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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..

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.Keywords: ROS, antioxidant activity, lichen, Cetraria aculeata. INTRODUCTIONActive oxygen exists in different forms, such as superoxide anion radicals (O2• −), hydrogen peroxide (H 2 O 2 ), hydroxyl radicals (OH•) and singlet oxygen ( 1 O2). These forms of oxygen are highly reactive intermediates, and have a collective name of reactive oxygen species (ROS) [1,2,3,4,5]. ROS are free radicals very important for living organisms, in which are formed in different ways. In normal aerobic respiration, stimulated polymorphonuclear leukocytes and macrophages, and peroxisomes appear to be the main endogenous sources of most oxidants produced by cells. However, despite the fact that ROS are necessary for cell function, in high concentrations leads to oxidative stress and to the development a large number of diseases such as arthritis, carcinogenesis, aging. In addition to endogenous sources of free radicals, a major contribution of the accumulation of free radicals in cells are provided by exogenous sources such as ionizing radiation, tobacco smoke, certain pollutants, organic solvents and pesticides [4,6,7,8,9,10]. The above mentioned diseases and accelerated aging are the consequence of oxidative tissue damage by free radicals because of unbalanced mechanisms of antioxidant protection under the influence of endogenous and exogenous factors [11]. ROS attack unsaturated fatty acids in membrane proteins, causing lipid peroxidation, and the result is damage to membrane proteins [12]. This leads to reduced permeability of membranes, receptors and enzyme activity, and reduced activation of cells. Free radicals attack the DNA, while leading to DNA damage, resulting in mutations that cause cancer. Therefore, the prevention of many diseases are important antioxidant defense systems, including food, drugs and antioxidant enzymes [1...

The present study provides new data concerning chemical characterization and biological activity of acetone, methanol and aqueous extracts of the lichen Physcia semipinnata. Chemical profiling of the extracts was done by high-performance liquid chromatography coupled with a UV detector (HPLC-UV) analysis. The antioxidant activity was evaluated by measuring total anti-oxidative capacity, reducing capacity, inhibition lipid peroxidation and scavenging capacity on 2,2-diphenyl-1picrylhydrazyl (DPPH) and hydroxyl (OH) radicals. In vitro anticancer activity was evaluated by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Lecanoric acid, methyl-β-orcinol carboxylate, ethyl haematommate, evernic acid, obtusic acid and atranorin were identified from this lichen. As a result of the study of the antioxidant activity, the acetone and the methanol extracts of P. semipinnata was found to have the better antioxidant activity than aqueous extract. Total phenolics and flavonoids in the extracts were determined spectrophotometrically, with the varied amount from 20.11 to 59.20 mg GA/g and from 5.48 to 19.27 mg RU/g, respectively. The results of the viability and proliferation study of HeLa, LS174 and A549 cells after the treatment with the extracts showed that the best cytotoxic/cytostatic activity was exhibited by the acetone extract of P. semipinnata. Investigated extracts can be used as natural antioxidant agents and as a significant source of biological active compounds. RezumatPrezentul studiu oferă noi informații privind caracterizarea chimică și activitatea biologică a extractelor apos, metanolic și acetonic ale lichenului Physcia semipinnata. Profilele chimice ale extractelor au fost realizate prin cromatografie lichidă de înaltă performanță cu detecție în UV (HPLC-UV). Activitatea antioxidantă a fost evaluată prin măsurarea capacității totale antioxidante, capacitatea de reducere, inhibarea peroxidării lipidice și capacitatea de chelatare a radicalilor 2,2-difenil-1picrilhidrazil (DPPH) și hidroxil (OH). Activitatea anticanceroasă in vitro a fost evaluată prin testul bromurii de 3-(4,5dimetiltiazol-2-il) -2,5-difeniltetrazoliu (MTT). Acidul lecanoric, carboxilatul de metil-β-orcinol, hematomatul de etil, acidul evernic, acidul obtusic și atranorina au fost identificate în acest lichen. Ca rezultat al studiului activității antioxidante, s-a descoperit că extractele metanolic și acetonic de P. semipinnata au o activitate antioxidantă mai bună decât extractul apos. Conținutul total în fenoli și flavonoidele totale s-au determinat în extracte spectrofotometric, variind de la 20,11 până la 59,20 mg GA/g și de la 5,48 până la 19,27 mg RU/g, respectiv. Rezultatele studiului de viabilitate și proliferare a celulelor HeLa, LS174 și A549, după tratamentul cu extracte, au arătat că cea mai bună activitate citotoxică/citostatică a fost prezentată de extractul obținut în acetonă din P. semipinnata. Extractele investigate pot fi folosite ca agenți antioxidanți naturali și ca o sursă importantă de compuși biolo...

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