Variegatic acid

Variegatic acid
Names
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
3D model (JSmol)
ChemSpider
UNII
  • InChI=1S/C18H12O9/c19-9-3-1-7(5-11(9)21)13-15(23)16(27-18(13)26)14(17(24)25)8-2-4-10(20)12(22)6-8/h1-6,19-23H,(H,24,25)/b16-14+
    Key: MRRYHTCWZKZVIH-JQIJEIRASA-N
  • O=C(C(C1=CC(O)=C(O)C=C1)=C/2O)OC2=C(C(O)=O)/C3=CC(O)=C(O)C=C3
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]

  1. ^ Cite error: The named reference Velíšek 2011 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Edwards 1967 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Kasuga 1995 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Vidovic 2010 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Huang 2009 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Ahmed 2005 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Tauber was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Eastwood was invoked but never defined (see the help page).