Names | |
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Preferred IUPAC name (E)-(3,4-Dihydroxyphenyl)[4-(3,4-dihydroxyphenyl)-3-hydroxy-5-oxofuran-2(5H)-ylidene]acetic acid | |
Other names 3,3′,4,4′-Tetrahydroxy pulvinic acid | |
Identifiers | |
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3D model (JSmol) | |
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Properties | |
C18H12O9 | |
Molar mass | 372.285 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
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 exposed to air, the chemical is enzymatically oxidized to blue quinone methide anions, specifically chinonmethid anions. [1] It is derived from xerocomic acid, which is preceded by atromentic acid and atromentin, and its genetic basis is unknown. In its oxidized form (due to the production of a second lactone ring) is variegatorubin, similar to xerocomorubin.
It was first isolated from Suillus variegatus . [2] It has strong antioxidant properties, [3] [4] and a nonspecific inhibitory effect on cytochrome P450 enzymes. [5] A total synthesis was reported in 2001 that uses a Suzuki cross coupling reaction. [6] It was found antibiotically inactive against an array of bacteria and fungi using the disk diffusion assay at 50 μg. [7] However, at similar concentrations it was found to inhibit swarming and (probably consequently) biofilm formation of Bacillus subtilis. In vitro data supports that this pigment is an Fe3+-reducant in Fenton chemistry during the initial attack of dead plant matter as part of the brown-rot saprobic lifestyle. [8]
Variegatic acid methyl ester, 3-O-methylvariegatic acid methyl ester, and 3,3',4,4'-tetra-O-methylvariegatic acid methyl ester are red-orange pigments found in Boletales . [9] [10]
The Boletales are an order of Agaricomycetes containing over 1300 species with a diverse array of fruiting body types. The boletes are the best known members of this group, and until recently, the Boletales were thought to only contain boletes. The Boletales are now known to contain distinct groups of agarics, puffballs, and other fruiting-body types.
The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface, instead of gills as are found in most agarics. Nearly as widely distributed as the agarics, the family is renowned for hosting some prime edible species highly sought after by mushroom hunters worldwide, such as the cep or king bolete . A number of rare or threatened species are also present in the family, that have become the focus of increasing conservation concerns. As a whole, the typical members of the family are commonly known as boletes.
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 Hemisphere, although some species have been introduced to the Southern Hemisphere.
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, Australia and New Zealand. Commonly referred to as slippery jack or sticky bun in English-speaking countries, its names refer to the brown cap, which is characteristically slimy in wet conditions. The fungus, initially described as Boletus luteus by Carl Linnaeus in 1753, is now classified in a different fungus family as well as genus. Suillus luteus is edible, though not as highly regarded as other bolete mushrooms. It is commonly prepared and eaten in soups, stews or fried dishes. The slime coating, however, may cause indigestion if not removed before eating. It is often sold as a dried mushroom.
Caloboletus calopus, commonly known as the bitter beech bolete or scarlet-stemmed bolete, is a fungus of the bolete family, found in Asia, Northern Europe and North America. Appearing in coniferous and deciduous woodland in summer and autumn, the stout fruit bodies are attractively coloured, with a beige to olive cap up to 15 cm (6 in) across, yellow pores, and a reddish stipe up to 15 cm (6 in) long and 5 cm (2 in) wide. The pale yellow flesh stains blue when broken or bruised.
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 naturalised in Tasmania and spread under native Nothofagus cunninghamii trees. A small bolete, the fruit body has a 1.6–9 cm orange-fawn cap with cinnamon to brown pores underneath, and a 4–9.5 cm high by 0.6–1.2 cm thick stipe. The flesh has a very peppery taste. The rare variety hypochryseus, found only in Europe, has yellow pores and tubes.
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 gardening and landscaping. Fruit bodies (mushrooms) are yellow–orange, with a funnel-shaped cap up to 8 cm across that has a felt-like surface. The thin, often forked gills on the underside of the cap run partway down the length of the otherwise smooth stipe. Reports on the mushroom's edibility vary – it is considered poisonous, but has historically been eaten internationally.
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 Australia. It was initially described as Boletus bovinus by Carl Linnaeus in 1753, and given its current binomial name by Henri François Anne de Roussel in 1806. It is an edible mushroom, though not highly regarded.
Suillellus luridus, commonly known as the lurid bolete, is a fungus of the family Boletaceae, found in calcareous broadleaved woodlands in Europe. Fruit bodies appear in summer and autumn and may be locally abundant. It is a firm bolete with an olive-brown cap up to 20 cm (8 in) in diameter, with small orange or red pores on the underside. The stout ochre stem reaches 8–14 cm (3–6 in) high and 1–3 cm (0.4–1.2 in) wide, and is patterned with a red network. Like several other red-pored boletes, it stains blue when bruised or cut.
Pulvinone, an organic compound belonging to the esters, lactones, alcohols and butenolides classes, is a yellow crystalline solid. Although the pulvinone is not a natural product, several naturally occurring hydroxylated derivatives are known. These hydroxylated pulvinones are produced by fungal species, such as the in Europe common Larch Bolete, or by moulds such as Aspergillus terreus.
Gomphidius roseus, commonly known as the rosy spike-cap or pink gomphidius, is a gilled mushroom found in Europe. Although it has gills, it is a member of the order Boletales, along with the boletes. It is a coral pink-capped mushroom which appears in pine forests in autumn, always near the related mushroom Suillus bovinus, on which it appears to be parasitic.
Suillus variegatus, commonly called the velvet bolete or variegated bolete, is a species of edible mushroom in the genus Suillus. Like all bolete-like species it has tubes, and pores, instead of gills under its cap. The mushroom forms a mycorrhizal relationship with pine and occurs in North America and Eurasia.
Gyroporus cyanescens, commonly known as the bluing bolete or the cornflower bolete, is a species of bolete fungus in the family Gyroporaceae. First described from France in 1788, the species is found in Asia, Australia, Europe, and eastern North America, where it grows on the ground in coniferous and mixed forests.
Suillus collinitus is a pored mushroom of the genus Suillus in the family Suillaceae. It is an edible mushroom found in European pine forests. The mushroom has a reddish to chestnut-brown cap that reaches up to 11 cm (4.3 in) in diameter, and a yellow stem measuring up to 7 cm (2.8 in) tall by 1 to 2 cm thick. On the underside of the cap are small angular pores, initially bright yellow before turning greenish-brown with age. A characteristic feature that helps to distinguish it from similar Suillus species, such as S. granulatus, is the pinkish mycelia at the base of the stem.
Atromentin is a natural chemical compound found in Agaricomycetes fungi in the orders Agaricales and Thelephorales. It can also be prepared by laboratory synthesis. Chemically, it is a polyphenol and a benzoquinone.
Pulvinic acids are natural chemical pigments found in some lichens, derived biosynthetically from the aromatic amino acids phenylalanine and tyrosine, via dimerization and oxidative ring-cleavage of arylpyruvic acids, a process that also produces the related pulvinones.
Norbadione A is a pigment found in the bay bolete mushroom. A polyphenol, norbadione A is related to a family of mushroom pigments known as pulvinic acids. The molecule has also been reported as a potassium salt from the mushrooms Pisolithus tinctorius and Chalciporus piperatus.
Variegatorubin is a pulvinic acid derivative. It is a red pigment that is present in many members of the Boletales, an order of the division Basidiomycota. It is generated from the oxidation of variegatic acid. Bolete species that contain variegatorubin include Neoboletus luridiformis, Chalciporus piperatus, Rhizopogon roseolus, Exsudoporus frostii, Suillellus luridus, Rubroboletus rhodoxanthus, and R. satanas. Variegatorubin was discovered by Wolfgang Steglich and colleagues, and described as a new compound in 1970.
Xerocomic acid is a red-orange pigment found in fungi of the order 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. An oxidase acting on xerocomic acid is responsible for the "bluing" reaction seen in mushrooms.
Xerocomorubin is a pigment from the fungus order Boletales. It is the oxidized form of isoxerocomic acid. Air oxidation is responsible its formation, and it oxidizes faster to a similar pulvinic acid type pigment oxidized variant, variegatorubin. The long wavelength has an absorption at 497 nm, 106 nm higher than its precursor isoxerocomic acid. Synthesis experiments have shown tetra-acetylation by acetic anhydride and sulfuric acid. Although xerocomorubin and variegatorubin give off the same deep red color and could simultaneously occur in a mushroom, extracts from the deep red colored mushroom Boletus rubellus Krombh. identified only variegatorubin by thin layer chromatography (TLC), leading to the question the natural abundance of xerocomorubin.