Determination of anthraquinones in rhubarb roots, dock flowers and senna leaves by normal-phase high performance liquid chromatography.

A normal-phase high performance liquid chromatography using a 5-microm Spherisorb-CN column (250 x 4.6 mm i.d.) has been used for determination of the monomeric anthraquinones and their glycosides present in rhubarb roots, senna leaves and dock flower. The effects of various parameters were studied and the conditions for the extraction of the anthraquinones from herbal samples and their chromatographic separation were optimized. The nature and the quantity of anthraquinones and their conjugates were determined with a good precision and accuracy.