Cytotoxic lycodine alkaloids from the aerial parts of Lycopodiastrum casuarinoides.

A phytochemical investigation on the 75% EtOH extract of the aerial parts of Lycopodiastrum casuarinoides resulted in the isolation of three new lycodine alkaloids, 16-hydroxy-9-oxo-lycocasuarinine D (1), 6α-hydroxy-16-dehydroxy-lycocasuarinine A (2), and 6α,16-dihydroxy-lycocasuarinine B (3). Structural elucidation of all the compounds was performed by spectral methods such as 1D- and 2D-NMR, infrared, ultraviolet, and HR-ESI-MS. The isolated alkaloids were tested in vitro for cytotoxic potential against six lung cancer cell lines. Consequently, alkaloid 1 exhibited cytotoxicity against all the tested tumor cell lines with IC₅₀ values less than 20 μM.