Lepidium sativum Linn., a plant in the Brassicaceae family, has been valued for its nutritional and medicinal properties. Its dried seeds, known as Jiaduxingcaizi in China, are a staple in Uyghur traditional medicine. According to Uyghur medical theory, the seeds treat conditions ranging from tracheitis to indigestion by clearing abnormal mucus, reducing swelling, and strengthening the spleen, among other benefits. While prior studies have explored its essential oils and extract bioactivity, research into its sinapic acid derivatives—key compounds in Brassicaceae plants—remains limited.

To address this gap, a research team led by Prof. Haji Akber Aisa from the Xinjiang Technical Institute of Physics & Chemistry of the Chinese Academy of Sciences, has isolated 17 sinapic acid derivatives—including 12 newly identified compounds—from L. sativum seeds using an LC-MS/MS guided strategy. Their findings, published in the Journal of Agricultural and Food Chemistry, shed new light on the plant's chemical composition and potential therapeutic value.

The researchers focused on sinapic acid's characteristic mass fragment, an ion with m/z 223.06 detected in negative-mode LC-MS experiments. This marker, confirmed via subsequent LC-MS/MS analysis of isolated compounds, guided the extraction of derivatives including six rare compounds with a uridine moiety, four sulfur glycoside-containing derivatives, four sinapoyl malates, and three sinapate esters.

Structural identification relied on mass spectrometry, nuclear magnetic resonance (NMR) data, ¹³C NMR calculations with DP4+ probability analyses, and quantum-chemical electronic circular dichroism (ECD) calculations. Acid hydrolysis and gas chromatography analysis further validated the findings. The team also summarized key mass fragments of the derivatives, laying groundwork for future efficient separations.

Moreover, the biological tests revealed eight of the compounds inhibited nitric oxide (NO) production in LPS-induced RAW264.7 cells, with IC₅₀ values between 16.20 and 86.37 μM. One compound stood out: it reduced NO, TNF-α, IL-6, and PGE₂ levels in a dose-dependent manner and lowered protein expression of COX2, iNOS, and MAPK pathway proteins (JNK and ERK). This suggests its anti-inflammatory effects may act through the iNOS/COX2 and MAPK signaling pathways.

Molecular docking simulations confirmed the active compound formed stable bonds with target proteins via hydrogen and hydrophobic interactions, supporting its potential as a therapeutic agent.

This study provides new insights into the chemical composition of sinapic acid derivatives in L. sativum seeds, and highlights their promise as anti-inflammatory components.