Secondary Metabolites from the Roots of Neolitsea daibuensis and Their Anti-inflammatory Activity

Bioassay-guided fractionation of the roots of Neolitsea daibuensis afforded three new β-carboline alkaloids, daibucarbolines A–C (1–3), three new sesquiterpenoids, daibulactones A and B (4 and 5) and daibuoxide (6), and 20 known compounds. The structures of 1–6 were determined by spectroscopic analysis and single-crystal X-ray diffraction. Daibucarboline A (1), isolinderalactone (7), 7-O-methylnaringenin (8), and prunetin (9) exhibited moderate iNOS inhibitory activity, with IC₅₀ values of 18.41, 0.30, 19.55, and 10.50 μM, respectively.