MPO and peptic ulcer disease: Flavonoids, such as quercetin [43], quercitrin and afzelin [45], genistein [62], aromadendrin-4′-O-methyl-ether and kaempferide [84], kaempferol [93], and rutin [94,95], have been shown to decrease MPO levels, thereby exhibiting anti-inflammatory activity in peptic ulcer.