Eight new monoterpenoid indole alkaloids, alstoyunines A-H (1-8), along with 17 known analogues, were isolated
from Alstonia yunnanensis. The structures of the new alkaloids were established by means of extensive spectroscopic
methods. Alstoyunines C (3), E (5), and F (6) showed selective inhibition of Cox-2 (>75%). Alstoyunine F (6) showed
weak cytotoxicity against the human myeloid leukemia HL-60 (IC50 ) 3.89 μM) and hepatocellular carcinoma SMMC-
7721 (IC50 ) 21.73 μM) cell lines.