Assessing the role of Berberine as an inhibitor of advanced glycation end products (AGEs) formation using in vitro and molecular interaction studies

Abstract

Glycation leads to the formation of protein aggregates and advanced glycation end products (AGEs) by non-enzymatic reaction. AGEs have been linked to several pathological conditions such as diabetes, cardiovascular disorders, Alzheimer's etc. Our research objective is understanding how methylglyoxal triggers AGEs and protein aggregate formation in human serum albumin (HSA) and how the phytochemical berberine protects it. Employing various biochemical and biophysical techniques, we explored how berberine alters human serum albumin's biochemical properties and structure during multiple glycation stages. HSA was incubated with methylglyoxal at varying concentrations of berberine for 7–14 days at a temperature range of 35–37 degrees C. Methylglyoxal induced the formation of AGEs, fibrillar aggregates and hydrophobic protein patches in HSA as demonstrated by AGEs fluorescence, Thioflavin T (ThT) fluorescence and 1-anilinonaphthalene-8-sulphonic acid (ANS) fluorescence studies. The secondary structure of HSA was also disrupted as demonstrated by CD spectroscopy. All the parameters were nearly reverted back to native HSA formed in the glycated HSA + berberine samples. Molecular docking was utilized to identify the essential HSA residues involved in the HSA-berberine complex interaction and to ascertain the spontaneous binding of berberine to the HSA subdomain, hence favouring thermodynamic binding. The binding energy of HSA-berberine was determined to be −9.1 kcal/mol. The binding of berberine to lysine and arginine residues might be linked to its anti-glycation potential, as these amino acids play an important role in the glycation of proteins. However, further research is required to validate this assertion. Therefore, our study identifies AGEs and aggregates of the clinically significant protein HSA.