Rubia tinctorum Alizarin , Madder, Purpurin

Rubia tinctorum alizarin and purpurin can be clearly identified by the marked spots. Pseudopurpurin has been converted into purpurin by decarboxylation, because the old extraction method (boiling with 10% sulfuric acid, followed by shaking with ethyl acetate) has been used to isolate the dyes from the madder roots. 

Figure 5 shows the comparison of the madder dyes taken from the Adler-dalmatika with samples of Rubia tinctorum, alizarin, and purpurin by TLC. The dye extracted from the sample of the Adlerdalmatika with dilute sulfuric acid is unmistakably madder. 

Anthraquinones The Oj Pile). Alizarin (1,2-dihydroxyanthraquinone) is the orange-red compound of Rubia tinctorum (madder) (Rubiaceae), a longstanding dyestuff in human history. A range of anthraquinones are variously cathartic, antimicrobial and cytotoxic. A variety of anthraquinones are protein kinase inhibitors including alizarin, chrysazin, damnacanthal, emodin and purpurin. 

The roots of Rubia tinctorum have been used for dyeing textiles in many parts of the world since ancient times. Madder was widely cultivated in Western Europe for the dye industry until the beginning of the twentieth century. Rubia tinctorum contains useful anthraquinone mordant dyes. Dried roots of madder contain the hydroxy anthraquinones alizarin, pseudopurpurin, rubiadin, purpurin, purpuroxanthin and some minor anthraquinones. Anthraquinone derivatives are good mordant dyes if they satisfy the following conditions ... 

Evidence to support this proposal has been obtained by Burnett and Thomson in work with the madder plant (Rubia tinctorum). 2-[ C]-Mevalonic acid was administered to this plant and was incorporated into a series of anthraquinone metabolites such as alizarin (101), purpurin (124) and pseudopurpurin (102). Degradation of the quinones to phthalic acid showed that all the radioactivity was confined to ring C. Decarboxylation of pseudopurpurin (102) gave purpurin (124) containing one half of the total radioactivity and this is in agreement with the hypothesis outlined above namely that ring C of these quinones is derived by cyclisation of a precursor such as lapachol (122). Burnett and Thomson s observations imply that the two methyl groups in the precursor (122)... 

Alizarin, Pseudopurpurin, Purpurin as well as Lucidin, Morindone, Munjistin and Rubiadin in Madder and other closely related dyestuffs of natural origin from plant species such as Rubia tinctorum L. and other R. species, Odenlandia species, Morinda species and Galium species. 

Another important organic red color that has served since ancient times for dyeing textile materials is madder. This colorant is derived from the roots of Rubia tinctorum and other plants in the Rubiaceae family it consists of a mixture of alizarin, purpurin, and pseudopurpurin, and thus one might expect that the natural product would yield a variety of shades. It was described by Strabo, Dioscorides, Pliny the Elder, and in the Tahnud. It has been identified on Egyptian textiles as early as 1300 BCE and in six paint pots of Greco-Roman origin that are now in the British Museum. In addition, textiles dyed with madder were sold at the St. Denis... 

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