A depside is a type of polyphenolic compound composed of two or more monocyclic aromatic units linked by an ester bond. Depsides are most often found in lichens, but have also been isolated from higher plants, including species of the Ericaceae, Lamiaceae, Papaveraceae and Myrtaceae. Depsides have antibiotic, anti-HIV, antioxidant, and anti-proliferative activity. As inhibitors of prostaglandin synthesis and leukotriene B4 biosynthesis, depsides are potent non-steroidal anti-inflammatories.
A depsidase is a type of enzyme that cuts depside bonds. One such enzyme is tannase.
Gyrophoric acid, found in the lichen Cryptothecia rubrocincta, is a depside.