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 EC 2.7.7.7 (DNA-directed DNA polymerase) inhibitor, a geroprotector, an antioxidant, 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, a food additive, an EC 2.5.1.18 (glutathione transferase) inhibitor, a plant metabolite, a fungal metabolite, an EC 2.3.1.5 (arylamine N-acetyltransferase) inhibitor, an EC 2.4.1.1 (glycogen phosphorylase) 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 and a skin lightening agent. It is a lactone, a polyphenol, a member of catechols, an organic heterotetracyclic compound and a cyclic ketone. It is functionally related to a gallic acid. It is a conjugate acid of an ellagic acid(2-).