Daidzein May Activate Antioxidant Enzyme System

Daidzein May Activate Antioxidant Enzyme System

DUSSELDORF, Germany--The soy isoflavone daidzein may have the ability to promote the body's antioxidant enzyme system, although it does not seem to have its own antioxidant abilities, according to an in vitro study conducted at theHeinrich-Heine-Universität and published in the March issue of the Journal of Nutrition (132:370-75, 2002) (www.nutrition.org). Based on the premise thatphytoestrogens, such as daidzein, exhibit antioxidant properties, researchers sought to determine if daidzein might also be able to modulate the antioxidant enzyme system, thereby indirectly defending cells against oxidative damage. Researchers treated rat cells with daidzein and found that catalase mRNA activity was increased two- to three-fold. In addition, glutathione peroxidase levels were increased slightly after exposure todaidzein. However, expression levels of copper zinc superoxide dismutase (SOD, a powerful antioxidant enzyme) and manganese SOD expression was decreased slightly after daidzein exposure. Researchers determined that while daidzein increased antioxidant enzyme activity to some extent, pretreatment of cells with the phytoestrogen did not protect against oxidative stress.