Four new diterpenoid alkaloids from Delphinium elatum

Diterpenoid alkaloids exhibit remarkable chemical properties and biological activities. Such compounds are frequently found in plants of the genera Aconitum, Delphinium, and Garrya. Several diterpenoid alkaloid components from Delphinium elatum cv. Pacific Giant and their derivatives exhibited cytotoxic activity against lung, prostate, nasopharyngeal, and vincristine-resistant nasopharyngeal cancer cell lines. Phytochemical investigations on the seeds of D. elatum cv. Pacific Giant led to the isolation of four new C-19-diterpenoid alkaloids, melpheline (1), 19-oxoisodelpheline (2), N-deethyl-19-oxoisodelpheline (3), and N-deethyl-19-oxodelpheline (4). The isolated alkaloids were elucidated by extensive spectroscopic methods including NMR (1D and 2D), IR, and MS (HRMS). (C) 2016 Phytochemical Society of Europe. Published by Elsevier Ltd. All rights reserved.