Two new diterpenoid alkaloids from the roots of Aconitum pendulum

Two new compounds, an aconitine-type C₁₉-diterpenoid alkaloid (1) and a denudatine-type C₂₀-diterpenoid alkaloid (2), along with five known compounds (4-8), were isolated from Aconitum pendulum. Additionally, the known napelline-type C₂₀-diterpenoid alkaloid turpelline was obtained; its structure was fully characterized through revised NMR data and the first determination of its absolute configuration by single-crystal X-ray diffraction, and it is redesignated as Pendulumine I (3). The structures of all compounds were elucidated by comprehensive spectroscopic analysis (1D/2D NMR, IR, HR-ESI-MS). The structures of all compounds were elucidated through comprehensive spectroscopic analysis, including 1D/2D NMR, IR, HR-ESI-MS, and single-crystal X-ray diffraction. All isolated compounds were evaluated for anti-inflammatory activity in LPS-induced RAW 264.7 murine macrophages. Notably, compound 3 significantly inhibited nitric oxide (NO) production. These findings not only enrich the phytochemical profile of Aconitum pendulum but also underscore its potential as a source of anti-inflammatory lead compounds, thereby supporting further investigation into its bioactive constituents.