Ellagitannins From the Seed Coat of Euryale ferox and Their Inhibitory Effects on LPS-Induced Inflammation in RAW264.7 Cells.

Four new compounds, euryallactone A (1) and euryallactannins A-C (2-4), along with three known ellagitannins (5-7) were isolated from the shells of Euryale ferox Salisb. Their structures were elucidated using NMR, HR-ESI-MS, ECD, and single-crystal x-ray diffraction. Compounds 2-7 exhibited anti-inflammatory activity by inhibiting NO production and reducing the levels of the proinflammatory TNF-α and IL-6 in LPS-induced RAW264.7 macrophages. The structure-activity relationship of compounds 1-7 was preliminarily assessed. The findings from this study highlight the potential of ellagitannins from Euryale shells as anti-inflammatory agents and provide a chemical basis for further functional studies. Moreover, this study enriches the material basis of the shells of E. ferox Salisb.