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, an EC 2.7.7.7 (DNA-directed DNA polymerase) inhibitor and a geroprotector. It is an organic heterotetracyclic compound, a cyclic ketone, a lactone, a member of catechols and a polyphenol. It is functionally related to a gallic acid.