Project Number: 1950-51000-065-00
Project Type: Appropriated

Start Date: Nov 01, 2004
End Date: Apr 30, 2009

Objective:
ANTIOXIDANTS RESEARCH LAB To determine if flavonoids are bioavailable as aglycones and glycosides and both parent compounds and their metabolites act in vitro and in vivo as antioxidants. To determine molecular and biochemical mechanisms of flavonoids and their interactions within the antioxidant defense network. CAROTENOIDS AND HEALTH LAB To determine bioavailability and vitamin A equivalents of plant-carotene. To determine antioxidant functions of lutein and tea polyphenols in relation to Age-related Macular degeneration (AMD). To determine the role of body fat on tissue uptake of carotenoids.

Approach:
ANTIOXIDANTS RESEARCH LAB 1(A)Weanling rats will be divided into groups fed vitamin E replete, depleted or supplemented diets with or without different doses of quercetin. Blood and tissues will be obtained at intervals over 14 wk for analysis of antioxidant status and metabolism and biomarkers of oxidative stress. (B)Hamsters fed extracts of oat bran, almond skin or bilberry and their blood/tissue collected to determine flavonoid pharmacokinetics and distribution and antioxidant actions. Randomized clinical trials with a cross-over design in healthy older adults will test the bioavailability and antioxidant capacity of these same plant extracts. (C)A pilot clinical trial will test the adequacy of dose and formulation of a manufactured beverage containing catechins and/or N-acetylcysteine. 2(A)Human LDL will be incubated with different flavonoids alone or in combination with other antioxidants to determine their impact on the resistance of nLDL and LDL to oxidation induced by various radical generators. (B)A hemochromatosis mouse model will be used to test the preventive actions of the green tea flavonoid. (C)The effect of bilberry anthocyanins alone or together with xanthophyll carotenoids will be tested in humans for their uptake and metabolism in retina cells and subsequent action on biomarkers of oxidative stress and apoptosis following challenges with hydrogen peroxide or glucose. The impact of anthocyanins on the expression of stress and apoptosis-related proteins and genes will be investigated utilizing mRNA expression gels and GeneChip arrays. CAROTENOIDS AND HEALTH LAB 1. Hydroponically grown deuterium labeled vegetables and Golden Rice will be used to determine bioavailability of beta-carotene, lutein, and zeazanthin, and vitamin A equivalence of provitamin A carotenoids. Labeled food will be given to volunteers, blood samples at different time points will be collected and analyzed using advanced high-performance liquid chromatography (HPLC) gas chromatography mass spectrometry (GC/MS) and liguid chromatography mass spectrometry (LC/MS). 2. Examine the absorption kinetics of major carotenoids, lutein, beta-carotene and lycopene, and measure the functional bioavailability of carotenoids in healthy women in response to an 8-week period of carotenoid supplementation. The antioxidant capacity, DNA oxidation, gene expression profile, lipid peroxidation, and antioxidant nutrient levels in the circulation will be determined in response to a combination or single dose of carotenoids. B.The alteration of macular pigment density, oxidizability both in blood lipid and aqueous compartments, lipid peroxidation and nitric oxide levels following the consumption of a fat-soluble antioxidant, lutein or a combination dose of lutein and water-soluble antioxidant, green tea polyphenols will be determined. 3. Daily supplementation of lutein will be given to subjects of varying body weights (normal, overweight, obese). Changes in carotenoid concentrations will be determined in serum, adipose tissue and macula using HPLC and psychophysical techniques.