Use of laccase-modified electrode for amperometric detection of plant flavonoids

In this study, laccase from Cerrena unicolor as a highly active enzyme was adsorptively immobilized on the surface of graphite electrode. The electrode inserted into flow-injection system served as a biosensor for detection of polyphenols, including flavonoids. We used catechin hydrate, epicatechin, epicatechin gallate, prodelphinidin, and caffeic acid as a target compounds in determination. The performed investigations demonstrate that laccase from white rot fungus C. unicolor can be applied for the construction of biosensors useful for determination of flavonoids and related compounds in flow-injection system. Electrodes modified with laccase yield responses for both simple compounds (caffeic acid) and compounds with three or more phenolic and non-phenolic rings, although with different sensitivity.