Isolation and structure-toxicity analysis of Diterpenoid alkaloids from Aconitum sinomontanum including a new C19-Diterpenoid alkaloid, Sinaconitine C.

Thirteen compounds were isolated from the dichloromethane fraction of Aconitum sinomontanum using silica gel column chromatography and semi-preparative chromatography. Their structures were mainly elucidated through MS and NMR analyses, and X-ray crystallography was employed to confirm the structure and absolute configuration of compound 13. Among them, compound 1 was a new compound, named sinaconitine C, and compounds 2 and 13 were obtained from this species for the first time. Acute toxicity assay, with LD₅₀ values calculated by the Bliss method, suggested that 1-OCH₃ and 7-OH groups enhance toxicity, whereas 2´-NHCOCH3 and 9-OH groups reduce toxicity for C18-diterpenoid alkaloids.