Antioxidative and Oxidative Profiles in Plasma and Saliva in Dairy Cows during Pregnancy

Increased metabolism that occurs during pregnancy can result in oxidative stress which is harmful to cells and, consequently, for the proper functioning of the whole organism. Plasma and recently also saliva are important resources for evaluating physiological and pathological conditions in animals. The study aimed to investigate the influence of the metabolic state on the effectiveness of the antioxidant profile of plasma and saliva during the pregnancy of cows. Seventy-six healthy pregnant and twelve non-pregnant control cows were included in the study. Blood and saliva samples were collected each month of the pregnancy course. Examined body fluids were used to evaluate both the total antioxidant capacity (TAC) and the oxidative parameters related to protein and lipid peroxidative processes. TAC, the content of hydroperoxides, and SH groups were determined spectrophotometrically while formylokinurenine and bityrosine contents were measured spectrofluorimetrically. The results showed dynamic changes depending on the period of pregnancy course. The highest antioxidant activity in plasma was mostly noted in early pregnancy and advanced pregnant cows. All tested parameters except SH groups expressed higher values in saliva compared to plasma. Obtained results reveal that the increase in oxidative intensity induced appropriate answers of cells reflected in the increase in antioxidative activity of the organism. Moreover, some examined parameters can indicate the intensity of oxidative stress and therefore could be used in a panel of markers of the physiological course of pregnancy. However, with regards to antioxidant/oxidative parameters, saliva reflects the content of plasma only in part, due to the local metabolism of the salivary gland. Further studies are necessary to establish physiological ranges of antioxidative/oxidative profiles in cows and to define the usefulness of saliva as biological material in oxidative stress diagnostics.

Effect of potassium humate and growth stage on phenolic compound and vitamin C accumulation in kale (Brassica oleracea var. sabellica)

Kale is one of the top economically valuable crops in the world because of its high antioxidant content. Research shows that the antioxidant profile of Brassica crops varies with growth stages due to soil fertility, temperature, light and other agronomic factors. This study aimed to analyze the effect of potassium humate on phenolic compound content, the greatest contributor to the antioxidant properties of the highest-ranking superfood kale (Brassica oleracea var. sabellica). Our results showed that potassium humate at different growth stages elicited phenolic compounds in the studied samples. Leaves of 22 weeks old plants accumulated phenolic compounds about two times higher than those of 7 weeks old plants. Vitamin C content was increased by potassium humate treatment at 7 weeks. At 22 weeks levels in controls and treated kale leaves did not significantly differ.

Comparison of Antioxidant Properties of a Conjugate of Taxifolin with Glyoxylic Acid and Selected Flavonoids

It is known that flavonoids can react with toxic carbonyl compounds in the process of the storage, aging, and digestion of flavonoid-rich foods and beverages. However, the effect of these reactions on the antioxidant properties of the polyphenolic fraction and the properties of the resulting products remain poorly studied. The aim of the present work was to study the antioxidant activity of quercetin, taxifolin, catechin, eriodictyol, hesperetin, naringenin and a product of the condensation of taxifolin with glyoxylic acid, as well as to reveal the structure–activity relationship of these polyphenols. It was found that flavonoids containing the catechol moiety exhibited higher antioxidant activity than hesperetin and naringenin. The product showed the highest hydrogen peroxide scavenging activity, a lower metal-reducing and a higher iron-binding ability than catechol-containing flavonoids, and a lipid peroxidation inhibitory activity comparable with that of taxifolin. Thus, the condensation of flavonoids with toxic carbonyl compounds might lead to the formation of products exhibiting high antioxidant activity. Meanwhile, the conditions under which parent flavonoids and their products exhibit the maximal antioxidant activity may differ. The data suggest that the antioxidant profile of the polyphenolic fraction and bioavailability of polyphenols, carbonyl compounds, and metal ions may change when these reactions occur.