Cytotoxic Alangium alkaloids from Alangium longiflorum

10-O-Demethylcephaeline (2) exhibited potent cytotoxic activity against human A549 lung carcinoma and MCF-7 breast adenocarcinoma (ED50 = 0.013 and 0.062 μM, respectively). Related compounds with different stereochemistry or hydroxy/methoxy substitution patterns were less potent or inactive. Thus, compound 2 merits attention as a cytotoxic lead for further study.