Molecular Networking-Guided Isolation of Anti-Inflammatory Isolariciresinol and Seco-Isolariciresinol Type Lignans from Alnus japonica

A comparative analysis of UPLC-DAD and MS chromatograms revealed distinct chemical profiles between the methanolic extracts of the branch and cortex of . MS/MS-based molecular networking further identified unique molecular features present in the branch extract, which facilitated the targeted isolation of five previously undescribed lignan derivatives. The structures of these compounds were elucidated using 1D and 2D NMR spectroscopy, along with high-resolution mass spectrometry (HRMS). The anti-inflammatory potential of the isolated compounds was evaluated by measuring the inhibition LPS-induced nitric oxide (NO) production in RAW 264.7 macrophage cells. Notably, compounds 1-5 exhibited significant NO inhibitory activity, with IC50 values of 3.7 and 7.4 μM.