Cephalotaxine homologous alkaloids from seeds of Cephalotaxus oliveri Mast

Abstract

Six undescribed isoquinoline alkaloids, named as cephaloliverines A−F, were isolated from the seeds of Cephalotaxus oliveri. They were identified by NMR and MS spectroscopic data analyses, combined with the time-dependent density functional theory ECD calculation for cephaloliverines A and B and also by X-ray crystal diffraction for cephaloliverine E. Biosynthetic considerations suggest that cephaloliverines A−D are homologous of cephalotaxine-, homoerythrina- and Erythrina-type alkaloids. The performed bioassay revealed no cytotoxic activity against cancer cells and no neuroprotective properties on HEI–OC–1 cells model.