N-Acetyl Cysteine Mitigates d-Ribose-Induced Protein Glycation and Aggregation Through Multiple Protective Mechanisms

Advanced glycation end-products (AGEs) arise from non-enzymatic reactions between reducing sugars and proteins, contributing to oxidative stress and metabolic dysfunction. Excessive AGE accumulation is implicated in chronic diabetic complications and may also be relevant to acute metabolic disturbances encountered in emergency medicine. N-acetylcysteine (NAC), a naturally occurring antioxidant found in Allium species, has demonstrated potential to attenuate oxidative and glycation-mediated damage. The effect of NAC on d-ribose-induced glycation of bovine serum albumin (BSA) was investigated using multiple physicochemical and spectroscopic techniques. AGE formation was assessed by measuring hyperchromicity, early glycation products (ketoamines), carbonyl content, hydroxymethylfurfural (HMF) levels, and fluorescent AGEs. The protective effect of NAC was further evaluated by determining free lysine and arginine contents. Protein aggregation and conformational changes were analyzed using Congo Red binding and fluorescence assays including thioflavin-T and 1-anilinonaphthalene-8-sulfonic acid. NAC significantly inhibited d-ribose-mediated glycation of BSA in a concentration-dependent manner. Treatment with NAC resulted in reduced hyperchromicity, decreased ketoamine formation, and lower carbonyl, HMF, and fluorescent AGE levels. NAC preserved protein integrity by maintaining higher free lysine and arginine contents. In addition, NAC markedly attenuated glycation-induced protein aggregation, as evidenced by reduced Congo Red binding and diminished thioflavin-T and ANS fluorescence, with maximal protection observed at 300 μM. NAC exhibits pronounced anti-glycation and anti-aggregation effects by limiting oxidative stress and glycation-mediated protein modification. These findings demonstrate that NAC effectively attenuates d-ribose-induced glycation and protein aggregation in vitro and provide mechanistic insights into its anti-glycation properties through multiple complementary biochemical mechanisms. Further studies are warranted to evaluate its biological relevance in more complex experimental models.