Introduction
Lipid peroxidation is a well-defined mechanism of cellular damage in animals and plants. Lipid
peroxides are unstable indicators of oxidative stress in cells that decompose to form more complex and
reactive compounds such as Malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), natural biproducts
of lipid peroxidation. Oxidative modification of lipids can be induced in vitro by a wide array
of pro-oxidant agents and occurs in vivo during aging and in certain disease conditions. Measuring the
end products of lipid peroxidation is one of the most widely accepted assays for oxidative damage.
These aldehydic secondary products of lipid peroxidation are generally accepted markers of oxidative
stress.
Thiobarbituric Acid Reactive Substances (TBARS) is a well-established assay for screening and
monitoring lipid peroxidation. The rapid and easy protocol has been modified by researchers in the
evaluation of drugs, food, as well as human and animal tissue samples. MDA forms a 1:2 adduct with
thiobarbituric acid (Figure 1). The MDA-TBA adduct formed from the reaction of MDA in samples
with TBA can be measured colorimetrically or fluorometrically. TBARS levels are determined from a
Malondialdehyde equivalence standard.
Figure 1. MDA-TBA Adduct
The TBARS Assay has provided relevant information concerning free radical activity in disease states
and measurement of many compounds anti-oxidant characteristics. Although the specificity of
TBARS toward compounds other than MDA has been controversial, the assay continues to be the most
widely employed format for monitoring lipid peroxidation. Lipids with higher degrees of unsaturated
bonds produce higher TBARS values. Interfering soluble TBARS can be minimized if lipoprotein
fractions are first acid precipitated from samples. Biological samples may contain a mixture of
thiobarbituric acid reactive substances such as hydroperoxides and aldehydes, which increase in
response to oxidative stress. If excessively high TBARS values are obtained, a more specific assay
such as HPLC should be employed.
Cell Biolabs’ TBARS Assay Kit offers a simple, reproducible, and consistent system for the detection
of lipid peroxidation in urine, plasma, serum, lysates, and tissue homogenates. This kit includes an
MDA standard for use as a positive control. Each kit provides sufficient reagents to perform 200 tests
including standard curve and unknown samples.