Rubia tinctorum pseudopurpurin from

Fig. 2.147. UV (254) trace of a crude extract of Rubia tinctorum roots and mass spectra (single MS) of the chromatographic peaks for individual anthraquinones lucidin primeveroside (1), ruberythic acid (2), pseudopurpurin (5) and munjistin (6). Mass spectra (a-b) were obtained with NI-ESI with post-column addition of ammonia. Reprinted with permission from G. C. H. Derksen et al. [320].

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. 

After the first isolation of alizarin a lot of other anthraquinones were isolated from Rubia tinctorum for example purpurin, munjistin, rubiadin, pseudopurpurin, nordamnacanthal, lucidin, xanthopurpurin and anthra-gallol. 

Some anthraquinones isolated from Rubia tinctorum are believed to be artefacts for example the anthraquinones which show the presence of a 2-methoxymethyl or 2-ethoxymethyl group. These anthraquinones have been formed during the extraction of lucidin with boiling methanol or ethanol [4,68,97]. According to Schweppe the anthraquinones purpurin (1,2,4-trihydroxy anthraquinone) and purpuroxanthin (1,3-dihydroxy-anthaquinone) are formed from respectively pseudopurpurin (3-carboxy-1,2,4-trihydroxyanthraquinone) and munjistin (2-carboxy-l,3-dihydroxy-anthraquinone) during drying of the roots [3]. Some anthraquinones were only isolated once from Rubia tinctorum. It is thus doubtful whether these... 

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. 

Pseudopurpurin, 1,2,4-trihydroxyanthraquinone-3-carboxylic acid, is one of the main anthraquinones, along with pupurin and alizarin, foimd in madder (qq.v) derived from Rubia tinctorum L. and many other plants of the Rubiaceae including Gallium and Relbunium species. It is selectively extracted and used for... 

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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