A new Amaryllidaceae alkaloid from the bulbs of Lycoris radiata

AIM: To study the Amaryllidaceae alkaloids of the bulbs of Lycoris radiata. METHODS: The chemical constituents were isolated and purified by various chromatographic techniques, and the chemical structures were elucidated on the basis of spectroscopic methods. In addition, the antiviral activities of alkaloids 1–10 were evaluated using flu virus A. RESULTS: One new homolycorine-type alkaloid 2α-methoxy-6-O-ethyloduline (1), together with nine known alkaloids 2α-methoxy-6-O-methyloduline (2), trispherine (3), 8-O-demethylhomolycorine (4), homolycorine (5), 9-O-demethylhomolycorine (6), oduline (7), lycorenine (8), 6α-O-methyllycorenine (9) and O-ethyllycorenine (10) were obtained. CONCLUSION: Alkaloid 1 is a new compound, and 1–3 were major alkaloids in this plant. Alkaloids 1–3 showed weak antiviral activities against flu virus A with IC50 values of 2.06, 0.69, and 2.71 μg·mL-1 and CC50 values of 14.37, 4.79, and 80.12 μg·mL-1, respectively.