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Journal of Thermal Analysis and Calorimetry
Authors: Zuzana Cibulková, Andrea Černá, Peter Šimon, Ján Uhlár, Karol Kosár and Peter Lehocký

-mechanical properties. The ageing can be retarded by the addition of antioxidants. The most common ones used in rubber industry are derivatives of aromatic amines and phenols [ 1 ]. Combinations of antioxidants are frequently used in rubber products. The main

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. , Sahu , A. , Bora , U. ( 2008 ) Indian medicinal herbs as sources os antioxidants . Food Res. Int. 41 , 1 – 15 . 3. Crowden , R. K. , Wright , J. , Harborne , J. B

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. 14. Foyer , C. H. , Noctor , G. ( 2005 ) Redox homeostasis and antioxidant signaling: a metabolic interface between stress perception and physiological responses . Plant Cell. 17 , 1866 – 1875

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The method described herein is a very powerful tool for rapid synthesis, separation, and screening of combinatorial libraries on planar media. Thirty compounds were synthesized and separated affording discrete chemical entities, including by-products, which were screened for antioxidant activity. The whole process from synthesis to screening was performed manually and took between 30 and 60 min after optimization of the reaction.A series of coumarin derivatives was synthesized by Knoevenagel condensation of salicylaldehyde derivatives with active methylene species, assisted by microwave irradiation, using a TLC plate as planar support. Elution of the reaction mixtures afforded discrete coumarin products which were screened directly on the plate for antioxidant activity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) test radical.Active compounds were scaled-up and re-screened for potency in comparison with Irgafos 38, a known antioxidant commonly incorporated as an additive in plastics. The potency of all the active species was of the same order of magnitude as that of Irgafos 38. The lower limit of activity of 8-hydroxy-2-oxo-2 H -chromene-3-carboxylic acid ethyl ester was 600 ng compared with 700 ng for Irgafos 38.

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treatments and on storage. Thus, the stabilization of organic polymers is important since these materials are exposed to oxygen throughout their lifetime. Numerous antioxidants have been found to reduce the rate of thermal oxidation for a certain period [ 1

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Sunflower biodiesel

Use of P-DSC in the evaluation of antioxidant efficiency

Journal of Thermal Analysis and Calorimetry
Authors: M. L. A. Tavares, N. Queiroz, I. M. G. Santos, A. L. Souza, E. H. S. Cavalcanti, A. K. D. Barros, R. Rosenhaim, L. E. B. Soledade and A. G. Souza

development of oxidative rancidity. It is possible to block the free radical formation by means of additives (antioxidants), which, in small amounts, act interfering in the lipid oxidation processes [ 7 ]. The Resolution number 7 from the Brazilian

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Gábor, E.-Tanács, L. (2002): Antioxidant Activity of Some Phenol Compounds of Durum Wheat Grains. ICC Conference, Budapest, May 26–29. CD-ROM. Gábor, E.-Tanács, L.-Kormos, M. (2003): A

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Acta Biologica Hungarica
Authors: Dragana Jakovljević, Sava Vasić, Milan Stanković, Ljiljana Čomić and Marina Topuzović

. 6. El-Agbar , Z. , Shakya , A. , Khalaf , N. , Al-Haroon , M. ( 2008 ) Comparative antioxidant activity of some edible plants . Turk. J. Biol. 32 , 193 – 196 . 7

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.O.A.C. AMR, S.A. (1991): Effectiveness of synthetic and potential natural antioxidants in improving the stability of sheep's anhydrous butter fat during long-term storage. J. Sci. Fd Agric., 55 , 75-85. Effectiveness of synthetic

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Duthie, G. G., Duthie, S. J. & Kyle, J. A. (2000): Plant polyphenols in cancer and heart disease: implications as nutritional antioxidants. Nutr. Res. Rev. , 13 , 79-106. Plant

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