Atractymacronoids A-L, sesquiterpenoids from the rhizomes of Atractylodes macrocephala and their anti-inflammatory activities.

Twelve previously undescribed eudesmane-type sesquiterpenoids, named atractymacronoids A-L (1-12), together with eighteen known ones (13-30), were obtained from the rhizomes of Atractylodes macrocephala. Their structures and absolute configurations were determined by analysis of spectroscopic data, electronic circular dichroism (ECD), and X-ray diffraction analyses. Atractymacronoids A and B (1 and 2) were the first example of an unprecedented noreudesmane-type scaffold featuring a 6/5 fused-ring system. A pair of C-9 epimers, atractymacronoids J and K (10 and 11), were assigned via X-ray crystallographic analysis. Among the isolated compounds, 8α-methoxyepiasterolid (24) exhibited weak inhibition of LPS-induced NO production in RAW264.7 macrophage cells.