New Iboga-Type Alkaloids from Ervatamia hainanensis.

Seven new iboga-type alkaloids (1–7) and six known ones (8–13) were obtained from Ervatamia hainanensis. Their structures with absolute configurations were determined by spectroscopic data, Mosher's method, single crystal X-ray diffraction and electric circular dichroism (ECD) analyses. The relationship between the absolute configuration of C-7 in iboga-type 7-hydroxyindolenine alkaloids and the Cotton effects in the ECD spectrum was established for the first time. The neural activities of these compounds were evaluated, and compound 11 exhibited protective effects against MPP+ (1-methyl-4-phenylpyridinium)-induced damage in primary cortical neurons.