Complexation of trans- and cis-resveratrol with bovine serum albumin, beta-lactoglobulin or alpha-lactalbumin

Clarification of the mechanism of protein-ligand interaction is important for the encapsulation of bioactive components. Trans-resveratrol is labile to convert to cis-isomer during fermentation and storage, but the cis-isomer interaction with proteins has not yet gained as much attention as that of trans-isomer. The influence of resveratrol's isomerization on interaction with ligand-binding proteins was investigated here. Cis-resveratrol exhibited higher affinity for bovine serum albumin than trans-isomer, but the isomerization to cis-isomer decreased the polyphenol affinity for alpha-lactalbumin and beta-lactoglobulin. For each protein, trans-and cis-resveratrol shared the same optimal docking site but showed clear diversity in the second best site. Protein ternary complex could be formed when trans-/cis-resveratrol were added in the sequence. Moreover, photostability of resveratrol and antioxidant activity of the polyphenol-protein mixtures were also discussed. The results gathered here should provide further insight into protein-polyphenol interactions and be useful for the development of protein-based carriers for the polyphenols. (C) 2018 Elsevier Ltd. All rights reserved.