Kojic acidis anorganic compoundwith the formulaHOCH2C5H2O2OH.It is a derivative of4-pyronethat functions in nature as achelationagent produced by several species of fungi, especiallyAspergillus oryzae,which has the Japanese common namekoji.[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 withferricions.[6]
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| Names | |
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| 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
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| Identifiers | |
3D model (JSmol)
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| 120895 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| DrugBank | |
| ECHA InfoCard | 100.007.203 |
| EC Number |
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| 3620 | |
| KEGG | |
PubChemCID
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| RTECS number |
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| UNII | |
CompTox Dashboard(EPA)
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| Properties | |
| C6H6O4 | |
| Molar mass | 142.110g·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 | |
| GHSlabelling: | |
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| Warning | |
| H351 | |
| P201,P280,P308+P313 | |
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).
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Biosynthesis
edit13C-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 casedihydroxyacetoneis invoked as an intermediate.[2]
Applications
editKojic acid may be used on cut fruits to preventoxidative browning,inseafoodto preserve pink and red colors, and in cosmetics to lighten skin. As an example of the latter, it is used to treat skin diseases likemelasma.[7]Kojic acid also has antibacterial and antifungal properties.[citation needed]
Chemical reactions
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Deprotonation of the ring-OH group converts kojic acid tokojate.Kojate chelates to iron(III), forming a red complexFe(HOCH2C5OH2O2)3.This kind of reaction may be the basis of the biological function of kojic acid, that is, to solubilize ferric iron.[8]
Being a multifunctional molecule, kojic acid has diverse organic chemistry. Thehydroxymethyl groupgives the chloromethyl derivative upon treatment withthionyl chloride.[9]
Safety
editKojic acid may be weaklycarcinogenic,according to some animal studies. It is not believed to reach carcinogenic thresholds in human skin, and is demonstrably safe at the level used in cosmetics.[10]
References
edit- ^Bjerrum, J., et al.Stability Constants,Chemical Society, London, 1958.
- ^abcBentley, R. (2006). "From miso, sake and shoyu to cosmetics: a century of science for kojic acid".Nat. Prod. Rep.23(6): 1046–1062.doi:10.1039/b603758p.PMID17119644.
- ^Yabuta T (1924). "The constitution of kojic acid, a γ-pyrone derivative formed byAspergillus oryzaefrom carbohydrates ".Journal of the Chemical Society.125:575–587.doi:10.1039/ct9242500575.
- ^Parvez, Shoukat; Kang, Moonkyu; Chung, Hwan-Suck; Cho, Chongwoon; Hong, Moo-Chang; Shin, Min-Kyu; Bae, Hyunsu (2006). "Survey and mechanism of skin depigmenting and lightening agents".Phytotherapy Research.20(11): 921–34.doi:10.1002/ptr.1954.PMID16841367.S2CID22156361.
- ^"Kojic acid and enzymatic browning]".Food and Agriculture Organization of the United Nations.2000. Archived fromthe originalon 2008-03-04.
- ^Nurchi, Valeria M.; Lachowicz, Joanna I.; Crisponi, Guido; Murgia, Sergio; Arca, Massimiliano; Pintus, Anna; Gans, Peter; Niclos-Gutierrez, Juan; Domínguez-Martín, Alicia; Castineiras, Alfonso; Remelli, Maurizio (2011-05-27). "Kojic acid derivatives as powerful chelators for iron(III) and aluminium(III)".Dalton Transactions.40(22): 5984–5998.doi:10.1039/C1DT00005E.ISSN1477-9234.PMID21552634.
- ^MelasmaArchived2009-12-23 at theWayback Machine,American Academy of Dermatology
- ^Zaremba, K.; Lasocha, W.; Adamski, A.; Stanek, J.; Pattek-Janczyk, A. (2007). "Crystal Structure and Magnetic Properties of Tris(2-hydroxymethyl-4-oxo-4H-pyran- 5-olato-κ2O5,O4)iron(III)".Journal of Coordination Chemistry.60(14): 1537–1546.doi:10.1080/00958970601084243.S2CID97627687.
- ^Agyemang, Nana; Murelli, Ryan P. (2019)."Synthesis of 5-Hydroxy-4-methoxy-2-methylpyrylium Trifluoromethanesulfonate from Kojic Acid".Organic Syntheses.96:494–510.doi:10.15227/orgsyn.096.0494.S2CID238194561.
- ^"Final Report of the Safety Assessment of Kojic Acid".ResearchGate.December 2010.
External links
edit- Safety MSDS data
- Mohajer, Fatemeh;Mohammadi Ziarani, Ghodsi(2021)."An Overview of Quantitative and Qualitative Approaches on the Synthesis of Heterocyclic Kojic Acid Scaffolds through the Multi-Component Reactions".Heterocycles.102(2). Japan Institute of Heterocyclic Chemistry: 211.doi:10.3987/REV-20-936.