High-performance liquid chromatographic method for the analysis of anthraquinone glycosides and aglycones in madder root ( Rubia tinctorum L.)

A HPLC method has been developed for the simultaneous characterisation of anthraquinone glycosides and aglycones in extracts of Rubia tinctorum L. The anthraquinones are separated on an end-capped C 18-RP column with a water–acetonitrile gradient as eluent and measured with UV detection at 250 nm. With this method the glycosides lucidin primeveroside and ruberythric acid and the aglycones lucidin, alizarin, purpurin, quinizarin and 2,6-dihydroxyanthraquinone can be analysed. Lucidin which is not commercially available was synthesised starting from resorcinol and phthalic anhydride. The glycosides ruberythric acid and lucidin primeveroside are commercially available as a mixture and were separated by droplet counter-current chromatography in ascending flow with chloroform–methanol–water as eluents prior to their use as standards.