Effects of A-type oligomer procyanidins on protein glycation using two glycation models coupled with spectroscopy, chromatography, and molecular docking

Non-enzymatic glycation of proteins can produce advanced glycation end products (AGEs) and important intermediates (α-dicarbonyl compounds such as methylglyoxal), which have potential health risks due to their association with diabetes complications. Therefore, it is of great significance to search for effective inhibitors on protein glycation. In this study, the anti-glycation potential of different kinds of A-type procyanidins was investigated by spectroscopy, chromatography and molecular docking. The results revealed that different kinds of A-type procyanidins could potently suppress the protein glycation in BSA-Glc and BSA-MGO models. Notably, these procyanidins exhibited the most potent AGEs inhibitory potential with IC50 values of 41.50, 37.00, 53.99, and 34.99 µg/mL in BSA-Glc models, respectively. A comparison analysis showed that these procyanidins with different structures have various inhibitory effects on the production of AGEs, which may be related to their spatial configuration, polymerization degree and bond connection mode. The inhibitory effect of A-type procyanidins on protein glycation may be attributed to their specific binding with some amino acid residues in BSA, inhibition on the formation of fructosamine and capture of MGO. Moreover, when 600 μg/mL of these procyanidins were incubated with MGO, 91.30%, 80.25%, 75.07%, and 70.82% MGO decrease were observed, respectively. And the formed three new types of A-type trimer procyanidin-MGO adducts adducts were verified by Orbitrap LC-MS/MS analysis. These results indicate that A-type procyanidins may be used as inhibitors of glycation and provide the theoretical basis for their application.