Crotiglianoids A-M, tigliane-type diterpenoids from the seeds of Croton tiglium and their anti-hepatic fibrosis activity.

The phytochemical investigation of the seeds of Croton tiglium led to the isolation and structural characterization of 20 tigliane-type diterpenoids (1-20), comprising 13 previously undescribed analogues designated as crotiglianoids A-M (1-13). Their structures were elucidated through comprehensive spectroscopic analysis, and the absolute configurations were determined by a combination of chemical transformation and comparative electronic circular dichroism data. Notably, crotiglianoids A (1) and B (2) were characterized as the first examples of 20-nor-tigliane diterpenoids. All isolates were evaluated for their anti-hepatic fibrosis potential using a TGF-β1-induced LX-2 cell model, and compounds 1 and 2 exhibited remarkable inhibitory effects on the expression of key fibrotic biomarkers, including fibronectin, α-smooth muscle actin, and collagen I.