Chemical constituents of <i>Pedicularis rex</i> C. B. Clarke and their hepatoprotective activities

A new sesquiterpenoid glycoside, 2 R,7R-cadinen-15-ol-4-one-14-O-<i>β</i>-D-glucoside (<b>1</b>), and a novel phenylpropanoid glycoside, 3-hydroxymethyl-7-methoxywutaifuranol-11-O-<i>β</i>-D-glucoside (<b>2</b>), along with eighteen documented phytocompounds (<b>3–20</b>), were isolated from the entire plant of <i>Pedicularis rex</i> 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 <b>1</b> was ascertained through ECD analysis. Preliminary screening for hepatoprotective activity using AML-12 hepatic cell models exposed to acetaminophen (APAP) cytotoxicity revealed that compounds <b>9</b>, <b>10</b>, <b>11</b>, and <b>20</b> exhibited significant protective effects.