Secondary Metabolites of Lepidium Sativum Seeds and Their Chemotaxonomic Significance

Phytochemical investigations on Lepidium sativum L. seeds led to the isolation and structural elucidation of eight secondary metabolites, including two lignan glucosides (1-2), three uridine derivatives (3-5), and three aromatic compounds (6-8). The structures of isolated compounds were unambiguously established by comprehensive spectroscopic methods, including 1D and 2D NMR experiments and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). All these compounds were discovered from L. sativum for the first time. Notably, three uridine derivatives, lepidiumuridine C (3), lepidiumuridine A (4), and lepidiumuridine K (5), were strictly distributed in L. sativum and L. apetalum, n-benzylformamide (6) was only found in L. sativum and L. meyenii, and 2-(4-hydroxyphenyl)ethanenitrile (7) only existed in several plants of Brassicaceae, supporting their potential as chemotaxonomic markers. These findings enhance the chemical profile of L. sativum and contribute to a better understanding of its systematic position within Brassicaceae.