Atramacronoids A -C, three eudesmanolide sesquiterpene-phenol hybrids with an unprecedented C -C linkage from the rhizomes of Atractylodes macrocephala

Three eudesmanolide sesquiterpene-phenol hybrids, atramacronoids A -C ( 1 -3 ), featuring an unusual 6/6/5/5/6 skeleton furnished by forming an unexpected C-8 -C-16 linkage, were obtained from the rhizomes of Atractylodes macrocephala . Their structures and absolute configurations were elucidated by spectroscopic data analysis, chemical calculations, combined with X-ray diffractions. The plausible biosynthetic pathways for compounds 1 -3 are proposed. Surprisingly, compound 1 exhibited cytotoxicity against SGC-7901 cells by inducing cells apoptosis, which might relate to the promotion of synthesis of neutrophil elastase.(c) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.