Monoterpenoid indole alkaloids from the bark of Alstonia scholaris.

Six new monoterpenoid indole alkaloids, scholarisines B-G (1-6), together with 15 known analogues (7-21), were isolated from the bark of Alstonia scholaris. Their structures were determined by 1D and 2D NMR spectra and MS analyses. The structure of 1 was further supported by the single-crystal X-ray.