Kojic acid
| Kojic acid | |
|---|---|
 | |
| 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 | |
| CAS number | 501-30-4  |
| PubChem | 3840 |
| ChemSpider | 3708 |
| UNII | 6K23F1TT52 |
| EC number | 207-922-4 |
| DrugBank | DB01759 |
| KEGG | C14516 |
| ChEBI | CHEBI:43572  |
| ChEMBL | CHEMBL287556 |
| RTECS number | UQ0875000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C6H6O4 |
| Molar mass | 142.11 g/mol |
| Appearance | white |
| Melting point | 152 - 155 °C |
| Solubility in water | Slight |
| Acidity (pKa) | 9.40[1] |
| Hazards | |
| R-phrases | R36/37/38 |
| S-phrases | S22, S24/25 |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |
| Infobox references | |
Kojic acid is a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji.[2][3] 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.[4] It forms a bright red complex with ferric ions.
Biosynthesis
13C-Labeling studies have revealed at least two pathways to kojic acid. In the usual route, dehydratase enzymes convert glucose to kojic acid. Also reduces the signs of redness. 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.[5] Kojic acid also has antibacterial and antifungal properties.[citation needed]
References
- ↑ Bjerrum, J., et al. Stability Constants, Chemical Society, London, 1958.
- ↑ 2.0 2.1 2.2 R. Bentley, "From miso, sake and shoyu to cosmetics: a century of science for kojic acid", Nat. Prod. Rep. 2006, 23, 1046-1062.
- ↑ Yabuta T (1924). "The constitution of kojic acid, a gamma-pyrone derivative formed by Aspergillus oryzae from carbohydrates". Journal of the Chemical Society 125: 575–587.
- ↑ Kojic acid and enzymatic browning
- ↑ Melasma, American Academy of Dermatology