Triterpenoid saponins from Ardisia pusilla and their cytotoxic activity

Three new triterpenoid saponins 3, 4 and 5, together with two known saponins, ardisiacrispin B (1) and ardisiacrispin A (2), were isolated from the whole plants of Ardisia pusilla A. DC. Their structures were elucidated by extensive spectral analysis and chemical evidence. Compound 3 is a hexaglycoside with a 13,28-epoxyoleanane type aglycone, while both 4 and 5 are triterpenoid tetraglycosides related to the olean-12-ene skeleton. Saponins 1-4 exhibited significant cytotoxicity against human glioblastoma U251MG cells, but did not affect the growth of primary cultured human astrocytes.