Amaryllidaceae Alkaloids from Lycoris radiata

A phytochemical investigation on bulbs of Lycoris radiata resulted in the isolation of three new Amaryllidaceae alkaloids, named 5,6‐dehydrodihydrolycorine ( 1 ), 6 β ‐acetoxycrinamine ( 2 ), and (+)‐8‐ O ‐acetylhomolycorine α ‐ N ‐oxide ( 3 ), together with eleven known alkaloids, 4 – 14 . The structures of the new alkaloids were established by means of spectroscopic methods, and the known compounds were identified by comparison of their data with those in the literature. Compound 2 showed cytotoxicity against HL‐60, A‐549, and MCF‐7 cells, with IC 50 values of 8.1, 24.3, and 15.0 μ M , respectively.