Isolation, structural elucidation, and biological evaluation of anti-inflammatory and cytotoxic compounds from Ligusticum wallichii.
Ligusticum wallichii Franch., an oriental medicinal herb widely used throughout East Asian countries, is well recognized for its therapeutic potential in treating cardiovascular, inflammatory, and neurodegenerative diseases. In this study, phytochemical investigation of the methanol extract of L. wallichii roots led to the isolation and structural elucidation of four previously undescribed compounds (1-4), and eight known analogues (5-12). Their structures were determined through extensive spectroscopic analyses, including 1D and 2D NMR, HR-ESI-MS, and CD spectroscopy, supported by quantum chemical ECD calculations. All isolated compounds were evaluated for anti-inflammatory and cytotoxic activities. Compounds 1, 3, 7, 9, and 12 significantly inhibited nitric oxide (NO) production in LPS-stimulated RAW 264.7 macrophages. Regarding pro-inflammatory cytokine modulation, compounds 1, 9 and 12 significantly reduced both TNF-α and IL-6 levels by more than 40% at 10 μM. Moreover, compounds 2, 3, 5-7, and 9 showed significant cytotoxic activity with IC50 values ranging from 2.8 to 13.2 μM. Mechanistic investigations in PC9 cells revealed that the cytotoxic effects of selected compounds (2, 3, 5-7, 9) were mediated via apoptosis induction. Their dual functional properties position them as promising anti-inflammatory and anti-cancer agents, which prompt further research and potential following development step in targeting inflammation-associated cancer.