Crinane, augustamine, and β -carboline alkaloids from Crinum latifolium

Three new crinane-type alkaloids, namely, 6-methoxyundulatine (1), 6-methoxycrinamidine (2), and undulatine N-oxide (3), along with the known compounds 6-hydroxyundulatine (4), 6-hydroxybuphanidrine (5), undulatine (6), crinamidine (7), ambelline (8), filifoline (9), augustamine (10), and perlolyrine (11), were isolated from the leaves of Crinum latifolium by using various chromatographic separations. Their structures were established by extensive analysis, including 1D and 2D NMR, HR-QTOF-MS, and CD data. Among the isolated compounds, perlolyrine (11) showed significant cytotoxicity against five human cancer cell lines, namely, KB, HepG2, MCF7, SK-Mel2, and LNCaP with the IC50 values ranging from 22.12 ± 2.80 to 28.45 ± 3.75 μM.