Antiproliferative Bufadienolides from the Bulbs of .

The bulbs of the South African (Asparagaceae or Hyacinthaceae sensu APGII) have yielded a range of previously undescribed bufadienolides, drimianins A-G (-), the known bufadienolides bovogenin A (), 3β-β-dglucopyranosylbovogenin A (), scillaren F (), and altoside (), the known homoisoflavonoid (3)3-(4'-methoxybenzyl)-5,6,7-trimethoxychroman-4-one (urgineanin C), the sesquiterpenoids 1β,6α-dihydroxy-4(15)-eudesmene and 6α-hydroxy-4(15)-eudesmen-1-one, polybotrin, adenosine, and 9-hydroxy-(10,12)-octadecadienoic acid ethyl ester. The bufadienolides isolated were tested at 10 μM in the NCI-60 cancer cell screen, and nine of these were selected for further screening at five concentrations. Drimianins C () and E () showed activity at the nanomolar level against a number of human cancer cell lines in the NCI-60 screen.