LC-ESI-MS/MS characterization of strophanthin-K

Forced degradation investigations done with strophanthin-K showed that k-strophanthidin (the aglycone of strophanthin-K glycosides) was the main product of degradation in acidic conditions; however, in basic conditions, the hydrolysis of the unsaturated 17β-lactones to the corresponding γ-hydroxy acids was the predominant degradation pathway.