Three New Indole Alkaloids from Tabernaemontana divaricata.

Three new monoterpene indole alkaloids, 3α-hydroxymethyl-ibogamine (1), 3α-acetatemethoxyl-ibogamine (2), 16α-hydroxyl-ibogamine (3) together with six known alkaloids were isolated from the branches and leaves of Tabernaemontana divaricata (Apocynaceae). The structures of these alkaloids were determined by spectroscopic analyses. All isolated compounds showed no significant cytotoxicity against SGC-7901 gastric cancer, HeLa, and A-549 lung cancer cell lines (IC50 > 20 µM).