Cyclocuneatol and Cuneatannin, New Cycloartane Triterpenoid and Ellagitannin Glycoside from Euphorbia cuneata

Abstract

Phytochemical investigation of the aerial parts of Euphorbia cuneata Vahl. (Euphorbiaceae) revealed new cycloartane triterpenoid, cyclocuneatol (2) and new ellagitannin glycoside, cuneatannin (11), along with nine known metabolites: β-sitosterol (1), 3β-hydroxycycloart-25-ene-24-one (3), cycloart-25-ene-3β,24β-diol (4), cycloart-23Z-ene-3β,25-diol (5), 2R-naringenin (6), β-sitosterol-3-O-β-D-glucopyranoside (7), quercetin (8), kaempferol-7-O-β-glucoside (9), and 2R-naringenin-7-O-β-glucoside (10). Their chemical structures were identified by detailed analyses of physical, chemical, and spectral data as well as comparison with literature. Their cytotoxic activity was assessed towards HepG2, MCF7, and HCT116 cancer cell lines by sulphorhodamine B test (SRB). It is noteworthy that 3 and 4 demonstrated the most significant activity towards HepG2, MCF7, and HCT116 cells (IC50 2.6, 2.7, and 2.4 μM, respectively for 3 and 3.4, 4.1, and 5.3 μM, respectively for 4) in comparison with doxorubicin (IC50 0.18, 0.6, and 0.2 μM, respectively).