Chemical Profiles of Cucumber ( Cucumis sativus L.) Seed Extracts, Immune Modulation, and Radical Scavenging Activities

Cucumber (Cucumis sativus L.) seeds have emerged as promising sources of bioactive compounds with potential health benefits. In this study, we investigated the chemical composition, antioxidant activity, and immunomodulatory effects of defatted cucumber seed extracts obtained using 50% acetone (798A) and 80% ethanol (798E) as extraction solvents. A total of 85 compounds were tentatively identified in cucumber seeds for the first time via UHPLC-MS/MS analysis. The 798A extract contained significantly higher total phenolics and exhibited greater DPPH· scavenging activity, while 798E showed significantly higher scavenging capacity against ABTS·+, suggesting a solvent-specific extraction efficiency. Both extracts significantly inhibited the expansion of activated CD8+ T cells, with insignificant effects on the activation marker CD25, indicating their potential for immune modulation. These findings highlighted the potential of cucumber seeds as functional food ingredients or nutraceutical components for mitigating oxidative stress and modulating immune function.