Direct proof of the deglycating effect of rosmarinic acid on a glycated protein

Abstract

Purpose: In a previous work, it was showed that rosmarinic acid is able to break AGE cross-links. This study focuses on the early stage of glycation: the objective is to highlight the ability of rosmarinic acid to deglycate glycated lysozyme and see to what extent the protein is recovered in its original state. Basic procedures: Purified lysozyme is glycated with ribose. After elimination of ribose by purification, glycated lysozyme is treated with rosmarinic acid. Glycation and deglycation are followed over time by ESI-MS analysis. Main findings: After 168 hours, the glycation leads to the binding of at least three molecules of ribose to the amino radicals of lysozyme forming Schiff bases. The deglycation test shows that glycation is a naturally reversible reaction. The presence of rosmarinic acid leads to a faster deglycation reaction. Principal conclusions: This study shows that rosmarinic acid has an important deglycating effect on a glycated protein. Further studies are required to better understand the mechanism behind the deglycation process between glycated lysozyme and rosmarinic acid.