Names | |
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IUPAC name
5,8-Dihydroxy-2-[(1S)-1-hydroxy-4-methylpent-3-en-1-yl]naphthalene-1,4-dione
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Other names
C.I. Natural Red 20; Alkanet extract
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.007.497 |
E number | E103 (colours) |
PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
C16H16O5 | |
Molar mass | 288.299 g·mol−1 |
Appearance | Red-brown crystalline prisms |
Melting point | 149 °C (300 °F; 422 K) |
Sparingly soluble | |
Hazards | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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3.0 g/kg (mice) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Alkannin is a natural dye that is obtained from the extracts of Alkanna tinctoria. The dye is used as a food coloring and in cosmetics. As a food additive it has the E number E103.[2]
The chemical structure as a naphthoquinone derivative was first determined by Brockmann in 1936.[3] Alkannin has a deep red color in a greasy or oily environment and a violet color in an alkaline environment. Biosynthetically, alkannin is produced in plants from the intermediates 4-hydroxybenzoic acid and geranyl pyrophosphate.[4]
Alkannin is an antioxidant[5] and has an antimicrobial effect against Staphylococcus aureus and Staphylococcus epidermidis. It is also known to have wound healing, antitumor, and antithrombotic properties.[4]
References
- ^ The Merck Index, 11th Edition, 243
- ^ Additives, Food Standards Australia New Zealand
- ^ H. Brockmann (1936). "Die Konstitution des Alkannins, Shikonins und Alkannans". Justus Liebigs Ann. Chem. 521: 1–47. doi:10.1002/jlac.19365210102.
- ^ a b Vassilios P. Papageorgiou, Andreana N. Assimopoulou, Elias A. Couladouros,
David Hepworth, and K. C. Nicolaou (1999). "The Chemistry and Biology of Alkannin, Shikonin, and Related
Naphthazarin Natural Products". Angew. Chem. Int. Ed. 38: 270–300. doi:10.1002/(SICI)1521-3773(19990201)38:3<270::AID-ANIE270>3.0.CO;2-0.
{{cite journal}}
: line feed character in|author=
at position 75 (help); line feed character in|title=
at position 61 (help)CS1 maint: multiple names: authors list (link) - ^ A.N. Assimopoulou, D. Boskou, V.P. Papageorgiou (2004). "Antioxidant activities of alkannin, shikonin and Alkanna
tinctoria root extracts in oil substrates". Food Chemistry. 87: 433–438. doi:10.1016/j.foodchem.2003.12.017.
{{cite journal}}
: line feed character in|title=
at position 57 (help)CS1 maint: multiple names: authors list (link)