Triterpenes from Echinops spinosissimus Turra subsp. spinosissimus

The phytochemical investigation of Echinops spinosissimus aerial parts led to the isolation of nine triterpenoids, one oleanane-type (1), four taraxastane-type (2, 3, 5, 6), three lupane-type (4, 7, 9) and one phytosterol (8). Their structures were elucidated through extensive analysis of NMR and HRMS spectra data. Compound 6, 20-oxo-30-nortaraxast-21-en-3 beta-ol, represent a previously undescribed taraxastane-type triterpene while compound 2, 21-hydroxytaraxasterol-3 beta-acetate, is described herein for the first time as a natural product. Furthermore, this is the first report of isolation of compound 3-5, 8, 9 from Echinops species. Isolated compounds were tested for their inhibitory activity on acetyl cholinesterase. Only compound 4 showed a moderate activity at 25 mu M (35.61 +/- 1.42%).