Arenarosides A-G, Polyhydroxylated Oleanane-Type Saponins from and their Cytotoxic and Antiangiogenic Activities.

Seven new polyhydroxylated oleanane-type triterpene saponins, arenarosides A-G (-), together with four known compounds, were isolated from an ethanol extract of the aerial parts of the Vietnamese plant . The chemical structures of the newly isolated oleanane saponins were elucidated on the basis of spectroscopic and spectrometric analysis, especially 2D NMR and HRMS. Biological evaluation revealed that , , , and showed moderate activities against four human cancer cell lines (A549, HTC116, PC3, and RT112) with IC values of 6.0-9.9 μM, and , , , and also displayed promising antiangiogenesis effects with IC values <5 μM in the test system used. Among the isolates, arenaroside D () exhibited the most potent inhibitory effects, not only in cancer cell proliferation but also in angiogenic activities. Preliminary SAR studies revealed that the presence of an acetyl group at C-22 in oleanane-type triterpene saponins increases these bioactivities.