In vitro antioxidant activities of barley, husked oat, naked oat, triticale, and buckwheat wastes and their influence on the growth and biomarkers of antioxidant status in rats

The study was aimed at verification of the following hypothesis: differences in antioxidant capacity of diets consisting of different cereals and byproducts affect the antioxidant status of the consumers of these diets. To validate that hypothesis this study investigated the contents of polyphenols and alpha-tocopherol as well as the total antioxidant capacity (TAC) in vitro of cereals and their fractions ( barley, husked and naked oat, oat bran, and triticale); the nutritional and antioxidant properties of diets containing these cereals, applied in a 4-week feeding experiment on rats, were also assessed. Among the cereals examined, the highest TAC was reported for barley (13.16 mu mol of Trolox/g) and the lowest for naked oat (3.84 mu mol of Trolox/g). Compared with cereals, the TAC of buckwheat waste was 2-3 times higher (25.2 mu mol of Trolox/g). The antioxidant capacity of diets, calculated in vitro, ranged from 6.35 mu mol of Trolox/g for naked oat type diet to 10.51 mu mol of Trolox/g for barley type diet. Results of an in vitro study were confirmed in changes of glutathione peroxidase (GPx) activities and the level of thiobarbituric acid-reactive substances (TBARS) in the serum of rats fed diets with the highest and lowest antioxidant capacities in vitro; the barley diet increased the activity of GPx (37.63 units/mL) and decreased the level of TBARS (4.82 mu g/g), whereas the naked oat diet had an opposite effect (31.16 units/mL and 5.91 mu g/g, respectively).