PPO-IN-13 (compound B16) is a potent inhibitor of protoporphyrinogen IX oxidase ( PPO ), with the K i of 32.14 nM.PPO-IN-13 exhibits broad-spectrum and excellent 100% herbicidal effects to Echinochloa crusgalli , Digitaria sanguinalis , Setaria faberii , Abutilon juncea , Amaranthus retroflexus , and Portulaca oleracea at a concentration of 37.5 g a.i./ha.