Determination of 20-hydroxyecdysone content by thin-layer chromatography and micellar electrokinetic chromatography

Seasonal dependence of 20-hydroxyecdysone content of Serratula tinctoria and Serratula wolffii (Asteraceae) was investigated by micellar electrokinetic chromatography (MEKC). Samples were collected each month through the vegetation period. The leaves were dried, milled and extracted with methanol. Clean-up of the extracts was by solid-phase extraction using a polyamide microcolumn to remove flavonoids and other plant phenolics which can interfere with the analysis. This work deals with the separation of 20-hydroxyecdysone from polypodine B and the seasonal variation of 20-hydroxyecdysone concentration. Determinations have been performed by both thin-layer chromatography and capillary electrophoresis using micellar electrokinetic chromatography.