The bulbs of the South African Drimia altissima (Asparagaceae or Hyacinthaceae sensu APGII) have yielded a range of previously undescribed bufadienolides, drimianins A–G (1–7), the known bufadienolides bovogenin A (8), 3β-O-β-d -glucopyranosylbovogenin A (9), scillaren F (10), and altoside (11), the known homoisoflavonoid (3S)-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 9R-hydroxy-(10E,12Z)-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 (3) and E (5) showed activity at the nanomolar level against a number of human cancer cell lines in the NCI-60 screen.

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Over three million people in South Africa use traditional plant medicine for health care purposes. South Africa's plant biodiversity indicate a high potential for the discovery of bioactive chemicals. The bulbs of Urginavia altissima (syn. Urginea altissima, Drimia altissima) is ethnomedicinally used in South Africa for treatment of gout, rheumatism and respiratory complaints. The compounds expected to be isolated from this plant include bufadienolides, which are polyhydroxylated steroids and their glycosides. Bufadienolides are reported to possess diverse biological activities. Proscillaridin, a drug traded by GSK as stellarid, is a bufadienolide used for the treatment of congestive heart failure and cardiac arrhythmia. In this study Urginavia altissima has yielded nine novel bufadienolides and several known compounds including, scilliglaucoside, 1β,6α-dihydroxy-4(15)-eudesmene and a polyhydroxylated furan derivative, polybotrin. The structures of the compounds were elucidated using Nuclear Magnetic Resonance, Infrared and Mass spectrometry. The compounds will be submitted to National Cancer Institute (NCI) for anticancer screening against NCI 59 human tumour cell lines.

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