Chemical constituents of Pedicularis rex C. B. Clarke and their hepatoprotective activities

A new sesquiterpenoid glycoside, 2 R,7R-cadinen-15-ol-4-one-14-O-β-D-glucoside (1), and a novel phenylpropanoid glycoside, 3-hydroxymethyl-7-methoxywutaifuranol-11-O-β-D-glucoside (2), along with eighteen documented phytocompounds (3-20), were isolated from the entire plant of Pedicularis rex C. B. Clarke. The structural elucidation was carried out through a series of spectral analyses: the initial determination of molecular weight was performed using HR-ESI-MS, followed by detailed stereochemical analysis using comprehensive 1D/2D NMR datasets. The absolute stereochemistry of 1 was ascertained through ECD analysis. Preliminary screening for hepatoprotective activity using AML-12 hepatic cell models exposed to acetaminophen (APAP) cytotoxicity revealed that compounds 9, 10, 11, and 20 exhibited significant protective effects.