Supramolecular characterization of reaction product of quercetin and caffeic acid with laccase and DFT approach

• 2 derivatives were obtained from Quercetin via laccase catalysis • DFT calculations elucidate a supramolecular pair for quercetin • Derivative characterization by theoretical and experimental correlation • Supramolecular structure exhibits greater antioxidant activity than individual ones Phenolic compounds display notable biological activities, including antioxidant, antiproliferative, and anti-inflammatory effects. Among them, quercetin and caffeic acid stand out as promising candidates for pharmaceutical and nutraceutical applications. Nevertheless, their poor water solubility and chemical instability significantly limit their practical use. Previous studies have shown that enzymatic polymerization can enhance the solubility of phenolic compounds; however, the underlying reaction mechanisms and interactions remain only partially understood. In this work, Trametes versicolor laccase was employed to catalyze the modification of quercetin and caffeic acid, leading to the generation of five reaction products, including three supramolecular structures. Spectroscopic (UV-Vis, FT-IR, and ¹H-NMR) and UHPLC-MS analyses confirmed the nature of these products, while molecular modeling provided further structural insights that supported the experimental evidence of supramolecular assembly. Additionally, the antioxidant activity of the reaction products was evaluated to compare it with that of the individual compounds, highlighting the relevance of these structures in biological activities. To our knowledge, this is the first report describing the formation of supramolecular assemblies between quercetin derivatives and caffeic acid mediated by fungal laccase. These findings not only contribute to a deeper mechanistic understanding of phenolic biotransformation but also demonstrate the potential of laccase-catalyzed reactions to generate bioactive supramolecular structures with enhanced properties, thereby opening new opportunities for their application in food, pharmaceutical, and biotechnological fields.