Lignans from the Twigs of Euonymus alatus (Thunb.) Siebold and Their Biological Evaluation

A new sesquilignan, euonymolin A (1), and six known lignans, (-)-de-O-methylmagnolin (2), (+)-de-O-methylepimagnolin A (3), (+)-syringaresinol (4), (+)-pinoresinol (5), (+)-medioresinol (6), and (+)-lariciresinol 4'-O-β-d-glucopyranoside (7), were isolated from the twigs of Euonymus alatus (Thunb.) Siebold (Celastraceae). The structures of the isolated compounds were elucidated based on spectroscopic analyses, including extensive 1D- and 2D-NMR techniques, HR-MS analysis and circular dichroism (CD) data, and the literature data. All of the isolated compounds were evaluated for antiproliferative activity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines and inhibition of nitric oxide (NO) production in a lipopolysaccharide (LPS)-activated BV2 cell line. All compounds showed cytotoxicity against the SK-MEL-2 cell line with IC₅₀ values of 23.24 - 48.14 μm and inhibited NO production in LPS-activated BV-2 cells with IC₅₀ values of 6.75 - 23.53 μm.