NEW ECDYSTEROIDS FROM POLYPODIUM VULGARE

Five phytoecdysteroids not previously reported in Polypodium vulgare h ave been isolated from methanol extracts of in vitro cultures of proth alli of this species. Among them, inokosterone, pterosterone and abuta sterone had already been identified in other plants, whereas 24-hydrox yecdysone and 5-hydroxyabutasterone are described for the first time. The structure of these compounds was inferred from the corresponding H -1 and C-13 NMR and thermospray-HPLC-MS spectral data. The complete de scription of the structures includes the stereochemical assignment at C-24, which was 24S for all compounds. This assignation was carried ou t by C-13 NMR spectroscopic studies of 22,24-benzylidene acetal deriva tives.