the following models. In model 1, the structure contains galloyl units (in some cases, shikimic acid units) that are linked to diverse polyol carbohydrate-, catechin-, or triterpenoid units. In model 2, contains at least two galloyl units C-C coupled to each other, and do not contain a glycosidically linked catechin unit. The antiproliferative and antioxidant properties of ellagic acid have spurred preliminary research into the potential health benefits of ellagic acid consumption. Ellagic acid's therapeutic action mostly involves antioxidant and anti-proliferative/anti-cancer effects. Ellagic acid is found, on average, in the highest concentration within a few different foods, such as chestnuts, common walnuts, and japanese walnuts and in a lower concentration in whiskies, arctic blackberries, and cloudberries. Ellagic acid has also been detected, but not quantified in several different foods, such as lowbush blueberries, bilberries, guava, strawberry guava, and bog bilberries.