Identification of Active Components in Connarus ruber Extract Exhibiting Anti-Glycation Effects

Background: Glycation, a non-enzymatic reaction between sugars and biomolecules, leads to the formation of advanced glycation end-products (AGEs), which are implicated in the progression of chronic diseases. Connarus ruber (Poepp.) Planch (C. ruber), a traditional medicinal plant used for diabetes, has shown anti-glycation activity. This study aimed to identify the active components in C. ruber extract and elucidate their anti-glycation mechanisms. Methods: Using NMR and LC-MS analyses, we identified epicatechin and procyanidin A2 as major polyphenolic constituents. Collagen glycation assays were performed to evaluate the inhibitory effects of these compounds on fructose- and glyceraldehyde (GA)-induced glycation. Additionally, their cytoprotective effects were assessed using GA-induced cytotoxicity assays in dental pulp stem cells (DPSCs). Results: Both epicatechin and procyanidin A2 inhibited fructose- and GA-induced glycation in a dose-dependent manner, showing greater efficacy than aminoguanidine. Furthermore, these compounds significantly alleviated GA-induced cytotoxicity in DPSCs. Conclusions: These findings suggest that epicatechin and procyanidin A2 are candidate contributors to the anti-glycation and cytoprotective effects of C. ruber. The results support the potential of C. ruber extract as a source of therapeutic agents for glycation-related diseases and for enhancing stem cell viability.