Variegatic acid (3,3',4,4'-tetrahydroxypulvinic acid) is an orange
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 compo ...
found in some mushrooms. It is responsible for the bluing reaction seen in many
bolete
{{refimprove, date=July 2020
A bolete is a type of mushroom, or fungal fruiting body. It can be identified thanks to a unique mushroom cap. The cap is clearly different from the stem. On the underside of the cap there is usually a spongy surfa ...
mushrooms when they are injured. When mushroom tissue containing variegatic acid is exposed to air, the chemical is
enzymatically oxidized to blue
quinone methide
A quinone methide is a type of conjugated organic compound that contain a cyclohexadiene with a carbonyl and an exocyclic methylidene or extended alkene unit. It is analogous to a quinone, but having one of the double bonded oxygens replaced wit ...
anions, specifically chinonmethid anions.
It is derived from
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 ...
, which is preceded by
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 ...
and
atromentin
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.
Occurrences
Atromentin has ...
, and its genetic basis is unknown. In its oxidized form (due to the production of a second lactone ring) is
variegatorubin
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 varieg ...
, similar to
xerocomorubin
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 ...
.
It was first isolated from ''
Suillus variegatus''.
It has strong
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 lubricant ...
properties,
and a nonspecific inhibitory effect on
cytochrome P450
Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...
enzymes.
A
total synthesis
Total synthesis is the complete chemical synthesis of a complex molecule, often a natural product, from simple, commercially-available precursors. It usually refers to a process not involving the aid of biological processes, which distinguishes ...
was reported in 2001 that uses a
Suzuki cross coupling reaction.
It was found antibiotically inactive against an array of bacteria and fungi using the disk diffusion assay at 50 μg.
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 Fe
3+-reducant in
Fenton chemistry
Fenton's reagent is a solution of hydrogen peroxide (H2O2) with ferrous iron (typically iron(II) sulfate, FeSO4) as a catalyst that is used to oxidize contaminants or waste waters as part of an advanced oxidation process. Fenton's reagent can be us ...
during the initial attack of dead plant matter as part of the brown-rot
saprobic
Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...
lifestyle.
Derivatives
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
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. ...
''.
See also
*
Pulvinic acid
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 aryl pyruvic acids, a process that also produ ...
*
Pulvinone
*
Vulpinic acid
Vulpinic acid is a natural product first found in and important in the symbiosis underlying the biology of lichens. It is a simple methyl ester derivative of its parent compound, pulvinic acid, and a close relative of pulvinone, both of which ...
References
{{Reflist, refs=
[{{cite journal , vauthors=Ahmed Z, Langer P , title=Synthesis of natural pulvinic acids based on a ' +2cyclization-Suzuki cross-coupling' strategy , journal=Tetrahedron , year=2005 , volume=61 , issue=8 , pages=2055–63 , doi=10.1016/j.tet.2004.12.048]
[{{cite journal , vauthors=Edwards RL, Elsworthy GC , title=Variegatic acid, a new tetronic acid responsible for the blueing reaction in the fungus ''Suillus (Boletus) variegatus'' (Swartz ex Fr.) , journal=Chemical Communications , year=1967 , issue=8 , pages=373b–374 , doi=10.1039/C1967000373B]
[{{cite journal , vauthors=Huang YT, Onose J, Abe N, Yoshikawa K , title=''In vitro'' inhibitory effects of pulvinic acid derivatives isolated from Chinese edible mushrooms, ''Boletus calopus'' and ''Suillus bovinus'', on cytochrome P450 activity , journal=Bioscience, Biotechnology, and Biochemistry , year=2009 , volume=73 , issue=4 , pages=855–60 , pmid=19352038 , doi=10.1271/bbb.80759, s2cid=39654350 {{open access]
[{{cite journal , vauthors=Kasuga A, Aoyagi Y, Sugahara T , title=Antioxidant activity of fungus ''Suillus bovinus'' (L: Fr.) O. Kuntze , journal=Journal of Food Science , year=1995 , volume=60 , issue=5 , pages=1113–85 , doi=10.1111/j.1365-2621.1995.tb06304.x]
[{{cite journal , vauthors=Velíšek J, Cejpek K , title=Pigments of higher fungi: A review , journal= Czech Journal of Food Sciences, year=2011 , volume=29 , issue=2 , pages=87–102 , url=http://www.agriculturejournals.cz/publicFiles/37205.pdf , doi=10.17221/524/2010-CJFS , doi-access=free ]
[{{cite journal , vauthors=Vidovic SS, Mujic IO, Zekovic ZP, Lepojevic ZD, Tumbas VT, Mujic AI , title=Antioxidant properties of selected ''Boletus'' mushrooms , journal=Food Biophysics , year=2010 , volume=5 , issue=1 , pages=49–58 , doi=10.1007/s11483-009-9143-6, s2cid=84061662 , url=https://www.semanticscholar.org/paper/e91673fc947f05ea107aa152f1cb07bb5fb445f7 ]
[Tauber, J. P., Schroeckh, V., Shelest, E., Brakhage, A. A. and Hoffmeister, D. (2016), Bacteria induce pigment formation in the basidiomycete Serpula lacrymans. Environ Microbiol, 18: 5218–5227. doi:10.1111/1462-2920.13558]
[Eastwood et al. (2011) The Plant Cell Wall- Decomposing Machinery Underlies the Functional Diversity of Forest Fungi. Science.]
[Gill, M., and Steglich, W. (1987) Pigments of fungi (Macromycetes). Prog Chem Org Nat Prod 51: 1–317.]
[https://edoc.ub.uni-muenchen.de/783/1/Gruber_Gertraud.pdf {{Bare URL PDF, date=March 2022]
Biological pigments
Polyphenols
Furanones
Catechols
Carboxylic acids