New cycloartane-type triterpene 23 R/S-3β-hydroxycycloart-24-ene-23-methyl ether 1a,b (as an C-23 epimeric mixture), along with ten known compounds, including 1 steroid, 3 fatty acids and 6 triterpenoids were isolated from the aerial parts of Euphorbia dendroides L. (Euphorbiaceae). The known compounds (2–11) were identified using 1 D & 2 D-NMR spectra and by comparison with data reported in the literature as well as using GC-MS for the isolated fatty acids. The new compound 1 (a,b) was elucidated by comprehensive 1 D & 2 D NMR experiments as well as LR & HR-FAB-MS. In addition, the isolated cycloartane-type triterpenoids have been tested for in vitro cytotoxicity against different cell lines. The new compound 1 (a,b) exhibited good to weak selective cytotoxic activities against HepG2, Huh-7, KLM-1, 1321N1 and HeLa cell lines with IC50 values of 20.67 ± 0.72, 16.24 ± 0.53, 22.59 ± 0.94, 25.99 ± 0.31 and 40.50 ± 3.14 μM, respectively.
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