Search

Seven young females and 1 male participant (between 24 and 29 years of age) were subjected to a 3,200-m run through uneven terrain. After the run, capillary blood samples were drawn for the determination of pH, pCO 2 , pO 2 , base excess (BE), HCO 3 , ionized magnesium (Mg), and lactate. 30, 60, and 90 minutes after the run, additional blood samples were taken to assess the metabolic situation during recovery. One week later, the candidates received two sachets of an effervescent preparation containing amino acids, vitamins, herbal antioxidants, trace elements, and electrolytes. Among them, a total of 300 mg Mg immediately after running and the same sampling times as in the control group were used. It turned out that the group averages of pH, BE, and HCO 3 were already significantly higher at 30, 60, and 90 minutes after the run in the test group than in controls. Correlation analyses further show that recovery of test persons is significantly faster, especially in those participants most affected by the running. Additionally, there is no “oxygen trapping” in the blood due to increased pH during the recovery period in test persons.

Antioxidant activity was measured by ferric reducing ability of plasma (FRAP) assay in seven types of infusions prepared from commercial dried berry fruit products: Rosa canina , Vaccinium vitis-idaea , Hiphophae rhamnoides , Hibiscus sabdariffa and three fruit mixtures. Total polyphenols (TP), total anthocyanins and the polyphenolic compounds were determined by HPLC equipped with diode array detector. To estimate the amount of elements released from fruits into the water extracts, levels of Fe, Mn, Zn and Cu in dried samples and in infusions were determined by flame atomic absorption spectrometry. The correlation between polyphenols content and the antioxidant activities and the microelements in the infusions and the antioxidant activities were estimated using the Pearson’s correlation test. The results showed a high, positive and significant correlation (r = 0.9465) between the FRAP values and TP content, meaning that the concentration of phenolic compounds may be a good indicator of the reducing capacity in the infusions. Correlations varied (positive, negative and weak) between antioxidant and mineral extractability of berry infusions. Among the polyphenolic compounds, gallic acid contributed particularly to the antioxidant capacity of the studied samples (r = 0.563). The correlation of antioxidants, total polyphenols with mineral extractability showed the influence of antioxidant compound on mineral bioavailability. KEY WORDS : Mixed berry infusion, Antioxidant activity, Phenolic compounds, Microelements Bull. Chem. Soc. Ethiop. 2018 , 32(1), 1-12 DOI: https://dx.doi.org/10.4314/bcse.v32i1.1

As continuous production of free radicals and reactive oxygen species is a normal metabolic process, increased metabolism during exercise/workload should increase free radical generation and oxidative stress. Oxidative stress intensity should then depend on the intensity of metabolic stress effects. Intensity of stress is usually reflected in norepinephrine (NE) levels, which correlate linearly and significantly with changes in blood gases, blood buffer systems, blood electrolytes, blood glucose and lactate [Porta, S., Leitner, G., Heidinger, D., Lang, T., Weiss, U., Smolle, K.H., Hasiba, K., 1997. Magnesium wahrend der Alpinausbildung bringt um 30% bessere Energieverwertung. Magnesium-Bulletin 19(2), 59–61]. Those parameters were used in an open study design to screen 64 subjects for metabolic stress effects along with their antioxidative capacity using both venous and capillary blood. To compare venous and capillary blood, we took venous blood samples from 12 healthy volunteers and capillary blood from 52 other healthy subjects. To show whether free radical changes indeed go along with metabolic stress effects, we tried to quantify relations between metabolic stress effects and oxidative stress by linear correlations. In conclusion, both venous and capillary blood are suitable for determining at least those parameters of the oxidative state that we used. All significant correlations of peroxidase activity and oxidation lag time (OLT) with pH, bicarbonate (HCO 3 ), base excess (BE) and magnesium (Mg) indicate that free radical production increases with metabolism. Those relationships could help to evaluate the oxidative state more precisely.