Nitrogen-containing compounds from the fruits of Elaeagnus angustifolia L.

Previous studies have suggested that the main chemical constituents of Elaeagnus angustifolia L. are phenols and organic acids. In this study, using a combination of multiple chromatographic and spectroscopic techniques, we focused for the first time on the less-investigated nitrogen-containing constituents of this plant. Sixteen nitrogen-containing compounds were isolated and identified from its fruits, including six new structures, designated as elangnitrogens A (1), B1 (2), B2 (3), C (4), D (5), and E (6), together with ten known analogues. All known compounds were reported from the Elaeagnus genus for the first time. Structurally, these compounds can be classified into two major categories, phenylpropenamides and oxindoles. Bioactivity evaluation revealed that all six new compounds exhibited significant inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages at non-cytotoxic concentrations, providing the first experimental evidence of their anti-inflammatory potential. This work significantly expands the chemical database of E. angustifolia, provides key information for the construction of a specialized constituent library, and establishes a direct pharmacological link between its newly discovered nitrogenous constituents and anti-inflammatory activity, thereby laying an important material foundation for further research and development in drug discovery.