Identification, characterization, and molecular docking of immunomodulatory peptides from Capsicum annuum var....

Plant-derived bioactive peptides offer an attractive strategy for developing immunomodulatory functional foods. This study investigated the structural characteristics and immunomodulatory potential of Capsicum annuum var. conoides seed protein hydrolysate (CSPH), prepared via simulated gastrointestinal digestion. Comparative structural analysis revealed significant conformational changes in CSPH relative to the native protein. CSPH significantly enhanced macrophage proliferation and phagocytosis, and increased NO and ROS production and pro-inflammatory cytokine secretion (IL-6, IL-1β, TNF-α). Treatment with the TLR4 inhibitor (TAK-242) significantly suppressed this CSPH-induced immunostimulation, confirming TLR4 as a critical mediating receptor. LC-MS/MS analysis combined with molecular docking identified three novel TLR4-binding peptides from CSPH. All three synthesized peptides exhibited immunomodulatory activity without cytotoxicity, validating their immunomodulatory effect. These findings provide new insights into the immunomodulatory mechanism of CSPH and underscore the potential of Capsicum annuum var. conoides seeds as a valuable source for immunomodulatory functional food.