Background: Dietary plant-based foods contain the combinations of various bioactive compounds such as phytochemical compounds and vitamins. The combined effect of vitamins and phytochemicals remains unknown, especially in the prevention of diabetes and its complications. The present study was to investigate the combined effect of ascorbic acid and gallic acid on fructose-induced protein glycation and oxidation.

Results: Ascorbic acid (15 μg/mL) and gallic acid (0.1 μg/mL) reduced fructose-induced formation of advanced glycation end products (AGEs) in bovine serum albumin (BSA; 10 mg/mL) by 15.06% and 37.83%, respectively. The combination of ascorbic acid (15 μg/mL) and gallic acid (0.1 μg/mL) demonstrated additive inhibition on the formation of AGEs after 2 weeks of incubation. In addition, it also revealed synergistic inhibition on the formation of amyloid cross-β structure and protein carbonyl content in fructose-glycated BSA. At the same concentration, the combination of ascorbic acid and gallic acid produced a significant additive effect on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity.

Conclusion: Combining natural compounds between ascorbic acid and gallic acid seems to be a promising strategy to prevent the formation of AGEs.