A depside is a type of

polyphenol Polyphenols () are a large family of naturally occurring organic compounds characterized by multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some o ...

ic compound composed of two or more monocyclic

aromatic In chemistry, aromaticity is a chemical property of cyclic (ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to sat ...

units linked by an

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

bond. Depsides are most often found in lichens, but have also been isolated from

higher plants Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They al ...

, including species of the

Ericaceae The Ericaceae are a family of flowering plants, commonly known as the heath or heather family, found most commonly in acidic and infertile growing conditions. The family is large, with c.4250 known species spread across 124 genera, making it th ...

Lamiaceae The Lamiaceae ( ) or Labiatae are a family of flowering plants commonly known as the mint, deadnettle or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil, mint, rosemary, sage, savo ...

Papaveraceae The Papaveraceae are an economically important family of about 42 genera and approximately 775 known species of flowering plants in the order Ranunculales, informally known as the poppy family. The family is cosmopolitan, occurring in tempera ...

and

Myrtaceae Myrtaceae, the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All spe ...

. Certain depsides have

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy, ...

, anti-

HIV The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immu ...

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricants ...

, and

anti-proliferative Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs ( chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemoth ...

activity ''

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and ...

''. As inhibitors of

prostaglandin The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are der ...

synthesis and leukotriene B₄ biosynthesis, some depsides have ''in vitro'' anti-inflammatory activity. A depsidase is a type of enzyme that cuts depside bonds. One such enzyme is

tannase The enzyme tannase (EC 3.1.1.20) catalyzes the following reaction: : digallate + H2O = 2 gallate It is a key enzyme in the degradation of gallotannins and ellagicitannins, two types of hydrolysable tannins. Specifically, tannase catalyzes the hy ...

Examples

Gyrophoric acid Gyrophoric acid is a depside that can be found in the lichen ''Cryptothecia rubrocincta'' and in '' Xanthoparmelia pokomyi''. It can also be found in most of the species of the '' Actinogyra'', ''Lasallia'', and ''Umbilicaria'' genera. See also ...

, found in the lichen ''

Cryptothecia rubrocincta ''Cryptothecia rubrocincta'' is a species of lichen in the fungal family Arthoniaceae. The species is distributed in subtropical and tropical locations throughout the southeastern United States, as well as Central and South America, and has been ...

'', is a depside.

Merochlorophaeic acid Merochlorophaeic acid is a depside with the molecular formula C24H30O8 which has been isolated from the lichen ''Cladonia merochlorophaea ''Cladonia'' is a genus of moss-like lichens in the family Cladoniaceae. They are the primary food sour ...

, isolated from lichens of the genus ''

Cladonia ''Cladonia'' is a genus of moss-like lichens in the family Cladoniaceae. They are the primary food source for reindeer/caribou. ''Cladonia'' species are of economic importance to reindeer-herders, such as the Sami in Scandinavia or the Nenets ...

'', is an inhibitor of

synthesis. Some depsides are described as anti-HIV.

References

{{reflist, 2 Polyphenols Carboxylate esters