Red Monascus pigments attenuate fructose-driven bovine serum albumin (BSA) glycation via non-covalent and covalent interactions with proteins

Two red Monascus pigments (R 1 and R 2 ) demonstrate inhibitory activity against AGEs. • R 1 and R 2 protect BSA from glycation through covalent modification. • Their anti-glycation effect is also mediated by noncovalent interactions with BSA. • Monascus pigments synergize with curcumin against glycation in a simulated system. • Monascus pigments and curcumin also act synergistically in grilled chicken wings. Two red Monascus pigments (rubropunctamine, R 1 ; monascorubramine, R 2 ) were obtained through the derivatization of orange Monascus pigments, demonstrating great promise for preventing protein glycation. R 1 and R 2 (1.4 mM) showed 43.72 ± 1.21% and 64.48 ± 1.81% inhibition of AGE formation, respectively, versus 50% for the aminoguanidine control. They also lowered fructosamine levels, and protected proteins from oxidation, cross-linking, and structural alterations. LC-MS/MS analysis revealed that R 1 and R 2 altered both the number and distribution of glycation sites on BSA and formed covalent adducts with the protein. Moreover, R 1 and R 2 were also found to interact with BSA non-covalently, thereby inducing structural modifications in the protein that ultimately resulted in further glycation suppression. Based on their IC 50 values, Monascus pigments and curcumin were combined at a fixed ratio, yielding a synergistic inhibition of AGE formation. Furthermore, this synergy was confirmed in a grilled chicken wing model, where the combination significantly reduced AGE levels. Download: Download high-res image (239KB) Download: Download full-size image