Effect of the citrus flavanone naringenin on oxidative stress in rats.

Flavonoids are non-nutrient plant phenolic compounds proposed to provide health benefits in humans. The antioxidant and prooxidant effects of the citrus flavanone naringenin have been tested only in vitro. The dose-response effect of naringenin consumption was tested in weanling rats (n=6-8/group) with a 2x4 factorial design using high or low oxidative stress (Hox or Lox, respectively) diets, created by adequate or deficient amounts of vitamin E and selenium, with three increasing naringenin concentrations (30, 60, or 120 mg/kg of diet). Hox compared to Lox rats exhibited reduced growth and liver hypertrophy, which was not prevented by naringenin consumption. Also, Hox rats exhibited severalfold higher liver NAD(P)H:quinone oxidoreductase-1 activity, which was further elevated in proportion to naringenin intake, but this was not sufficient to protect against oxidative stress indicated by higher liver total aldehydes. In addition, dietary naringenin did not affect antioxidant nutrient status or physiological markers of growth under Lox conditions. Thus, dietary naringenin did not exhibit antioxidant or prooxidant effects in vivo in this rat model.