Introduction: Long-term intake of Collagen Tripeptide (CTP), which is rich in Glycine- X-Y sequences, improves blood vessel elasticity and reduces the serum levels of cytotoxic glyceraldehyde (GA)-derived Advanced Glycation End-Products (AGEs), also known as Toxic AGEs (TAGE). Therefore, the anti-glycation effect of CTP may be one of the mechanisms contributing to its ability to improve vascular elasticity. This study aims to investigate the antiglycation effects of the tripeptide, glycine-proline-hydroxyproline (Gly-Pro-Hyp; GPHyp), the main component of CTP, using in vitro GA glycation models and comparing its metabolite sequences. Methods: Cell viability and mRNA expression were measured in GA-treated HepG2 cells with or without the addition of GPHyp. The half-maximal inhibitory concentration (IC50) of GPHyp for inhibiting TAGE formation and for inhibiting lysozyme glycation crosslinking was evaluated. Results: Only GPHyp significantly suppressed cell death and interleukin-8 (IL-8) mRNA expression in GA-treated cells. The IC50 for TAGE production and inhibitory effect on lysozyme crosslinking demonstrated that GPHyp exhibited stronger anti-glycation effects than its metabolite amino acids and peptides. The addition of GPHyp also resulted in increased GA consumption. Analysis of the changes in GA concentrations during the reaction revealed that the addition of GPHyp significantly reduced GA levels within the first hour. Discussion: These results suggest that GPHyp possesses potent GA-scavenging activity and inhibits TAGE production, contributing to the CTP-mediated reduction in serum TAGE levels and to improvements in vascular elasticity. Conclusion: The anti-glycation effect of GPHyp may support a healthy lifestyle and warrant further investigation.
Yamamoto et al. (Sun,) studied this question.