New diterpene alkaloids from the roots of Spiraea japonica

Chemical investigation on an ethanol extract from the roots of Spiraea japonica var. acuta resulted in the isolation of three new diterpene alkaloids named spiramide (1) and spiratine A (2) and spiratine B (3). Structures of 1-3 were elucidated primarily on the basis of 1D and 2D NMR experiments.