Chemical components and bioactivity of Lepidium sativum seeds

Phytochemical investigation on the seeds of Lepidium sativum L. led to the isolation of six undescribed compounds, including two flavonoid glycosides (lepisativutimines M and N), two sinapic acid thioglucosides (lepisativutimines O and P), a pair of lignan enantiomers [(+)-lepisativumligan C and (-)-lepisativumligan C], and a previously unreported natural imidazole alkaloid, (lepisativumalkan A). Their structures were established by extensive spectroscopic analyses including HR-ESI-MS, 1D and 2D NMR, ECD in combination with quantum chemical calculations, and single-crystal X-ray diffraction. The sugar moieties were identified by acid hydrolysis followed by GC-MS analysis of their aldononitrile acetate derivatives, and their absolute configurations were assigned by comparison with literature data. All isolated compounds were evaluated for their in vitro protein tyrosine phosphatase 1B inhibitory activity and anti-inflammatory activity. Lepisativutimine O showed weak anti-inflammatory activity with an IC₅₀ value of 69.36 ± 1.78 μM.