Atramacronins A−P, eudesmane-type sesquiterpenoid dimers from Atractylodes macrocephala with anti-hepatocellular carcinoma activities

Atractylodes macrocephala Koidz. (A. macrocephala) is a medicinal and edible plant species belonging to the Compositae family. Its rhizome serves both therapeutic and nutritional purposes in China. This investigation led to the isolation of thirteen novel rearranged 9(8→7)-abeo-eudesmane-type sesquiterpenoid dimers (SDs), atramacronins A−M (1−13), three eudesmane-type SDs, atramacronins N−P (14−16), and two previously identified meroterpenoids, atrachinenin G (17) and atrachinenin Ι (18), from Atractylodes macrocephala. Structure elucidation was accomplished through comprehensive spectroscopic analysis and single-crystal X-ray diffraction. Compounds 1, 4−7, 9, and 10 exhibited notable cytotoxicity against Hep3B, HepG2, and Huh7 cell lines, with half maximal inhibitory concentration (IC₅₀) values ranging from 3.71 to 13.99 μmol·L⁻¹.