Combined determination of sennosides, monomeric hydroxyanthacene glycosides and anthraquinone aglycones by UHPLC-DAD

Using a coreshell column, the new UHPLC-DAD method allows almost a baseline separation of seven sennosides and the monomeric hydroxyanthracene glycosides rhein 8-glycoside and aloe emodin 8-glycoside in senna pod dry extract and in a senna-fig syrup preparation. UV and mass spectrometry studies show that none of the peaks of interest is underlaid by flavonoids, a fact which, in the case of other LC methods for sennosides, requires a sample processing by means of SPE. Sennosides are determined by sennoside B, monomeric hydroyanthracene glycosides by rhein 8-glycoside as external standard. The combined determination of all hyrdoxyanthracene glycosides is important for pharmaceutical stability testing because sennosides are partly degraded to rhein- and aloe emodin 8-glycoside. In the posterior part of the chromatogram the aglycones rhein and aloe emodine can be determined. The complete assay runs 19 min.