Alkaloids from the Roots of Stemona tuberosa

Four new alkaloids, didehydrotuberostemonine A (1), stemoninone (2), tuberostemospiroline (3), and tuberostemonine L (4), together with seven known alkaloids, were isolated from the roots of Stemona tuberosa. Their structures were elucidated on the basis of spectroscopic analysis. The known alkaloids were identified as 2‐oxostenine (5), tuberostemonine (6), sessilifoliamide H (7), tuberostemonone (8), didehydrotuberostemonine (9), bisdehydrostemoninine (10), and tuberostemoamide (11).