Cytotoxic quaternary alkaloids from the flowers of Narcissus tazetta.

Intensive chromatographic separation of the polar fraction of an ethanolic extract of the fresh flowers of Narcissus tazetta L. (Amaryllidaceae) yielded two new quaternary alkaloids with a phenanthrene skeleton, N-methyl-8,9-methylenedioxy-phenantridinium methylsulfate (1) and N-methyl-8,9-methylenedioxy-phenantridinium malate (2). The structure determination of the alkaloids was based on one- and two-dimensional NMR studies including HMQC, and HMBC studies, and mass spectroscopic analysis. The existence, in 1, of the methylsulfate group was confirmed by X-ray diffraction analysis. Cytotoxic activities for 1 and 2 against a panel of cancer cell lines are also reported.