Performed experiments and simulations of petroleum microbiological degradation may serve for the prediction of the fate of petroleum type pollutants, as well as for definition of conditions for bioremediation of some environmental segments.

The goal of this work was to investigate the relationship between antioxidants' content and the oxidative stabilities of grape seed oils obtained from the Cabernet Sauvignon variety. The samples of grape seed oils were obtained by ultrasound assisted extraction. The time of extraction was varied, while the other relevant parameters: extraction temperature, solvent to solid ratio and sonication power were kept constant. For the sake of comparison, the extraction was also done using the conventional Soxhlet method. For all the oil samples obtained, the contents of total phenolic compounds (TPC), atocopherol and fatty acids were determined using relevant analytic methods. Importantly, in the present study, the modern analytical techniques for estimation of antioxidant capacity (measuring the chemiluminescence intensity of a luminol-hemin solution) and oxidative stability [differential scanning calorimetry (DSC), coupled with thermogravimetry (TG)] were proposed. The obtained results prove that ultrasonic irradiation enables effective extraction of grape seed oil. It was shown that the extractive yields and the amounts of total phenolic compounds and atocopherol increase with time of extraction; the optimum time was determined. Results obtained in this work show that, for both oxidative stability and antioxidant capacity, TPC have a more important role then a-tocopherol.

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Antioxidant (AO) capacity of various medicinal plants extracts and phenolic compounds was assessed by the most widely used spectrophotometric assays such as ferric reducing antioxidant power (FRAP) and scavenging of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). In addition, two direct current (DC) polarographic assays, one based on a decrease of anodic current of [Hg(O2H)(OH)] - HydroxoPerhydroxoMercury(II) Complex (HPMC) formation in alkaline solution of H2O2, at the potential of mercury dissolution and another recently developed Mercury Reduction Antioxidant Power (MRAP), based on a a decrease of cathodic current of Hg(II) reduction were employed. Percentage of both currents decrease was plotted versus the volume of gradually added complex samples or the amount of individual ones and the slopes of these plots were used to express AO capacity. Total phenolic content (TPC) of extracts was determined by Folin- Ciocalteu (FC) assay. Correlations between applied assays were calculated by regression analysis. Relative Antioxidant Capacity Index (RACI), calculated by assigning equal weight to all applied assays and Phenolic Antioxidant Coefficients (PAC), calculated as a ratio between particular AO capacity and TPC, were used to achieve more comprehensive comparison between analyzed samples, as well as applied assays.