C19-Diterpenoid alkaloids from two plants of Aconitum sinoaxillare and Aconitum chasmanthum.

Five new compounds (1-5) were isolated from the whole plants of two species of Aconitum, including two aconitine-type C19-diterpenoid alkaloids, sinoaxidines A (1) and B (2) and a franchetine-type C19-diterpenoid alkaloid, sinoaxidine C (3) from Aconitum sinoaxillare W. T. Wang. Two aconitine-type C19-diterpenoid alkaloids, chasmanthumines A (4) and B (5) from Aconitum chasmanthum Stapf, and forty known diterpenoid alkaloids were also isolated. The structures of all compounds were identified based on extensive IR, 1D, 2D NMR and HR-ESI-MS data analysis. Compound 6 exhibited potent inhibitory effects on the production of NO in RAW 264.7 cells with IC50 of 29.60 μM respectively.