Peptide profiling and anti-inflammatory potential of Guizhou traditional suan-rou during simulated gastrointestinal digestion.

Guizhou traditional suan-rou is a traditional fermented product rich in bioactive peptides generated during fermentation and ripening. However, the physiological relevance of these peptides depends on their stability and bioavailability during gastrointestinal (GI) digestion. This study investigated the impact of in vitro simulated GI digestion on the peptide profile and anti-inflammatory activities of suan-rou. Results demonstrated that GI digestion significantly increased the peptide and total amino acids contents of suan-rou, accompanied by enhanced anti-inflammatory activity. Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was used to monitor the peptide profile changes during digestion. The results showed that GI digests exhibited the greatest peptide diversity and abundance, and shared and unique peptides were identified in suan-rou and its digests. In silico screening identified three peptides (PYF, PYGP, and EPPY) with potential anti-inflammatory properties. Cellular assays confirmed that these peptides significantly inhibited lipopolysaccharide (LPS)-induced inflammation by downregulating tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1), while upregulating interleukin-10 (IL-10) expression. In LPS-treated RAW264.7 cells, PYF partially suppresses the MAPK signaling cascade by downregulating ERK extracellular-signal regulated protein kinase (ERK) and mitogen-activated protein kinase (p38). This study highlights the critical role of GI digestion in releasing anti-inflammatory peptides, further supporting the potential of Guizhou traditional suan-rou as a functional food ingredient.