Kojic acid

Source: Wikipedia, the free encyclopedia.
Kojic acid
Names
Preferred IUPAC name
5-Hydroxy-2-(hydroxymethyl)-4H-pyran-4-one
Other names
Kojic acid, 5-Hydroxy-2-(hydroxymethyl)-4-pyrone, 2-hydroxymethyl-5-hydroxy-γ-pyrone
Identifiers
3D model (
JSmol
)
120895
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.007.203 Edit this at Wikidata
EC Number
  • 207-922-4
3620
KEGG
RTECS number
  • UQ0875000
UNII
  • InChI=1S/C6H6O4/c7-2-4-1-5(8)6(9)3-10-4/h1,3,7,9H,2H2 checkY
    Key: BEJNERDRQOWKJM-UHFFFAOYSA-N checkY
  • InChI=1/C6H6O4/c7-2-4-1-5(8)6(9)3-10-4/h1,3,7,9H,2H2
  • O=C1/C=C(\O/C=C1/O)CO
Properties
C6H6O4
Molar mass 142.110 g·mol−1
Appearance white
Melting point 152 to 155 °C (306 to 311 °F; 425 to 428 K)
Slight
Acidity (pKa) 9.40[1]
Hazards
GHS labelling:
GHS08: Health hazard
Warning
H351
P201, P280, P308+P313
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Kojic acid is an organic compound with the formula HOCH2C5H2O2OH. It is a derivative of 4-pyrone that functions in nature as a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji.[2][3][4] Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine.[2] It is a mild inhibitor of the formation of pigment in plant and animal tissues, and is used in food and cosmetics to preserve or change colors of substances.[5] It forms a bright red complex with ferric ions.[6]

Biosynthesis

13C-Labeling studies have revealed at least two pathways to kojic acid. In the usual route, dehydratase enzymes convert glucose to kojic acid. Pentoses are also viable precursors in which case dihydroxyacetone is invoked as an intermediate.[2]

Applications

Kojic acid may be used on cut fruits to prevent oxidative browning, in seafood to preserve pink and red colors, and in cosmetics to lighten skin. As an example of the latter, it is used to treat skin diseases like melasma.[7] Kojic acid also has antibacterial and antifungal properties.[citation needed] The

colon cancer cells (Caco-2) in comparison with quercetin itself.[8]

Other effects

Kojic acid has been shown to protect Chinese hamster ovary cells against ionizing radiation-induced damage. When exposed to a lethal dose of 3 Gy gamma radiation, dogs pretreated with kojic acid had a 51-day survival rate of 66.7% while the control group died within 16 days.[9]

Chemical reactions

Structure of the coordination complex Fe(kojate)3. Color code: red = O, gray = C, dark blue = Fe, white = H.

Deprotonation of the ring-OH group converts kojic acid to kojate. Kojate chelates to iron(III), forming a red complex Fe(HOCH2C5OH2O2)3. This kind of reaction may be the basis of the biological function of kojic aicd, that is, to solubilize ferric iron.[10]

Being a multifunctional molecule, kojic acid has diverse organic chemistry. The hydroxymethyl group gives the chloromethyl derivative upon treatment with thionyl chloride.[11]

Safety

Kojic acid has been shown to be

carcinogenic.[12]

References

  1. ^ Bjerrum, J., et al. Stability Constants, Chemical Society, London, 1958.
  2. ^
    PMID 17119644
    .
  3. doi:10.1039/ct9242500575
    .
  4. S2CID 22156361
    .
  5. Food and Agriculture Organization of the United Nations. 2000. Archived from the original
    on 2008-03-04.
  6. PMID 21552634
    .
  7. ^ Melasma Archived 2009-12-23 at the Wayback Machine, American Academy of Dermatology
  8. doi:10.1007/s00706-014-1314-6
  9. S2CID 19066551
    .
  10. S2CID 97627687
    .
  11. S2CID 238194561
    .
  12. ^ "Final Report of the Safety Assessment of Kojic Acid". ResearchGate. December 2010.


External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Kojic_acid&oldid=1213612189"