New alkaloids from Cephalotaxus fortunei.

Four new cephalotaxus alkaloids, cephalotaxine alpha-N-oxide (1), cephalotaxine beta-N-oxide (2), 11-beta-hydroxycephalotaxine beta-N-oxide (3), and isocephalotaxine (4), were isolated, together with several known alkaloids from an EtOAc extract of the fruits of Cephalotaxus fortunei. The structures were determined by spectral analysis including mass spectrometry and 2D NMR. Compounds 1, 2, 3, and 4 displayed cytotoxicity against nasopharynx KB cells with IC50 values of 30, 14, 31, and 15 micro g/mL, respectively.