Alkaloids of Crinum x powellii "Album" (Amaryllidaceae) and their topoisomerase inhibitory activity.

The alkaloids lycorine, 1-O-acetyllycorine and ismine were isolated from the basic dichloromethane-soluble fraction of Crinum x powellii "Albu m" bulbs. The alkaloid structures were established by physical and spectroscopic analyses, including 1D NMR techniques and GC-MS analysis. The three alkaloids are reported for the first time for this hybrid.