Germacrane-type sesquiterpenes from Artemisia atrovirens and their anti-inflammatory activity

Artemisia plants are well-known for their abundant sesquiterpene compounds, which encompass various structural types and exhibit a range of biological activities. In this study, a systematic investigation of Artemisia atrovirens revealed the presence of germacrane-type sesquiterpenes for the first time. This included the discovery of 10 new compounds and three known analogues, among which were two rare dimeric germacrane-type compounds. Their structures were fully characterized through a comprehensive analysis involving MS, IR, 1D- and 2D-NMR spectroscopic data, single crystal X-ray diffraction, density functional theory (DFT) NMR calculations, and time-dependent DFT electronic circular dichroism (TDDFT ECD) calculations. Furthermore, all isolated compounds were evaluated for their anti-inflammatory activity in LPS-stimulated RAW 264.7 murine macrophages. Compound 10 demonstrated a potent inhibitory effect on NO production, with an IC₅₀ value of 4.01 ± 0.09 μM. This study highlights the diverse chemical repertoire of Artemisia species and underscores their potential in drug discovery and development.