Flavonoids Produce Free Radicals

Flavonoids are phytochemicals which are well known for their antioxidant capabilities. Flavonoids disrupt systems which produce free radicals and can also stimulate other antioxidant activity. One way that flavonoids disrupt free radicals is by direct contact. More specifically, when flavonoids become oxidized by free radicals, the radical is stabilized. When free radicals become stable, they do not have the power to cause damage like before, because they are less reactive. Flavonoids also affect nitric oxide when they act as antioxidants. Normally, nitric oxide can react with free radicals. When this reaction occurs, peroxynitrite is formed which is incredibly harmful to the cell membrane. However, when flavonoids work as antioxidants and
scavenge free radicals, the radicals are unable to react with the nitric oxide. Flavonoids also prevent cell damage by stopping xanthine oxidase activity. Xanthine oxidase provides oxygen to free radicals, which can subsequently produce superoxide free radicals. When flavonoids block xanthine oxidase, less oxidative damage occurs. Lastly, flavonoids' antioxidant properties affect leukocytes. Typically, leukocytes easily move along the endothelial wall. However, during times of inflammation, leukocytes become paralyzed and stick to the endothelial wall, which causes free radicals to be produced. Flavonoids act as antioxidants by decreasing the amount of inactive leukocytes. Besides antioxidant activity, flavonoids are also thought to be involved in other roles, such as iron chelating and preventing arachidonic acid from being metabolized, which means flavonoids have both anti-inflammatory and antithrombogenic abilities in addition to their antioxidant properties.