Antioxidantes: importancia biológica y métodos para medir su actividad
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Date
2012-03-29
Authors
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Journal ISSN
Volume Title
Publisher
Corporación Universitaria Lasallista
Abstract
Resumen
La actividad antioxidante es la capacidad de una sustancia para inhibir la degradación oxidativa (por ejemplo, la peroxidación lipídica), de tal manera que un
antioxidante actúa, principalmente, gracias a su capacidad para reaccionar con radicales libres y, por lo
tanto, recibe el nombre de antioxidante terminador de
cadena. Sin embargo, es necesario distinguir también
entre actividad estabilizadora de radicales libres o antiradicalaria (en inglés, scavenger) y actividad antioxi -dante. La primera está determinada completamente
por la reactividad de un antioxidante frente a radicales
libres, lo cual puede ser caracterizado por la velocidad
de esa reacción. Por su parte, la segunda mide la ca-pacidad para retardar la degradación oxidativa. Por
lo tanto, una alta actividad anti-radicalaria no siempre correlaciona con una alta actividad antioxidante;
en particular, algunos compuestos fenólicos sintéticos
presentan alta reactividad frente a radicales libres, pero
muestran moderada actividad antioxidante.
De hecho, hasta ahora, no existen métodos mundialmente unificados para medir capacidad antioxidante,
en parte, debido a la disparidad de condiciones en las
cuales se desarrollan estas metodologías, además de la
complejidad de los sistemas y de la diversidad de ma -trices que necesitan ser evaluadas.
En general, el objetivo de este trabajo es presentar una revisión actualizada de los conceptos fundamentales de los antioxidantes, abarcando
desde los radicales libres de importancia biológica, hasta los sistemas de
defensa antioxidante y los métodos para medir esta actividad.
Abstract Anti oxidative activity is the capability of a substance to inhibit the oxidative degradation (lipid peroxidation, for instance), in such a way that an antioxidant acts, mainly, thanks to its capability to react with free radicals and, therefore, it is called a chain terminator antioxidant. It is, nonetheless, necessary to differentiate between the stabilization activity of free radicals, or scavenging, and antioxidant activity. The first is completely determined by the reactivity of an antioxidant before free radicals, and can be characterized according to the velocity of such reaction. The second measures the capability to retard the oxidative degradation. Therefore, a high scavenging does not necessarily correlates a high ant oxidative activity. Particularly, some phenolic synthetic compounds are highly reactive before free radicals, but have a moderated anti oxidative activity. As a matter of fact, there are not standardized measurement methods for anti oxidative capability so far, partly due to the disparity of the conditions under which these methods are developed, plus the complexity of the systems and the diversity of matrices to be evaluated. The objective of this work is to present an updated revision of the anti oxidant´s main concepts, from the biologically pertinent free radicals to the anti oxidant defense systems and the methods for measuring this activity
Abstract Anti oxidative activity is the capability of a substance to inhibit the oxidative degradation (lipid peroxidation, for instance), in such a way that an antioxidant acts, mainly, thanks to its capability to react with free radicals and, therefore, it is called a chain terminator antioxidant. It is, nonetheless, necessary to differentiate between the stabilization activity of free radicals, or scavenging, and antioxidant activity. The first is completely determined by the reactivity of an antioxidant before free radicals, and can be characterized according to the velocity of such reaction. The second measures the capability to retard the oxidative degradation. Therefore, a high scavenging does not necessarily correlates a high ant oxidative activity. Particularly, some phenolic synthetic compounds are highly reactive before free radicals, but have a moderated anti oxidative activity. As a matter of fact, there are not standardized measurement methods for anti oxidative capability so far, partly due to the disparity of the conditions under which these methods are developed, plus the complexity of the systems and the diversity of matrices to be evaluated. The objective of this work is to present an updated revision of the anti oxidant´s main concepts, from the biologically pertinent free radicals to the anti oxidant defense systems and the methods for measuring this activity
Description
Keywords
Antioxidantes, Especies reactivas del oxígeno (EROS), Química, Corporación Universitaria Lasallista, Métodos para la medición de la actividad antioxidante