Bidirectional effects of cuminaldehyde–pepsin interaction on enzymatic and antioxidant activity: Potential implications for gastrointestinal health and disorder modulation

decreased (0.2419 to 0.1156 μmol/min/mL), confirming inhibitory effects of cuminaldehyde against pepsin. Importantly, the interaction also modulated the functional properties of cuminaldehyde itself, as its radical-scavenging capacity assessed by DPPH and ABTS assays was attenuated upon binding, likely due to hydrogen-bond interactions involving Gly-109. Molecular dynamics (MD) simulations confirmed the stability of the cuminaldehyde-pepsin complex and revealed localized flexibility changes within the enzyme structure. In conclusion, these findings demonstrate a bidirectional interaction in the gastric environment, whereby cuminaldehyde modulates pepsin-mediated protein digestion while its antioxidant activity is partially compromised through enzyme binding. This study provides mechanistic insight into phytochemical-enzyme interactions during digestion and suggests potential implications for dietary regulation of gastric function and gastrointestinal disorder modulation.