Anti-inflammatory Germacrane-Type Sesquiterpene Lactones from Vernonia sylvatica

Nine new germacranolides, sylvaticalides A−H ( 1 - 9 ), and three known analogues ( 10-12 ) were isolated from the aerial part of Vernonia sylvatica. Their structures were established based on extensive analysis of spectroscopic data including HR-ESIMS, 1D and 2D NMR spectra, and their absolute configurations were determined by X-ray diffraction experiments. All isolated compounds were evaluated for their anti-inflammatory activities by testing the inhibition of NF-κB pathway in lipopolysaccharide (LPS)-stimulated human THP1-Dual cells and interferon-stimulated genes (ISG) pathway in STING agonist MSA-2 stimulated human THP1-Dual cells. Compounds 1 , 2 and 6 showed inhibitory effect against activation of NF-κB and ISG signaling pathways with IC₅₀ values ranging from 4.12 to 10.57 μM.