Formation mechanism of nanocomplex of resveratrol and glycated bovine serum albumin and their glycation-enhanced stability showing glycation extent

The application of protein-based bioactive molecule complexes is limited by their instability under environmental conditions, such as pH, ionic strength, and ultraviolet irradiation. In this study, Bovine serum albumin (BSA) and BSA-glucose conjugates (GBSA) with different glycated extent were complexed with resveratrol (RES). Formation of the BSA/GBSA-RES nanocomplexes was confirmed by UV–visible spectroscopy. Fluorescence quenching spectra indicated that the BSA-RES and GBSA-RES nanocomplexes were formed via noncovalent interactions by a self-assembly method. Interestingly, BSA with a greater glycation extent showed a higher binding affinity for RES. Compared with BSA/GBSA I (BSA glycated in water system)-RES, the GBSA II (BSA glycated in natural deep eutectic solvent system)-RES nanocomplex obtained highest Z-average diameter, encapsulation efficiency and loading capacity. Fourier transform infrared and X-ray diffraction spectra indicated that RES was complexed with BSA/GBSA in an amorphous form. Compared with BSA-RES nanocomplexes, GBSA-RES (particularly GBSA II) nanocomplexes showed better environmental stress (ionic strength, heat, and pH) and storage stability. The advantages of the glycated proteins may provide an effective alternative to protect and deliver bioactive compounds in the food and pharmaceutical industries.