Two new nitrogenous compounds identified as (2S)-2-sinapoyl-4-pentenenitrile (1) and brassicalkaloid A (2) have been isolated from the seed of Brassica napus L. along with four known alkaloids (3–6). The chemical structures of the new compounds were determined by detailed analysis of spectral data including 1D and 2D NMR spectroscopy. The antineuroinflammatory activity of the isolated compounds was investigated. Brassicalkaloid A (2) and coixspirolactam C (5) were found to exhibit potent activities with IC50 values of 36.6 ± 0.04 μM and 51.0 ± 0.01 μM. © 2022, Springer Science+Business Media, LLC, part of Springer Nature.