In silico and in vitro analysis of umami peptides from Termitomyces albuminosus (Berk.) Heim: Digestive stability and bioactivity of native peptides and their gastrointestinal digests

This study investigated the digestive stability of four umami peptides (QNDF, QGGDF, EPVTLT, and EVNYDFGGK) derived from Termitomyces albuminosus and the bioactivity of native and digested forms. EVNYDFGGK was almost completely degraded, yielding small fragments (EVNYD, YDFGG, and VNYD), whereas EPVTLT showed high retention with a minor fragment (EPVTL). QNDF and QGGDF displayed moderate resistance without the emergence of new fragments. The intact and digested peptides exhibited ACE1 inhibitory activity. EVNYDFGGK and YDFGG showed the lowest IC₅₀ values (151.22 and 16.33 μM, respectively), supported by molecular docking and dynamics simulation. Biochemical assays confirmed competitive inhibition via direct peptide-ACE1 interaction. Peptides enhanced nitric oxide release and reduced endothelin-1 levels in endothelial cells, indicating vasoprotective effects. These findings demonstrated that umami peptides from T. albuminosus retain function after digestion and may aid in dietary hypertension management, highlighting the mushroom's potential as a functional food source and its nutritional and economic benefits.