Digestion and absorption of an egg white ACE-inhibitory peptide in human intestinal Caco-2 cell monolayers

The objective of this study was to investigate the digestion and absorption of egg white-derived angiotensin I-converting enzyme (ACE)-inhibitory peptide TNGIIR in human intestinal Caco-2 cell monolayers. Results showed that the digestion of TNGIIR to simulated gastrointestinal enzymes and brush border membrane peptidases were 5.87% ± 1.92% and 17.17% ± 0.64%, respectively (p < 0.05). The apparent permeability coefficients (P(app)) of TNGIIR from the apical to basolateral side in Caco-2 cell monolayers was determined to be (4.92 ± 0.40) × 10(-6) cm/s, indicating that TNGIIR can transport across Caco-2 cell monolayers in intact form. In addition, only cytochalasin D, a disruptor of tight junctions (TJs), changed TNGIIR transport rate significantly (p < 0.05), suggesting that the main transport route for TNGIIR across Caco-2 cell monolayers was paracellular pathway via TJs.