Tyrian Purple: 6,6’-Dibromoindigo and Related Compounds

Molecules (Impact Factor: 2.42). 09/2001; 6(9):736-769. DOI: 10.3390/60900736
Source: DOAJ


The genesis of the purple dye from shellfish, its composition, origin, intermediates, analysis and synthesis of the components, 6,6'-dibromoindigo, 6- bromoindigo and 6,6'-dibromoindirubin are reviewed

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    • "The proportions of these components in the dye are affected by many factors, such as the sex and age of the mollusks, the geographic location , the dyeing process, and the method of analysis (Cardon, 2007, 556–557; Cooksey, 2001; Koren, 2008a, 388–389; Michel et al., 1992b). Nevertheless, a clear trend with respect to the ratios of the dye substances in each of the species was found (Table 2; see also Koren, 2008a; Michel and McGovern, 1990; Michel et al., 1992a), a trend which helps to identify the species of the Murex used in the dyeing of archaeological textiles with a high level of certainty. "
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    ABSTRACT: In this article we shall focus on the chemical and chromatographic analyses that were used in the study of three textiles that were found in a cave in wadi Murabba'at, the Judean desert. The textiles date to the Roman period, and were dyed with a prestigious purple dye. High Performance Liquid Chromatography (HPLC) identified the Murex sea snail Hexaplex trunculus as a source of dye for the three textiles. Nevertheless, the dyeing process was not uniform. The color of one textile was modified to greenish-blue, apparently by exposure to the sun during the dyeing process. The two other textiles were subject to a double-dyeing process, and underwent a second dipping in a dye solution extracted from the Armenian cochineal insect. This process resulted in a reddish-purple color, which was indicative of high status. This is the first time that this dyeing technique was identified in ancient textiles from Israel. The multi-disciplinary research also identified different origins for the textiles.
    Full-text · Article · Sep 2015
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    • "Supercritical CO 2 could therefore act as a natural dye extraction medium for precursor compounds prior to Tyrian purple dye development. The reaction of precursors leading to Tyrian purple formation is an interesting example of a novel reactive dye, where the precursor characteristics are more suitable to both the dyeing process and the impregnation in natural fibers, whilst the resulting dye is insoluble in the dyeing medium and is colorfast [23]. Supercritical dyeing has not been previously tested using Tyrian purple or Muricidae mollusc extracts. "
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    ABSTRACT: Supercritical CO2 provides considerable advantages over traditional solvents for the extraction of bioactive compounds from organic matter. Here we demonstrate the use of supercritical CO2 as an efficient and safe alternative to traditional solvent extraction for the recovery of bioactive Tyrian purple precursors tyrindoleninone, 6-bromoisatin and tyriverdin from the marine mollusc Dicathais orbita. The effect of pressure on the selective extraction of brominated indoles was tested at 15,30 and 50 MPa CO2, and was compared to traditional chloroform extract composition and yields. Extracts obtained from 15 MPa selectively concentrated 6-bromoisatin, at 78% of the extract composition, whereas increased pressures of 30 and 50 MPa increased the solvating power of supercritical CO2 to include the more lipophilic tyrindoleninone at 35 and 29% respectively, and tyriverdin at 23 and 40% respectively. This extraction method was also effective in separating the brominated indoles from toxic choline esters in the mollusc extracts. Extract yields from supercritical CO2 were comparable to solvent extraction relative to whole whelk weight. This provides a viable alternative for nutraceutical development that does not rely on the use of toxic solvents.
    Full-text · Article · Oct 2014 · Journal of Supercritical Fluids The
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    • "The characteristic colorant of Tyrian purple, DBI, was identified by Friedländer [22]. Subsequently many syntheses of it have appeared, which have been reviewed by Cooksey [13], who, along with Clark also developed a synthesis of MBI [23]. A more recent treatment of existing DBI syntheses has been presented by Wolk and Frimer [24]. "
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    ABSTRACT: Fundamental dyeing properties of three dyes of historical importance - indigo, 6-bromoindigo, and 6,6’-dibromoindigo - on 13 fabrics are examined. The hues of the dyed fabrics vary from blue-green to blue for indigo, blue to violet for 6-bromoindigo, and violet-blue to purple for 6,6’-dibromoindigo, as determined by reflectance measurements. Many of the dyed fabrics change color markedly with application of gentle heat. For indigo and 6-bromoindigo, the color changes are predominantly towards absorption of longer wavelengths (giving a bluer fabric color), while for 6,6’-dibromoindigo, the color changes are towards absorption of shorter wavelengths (giving a redder fabric color). The greatest thermochromic effects are seen for dyed wool: with 6-bromoindigo, the color changes from violet to blue, while with 6,6’-dibromoindigo, the color changes from violet to red-purple upon brief boiling in water. Transmission electron microscopy analysis of 6-bromoindigo-dyed carbon nanotubes, used as surrogates for dyed fabric fibers, suggests that the basis of the thermochromic effect is a change in the size distribution of dye aggregates.
    Full-text · Article · Feb 2013 · Dyes and Pigments
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