Pulvinic acids are natural chemical

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

s found in some

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

s, derived biosynthetically from the aromatic amino acids

phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the chemical formula, formula . It can be viewed as a benzyl group substituent, substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of ...

and

tyrosine -Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a conditionally essential amino acid with a polar side group. The word "tyrosine" is ...

, via

dimerization In chemistry, dimerization is the process of joining two identical or similar molecular entities by bonds. The resulting bonds can be either strong or weak. Many symmetrical chemical species are described as dimers, even when the monomer is u ...

and oxidative ring-cleavage of aryl

pyruvic acid Pyruvic acid (CH3COCOOH) is the simplest of the keto acids, alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate acid, conjugate base, CH3COCOO−, is an metabolic intermediate, intermediate in several m ...

s, a process that also produces the related pulvinones. Hydroxypulvinic acid pigments (pulvinic acid type family of pigments) have been found in ''Boletus'' (e.g. '' Boletus erythropus''), ''

Boletinus ''Boletinus'' is a genus of fungi belonging to the family Suillaceae. The genus was first described by Károly Kalchbrenner in 1867. The genus has cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a ...

'', '' Chalciporus'', '' Gyrodon'', ''

Leccinum ''Leccinum'' is a genus of fungi in the family Boletaceae. It was the name given first to a series of fungi within the genus '' Boletus'', then erected as a new genus last century. Their main distinguishing feature is the small, rigid projection ...

'', ''

Pulveroboletus ''Pulveroboletus'' is a genus of fungi in the family Boletaceae. The genus has a cosmopolitan distribution and contains 41 species. Taxonomy The genus was first described by American mycologist William Alphonso Murrill in 1909. He defined specie ...

'', ''

Suillus ''Suillus'' is a genus of basidiomycete fungi in the family Suillaceae and order Boletales. Species in the genus are associated with trees in the pine family (Pinaceae), and are mostly distributed in temperate locations in the Northern Hemisphe ...

'' (e.g. ''

Suillus luteus ''Suillus luteus'' is a bolete fungus, and the type species of the genus ''Suillus''. Commonly referred to as slippery jack or sticky bun in English-speaking countries, its names refer to the brown pileus (mycology), cap, which is characterist ...

'', '' Suillus bovinus'', and '' Suillus grevillei''), ''

Paxillus ''Paxillus'' is a genus of mushrooms of which most are known to be poisonous mushroom, poisonous or inedible. Species include ''Paxillus involutus'' and ''Paxillus vernalis''. Two former species—''Tapinella panuoides'' and ''Tapinella atrotomen ...

'' (e.g. ''

Paxillus involutus ''Paxillus involutus'', also known as the brown roll-rim or the common roll-rim, is a species of basidiomycete fungus. Although it has lamella (mycology), gills, it is more closely related to the pored boletes than to typical gilled mushroom ...

''), ''

Serpula ''Serpula'' (also known as calcareous tubeworm, serpulid tubeworm, fanworm, or plume worm) is a genus of sessile, marine annelid tube worms that belongs to the family Serpulidae. Serpulid worms are very similar to tube worms of the closely r ...

'' (e.g. '' Serpula lacrymans''), ''

Xerocomus ''Xerocomus'' is a genus of poroid fungi related to ''Boletus''. Most members of ''Xerocomus'' are edible mushroom, edible, though of mediocre gastronomical value and inferior to the sought-after Boletus edulis, porcini. Taxonomy Many mycol ...

'' (e.g. '' Xerocomus chrysenteron''), '' Hygrophoropsis'' (e.g. '' Hygrophoropsis aurantiaca''), ''

Retiboletus ''Retiboletus'' is a genus of fungi in the family Boletaceae. The genus, first described in 2002, contained six species distributed in north temperate regions. Species , Index Fungorum lists the following species: References External links

'' (e.g. ''

Retiboletus nigerrimus ''Retiboletus'' is a genus of fungi in the family Boletaceae. The genus, first described in 2002, contained six species distributed in north temperate regions. Species , Index Fungorum lists the following species: References External links

''), ''

'' (e.g. '' Pulveroboletus auriflammeus''), and are generally characteristic of Boletales. In addition to pulvinone, derivatives and related pigments of this family include atromentic acid, xerocomic acid, isoxerocomic acid, variegatic acid, variegatorubin, xerocomorubin, chinomethide,

methyl bovinate In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula (whereas normal methane has the formula ). In formulas, the group is often abbreviated as ...

, badion A, norbadion A, bisnorbadiochinone A, pisochinone, and sclerocitrin. More complex dimers of the pulvinic acid dimer (dimers of dimers) have been found in the fungi ''

Scleroderma citrinum ''Scleroderma citrinum'', commonly known as the common earthball, pigskin poison puffball, or common earth ball, is a species of earthball fungus found in Europe and in North America. It is the most common species of Scleroderma (genus), earthba ...

'' and ''

Chalciporus piperatus ''Chalciporus piperatus'', commonly known as the peppery bolete, is a species of fungus in the family Boletaceae. Described by Jean Baptiste François Pierre Bulliard, Pierre Bulliard in 1790 as ''Boletus piperatus'', it is only distantly rela ...

''.

References

Sources

* * * * {{refend Fungal pigments Carboxylic acids Furanones Phenyl compounds Lichen products