Small laccase-catalyzed synthesis of a caffeic acid dimer with high antioxidant capacity

Abstract

The increase in the demand for antioxidant compounds for application in industries such as food and pharmaceutical, has necessitated the need to investigate new production methods The application of laccase for antioxidant synthesis is gaining notable attention as a viable approach to address this need. In this study, a β-β caffeic acid dimer, phellinsin A, was synthesized using the small laccase, SLAC, a two-domain bacterial laccase native to Streptomyces coelicolor A3(2). Phellinsin A showed a 1.5-fold increase in 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and a 1.8-fold improvement in trolox equivalence antioxidant capacity (TEAC) when compared to caffeic acid. Phellinsin A also showed improved solubility properties in aqueous media and remarkable stability at acidic pH (pH 2.2 and pH 5.5). This study demonstrates the potential of the bacterial laccase, SLAC, as a catalyst for the biotransformation of natural phenolics into value-added compounds.