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The aim of the present study is to investigate the antioxidant properties of the lichen Cetraria aculeata. Antioxidant activity of the methanol and ethyl acetate extracts of lichen was tested by different methods including determination of total phenolics content, determination of total antioxidant capacity, DPPH free radical scavenging activity, inhibitory activity towards lipid peroxidation, ferrous ion chelating ability and hydroxyl radical scavenging activity. The extracts of the lichen C. aculeata showed significant antioxidant activity. The methanol extract showed higher values for total phenolics and total antioxidant capacity compared to the ethyl acetate extract, while the ethyl acetate extract demonstrated better results for DPPH radical scavenging, inhibitory activity towards lipid peroxidation, chelating ability and hydroxyl radical scavenging than the methanol extract. This is the first report of the antioxidant properties of Cetraria aculeata growing in Serbia. The results of antioxidant activity indicate the application of this lichen as source of natural antioxidants that could be used as a possible food supplement, in the pharmaceutical industry and in the treatment of various diseases.

The aim of the present study is to investigate the antioxidant properties of the lichen Cetraria aculeata. Antioxidant activity of the methanol and ethyl acetate extracts of lichen was tested by different methods including determination of total phenolics content, determination of total antioxidant capacity, DPPH free radical scavenging activity, inhibitory activity towards lipid peroxidation, ferrous ion chelating ability and hydroxyl radical scavenging activity. The extracts of the lichen C. aculeata showed significant antioxidant activity. The methanol extract showed higher values for total phenolics and total antioxidant capacity compared to the ethyl acetate extract, while the ethyl acetate extract demonstrated better results for DPPH radical scavenging, inhibitory activity towards lipid peroxidation, chelating ability and hydroxyl radical scavenging than the methanol extract. This is the first report of the antioxidant properties of Cetraria aculeata growing in Serbia. The results of antioxidant activity indicate the application of this lichen as source of natural antioxidants that could be used as a possible food supplement, in the pharmaceutical industry and in the treatment of various diseases.

Human serum albumin (HSA) has a very significant role in the transport of drugs, in their pharmacokinetic and pharmacodynamic properties, as well as the unbound concentration of drugs in circulating plasma. The aim of this study was to look into the competition between tigecycline (TGC) and alkaloid (ALK) (caffeine (CAF)), and flavonoids (FLAVs) (catechin (CAT), quercetin (QUE), and diosmin (DIO)) in binding to HSA in simulated physiological conditions using multiple spectroscopic measurements and docking simulations. Fluorescence analysis was used to find the binding and quenching properties of double HSA-TGC and triple HSA-TGC-CAF/FLAV systems. The conformational change of the HSA was analyzed using synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism. Obtained results of spectroscopic analyses indicate that triple complexes of HSA-TGC-CAF/FLAVs are formed without problems and have higher binding affinities than double HSA-TGC. In addition, TGC does not change the microenvironments around the tryptophan (Trp) and tyrosine (Tyr) residues in the presence of ALK and FLAVs. Ultimately, the binding affinity, competition, and interaction nature were explored by docking modeling. Computational outcomes are in good accordance with experimentally obtained results. Accordingly, concluding remarks may be very useful for potential interactions between common food components and drugs.

In this study, the binding of olanzapine (OLZ) to human serum albumin (HSA) and the influence of metal ions (Ca 2+ , Mg 2+ , Cu 2+ , Zn 2+ , Fe 3+ ), caffeine (CAF) and flavonoids (diosmin (DIO), catechin (CAT), quercetin (QUE)), on their affinity, was investigated by fluorescence spectroscopy and UV-vis absorption spectroscopy. Fluorescence experiments suggest that OLZ quench the fluorescence of HSA through the mixed quenching mechanism and non-radiation energy transferring as a result of the HSA-OLZ complex formation. OLZ spontaneously bind in the site I on HSA, and according to thermodynamic parameters, the reaction was spontaneous and mainly driven by hydrogen bonds and van der Waals interactions. The presence of M n+ ions, CAF, DIO and CAT decreased binding affinity between OLZ and HSA which indicates that they could compete against OLZ in the site I. Contrary, in the presence of QUE the binding affinity of the HSA-OLZ system enhanced, which may be explained by conformational changes in HSA (non-competitive interference)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: The purpose of this study is to determine the effect of L-ascorbic acid and alpha-tocopherol as well as combination of these vitamins with or without exposure to physical exercise on intensity of lipid peroxidation, activity of xanthine oxidase, activity of total antioxidative system, concentration of glutathione, and activity of catalase in the serum of guinea pigs., Materials and Methods: The experimental measurements of intensity of lipid peroxidation, activity of xanthine oxidase, activity of total antioxidative system, concentration of glutathione, and activity of catalase were done in the serum of guinea pigs. The animals were exposed to the test load to achieve exhaustion and the test was terminated when the animal for the third time to sink into the water., Results: The results of this study demonstrated that endurance exercise of guinea pigs induced oxidative stress response in terms of increased lipid peroxidation and activity of xanthine oxidase in the serum of experimental animals. Our study investigated the antioxidant activity of L-ascorbic acid and alpha-tocopherol also measuring three protective markers in the serum: total antioxidant activity, content of glutathione and activity of catalase. The results obtained show that the vitamins influence the concentrations of above mentioned biochemical parameters, which points out their protective effect of swimming-induced oxidative stress., Conclusion: Single or combined administration of L-ascorbic acid and alpha-tocopherol caused significant inhibition of these markers indicating the important antioxidant activity of the vitamins. Results lead to conclude that the combined treatments with vitamins with or without exposure to physical exercise showed the clear synergistic effect..

This paper studies the phytochemical analysis of the acetone extracts of the Ramalina fraxinea and Ramalina fastigiata lichens and the antioxidant, antimicrobial and antitumour activities of these species and their constituents. The phytochemical analysis of two Ramalina species was evaluated using HPLC-UV test. The depsides (evernic acid, obtusatic acid, sekikaic acid and atranorin), depsidones (protocetraric acid) and dibenzofurane (usnic acid) were identified from these lichens. Antioxidant activity was evaluated by DPPH assay, reducing power assay and by measuring the amounts of total phenolics in extracts. Antimicrobial activity was tested towards five bacterial and 10 fungal species, using broth microdilution method to determine the minimum inhibitory concentration. Cytotoxic activity was tested using MTT method on the human epithelial carcinoma (Hela), human lung carcinoma (A549) and human colon carcinoma (LS174) cells. As a result of the study, tested samples showed strong free radical scavenging activity with I50 values within the range of 285.45-423.51 μg/mL. Absorbance for reducing power was found to be from 0.0043 to 0.1747. The total amount of phenol concentrations in extracts of Ramalina fraxinea and Ramalina fastigiata was 32.63 and 33.49 μg PE/mg, respectively. Methyl evernate showed the strongest antimicrobial properties with the least measured MIC value being 0.125 mg/mL. In addition, all samples exhibited strong anticancer activities against tested cells (I50 values were between 24.63 and 161.37 μg/mL). These results indicate that lichen appears to be a possible natural biopharmaceutical.

Background/aim: Severe dental anxiety (SDA) is the most severe form of dental anxiety, thus the aim of this study was to determine the factors associated with SDA in students of health-related disciplines., Methods: In this case-control study the cases were students with severe dental anxiety. The study was conducted at the Faculty of Medical Sciences, University of Kragujevac, Serbia. The participants were undergraduate students attending lectures during spring semester 2010/2011 (n = 1,812). A random sample of 800 students was assessed for the association between various risk factors and the severe dental anxiety. The main outcome measures were the data on demographics, dental anxiety, habits concerning oral hygiene, nutrition, general anxiety and (co)morbidity which were collected from the study participants by semi-structured questionnaire., Results: Less frequent visits to the dentist (OR adjusted = 7.02 [2.65; 18.60]) and visiting the dentist only when there is a dental problem (OR adjusted = 8.08 [1.28; 50.93]) were associated with severe dental anxiety. The same was true for improper oral hygiene (OR adjusted = 4.25 [1.16; 15.60]). Factors as changing toothbrush more frequently (OR adjusted = 0.33 [0.14; 0.76]) and having chronic disease (OR adjusted = 0.01 [0.00; 0.09]) were inversely associated with severe dental anxiety. The level of education of students was not associated with severe dental anxiety., Conclusion: Inappropriate oral hygiene, less frequent changes of a toothbrush and less frequent visits to the dentist are important risk factors for severe dental anxiety.