ABSTRACT
The antioxidant activity of resinous extracts obtained from H. stenophylum and H. sinuatum species, was evaluated through ORAC index (Oxygen Radical Absorbance Capacity) in water phase and in presence of Triton X-100 micelles, using as test molecules to pyrogallol red (PGR) and evaluating their reduction by the action of peroxyl radicals obtained from thermolysis of AAPH. The results show that these extracts protect to PGR of the action of the radicals. This protection is reduced drastically in the presence of Triton X-100 micelles. The same effect was observed with the main flavonoid of these extracts (3-O-methylgalangin). These results show the importance of the media of reaction of pure compounds and/or extracts at the time of to take into account their use as antioxidants.
La actividad antioxidante de exudados resinosos obtenidos desde las especies H. stenophylum y H. sinuatum, fue evaluada a través del ensayo ORAC (Oxygen Radical Absorbance Capacity) en fase acuosa y en presencia de micelas de Triton X-100, usando como molécula prueba a pirogalol rojo (PGR) y evaluando su reducción frente a la acción de radicales peróxidos obtenidos desde la termólisis de AAPH. Los resultados muestran que estos extractos protegen al PGR de la acción de los radicales. Esta protección es reducida drásticamente en presencia de micelas de Tritón X-100. El mismo efecto fue observado con el flavonoide mayoritario de estos extractos (3-O-metilgalangina). Estos resultados muestran la importancia de considerar el medio de reacción de compuestos puros y/o extractos al momento de tomar en cuenta su uso como antioxidantes.
Subject(s)
Antioxidants/chemistry , Flavonoids/chemistry , Heliotropium/chemistry , Resins, Plant/chemistry , Reactive Oxygen Species/chemistry , MicellesABSTRACT
The antioxidant effect of 5-Aminosalicylic acid (5-ASA) on copper-mediated LDL oxidation was followed either by the emitted chemiluminiscence (CL) or by UV-vis spectroscopy. 5-ASA addition extends the lag phase in a concentration-dependent manner without changes in the rate of the process in the autoaccelerated phase. The antioxidant behavior of 5-ASA was very similar to that of Trolox, a very efficient water soluble antioxidant. The copper-binding capacity of 5-ASA was evaluated by UV-visible spectroscopy. The addition of copper to a 5-ASA solution increases the absorbance at 332 nm and generates a new band at 298 nm. These changes in the UV-vis spectra indicate formation of a complex between 5-ASA and copper. However, LDL protection by 5-ASA is unrelated to its copper chelating capacity.
Subject(s)
Aminosalicylic Acids/pharmacology , Antioxidants/pharmacology , Copper/chemistry , Lipoproteins, LDL/metabolism , Aminosalicylic Acids/chemistry , Aminosalicylic Acids/metabolism , Antioxidants/chemistry , Antioxidants/metabolism , Copper/toxicity , Luminescent Measurements , Oxidation-Reduction/drug effects , Spectrophotometry, Ultraviolet , Time FactorsABSTRACT
A novel procedure for the evaluation of total reactive antioxidant potentials (TRAP) is described. The method is based on the measurement of the bleaching of pyranine by peroxyl radicals. The addition of the antioxidants produces a clear induction time whose magnitude is directly related to the antioxidant concentration. A comparison of the values obtained with those reported employing closely related methodologies shows that the results are significantly affected by the substrate employed to monitor the steady state free radical concentration. Possible sources of this dependence are discussed.
Subject(s)
Antioxidants , Fluorescence , Time FactorsSubject(s)
Humans , Male , Female , Antioxidants , Oxidative Stress , Antioxidants , Free Radicals , Oxidative Stress , Reactive Oxygen SpeciesABSTRACT
There exists a variety of procedures to evaluate the total content of antioxidants in complex mixtures such as biological fluids or plant extracts. Based on these procedures, different indexes (TRAP, TAR, ORAC) have been proposed to quantify the level of the antioxidant status of the fluid. Depending upon the procedure employed, these indexes measure the total concentration of antioxidants and/or their ability to modulate the steady state concentration of the active free radicals in the system. In the present article most of the experimental procedures that can be employed to evaluate the total content of antioxidants in complex samples are reviewed, with special emphasis on the information that can be obtained from this type of measurements.