Search Results

You are looking at 1 - 10 of 1,286 items for :

  • "Antioxidants" x
  • Refine by Access: All Content x
Clear All
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

Restricted access

. , 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

Restricted access

. 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

Restricted access

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.

Restricted access

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

Restricted access

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

Restricted access
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

Restricted access

References [1] F. Shahidi , C.-T. Ho , Antioxidant Measurement and Applications , American Chemical Society , Washington, DC

Restricted access

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

Restricted access

The color pigments from different sorts of red wine (Cabernet Sauvignon, Merlot, and Burgundy) produced in different years, purchased from the Recas and Minis Romanian wineries, were separated using a new reversed-phase thin-layer chromatographic (RP-TLC) method. Chromatographic separation of the pigments was performed on silica gel RP-18F 254 with acetonitrile-water-formic acid 40:58:2 ( v/v ) as mobile phase. Most of the natural pigments are phenolic compounds with antioxidant activity that can be evaluated by use of a stable free radical, for example DPPH (2,2-diphenyl-1-picrylhydrazyl). The proposed RP-TLC method can be used in wine monitoring to identify the origin of wine and to detect adulteration.

Restricted access