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.
Ellagic acid is a naturally occurring plant phenol that is a potent antioxidant presumably by acting as a scavenger of oxygen species produced by hydrogen peroxide treatment, and as a protector of the DNA double helix from alkylating agent injury.