Cycloschimperols A and B, new cytotoxic cycloartane triterpenoids from Euphorbia schimperi.

• The MeOH extract of the Euphorbia schimperi aerial parts was investigated. • Two new cycloartanes and two known compounds were isolated. • Their structures were established by various spectroscopic analyses. • Cytotoxicity of all metabolites was evaluated. Two new cycloartane-type triterpenoids, cycloschimperols A [cycloart-20,24-dien-3β-ol] (3) and B [26,27-dinor-3β-hydroxy cycloartan-25-al] (4) and two known compounds, 24-methylenecycloartane (1) and cycloart-25-en-3-one (2) were separated from the aerial parts of Euphorbia schimperi C. Presl (Euphorbia ceae). The structural characterization of these metabolites was achieved by various spectroscopic analyses, including 1D and 2D NMR and HRESIMS as well as comparison with the published data. The cytotoxic activities of these metabolites were assessed towards breast adenocarcinoma (MCF-7), human hepatocellular carcinoma (HepG2), and colorectal adenocarcinoma (HCT-116) cancer cell lines using sulphorhodamine B assay (SRB). Compounds 2 and 4 had the most potent cytotoxic profile against the tested cells lines with IC 50 s ranging from 1.4 to 4.7 μM, in comparison to doxorubicin (IC 50 0.18, 0.60, and 0.20 μM, respectively). [ABSTRACT FROM AUTHOR]