Extraction of anthraquinone compounds from Rubia tinctorum plant

The roots of Rubia tinctorum (madder) are the source of a natural dye and have been used to dye textiles in many parts of the world since ancient times. The dye components are anthraquinones with alizarin, the hydrolysis product of ruberythric acid, being the main dye constituent. Direct and indirect HPLC methods for the quantitative analysis determination of anthraquinones in dried madder root have been developed, validated and compared. In the direct method, madder root was extracted twice with refluxing ethanol–water.This method allowed the determination of the two major native anthraquinone glycosides lucidin primeveroside and ruberythric acid. In the indirect extraction method, the anthraquinone glycosides were first converted into aglycones by endogenous enzymes and the aglycones were subsequently extracted with tetrahydrofuran–water and then analysed.

Keywords:

alizarin , anthraquinones , , madder. HPLC , quantitative analysis