NATURAL ANTHRAQUINOID DYES
The roots of this plant yield a red to pink dye, whereas the stems and tops yield a yellow dye. The dyes involved are
Pseudopurpurin, all of which are anthraquinoid dyes. All four here are also found in the roots of
Madder, which belongs to the same Bedstraw Family.
Alizarin, or 1,2-dihydroxyanthraquinone, is an important red dye which is found in the roots of the Madder plant. There are many artificial derivatives of Alizarin used commercially as dyes. It is used in the manufacture of other dyes such as Rose madder (which contains Alizarin and Purpurin) and
Purpurin, a reddish dye, also occurs in the root of the
Madder plant, although it appears to form during storage.
Xanthopurpurin, or 1,3-Dihydroxanthaquinone, is another reddish dye. Like many similar dyes, it has a purgative effect if ingested. There are 10 structural isomers of Xanthopurpurin, not necessarily all naturally occurring. Its name suggests it is coloured both yellow and purple, which for a subtractive dye, would make it a near-black! However, it does not exhibit both colours at the same time, but is rather yellow in acids, and red in alkalis.
Pseudopurpurin is a monocarboxyl derivative of purpurin, and is also present in Madder to a greater or lesser extent, depending upon the amount of lime in the soil, the more lime, the less pseudopurpurin.
Rubiadin, a naturally occurring dihydroxy quinone found within Lady's Bedstraw, is a potent anti-oxidant and is hepatoprotective, helping prevent deterioration of the liver. It crystallizes as slender yellow plates and is a yellow dye.
Lucidin is also a hydroxy quinone that is found within this plant, it is possible that it is colourless, hence the root 'lucid' within the name.
All of these naturally occurring dyes will probably occur within the plant as their glycosides. If consumed, they possess laxative and diuretic effects.