Arteannoides U–Z: Six undescribed sesquiterpenoids with anti-inflammatory activities from the aerial parts of Artemisia annua (Qinghao)

Four previously unreported sesquiterpenoid diasteromers, arteannoides U–X (1–4), together with one new norsesquiterpenoid 5 (arteannoide Y) and one undescribed rearranged cadinene sesquiterpenoid 6 (arteannoide Z) were obtained from the dried aerial parts of Artemisia annua (Qinghao). Notably, arteannoides U–X (1–4) are four stereoisomers that possess the same molecules and the same planar connectivity, but differ from each other in configuration at a certain stereocenter. Their accurate structures were unambiguously identified and distinguished by extensive spectroscopic analyses, NMR calculations with DP4+ analysis, electronic circular dichroism (ECD) calculations and X-ray diffraction analyses. Compounds 1, 3, and 4 showed inhibitory activities against the production of inflammatory cytokines (PGE2, NO, IL-6 and TNF-α) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. [Display omitted] •Six previously unreported sesquiterpenoids, Arteannoides U–Z were obtained from the dried aerial parts of Artemisia annua.•Comp. 1~4 are four stereoisomers that possess the same planar connectivity, but differ from each other in configuration.•Their structures were identified by extensive spectroscopic analyses, NMR and ECD calculations, X-ray diffraction.•Comp. 1, 3~4 showed inhibitory activities against the production of PGE2, NO, IL-6, TNF-α in LPS induced RAW 264.7.