Pulvinic acids are natural chemical

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...

s found in some lichens, derived biosynthetically from the aromatic amino acids phenylalanine 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 non-essential amino acid with a polar side group. The word "tyrosine" is from the G ...

, via dimerization and oxidative ring-cleavage of aryl pyruvic acids, 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'', ''

Chalciporus ''Chalciporus'' is a genus of fungi in the family Boletaceae (suborder (biology), suborder Boletineae). There are approximately 25 species in the genus. French mycologist Frédéric Bataille erected the genus in 1908, though it did not gain gener ...

'', ''

Gyrodon ''Gyrodon'' is a genus of pored mushroom bearing close affinity to the genus ''Paxillus''. Recent molecular research has confirmed this relationship of the two genera as sister taxa, together diverging as one of the most basal lineages in the B ...

'', ''

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 projections ...

'', '' Pulveroboletus'', ''

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''. A common fungus native all across Eurasia from Ireland to Korea, it has been introduced widely elsewhere, including North and South America, southern Africa ...

'', ''

Suillus bovinus ''Suillus bovinus'', also known as the Jersey cow mushroom or bovine bolete, is a pored mushroom of the genus '' Suillus'' in the family Suillaceae. A common fungus native to Europe and Asia, it has been introduced to North America and Aust ...

'', and ''

Suillus grevillei ''Suillus grevillei'' ( commonly known as Greville's bolete and larch bolete) is a mycorrhizal mushroom with a tight, brilliantly coloured cap, shiny and wet looking with its mucous slime layer. The hymenium easily separates from the flesh of t ...

''), ''

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

'' (e.g. ''

Paxillus involutus ''Paxillus involutus'', commonly known as the brown roll-rim, common roll-rim is a basidiomycete fungus that is widely distributed across the Northern Hemisphere. It has been inadvertently introduced to Australia, New Zealand, South Africa, ...

''), ''

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 re ...

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

Hygrophoropsis ''Hygrophoropsis'' is a genus of gilled fungi in the family Hygrophoropsidaceae. It was circumscribed in 1888 to contain the type species, '' H. aurantiaca'', a widespread fungus that, based on its appearance, has been affiliated with ''Ca ...

'' (e.g. ''

Hygrophoropsis aurantiaca ''Hygrophoropsis aurantiaca'', commonly known as the false chanterelle, is a species of fungus in the family Hygrophoropsidaceae. It is found across several continents, growing in woodland and heathland, and sometimes on woodchips used in gar ...

''), '' Retiboletus'' (e.g. '' Retiboletus nigerrimus''), '' Pulveroboletus'' (e.g. '' Pulveroboletus auriflammeus''), and are generally characteristic of Boletales. In addition to pulvinone, derivatives and related pigments of this family include

atromentic acid Atromentic acid is a red-organge pigment found in fungi within the Boletales group. It is the precursor to variegatic acid and xerocomic acid, and is preceded by atromentin. As an example, it is isolated from ''Serpula lacrymans ''Serpula l ...

xerocomic acid Xerocomic acid is a red-orange pigment found in fungi of the order ''Boletales'' (and is named after the genus '' Xerocomus''). It is the precursor to variegatic acid, and is preceded by atromentic acid and atromentin. As an example, it is isolate ...

isoxerocomic acid Isoxerocomic acid is a red-orange pigment found in ''Boletales''. It is the precursor to variegatic acid, and is preceded by atromentic acid and atromentin. As an example, it is isolated from ''Serpula lacrymans''. It is soluble in methanol. It i ...

variegatic acid Variegatic acid (3,3',4,4'-tetrahydroxypulvinic acid) is an orange pigment found in some mushrooms. It is responsible for the bluing reaction seen in many bolete mushrooms when they are injured. When mushroom tissue containing variegatic acid is e ...

, variegatorubin, xerocomorubin, chinomethide, methyl bovinate, 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 the most common species of earthball in the UK and occurs widely in woods, heathland and in short grass from autumn to winter. '' ...

'' and ''

Chalciporus piperatus ''Chalciporus piperatus'', commonly known as the peppery bolete, is a small pored mushroom of the family Boletaceae found in mixed woodland in Europe and North America. It has been recorded under introduced trees in Brazil, and has become n ...

''.

References

{{Reflist Biological pigments Carboxylic acids Furanones Phenyl compounds Lichen products