Chemical constituents of Alstonia scholaris (L.) R. Br. and their chemotaxonomic significance

Phytochemical investigation on the stems of Alstonia scholaris (L.) R. Br. led to the isolation and identification of 30 natural products, including sixteen alkaloids (1–16), nine triterpenoids (17–25), two phenols (26–27), and three lignans (28–30). Their structures were established by comprehensive spectroscopic analyses together with the comparison with reported data. Compound 1 was a new indole alkaloid. Compound 24 was firstly isolated from Apocynaceae family, compounds 22–23 and 26–30 were obtained from the genus Alstonia for the first time, and this is the first report of the presence of 11 and 16 in A. scholaris. The chemotaxonomic significance of these isolated compounds was also discussed.