Antioxidant capacity of phenolic compounds on human cell lines as affected by grape-tyrosinase and Botrytis-laccase oxidation

Abstract Phenolic components (PCs) are well-known for their positive impact on human health. In addition to their action as radical scavengers, they act as activators for the intrinsic cellular antioxidantsystem. Polyphenol oxidases(PPOs) such as tyrosinaseand laccasecatalyze the enzymatic oxidation of PCs and thus, can alter their scavenging and antioxidativecapacity. In this study, oxidation by tryosinase was shown to increase the antioxidantcapacity of many PCs, especially those that lack adjacent aromatic hydroxyl groups. In contrast, oxidation by laccasetended to decrease the antioxidantcapacity of red wine and distinct PCs. This was clearly demonstrated for p- coumaric acidand resveratrol, which is associated with many health benefits. While oxidation by tyrosinaseincreased their antioxidantactivity laccasetreatment resulted in a decreased activity and also of that for red wines.