Artemordins A—S, Cadinane‐Type Sesquiterpenoid Dimers from Artemisia ordosica and Their Antihepatoma Activities

Abstract

Comprehensive SummaryNineteen new cadinane‐involving sesquiterpenoid dimers, artemordins A—S (1—19), together with 13 known SDs (20—32) were isolated from Artemisia ordosica. Their structures and absolute configurations were established by comprehensive spectral analyses, X‐ray single crystal diffraction, theoretical ECD, and NMR calculations. Chemically, artemordins A—F (1—6) were the first examples of two cadinane units constructed by unprecedented C‐3−C‐15′ or C‐3−C‐13′ single bond with an oxido‐rearranged 6/5/6/6 fused ring system; artemordins G—K (7—11) were biogenetically connected by [4 + 2] cycloaddition reaction and artemordins G—J (7—10) possessed a novel 5/6/6/6/6/6/5‐heptacyclic fused ring system. Artemordins L—S (12—19) were formed by esterification, which involved three different types of sesquiterpenoids. Antihepatoma assay suggested that the most active compounds, artemordins B and H (2 and 8), exhibited inhibitory activities on three hepatoma cell lines with IC50 values of 26.9 and 25.1 μmol/L (HepG2), 29.5 and 18.3 μmol/L (Huh7), 19.7 and 15.7 μmol/L (SK‐Hep‐1).