Alkannin

Names
Preferred IUPAC name

5,8-Dihydroxy-2-[(1S)-1-hydroxy-4-methylpent-3-en-1-yl]naphthalene-1,4-dione

Other names

C.I. Natural red 20
Alkanet extract
Anchusaic acid
Anchusin

Identifiers

CAS Number

* 517-88-4 Y

3D model (JSmol)

* Interactive image

ChEMBL |

* ChEMBL28457 Y

ChemSpider |

* 65430 Y

KEGG |

* C10292 Y

PubChem CID

* 72521

UNII |

* 075CRZ9995 Y

InChI

* InChI=1S/C16H16O5/c1-8(2)3-4-10(17)9-7-13(20)14-11(18)5-6-12(19)15(14)16(9)21/h3,5-7,10,17-19H,4H2,1-2H3/t10-/m0/s1 Y

Key: NEZONWMXZKDMKF-JTQLQIEISA-N Y

* InChI=1/C16H16O5/c1-8(2)3-4-10(17)9-7-13(20)14-11(18)5-6-12(19)15(14)16(9)21/h3,5-7,10,17-19H,4H2,1-2H3/t10-/m0/s1

SMILES

* O=C\2c1c(O)ccc(O)c1C(=O)/C(=C/2)[C@@H](O)CC=C(C)C

Properties[1]

Chemical formula

| 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)

Solubility in water

| 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).

N verify (what is YN ?)
Infobox references

Alkannin is a natural dye that is obtained from the extracts of plants from the borage family Alkanna tinctoria that are found in the south of France. The dye is used as a food colouring and in cosmetics. It is used as a red-brown food additive in regions such as Australia.[2] Alkannin is deep red in an acid and blue in an alkaline environment.[3] The chemical structure as a naphthoquinone derivative was first determined by Brockmann in 1936.[4] The R-enantiomer of alkannin is known as shikonin, and the racemic mixture of the two is known as shikalkin.[5][6]

## Contents

* 1 Biosynthesis
* 2 Research
* 3 References
* 4 External links

## Biosynthesis

The enzyme 4-hydroxybenzoate geranyltransferase utilises geranyl diphosphate and 4-hydroxybenzoate to produce 3-geranyl-4-hydroxybenzoate and diphosphate. These compounds are then used to form alkannin.[6]

## Research

Because the root bark (cork layers) of this plant contains large amounts of red naphthoquinone pigments, the roots of these plants are red-purple. If shikonin is extracted from fresh tissues, it gradually darkens over several days, finally forming black precipitates, which are thought to be polymers.[7]

## References

1. ↑ The Merck Index, 11th Edition, 243
2. ↑ Additives , Food Standards Australia New Zealand
3. ↑ "Alkanet" in Dispensatory of the United States of America, year 1918, edited by Joseph P. Remington and Horatio C. Wood.
4. ↑ H. Brockmann (1936). "Die Konstitution des Alkannins, Shikonins und Alkannans". Justus Liebigs Ann. Chem. 521: 1–47. doi:10.1002/jlac.19365210102.
5. ↑ Shmuel Yannai (2012). Dictionary of Food Compounds. CRC Press. p. 478.
6. ↑ 6.0 6.1 Vassilios P. Papageorgiou; Andreana N. Assimopoulou; Elias A. Couladouros et al. (1999). "The Chemistry and Biology of Alkannin, Shikonin, and Related Naphthazarin Natural Products". Angew. Chem. Int. Ed. 38 (3): 270–300. doi:10.1002/(SICI)1521-3773(19990201)38:3<270::AID-ANIE270>3.0.CO;2-0. PMID 29711637.
7. ↑ Kazufumi Y. (2017). Lithospermum erythrorhizon cell cultures: Present and future aspects. Plant Biotechnology 34: 131–142.

## External links

* Shikonin at Sigma-Aldrich

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Alkannin. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Alkannin&oldid=442738"
*[CID]: Compound ID