Anti-inflammatory terpenoids from the seeds of Eucommia ulmoides

Eucommia ulmoides, a highly valuable economic crop, has been used in traditional Chinese medicine for over 2000 years. In this study, three new iridoids and one new alkaloid, along with 16 known compounds, were isolated from the seeds of E. ulmoides. Their structures incorporating absolute configurations were elucidated based on the comprehensive analyses of NMR data, HR-ESI-MS spectrometry, optical rotation, and ECD data. All compounds were tested for their anti-inflammatory effects in lipopolysaccharide-stimulated RAW 264.7 macrophages. Compounds 14, 17, and 18 significantly inhibited the production of NO with IC₅₀ values of 10.37, 27.34, and 21.58 μM respectively. Further experiments demonstrated that compound 17 could intercept the nuclear translocation of NF-κB, and down-regulate the expression of iNOS, COX-2, IL-1β, and IL-6 in a dose-dependent manner.