Peptides Released from Extruded Adzuki Bean Protein through Simulated Gastrointestinal Digestion Exhibit Anti-inflammatory Activity

Increasing attention has been focused on plant-derived peptides because of their potential bioactivities. In this study, bioactive peptides were released from extruded adzuki bean protein by simulated gastrointestinal digestion. A peptide (KQS-1) sequenced as KQSESHFVDAQPEQQQR was separated and identified using ultrafiltration, pre-high-performance liquid chromatography (HPLC), and ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). KQS-1 was shown to exert significant anti-inflammatory effects in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages by reducing the production of IL-1, IL-6, TNF-α, and MCP-1 to 38.31, 6.07, 43.96, and 41.74%, respectively. The involved signaling pathways were identified by transcriptome analysis. Overall, 5236 differentially expressed genes (DEGs) were identified. Gene ontology (GO) functions demonstrated that DEGs were significantly related to the NF-κB pathway. In conclusion, KQS-1 prevented the activation and expression of NF-κB/caspase-1 by upstream and downstream factors. These findings highlight the bioactivity of adzuki bean peptides.