Germacrane-Type Sesquiterpene Lactones from Achillea millefolium L. and Their Anti-Inflammatory Activity.

Six undescribed germacrane-type sesquiterpene lactones, millefoliumons A-F, and two known analogs were isolated from the ethyl acetate fraction of the whole plant of Achillea millefolium L. growing in Xinjiang, China. The structures of these compounds were fully elucidated by their 1D and 2D nuclear magnetic resonance (NMR), and high resolution mass (HR-ESI-MS) spectral data, and comparison with literatures. The absolute configurations of millefoliumons A-F were confirmed by experimental and calculated electronic circular dichroism data (ECD), and C-NMR calculations and DP4+ probability analysis. All compounds displayed the approximate tendency to inhibit the nitric oxide (NO) release in lipopolysaccharide (LPS)-induced BV2 cells.