Phytoecdysteroids from the juice of Serratula coronata L. (Asteraceae)

Abstract

Seven phytoecdysteroids have been isolated from Serratula coronata L.. One of them is a new phytoecdysteroid, 3- epi-20-hydroxyecdysone. Two further ecdysteroids, 20-hydroxyecdysone 22-acetate and taxisterone, are isolated from this species for the first time in addition to the typical S. coronata ecdysteroids, 20-hydroxyecdysone, ecdysone, ajugasterone C and polypodine B. The juice squeezed from aerial parts of fresh plants of S. coronata was extracted with ethyl acetate. The ecdysteroids were isolated by a combination of chromatographic techniques (mainly HPLC) and identified by 1D and 2D 1H and 13C NMR experiments and mass-spectrometry. The biological activities of 3- epi-20-hydroxyecdysone ( EC 50=1.6×10 −7 M), taxisterone ( EC 50=9.5×10 −8 M) and ajugasterone C ( EC 50=6.2×10 −8 M) have been determined in the Drosophila melanogaster B II bioassay for ecdysteroid agonist activity.