Chemical Properties
red to dark red crystalline powder
Chemical Properties
Cochineal extract is a concentrated solution obtained after removing alcohol from an aqueous–alcoholic extract of
cochineal (Dactylopius coccus Costa, also called Coccus cati L.). This extract is used as a color additive, the primary colorant being
carminic acid.
History
CI Natural Red 4(CI 75470), is a red dye occurring as a glycoside in the body of the cochineal insect Dactylopius coccus of the order Homoptera, family Coccidae. This insect is native to Central and South America. The Aztecs had extracted the dye from the insect centuries before the coming of the Spaniards. For breeding purposes, the insects were collected in the autumn and carefully protected during the winter months. Cochineal was harvested after three months, and then the bugs were killed by immersion in hot water, by placing in hot ovens, or by exposure to the hot sun. The latter method produced the highest quality dye. At present, Peru and the Canary Islands are the main source of the dye. Until the advent of synthetic dyes, the principal use for carminic acid was for dyeing tin-mordanted wool or silk. Its aluminum lake, carmine, finds use in the coloring of foods.
Uses
Carminic acid (C.I. 75470) For staining nuclei in histological sections. Used to prepare staining solutions.
CAS 1260-17-9, pH 1.6 (10?g/l, H?O, 20?°C).
Uses
antineoplastic, glucosyltransferase inhibitor
Uses
A red glucosidal hydroxyanthrapurin, it is produced naturally within some insects as a defense mechanism.
Definition
ChEBI: A tetrahydroxyanthraquinone that is that is 1,3,4,6-tetrahydroxy-9,10-anthraquinone substituted by a methyl group at position 8, a carboxy group at position 7 and a 1,5-anhydro-D-glucitol moiety at position 2 via a C-gly
osidic linkage. It is a natural dye isolated from several insects such as Dactylopius coccus.
General Description
Dark purplish-brown mass or bright red or dark red powder. Darkens at 248°F. Deep red color in water. Yellow to violet in acidic aqueous solutions.
Air & Water Reactions
Soluble in water [Hawley].
Reactivity Profile
CARMINE neutralizes bases in exothermic reactions. Incompatible with strong oxidizing agents.
Fire Hazard
Flash point data for CARMINE are not available. CARMINE is probably combustible.
Purification Methods
Carminic acid forms red prisms from EtOH. It gives a red colour in Ac2O and yellow to violet in acidic solution. UV: max (H2O) 500nm ( 6,800); (0.02N HCl) 490-500nm ( 5,800) and (0.0001N NaOH) 540nm ( 3,450). IR: max (Nujol) 1708s, 1693s, 1677m, 1648m, 1632m, 1606s, 1566s, 1509 cm-1. Periodate oxidation is complete after 4hours at 0o with the consumption of 6.2 mols. The tetra-O-methyl carminate has m 186-188o (yellow needles from *C6H6/pet ether). [IR: Ali & Haynes J Chem Soc 1033 1959, Bhatia & Venkataraman Indian J Chem 3 (2) 92 1965, Synthesis: Davis & Smith Biochemical Preparations 4 38 1955, Beilstein 18 III/1V 6697.]
