The Antioxidants and Pro-Antioxidants Network: An Overview

Abstract

Living beings have evolved over the past two billion years through adaptation, to an increasing atmospheric oxygen concentration, by both taking advantage of oxygen activating function and developing a complex control network. In these regards, potentially damaging species (reactive oxygen, nitrogen and chlorine species) arise as by-products of metabolism and also work as physiological mediators and signalling molecules. Oxidative stress may be an important factor in numerous pathological conditions, i.e. infection if micronutrients are deficient. Levels of these species are controlled by the antioxidant defence system, which is composed by antioxidants and pro-antioxidants. Several components of this system are micronutrients (e.g. vitamins C and E), are dependent upon dietary micronutrients (e.g. CuZn and Mn superoxide dismutase) or are produced by specific endogenous pathways. The antioxidant defences act, to control levels of these species, as a coordinated system where deficiencies in one component may affect the efficiency of the others. In this network some of the components act as direct antioxidants whereas others act indirectly (pro-antioxidants) either by modulation of direct agents or by regulation of the biosynthesis of antioxidant proteins. Thus, entities usually not considered as antioxidants, also act efficiently counteracting damaging effects of oxidative species. In this contest, the design of new molecules that take into account synergistic interactions among different antioxidants, could be useful both to address mechanistic studies and to develop possible therapeutic agents. In this review the principal categories of antioxidants and pro-antioxidants that goes from vitamins through phyto-derivatives to minerals, are critically reviewed, with particular emphasis on structure-function considerations, together with the perspective opened, in the design of possible therapeutic agents, by the antioxidants interplay.

Bioactive Compound and Antioxidant Activity of Methanol Extract Mauli Bananas (Musa sp) Stem

“…Secondly, it has been shown that ascorbate can recycle alpha-tocopherol, which in turn helps to prevent lipids oxidation. Without ascorbate, the alpha-tocopheroxyl radical can assume a prooxidant role and continue or even enchance the chain reaction of lipid peroxidation [20].…”

“…For example, we have recently highlighted its possible role in the transport of drugs, which do not cross itself the blood brain barrier. In these regards, it may act as a double targeting molecule, working both as a carrier and as antioxidant in neurodegenerative diseases [20].…”

Conceitos atuais e perspectivas na prevenção da degeneração macular relacionada à idade

“…É importante lembrar que suplementos antioxidantes são sintéticos e possuem também propriedades pró-oxidantes (26) . Estes fatores poderiam explicar um possível aumento no risco de câncer (20,21,25) e doenças cardiovasculares (19) .…”

“…Por outro lado, depois de décadas de uso para prevenir e combater doenças sistêmicas, vários relatos demonstram que o uso indiscriminado de antioxidantes pode ser extremamente maléfico à saúde (19)(20)(21)(22)(23)(24)(25)(26)(27) .…”

Mentha pulegium crude extracts induce thiol oxidation and potentiate hemolysis when associated to t-butyl hydroperoxide in human’s erythrocytes

“…Mentha pulegium (Lamiaceae) tea has been used as a traditional medicine for the treatment of fever, pain and dysentery (Vertuani et al 2004). Of note, M. pulegium was found to contain flavonoids that may account for the high antioxidant activity observed for the polar extracts of this aromatic herb (Zaidi et al 1998, Justesen andKnuthsen 2001).…”