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

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 H-1 and C-13 NMR experiments and mass-spectrometry. The biological activities of 3-epi-20-hydroxyecdysone (EC50=1.6x10(-7) M), taxisterone (EC50=9.5x10(-8) M) and ajugasterone C (EC50=6.2x10(-8) M) have been determined in the Drosophila melanogaster B-II bioassay for ecdysteroid agonist activity. (C) 2002 Elsevier Science Ltd. All rights reserved.