Isolation and Synthesis of Antiproliferative Eupolauridine Alkaloids of Ambavia gerrardii from the Madagascar Dry Forest

Investigation of the Madagascan endemic plant Ambavia gerrardii for antiproliferative activity against the A2780 ovarian cancer cell line led to the isolation of the three new alkaloids 8-hydroxyeupolauridine (1), 9-methoxyeupolauridine 1-oxide (2), and 11-methoxysampangine (3) and the three known alkaloids 4-6. The structures of 1 and 2 were confirmed by synthesis. Compounds 3, 4, and 6 showed moderate to good antiproliferative activities, with IC50 values of 10.3, 3.5, and 0.60 mu M, respectively, against the A2780 human ovarian cancer cell line and with IC50 values of 0.57, 1.77, and 0.58 mu M, respectively, against the H460 human lung cancer cell line.