Alkaloids from Nerine filifolia.

The novel compounds N-demethylbelladine, 6alpha-methoxybuphanidrine and filifoline, in addition to five known alkaloids, and phenol have been isolated from fresh bulbs of Nerine filifolia (Amaryllidaceae). The structure and stereochemistry of the compounds were determined by physical and spectroscopic methods, including 1D and 2D NMR and mass spectroscopic techniques. An unusual circular dichroism response from filifoline has required a semi-synthetic derivatisation strategy towards key C-11endo analogues of the beta-crinane representative ambelline in which the nature of substituents was observed to have a profound effect on molecular ellipticity. Filifoline was not cytotoxic to myoblast (L6) cells and exhibited no anti-protozoal activity in an in vitro screen against four different parasitic protozoa.