Major metabolite of F2-isoprostane in urine may be a more sensitive biomarker of oxidative stress than isoprostane itself

Background: There is limited literature on the contributors to isoprostane metabolite 2,3-dinor-5,6-dihydro-15-F-2t-isoprostane (15-F-2t-IsoP-M) compared with F-2-isoprostanes (F-2-IsoPs) as an oxidative stress biomarker. Objective: The objective of this study was to investigate whether plasma concentrations of antioxidants, urinary excretion rates of polyphenols, and antioxidants in food and dietary supplements are attributable to both urinary F-2-IsoP and 15-F-2t-IsoP-M concentrations. Design: Dietary intake information and blood and urine samples were obtained from 845 healthy middle-aged and elderly female participants of the Shanghai Women's Health Study. Urinary isoprostanes (F-2-IsoPs and 15-F-2t-IsoP-M) were measured and adjusted for creatinine concentrations. Results: Urinary 15-F-2t-IsoP-M and F-2-IsoP concentrations were lower in subjects who used a multivitamin. Lower F-2-IsoP concentrations were observed in ginseng users, whereas lower concentrations of 15-F-2t-IsoP-M were shown in subjects who used a vitamin E supplement. Plasma concentrations of several antioxidants (ie, beta-carotenes, both trans and cis beta-carotenes, lycopene other than trans, 5-cis and 7-cis isomers, cis anhydrolutein, and cis beta-cryptoxanthin) were inversely associated with 15-F-2t-IsoP-M but not with F-2-IsoPs, whereas beta-, gamma-, and delta-tocopherols were positively associated with 15-F-2t-IsoP-M but not with F-2-IsoPs. Urinary polyphenol quercetin was positively associated with both F-2-IsoPs and 15-F-2t-IsoP-M. Conclusion: The results suggest that the F-2-IsoP major metabolite 15-F-2t-IsoP-M may be a more sensitive marker of endogenous oxidative stress status than are F-2-IsoPs in the assessment of effects of antioxidants on age-related diseases. Am J Clin Nutr 2012;96:405-14.