Rayudika Aprilia Patindra Purba, Suchanya Sinsranoi, Phanthipha Laosam, Phornpilat Senanok, Pichitpon Luasiri, Pornphutthachat Sota, Nattapol Pongsamai, Saranya Suwanangul, Jukkrapong Pinyo, Sasikan Katemala, Saruttiwong Boonkong, Kamonpan Sanachai, Papungkorn Sangsawad
Porcine tracheal cartilage, an underutilized Type II collagen-rich by-product, was systematically evaluated as a source of angiotensin I-converting enzyme (ACE) inhibitory, dipeptidyl peptidase-IV (DPP-IV) inhibitory, and antioxidant peptides. Neutrase at 4 h outperformed Papain in generating ACE-inhibitory and antioxidant peptides. The <3 kDa ultrafiltration fraction, enriched in small hydrophobic peptides, exhibited the highest bioactivities. LC-MS/MS identified eight sequences (870-1565 Da). Chemical synthesis confirmed LGLGADMFHR as the most potent ACE inhibitor (IC50 = 0.52 mM), QGLPGPGAVAEYT as the lead DPP-IV inhibitor (IC50 = 1.84 mM), and LGFGADRAGPQ as the strongest antioxidant (5.64 mM Trolox equivalents). Molecular docking revealed LGLGADMFHR binding through Zn2+ coordination and hydrogen bonds with Cys352, Glu376, and Asp453. Standardised INFOGEST gastrointestinal digestion progressively enhanced ACE inhibition and antioxidant activities while DPP-IV inhibition declined, establishing porcine tracheal cartilage as a viable source of gastrointestinally stable cardiovascular bioactive peptides.