Alkannin
| Names | |
|---|---|
| Preferred IUPAC name
5,8-Dihydroxy-2-[(1S)-1-hydroxy-4-methylpent-3-en-1-yl]naphthalene-1,4-dione | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.007.497 |
| E number | E103 (colours) |
| KEGG | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C16H16O5 | |
| Molar mass | 288.299 g·mol−1 |
| Appearance | Red-brown crystalline prisms |
| Density | 1.15 g/mL |
| Melting point | 149 °C (300 °F; 422 K) |
| Boiling point | 567 °C (1,053 °F; 840 K) |
| Sparingly soluble | |
| Hazards | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
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).
Infobox references | |
Alkannin is a natural dye that is obtained from the extracts of the plant dyer's alkanet (Alkanna tinctoria) which is found in the Mediterranean region. The dye is used as a food coloring and in cosmetics; within the European E number schedule, it is numbered E103. It is used as a red-brown food additive in regions such as Australia. Alkannin is deep red in an acid and blue in an alkaline environment. The chemical structure as a naphthoquinone derivative was first determined by Hans Brockmann in 1936. The (R)-enantiomer of alkannin is known as shikonin, and the racemic mixture of the two is known as shikalkin.