8/18/2019 Malondialdehid
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Malondialdehid
Malondialdehyde (MDA) is an end-product of the radical-initiated
oxidativedecomposition of polyunsaturated fatty acids; therefore,
it is frequently used as a biomarker of
oxidative stress !
"he overproduction of reactive species results in
oxidative stress #n other $ords, it can
be a combination of an increased formation of
oxy%en-nitro%en derived radicals and reducedantioxidant capacity,
causin% an imbalance that mi%ht result in the attack of cellular
components,
especially lipids #t has been implicated in the patho%enesis of
various diseases includin%diabetes,& cancer,' and
atherosclerosis
ince it is complex measurin% free radicals directly in vivo, it
is necessary to carry out the
quantification of cellular components $hich can react $ith these
free radicals, such as proteins,D*A and mainly lipids+ nce lipid
peroxides are unstable compounds, they tend to de%rade
rapidly in a variety of sub products MDA is one of the most
kno$n secondary products of lipid
peroxidation, and it can be used as a marker of cell
membrane inury
.ipid peroxidation is a free-radical-mediated chain of
reactions that, once initiated,results in an oxidative
deterioration of polyunsaturated lipids "he most common tar%ets
are
components of biolo%ical membranes /hen propa%ated in biolo%ical
membranes, thesereactions can be initiated or enhanced by a number
of toxic products, includin% endoperoxidesand aldehydes
MDA, is a hi%hly reactive three carbon dialdehyde produced as a
byproduct of polyunsaturated
fatty acid peroxidation and also durin% arachidonic acid
metabolism for the synthesis of prosta%landins MDA can
combine $ith several functional %roups on molecules includin%
proteins, lipoproteins, 0*A and D*A "he monitorin% of MDA
levels in biolo%ical materials can
be used as an important indicator of lipid peroxidation in
vitro and in vivo for various diseases&
A MDA formation route is described in1i%ure ! "he tar%et of
reactive speciesis the
carbon-carbon double bond of polyunsaturated fatty
acids (#) "his double bond $eakens the carbon-hydro%en bond,
allo$in% easy abstraction of the
hydro%en by a free radical "hen, a free radical can
abstract the hydro%en atom and a lipid free radicalis formed
(##), $hich suffers oxidation %eneratin% a
peroxyl radical (###) "he peroxyl radical can react
$ith other polyunsaturated fatty acids, abstractin%an electron
and producin% a lipid hydroperoxide
(#2) and another lipid free radical "his process can
be propa%ated continually in a chain reaction"he
lipid hydroperoxide is unstable and its
fra%mentation yields products such asmalondialdehyde (2) and
'-hydroxy--nonenal
#n diabetes, persistent hyper%lycemia may cause hi%h
production of free radicalattributed to protein %lycation or
%lucose auto-oxidation MDA levels $ere found hi%her in "ype
diabetics than in healthy controls in a study carried out by
3esavulu et al.& "he research %roup
also observed that diabetic patients $ith coronary heart disease
had hi%her levels of MDA thanthose diabetics $ithout this disease
#t sho$s that cardiovascular diseases have also been related
to free radical-mediated mechanisms and to lipid peroxidation,
alon% $ith the fact that they are a
4ambar skema pembentukan MDA
dari polyunsaturated fatty acid
