Laccaic acids

Lack-saure, /. laccaic acid, -schicht, /. coat or film of lacquer or varnish, -sieder, m. varnish boiler, -siegel, n. wax seal, -sud, m. varnish boiling, -uberzug, m. = Lackanstrich. -verdiinner, m. lacquer (or varnish) thinner, -waren, /.pi. lacquered goods, japanned goods. 

Lac is derived from lac resin, the hardened secretion of the lac insect, the only known resin of animal origin. The lac insect, Kerria lacca, formerly known as Laccifer lacca, is a natural parasite of a variety of trees in large areas of southern Asia. Three different products are derived from lac resin lac dye, lac wax, and shellac. To obtain the lac resin, twigs encrusted with the secretion of the insects are cut down from the trees, then the incrustation is separated from the twigs, washed with water, and filtered. The wax and shellac, which are insoluble in water, remain as a solid residue of the filtration, while the soluble red dye (lac) is obtained as a powder when the water from the filtered solution is evaporated. The coloring matter in lac dye is an organic compound known as laccaic acid. 

Carminic Kermesic Flavokermesic acid dc II Laccaic acid A Laccaic acid B... 

Statistical evaluation of HPLC UV MS[19] and CE UV MS[20] methods proves that MS detection of anthraquinone dyes is more sensitive than UV, especially in the case of chromatographic analysis of laccaic acids (almost 20 times) and purpurin (almost 40 times). However, detection limits of HPLC ESI MS determination of alizarin and purpurin (0.03 gg ml ) are about 20 times lower than those of CE ESI MS (0.52 0.58 gg ml x). 

Madder lake, lac dye, cochineal Alizarin, purpurin, ruberythric acid, lucidin, laccaic acid A, carminic acid hci/h2o, n amyl alcohol, MeOH H20/MeOH with AcOH 250, 280 nm/ ESI( ) HPLC optimization... 

Madder, Armenian cochineal, lac dye historical samples pigment and wall painting Alizarin, munjistin, purpurin, xanthopurpurin, rubiadin, laccaic acid A, laccaic acid B, carminic acid, kermesic acid, flavokermesic acid HCI/MeOH/ h2o A H20 B ACN with TFA 275 nm/ESI ( ) HPLC optimization... 

Cochineal and lac dye can be studied by HPLC with spectrophotometric and NI ESI MS detection. [34] In cochineal, carminic acid appears as a dominant colouring agent. In lac dye extracts, the signal at m/z 536 corresponding to a quasi-molecular ion of laccaic acid A is observed as the dominant one. [19]... 

A similar analysis of cochineal can be performed with the use of CE with ESI MS detection. The results are similar to those obtained with HPLC MS.[20] In the lac dye extract, the signal of laccaic acid A is found in the mass spectrum as the dominant one at m/ z 536. However, a second peak is observed on the electropherogram, and the eluted substance can be identified as laccaic acid E, on account of the mass spectrum which consists of the following signals at m/z 494 [M H], 476 [M H20 H] and 450 [M C02 H]. ... 

Silk and wool fibres of Coptic textiles from fourth to twelfth century Carminic acid, laccaic acids A, B, C and E, xantholaccaic acid A, purpurin, xanthopurpurin, alizarin, monochloroalizarin, dichloroalizarin, ellagic acid, luteolin, apigenin, rhamnetin, indirubin HCI/EtOH, pyridine A ACN B H20 with TFA 278, 350 nm/ESI (+)... 

Laccaic acid has been designated (Cl Natural Red 25 Cl 75450). Lac dye ranks as ihe most ancient of animal dyes. It is found in lac. the resinous secretion of a eery small insect. Coccus laccae. found growing in India and Southeast Asia. Lac dye is actually a mixture of acids derived front 2-phenylanthraquinonc... 

The wide varity of anthraquinone dyes identified in various madder plants is not to be found in the dye insects American cochineal, kermes, Polish and Armenian cochineal. These insects contain two dyes whose constitutions are known and a third dye whose constitution has not yet been clarified. However, the fifth in the class of dye insects, lac dye, contains five water-soluble dyes ( = laccaic acids) and traces of three water-insoluble dyes. 

Constituents (See also tables IV and V) Besides shellac rosin, lac dye contains the water-soluble dyes laccaic acid A, B, C, D, and E and three water-insoluble dyes (62-68). 

If the sulfuric acid layer is stained orange to red, this could indicate the presence of carminic acid (XXVII) or laccaic acids (XXVIII -XXXII). If the sulfuric acid layer is colorless and the ethyl acetate layer is orange, the ethyl acetate layer is separated off in a small separating funnel and a specimen for the TLC is prepared as described above for madder dyeings (page 202). 

The solutions obtained after concentration of the ethyl acetate and/ or ethyl acetate - 3-methylbutanol-l solution(s) are applied side by side with the following reference solutions to a Mikropolyamid F 1700 thin-layer plate American cochineal, kermes, Polish cochineal, and laccaic acids from lac dye. 

Figure 9. TLC comparison of the red insect dyes in the Karabagh carpets, figures 7 and 8, after dissolving the dye extracts in different organic solvents. 1 and 2, extracts of the Karabagh carpet (figure 7) 1, soluble in ether 2, soluble in ethyl acetate + methanol 3 and 4, extracts of the Karabagh carpet (figure 8) 3, soluble in ether 4, soluble in ethyl acetate + methanol 5 and 6, extracts of Armenian cochineal S, soluble in ether 6, soluble in ethyl acetate + methanol 7, Polish cochineal 8, American cochineal 9, kermes 10, laccaic acids (XXVIII - XXXII) 11, erythrolaccin (XXXIII) 12, deoxyerythrolaccin (XXXTV).

Figure 12. Identification of the insect dyes in the Sicilian coronation robe (figure 10) and in the Tunicella (figure 11) by TLC comparison. Solvent butanone-2 - formic acid (7 3) 1-3, extracts of the three samples of dyeings of the coronation robe 1, red silk 2, lining material, filling threads 3, lining material, warp threads 4, red silk from the border material of the Tunicella 5, kermes 6, Polish cochineal 7, American cochineal 8, laccaic acids from lac dye.

In the case of lac dye, clearly the separation of the laccaic acids A, B, C, D, and E (39-42) can be seen, and in the case of kermes, the separation into kermesic acid (green spot) and flavokermesic acid (red spot) can be seen. References 39-42 describe the determination of the constitutions of the laccaic acids A-E and indicate their constitutions. 

Thus one of the products of the methylation of laccaic acid B (I) proved to be (II). This was confirmed by heating jS-phenylethanol with dimethyl sulfate and potassium... 

Laccifer lacca Kerr), and is widely used for coloring food. It is known that the red color is derived from a water-soluble pigment including laccaic acids A, B, C, and E. Cochineal color extracted from the dried female bodies of the scale insect (Coccus cacti L.) is water-soluble and has a reddish color. The main coloring component is carmic acid. 

Laccaic acids have two or three carboxyl groups, five or six hydroxyl groups, and/or one amino group, and are freely soluble in water, but only slightly soluble in organic solvents such as chloroform and ethyl acetate. Based on these physicochemical properties of laccaic acids, we selected a two-phase solvent system composed... 

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