Eucosterol-type nortriterpenoids from Merwilla natalensis.

The bulbs of Merwilla natalensis have yielded two known homoisoflavanones, the known spirocyclic homoisoflavanone, scillascillin, four known nortriterpenoids, and the new nortriterpenoid, (22R,23S)-17alpha,23-epoxy-22,29-dihydroxy-27-nor-lanost-8-en-3,24-dione (1), bisnortriterpenoid, (22R,23S)-17alpha,23-epoxy-3beta,22,24xi-trihydroxy-27,28-bisnor-lanost-8-ene (2), and trisnortriterpenoid, (23S)-17alpha,23-epoxy-3beta,24xi-dihydroxy-27,28,29-trisnor-lanost-8-ene (3). The structures of 1-3 were determined by spectroscopic methods.