Aleksandra N. Pavlović

Antioxidant Capacities and Phenolic Levels of Different Varieties of Serbian White Wines

The biologically active compounds in wine, especially phenolics, are responsible for reduced risk of developing chronic diseases (cardiovascular disrease, cancer, diabetes, etc.), due to their antioxidant activities. We determined the contents of total phenolics (TP) and total flavonoids (TF) in selected Serbian white wines by colorimetric methods. Total antioxidant activity (TAA) of the white wines was analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay. Međaš beli had the highest content of TP, TF and TAA. The radical scavenging capacity (RSC) and total antioxidant activity (TAA) of white wines were 15.30% and 1.055 mM Trolox equivalent, respectively. Total phenolic (TP) and total flavonoid (TF) contents in white wines ranged from 238.3 to 420.6 mg gallic acid equivalent per L of wines and 42.64 to 81.32 mg catechin equivalent per L of wines, respectively. A high and significant correlation between antioxidant activity and total phenolic content was determined in wines (R2 = 0.968, p < 0.01). For the individual polyphenols determination we used a high performance liquid chromatography (HPLC)-diode array detection (DAD) technique. The majority of white wine polyphenols was represent by four hydroxycinnamic acids (HCAs).

Determination of doxycycline in pharmaceuticals based on its degradation by Cu(II)/H2O2 reagent in aqueous solution

The reaction between doxycycline, hydrogen peroxide and Cu(II) was investigated spectrophotometrically in aqueous solutions. The absorption spectra show that the degradation of antibiotic drug occurs in weak alkaline aqueous solutions. The kinetics of the reaction was studied by applying the initial-rate method and the relative rate constants were calculated at different temperatures. The kinetic-spectrophotometric method for the determination of doxycycline based on the kinetics of pseudo-first order reaction at 20°C is proposed. The effects of several molecules and ions usually present in pharmaceutical formulations were studied in order to assess their interference. The calibration graph was applied to the determination of doxycycline in capsule dosage form. The relative standard deviation was no greater than 3.80%. The results were compared to those obtained by the official HPLC method.

Elemental composition of edible nuts: fast optimization and validation procedure of an ICP-OES method.

BACKGROUND An inductively coupled plasma-optical emission spectrometry method for the speedy simultaneous detection of 19 elements in edible nuts (walnuts: Juglans nigra; almonds: Prunus dulcis; hazelnuts: Corylus avellana; Brazil nuts: Bertholletia excelsa; cashews: Anacardium occidentalle; pistachios: Pistacia vera; and peanuts: Arachis hypogaea) available on the Serbian markets, was optimized and validated through the selection of instrumental parameters and analytical lines free from spectral interference and with the lowest matrix effects. RESULTS The analysed macro-elements were present in the following descending order: Na > Mg > Ca > K. Of all the trace elements, the tested samples showed the highest content of Fe. The micro-element Se was detected in all the samples of nuts. The toxic elements As, Cd and Pb were either not detected or the contents were below the limit of detection. One-way analysis of variance, Students t-test, Tukeys HSD post hoc test and hierarchical agglomerative cluster analysis were applied in the statistical analysis of the results. CONCLUSION Based on the detected content of analysed elements it can be concluded that nuts may be a good additional source of minerals as micronutrients.

Plant parts of the apple tree (Malus spp.) as possible indicators of heavy metal pollution

The content of Cu, Zn, Pb, As, Cd, and Ni was determined by ICP-OES in spatial soil and parts (root, branches, leaves, and fruit) of the apple tree (Malus spp.) from polluted sites near The Mining and Smelting Complex Bor (Serbia). The aim of this study was to examine if the obtained results can be used for biomonitoring purposes. Data recorded in plant parts, especially leaves, gave very useful information about the environmental state of the Bor region. Conveniently, these data described well the capability of investigated plant species to assimilate and tolerate severely high concentrations of heavy metals in its tissues, which may further allow the possibility for utilization of the apple tree for phytostabilization.

Statistical characteristics of selected elements in vegetables from Kosovo

Zinc, copper, iron, chromium and cobalt are essential elements for human health, showing toxicity only in high concentrations, while lead and cadmium are extremely toxic even as traces. Therefore, it is important to monitor the contents of toxic metals in vegetables. Large number of vegetables is grown and used in nutrition, in Kosovo. The concentrations of selected elements in vegetables (radish, onion, garlic and spinach) from Kosovo were determined using ICP-OES method. Oral intake of metals and health risk index were calculated. Statistical analysis indicated numerous positive correlations between concentrations of selected elements in vegetables. As a result of principal component analysis, 15 new variables were obtained which were characterized by eigenvalues. The sequence of health quotients for the heavy metals followed the decreasing order Zn = Mn > Pb > Cu > Ni > Fe > Cd > Co > Cr. The health quotients for all investigated heavy metals were below 1 (one), which is considered safe. The vegetables from Kosovo are mainly safe for use in everyday diet.

Metals content of soil, leaves and wild fruit from Serbia

AbstractThe concentrations of Zn, Mn, Fe, Pb, Ni, Cu and Cd in soil, leaves and edible wild fruit (Crataegus laevigata L., Cornus mas L. and Prunus spinosa L.) from southeast Serbia were determined by atomic absorption spectroscopy. Metal translocations from soil to fruit were calculated as well as their oral intake and health risk indices. Positive correlations were found among metal concentrations in soil, leaves and fruit.

Heavy metal content in different types of smoked meat in Serbia

Concentrations of Fe, Cu, Ni, Cr, Pb, Mn, Zn and Cd in pork, beef, turkey and chicken samples were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). The mean concentration ranges in milligrams per 100 g of the studied metals in all samples were 0.6924–1.2154 for Fe, 0.6492–0.9831 for Cu, 0.0012–0.0027 for Pb, 0.041–0.0510 for Ni, 0.1186–0.1481 for Mn, 0.7257–5.2726 for Zn and 0.0042–0.0050 for Cd. The levels of analysed elements were in accordance with European standards for all metals except for manganese in all samples and for nickel in a certain number of samples. Zn level in beef was significantly higher compared to other samples, and Pb and Cd were found in concentrations well below the recommended daily intake.

Kinetic quantification of sodium salicylate in human serum and wine

AbstractA rapid, relatively sensitive and simple kinetic-spectrophotometric method for determining sodium salicylate content has been developed and validated. This method was based on the Fenton reaction that involved mixing of ferrous ions, hydrogen peroxide and sodium salicylate in acetic buffer medium. Ferrous ions, oxidized by hydrogen peroxide, formed with salicylate anion purple complex whose degradation started immediately. This effect was monitored by the decrease of absorbance at 525 nm. The experimental results showed that the most favorable conditions for complex degradation are: pH = 3.9,

Phenolic profiles and metal ions analyses of pulp and peel of fruits and seeds of quince (Cydonia oblonga Mill.)

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