Leucovernine and acetylleucovernine, alkaloids from Leucojum vernum.

The fresh bulbs of Leucojum vernum provided seven tyrosine-derived alkaloids; two of them have not been reported before and are named leucovernine and acetylleucovernine. The five known alkaloids were N-demethylgalanthamine, hippeastrine, 9-O-demethylhomolycorine, 5alpha-hydroxyhomolycorine, and 11-hydroxyvittatine. These compounds have been isolated from this species for the first time. The structure determination was carried out by the combination of liquid-phase one- and two-dimensional NMR spectroscopy and high-resolution mass spectrometry.