Nematicidal amide alkaloids from the seeds of Clausena lansium.

Five new amide alkaloids (1-3, 5-6) were isolated from the seeds of Clausena lansium together with one new natural product (4) and four known analogues (7-10). The structures of the new amide alkaloids were elucidated based on a comprehensive spectroscopic data analysis including 1D and 2D NMR as well as HRESIMS, and by comparison with the literature. The bioactivity results showed that compound 8 expressed potent nematicidal activity against Panagrellus redivevus, with IC50 value of 0.12 mM, while compounds 3 and 5 presented moderate nematicidal activity with IC50 values of 2.75 and 3.93 mM, respectively (abamectin as the positive control with IC50 value of 1.05 mM).