HPLC-PDA characterisation of Daphne gnidium L. (Thymemeacea) dyeing extracts using two different C-18 stationary...

Raw aqueous extracts and acid-hydrolysed extracts from leaves and stems of Daphne gnidium L. were investigated by HPLC-PDA under two different separation conditions. This approach provides improved characterisation of natural compounds, especially those with similar structures, thanks to better resolution of critical pairs which can be difficult to separate by modification of gradient parameters only. In the leaf extracts, the presence of luteolin-3',7-di-O-glucoside was found according to the results obtained for a standard sample. This compound is reported for the first time in this species. The presence of some other, previously reported flavonoids is confirmed. The stem extract is rich in coumarins and seems not to contain any significant amounts of flavonoids. Further investigation of hydrolysed extracts is a useful additional step in the indirect identification of flavonoid and coumarin glycosides.