Triterpenoid saponins from the roots of Spergularia marginata

Phytochemical investigations of the roots of Spergularia marginata had led to the isolation of four previously undescribed triterpenoid saponins, a known one and one spinasterol glycoside. Their structures were established by extensive NMR and mass spectroscopic techniques as 3-0-1 beta-D-glucuronopyranosyl echinocystic acid 28-O-alpha-L-arabinopyranosyl-(1 -> 2)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-alpha-L- arabinopyranosyl ester, 3-O-beta-D-glucopyranosyl(1 -> 3)-beta-D-glucuronopyranosyl echinocystic acid 28-O-alpha-L-arabinopyranosyl-(1 -> 2)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-alpha-L-arabinopyranosyl ester, 3-O-beta-D-glucopyranosyl-(1 -> 4)-3-O-sulfate-beta-D-glucuronopyranosyl echinocystic acid 28-O-alpha-L-arabinopyranosyl-(1 -> 2)-alpha-L-arhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-alpha-L-arabinopyranosyl ester, and 3-O-beta-D-glucopyranosyl-(1 -> 4)-beta-D-glucuronopyranosyl 21-O-acetyl acacic acid. Their cytotoxicity was evaluated against two human cancer cell lines SW480 and MCF-7. The most active compound showed a cytotoxicity with IC50 14.2 +/- 0.8 mu M (SW480), and 18.7 +/- 0.8 mu M (MCF-7), respectively. (C) 2017 Elsevier Ltd. All rights reserved.