Abstract: From the roots of Stemona tuberosa Lour, three new alkaloids, named tuberostemoenone (1), N-oxy-tuberostemonine (2), isodidehydrotuberostemonine (3), together with three known alkaloids didehydrotuberostemonine (4), tuberostemonone (5) and oxotuberostemonine (6)were isolated, and their struetures were identified by various spectral analyses (IR, MS, 1H, 13C NMR,1H-1H COSY, NOESY, HMQC, HMBC) as well as 1H NMR line broadening effect.

Key words: Stemona tuberosa Lour, Tuberostemoenone, N-Oxy-tuberostemonine, Isodide-hydrotuberostemonine