Purity >95%. Butein is a plant polyphenol that is classified as a chalcone, due to the propenone linkage between the phenol groups. Like other polyphenols, butein is a potent antioxidant and affects the numerous pathways modulated by oxidant tone, including inflammation, cancer, and immune response. It inhibits 5-lipoxygenase, the enoyl-acyl-carrier protein reductase of P. falciparum, angiotensin-converting enzyme, and Src kinase (IC50 or Ki values of 0.01, 2.97, 0.73, and 65 μM, respectively). Butein is also a sirtuin activator, increasing trichostatin A -insensitive deacetylase activity.