Fabbrini E.,University of Washington |
Serafini M.,Agricultural Research Council Research Center on Food and Nutrition |
Colic Baric I.,Agricultural Research Council Research Center on Food and Nutrition |
Hazen S.L.,Cleveland Clinic |
Klein S.,University of Washington
Diabetes | Year: 2014
Oxidative stress is purported to be involved in the pathogenesis of obesity-associated insulin resistance. We evaluated whether alterations in levels of circulating uric acid (UA), a systemic antioxidant, affects the following: 1) systemic (plasma and saliva) nonenzymatic antioxidant capacity (NEAC); 2) markers of systemic (urinary 8-iso-prostaglandin-F2a) and muscle (carbonylated protein content) oxidative stress; and 3) whole-body insulin sensitivity (percentage increase in glucose uptake during a hyperinsulinemic- euglycemic clamp procedure). Thirty-one obese subjects (BMI 37.1 ± 0.7 kg/m2) with either high serum UA (HUA; 7.1 ± 0.4 mg/dL; n = 15) or normal serum UA (NUA; 4.5 ± 0.2 mg/dL; n = 16) levels were studied; 13 subjects with HUA levels were studied again after reduction of serum UA levels to 0 by infusing a recombinant urate oxidase. HUA subjects had 20-90% greater NEAC, but lower insulin sensitivity (40%) and levels of markers of oxidative stress (30%) than subjects in the NUA group (all P < 0.05). Acute UA reduction caused a 45-95% decrease in NEAC and a 25-40% increase in levels of systemic and muscle markers of oxidative stress (all P < 0.05), but did not affect insulin sensitivity (from 168 ± 25% to 156 ± 17%, P = NS). These results demonstrate that circulating UA is a major antioxidant and might help protect against free-radical oxidative damage. However, oxidative stress is not a major determinant of insulin action in vivo. © 2014 by the American Diabetes Association..
D'Evoli L.,Agricultural Research Council Research Center on Food and Nutrition |
Moscatello S.,CNR Institute of Neuroscience |
Lucarini M.,Agricultural Research Council Research Center on Food and Nutrition |
Aguzzi A.,Agricultural Research Council Research Center on Food and Nutrition |
And 6 more authors.
Journal of Food Composition and Analysis | Year: 2015
This study provides original data on the compositional profile and antioxidant capacity of kiwifruit grown in five orchards of the largest Italian production area (Lazio region). Data on macronutrients (moisture, protein, lipid, carbohydrate), starch, total dietary fiber, oxalic acid, organic acids, minerals, trace elements, and bioactive molecules including ascorbic acid, total polyphenols, carotenoids (lutein and ß-carotene), tocols (α-tocopherol, γ-tocopherol, γ-tocotrienol) content are reported. Kiwifruit was rich in ascorbic acid (mean value 60. mg/100. g). Lutein was the most abundant carotenoid (mean value 0.2. mg/100. g) followed by b-carotene. Among tocols, a-tocopherol was the most abundant (mean value 0.9. mg/100. g) followed by γ-tocotrienol (mean value 0.12. mg/100. g). The antioxidant activity (evaluated by means of FRAP, ABTS, ORAC assays) was significantly higher (P<. 0.05) in Borgo Podgora orchard than in any other one, the fruit of this orchard showed also the highest bioactive molecules content. Antioxidant activity positively correlated with hydrophilic molecules content mostly with ascorbic acid (r= 0.97) suggesting vitamin C as the major contributor to the total antioxidant activity in kiwifruit. © 2014 Elsevier Inc..