CHBO4 is an hMAO-B inhibitor that is potent, reversible, competitive and selective.The IC50 value of CHBO4 against hMAO-B in the CHBO assay was 0.031 µM, and the Ki value was 0.010 0.005 µM.CHBO4 reduces cellular damage by scavenging intracellular reactive oxygen species (ROS), and can be used to study Parkinsons disease (PD).