Structurally diverse sesquiterpenoid glycosides with anti-inflammatory activity from Cissampelopsis spelaeicola

Sixteen previously undescribed sesquiterpenoid glycosides (1-16), bearing eudesmane-type (1-4) and cadinane-type skeletons (5-16), were obtained from the stems of Cissampelopsis spelaeicola. The structural elucidation and absolute configuration assignment of compounds 1-16 were accomplished through multiple spectroscopic analyses, computed ECD/NMR, and X-ray crystallography. Furthermore, anti-neuroinflammatory effects of all isolates were assessed by NO inhibition in LPS-stimulated BV-2 microglia. Compounds 12 and 14-16 exhibited potent NO inhibitory effects (IC₅₀ = 5.62-19.29 μM), outperforming the positive control L-NMMA (IC₅₀ = 21.20 ± 0.57 μM). Further evaluation revealed that compound 15 (IC₅₀ = 5.62 ± 0.37 μM) effectively attenuated LPS-stimulated overexpression of IL-1β, IL-6, iNOS, and TNF-α in BV-2 cells.