The effects of blueberry extract supplementation on basal oxidative stress in young healthy rats
Dulebohn, Rachel Victoria
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Blueberry extracts reduce oxidative stress and increase phase II enzyme activities in vitro. We examined these effects in vivo. Young, non-stressed male Sprague-Dawley rats (n=8) were fed AIN-93 or modified AIN-93 diets for three weeks. Modified diets were 10% crude blueberries substituting sucrose, blueberry polyphenol extract and sugars matching the 10% blueberry diet, sugars equivalent to the 10% blueberry diet, 1% and 0.2% blueberry flavonoids, primarily anthocyanins. Colon mucosa and liver glutathione-S-transferase (GST), quinone reductase and liver UDP-glucuronosyltransferase activities were not significantly increased by crude blueberries or blueberry fractions. However, liver GST activity was approximately 26% higher than controls for the blueberry, polyphenol, and 1% flavonoid groups. Urinary F2-isoprostanes were unaffected. DNA damage was lowest for liver and lymphocytes in the 1% flavonoid group, significantly in the liver. This study shows in vivo and in vitro findings disagree and higher supplementation or stressed model may be required for significant effects.