<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>Any substance that inhibits xanthine oxidase, an enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid, along with the generation of reactive oxygen species (ROS). Inhibition of xanthine oxidase can reduce the production of uric acid.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>